├── .github └── workflows │ ├── build.yaml │ └── lint.yaml ├── .gitignore ├── .golangci.yml ├── LICENSE ├── README.md ├── auth.go ├── config.go ├── context.go ├── examples ├── auth │ ├── README.md │ └── main.go ├── mitm │ ├── README.md │ ├── demo.crt │ ├── demo.key │ └── main.go └── simple │ └── main.go ├── go.mod ├── go.sum ├── helper.go ├── hopbyhop.go ├── mitm ├── mitm.go └── mitm_test.go ├── proxy.go └── proxyutil └── util.go /.github/workflows/build.yaml: -------------------------------------------------------------------------------- 1 | name: Build 2 | 3 | 'env': 4 | 'GO_VERSION': '1.20' 5 | 6 | 'on': 7 | 'push': 8 | 'tags': 9 | - 'v*' 10 | 'branches': 11 | - '*' 12 | 'pull_request': 13 | 14 | jobs: 15 | tests: 16 | runs-on: ${{ matrix.os }} 17 | strategy: 18 | matrix: 19 | os: 20 | - windows-latest 21 | - macos-latest 22 | - ubuntu-latest 23 | steps: 24 | - uses: actions/checkout@v3 25 | - uses: actions/setup-go@v3 26 | with: 27 | go-version: '${{ env.GO_VERSION }}' 28 | - name: Run tests 29 | env: 30 | CI: "1" 31 | run: |- 32 | go test -race -v -bench="." -coverprofile="coverage.txt" -covermode=atomic ./... 33 | - name: Upload coverage 34 | uses: codecov/codecov-action@v1 35 | if: "success() && matrix.os == 'ubuntu-latest'" 36 | with: 37 | token: ${{ secrets.CODECOV_TOKEN }} 38 | file: ./coverage.txt 39 | 40 | notify: 41 | needs: 42 | - tests 43 | if: 44 | ${{ always() && 45 | ( 46 | github.event_name == 'push' || 47 | github.event.pull_request.head.repo.full_name == github.repository 48 | ) 49 | }} 50 | runs-on: ubuntu-latest 51 | steps: 52 | - name: Conclusion 53 | uses: technote-space/workflow-conclusion-action@v1 54 | - name: Send Slack notif 55 | uses: 8398a7/action-slack@v3 56 | with: 57 | status: ${{ env.WORKFLOW_CONCLUSION }} 58 | fields: workflow, repo, message, commit, author, eventName,ref 59 | env: 60 | GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} 61 | SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }} 62 | 63 | -------------------------------------------------------------------------------- /.github/workflows/lint.yaml: -------------------------------------------------------------------------------- 1 | name: golangci-lint 2 | 3 | 'env': 4 | 'GO_VERSION': '1.19' 5 | 6 | 'on': 7 | 'push': 8 | 'tags': 9 | - 'v*' 10 | 'branches': 11 | - '*' 12 | 'pull_request': 13 | 14 | jobs: 15 | golangci: 16 | runs-on: 17 | ${{ matrix.os }} 18 | strategy: 19 | matrix: 20 | os: 21 | - ubuntu-latest 22 | - macos-latest 23 | steps: 24 | - uses: actions/checkout@v3 25 | - uses: actions/setup-go@v3 26 | with: 27 | go-version: '${{ env.GO_VERSION }}' 28 | 29 | - name: golangci-lint 30 | uses: golangci/golangci-lint-action@v3 31 | with: 32 | # This field is required. Dont set the patch version to always use 33 | # the latest patch version. 34 | version: v1.52.2 35 | notify: 36 | needs: 37 | - golangci 38 | # Secrets are not passed to workflows that are triggered by a pull request 39 | # from a fork. 40 | # 41 | # Use always() to signal to the runner that this job must run even if the 42 | # previous ones failed. 43 | if: 44 | ${{ always() && 45 | ( 46 | github.event_name == 'push' || 47 | github.event.pull_request.head.repo.full_name == github.repository 48 | ) 49 | }} 50 | runs-on: ubuntu-latest 51 | steps: 52 | - name: Conclusion 53 | uses: technote-space/workflow-conclusion-action@v1 54 | - name: Send Slack notif 55 | uses: 8398a7/action-slack@v3 56 | with: 57 | status: ${{ env.WORKFLOW_CONCLUSION }} 58 | fields: workflow, repo, message, commit, author, eventName, ref 59 | env: 60 | GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} 61 | SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }} 62 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | .DS_Store 2 | .idea -------------------------------------------------------------------------------- /.golangci.yml: -------------------------------------------------------------------------------- 1 | # options for analysis running 2 | run: 3 | # default concurrency is a available CPU number 4 | concurrency: 4 5 | 6 | # timeout for analysis, e.g. 30s, 5m, default is 1m 7 | deadline: 2m 8 | 9 | # which files to skip: they will be analyzed, but issues from them 10 | # won't be reported. Default value is empty list, but there is 11 | # no need to include all autogenerated files, we confidently recognize 12 | # autogenerated files. If it's not please let us know. 13 | skip-files: 14 | - ".*generated.*" 15 | 16 | # all available settings of specific linters 17 | linters-settings: 18 | gocyclo: 19 | min-complexity: 20 20 | lll: 21 | line-length: 120 22 | 23 | linters: 24 | enable: 25 | - errcheck 26 | - govet 27 | - ineffassign 28 | - staticcheck 29 | - unused 30 | - depguard 31 | - dupl 32 | - gocyclo 33 | - goimports 34 | - revive 35 | - gosec 36 | - misspell 37 | - stylecheck 38 | - unconvert 39 | disable-all: true 40 | fast: true 41 | 42 | issues: 43 | exclude-use-default: false 44 | 45 | # List of regexps of issue texts to exclude, empty list by default. 46 | # But independently from this option we use default exclude patterns, 47 | # it can be disabled by `exclude-use-default: false`. To list all 48 | # excluded by default patterns execute `golangci-lint run --help` 49 | exclude: 50 | # gosec: False positive is triggered by 'src, err := os.ReadFile(filename)' 51 | - Potential file inclusion via variable 52 | # gosec: TLS InsecureSkipVerify may be true 53 | # We have a configuration option that allows to do this 54 | - G402 55 | # gosec: Use of weak random number generator 56 | - G404 57 | # gosec: Use of weak cryptographic primitive 58 | - G401 59 | # gosec: Blocklisted import crypto/sha1: weak cryptographic primitive 60 | - G505 61 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | ### GNU GENERAL PUBLIC LICENSE 2 | 3 | Version 3, 29 June 2007 4 | 5 | Copyright (C) 2007 Free Software Foundation, Inc. 6 | 7 | 8 | Everyone is permitted to copy and distribute verbatim copies of this 9 | license document, but changing it is not allowed. 10 | 11 | ### Preamble 12 | 13 | The GNU General Public License is a free, copyleft license for 14 | software and other kinds of works. 15 | 16 | The licenses for most software and other practical works are designed 17 | to take away your freedom to share and change the works. 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The output from running a 165 | covered work is covered by this License only if the output, given its 166 | content, constitutes a covered work. This License acknowledges your 167 | rights of fair use or other equivalent, as provided by copyright law. 168 | 169 | You may make, run and propagate covered works that you do not convey, 170 | without conditions so long as your license otherwise remains in force. 171 | You may convey covered works to others for the sole purpose of having 172 | them make modifications exclusively for you, or provide you with 173 | facilities for running those works, provided that you comply with the 174 | terms of this License in conveying all material for which you do not 175 | control copyright. Those thus making or running the covered works for 176 | you must do so exclusively on your behalf, under your direction and 177 | control, on terms that prohibit them from making any copies of your 178 | copyrighted material outside their relationship with you. 179 | 180 | Conveying under any other circumstances is permitted solely under the 181 | conditions stated below. Sublicensing is not allowed; section 10 makes 182 | it unnecessary. 183 | 184 | #### 3. Protecting Users' Legal Rights From Anti-Circumvention Law. 185 | 186 | No covered work shall be deemed part of an effective technological 187 | measure under any applicable law fulfilling obligations under article 188 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or 189 | similar laws prohibiting or restricting circumvention of such 190 | measures. 191 | 192 | When you convey a covered work, you waive any legal power to forbid 193 | circumvention of technological measures to the extent such 194 | circumvention is effected by exercising rights under this License with 195 | respect to the covered work, and you disclaim any intention to limit 196 | operation or modification of the work as a means of enforcing, against 197 | the work's users, your or third parties' legal rights to forbid 198 | circumvention of technological measures. 199 | 200 | #### 4. Conveying Verbatim Copies. 201 | 202 | You may convey verbatim copies of the Program's source code as you 203 | receive it, in any medium, provided that you conspicuously and 204 | appropriately publish on each copy an appropriate copyright notice; 205 | keep intact all notices stating that this License and any 206 | non-permissive terms added in accord with section 7 apply to the code; 207 | keep intact all notices of the absence of any warranty; and give all 208 | recipients a copy of this License along with the Program. 209 | 210 | You may charge any price or no price for each copy that you convey, 211 | and you may offer support or warranty protection for a fee. 212 | 213 | #### 5. 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This License gives no 231 | permission to license the work in any other way, but it does not 232 | invalidate such permission if you have separately received it. 233 | - d) If the work has interactive user interfaces, each must display 234 | Appropriate Legal Notices; however, if the Program has interactive 235 | interfaces that do not display Appropriate Legal Notices, your 236 | work need not make them do so. 237 | 238 | A compilation of a covered work with other separate and independent 239 | works, which are not by their nature extensions of the covered work, 240 | and which are not combined with it such as to form a larger program, 241 | in or on a volume of a storage or distribution medium, is called an 242 | "aggregate" if the compilation and its resulting copyright are not 243 | used to limit the access or legal rights of the compilation's users 244 | beyond what the individual works permit. Inclusion of a covered work 245 | in an aggregate does not cause this License to apply to the other 246 | parts of the aggregate. 247 | 248 | #### 6. 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But this requirement does not apply 325 | if neither you nor any third party retains the ability to install 326 | modified object code on the User Product (for example, the work has 327 | been installed in ROM). 328 | 329 | The requirement to provide Installation Information does not include a 330 | requirement to continue to provide support service, warranty, or 331 | updates for a work that has been modified or installed by the 332 | recipient, or for the User Product in which it has been modified or 333 | installed. Access to a network may be denied when the modification 334 | itself materially and adversely affects the operation of the network 335 | or violates the rules and protocols for communication across the 336 | network. 337 | 338 | Corresponding Source conveyed, and Installation Information provided, 339 | in accord with this section must be in a format that is publicly 340 | documented (and with an implementation available to the public in 341 | source code form), and must require no special password or key for 342 | unpacking, reading or copying. 343 | 344 | #### 7. Additional Terms. 345 | 346 | "Additional permissions" are terms that supplement the terms of this 347 | License by making exceptions from one or more of its conditions. 348 | Additional permissions that are applicable to the entire Program shall 349 | be treated as though they were included in this License, to the extent 350 | that they are valid under applicable law. If additional permissions 351 | apply only to part of the Program, that part may be used separately 352 | under those permissions, but the entire Program remains governed by 353 | this License without regard to the additional permissions. 354 | 355 | When you convey a copy of a covered work, you may at your option 356 | remove any additional permissions from that copy, or from any part of 357 | it. (Additional permissions may be written to require their own 358 | removal in certain cases when you modify the work.) You may place 359 | additional permissions on material, added by you to a covered work, 360 | for which you have or can give appropriate copyright permission. 361 | 362 | Notwithstanding any other provision of this License, for material you 363 | add to a covered work, you may (if authorized by the copyright holders 364 | of that material) supplement the terms of this License with terms: 365 | 366 | - a) Disclaiming warranty or limiting liability differently from the 367 | terms of sections 15 and 16 of this License; or 368 | - b) Requiring preservation of specified reasonable legal notices or 369 | author attributions in that material or in the Appropriate Legal 370 | Notices displayed by works containing it; or 371 | - c) Prohibiting misrepresentation of the origin of that material, 372 | or requiring that modified versions of such material be marked in 373 | reasonable ways as different from the original version; or 374 | - d) Limiting the use for publicity purposes of names of licensors 375 | or authors of the material; or 376 | - e) Declining to grant rights under trademark law for use of some 377 | trade names, trademarks, or service marks; or 378 | - f) Requiring indemnification of licensors and authors of that 379 | material by anyone who conveys the material (or modified versions 380 | of it) with contractual assumptions of liability to the recipient, 381 | for any liability that these contractual assumptions directly 382 | impose on those licensors and authors. 383 | 384 | All other non-permissive additional terms are considered "further 385 | restrictions" within the meaning of section 10. If the Program as you 386 | received it, or any part of it, contains a notice stating that it is 387 | governed by this License along with a term that is a further 388 | restriction, you may remove that term. If a license document contains 389 | a further restriction but permits relicensing or conveying under this 390 | License, you may add to a covered work material governed by the terms 391 | of that license document, provided that the further restriction does 392 | not survive such relicensing or conveying. 393 | 394 | If you add terms to a covered work in accord with this section, you 395 | must place, in the relevant source files, a statement of the 396 | additional terms that apply to those files, or a notice indicating 397 | where to find the applicable terms. 398 | 399 | Additional terms, permissive or non-permissive, may be stated in the 400 | form of a separately written license, or stated as exceptions; the 401 | above requirements apply either way. 402 | 403 | #### 8. Termination. 404 | 405 | You may not propagate or modify a covered work except as expressly 406 | provided under this License. Any attempt otherwise to propagate or 407 | modify it is void, and will automatically terminate your rights under 408 | this License (including any patent licenses granted under the third 409 | paragraph of section 11). 410 | 411 | However, if you cease all violation of this License, then your license 412 | from a particular copyright holder is reinstated (a) provisionally, 413 | unless and until the copyright holder explicitly and finally 414 | terminates your license, and (b) permanently, if the copyright holder 415 | fails to notify you of the violation by some reasonable means prior to 416 | 60 days after the cessation. 417 | 418 | Moreover, your license from a particular copyright holder is 419 | reinstated permanently if the copyright holder notifies you of the 420 | violation by some reasonable means, this is the first time you have 421 | received notice of violation of this License (for any work) from that 422 | copyright holder, and you cure the violation prior to 30 days after 423 | your receipt of the notice. 424 | 425 | Termination of your rights under this section does not terminate the 426 | licenses of parties who have received copies or rights from you under 427 | this License. If your rights have been terminated and not permanently 428 | reinstated, you do not qualify to receive new licenses for the same 429 | material under section 10. 430 | 431 | #### 9. Acceptance Not Required for Having Copies. 432 | 433 | You are not required to accept this License in order to receive or run 434 | a copy of the Program. Ancillary propagation of a covered work 435 | occurring solely as a consequence of using peer-to-peer transmission 436 | to receive a copy likewise does not require acceptance. However, 437 | nothing other than this License grants you permission to propagate or 438 | modify any covered work. These actions infringe copyright if you do 439 | not accept this License. Therefore, by modifying or propagating a 440 | covered work, you indicate your acceptance of this License to do so. 441 | 442 | #### 10. Automatic Licensing of Downstream Recipients. 443 | 444 | Each time you convey a covered work, the recipient automatically 445 | receives a license from the original licensors, to run, modify and 446 | propagate that work, subject to this License. You are not responsible 447 | for enforcing compliance by third parties with this License. 448 | 449 | An "entity transaction" is a transaction transferring control of an 450 | organization, or substantially all assets of one, or subdividing an 451 | organization, or merging organizations. If propagation of a covered 452 | work results from an entity transaction, each party to that 453 | transaction who receives a copy of the work also receives whatever 454 | licenses to the work the party's predecessor in interest had or could 455 | give under the previous paragraph, plus a right to possession of the 456 | Corresponding Source of the work from the predecessor in interest, if 457 | the predecessor has it or can get it with reasonable efforts. 458 | 459 | You may not impose any further restrictions on the exercise of the 460 | rights granted or affirmed under this License. For example, you may 461 | not impose a license fee, royalty, or other charge for exercise of 462 | rights granted under this License, and you may not initiate litigation 463 | (including a cross-claim or counterclaim in a lawsuit) alleging that 464 | any patent claim is infringed by making, using, selling, offering for 465 | sale, or importing the Program or any portion of it. 466 | 467 | #### 11. Patents. 468 | 469 | A "contributor" is a copyright holder who authorizes use under this 470 | License of the Program or a work on which the Program is based. The 471 | work thus licensed is called the contributor's "contributor version". 472 | 473 | A contributor's "essential patent claims" are all patent claims owned 474 | or controlled by the contributor, whether already acquired or 475 | hereafter acquired, that would be infringed by some manner, permitted 476 | by this License, of making, using, or selling its contributor version, 477 | but do not include claims that would be infringed only as a 478 | consequence of further modification of the contributor version. For 479 | purposes of this definition, "control" includes the right to grant 480 | patent sublicenses in a manner consistent with the requirements of 481 | this License. 482 | 483 | Each contributor grants you a non-exclusive, worldwide, royalty-free 484 | patent license under the contributor's essential patent claims, to 485 | make, use, sell, offer for sale, import and otherwise run, modify and 486 | propagate the contents of its contributor version. 487 | 488 | In the following three paragraphs, a "patent license" is any express 489 | agreement or commitment, however denominated, not to enforce a patent 490 | (such as an express permission to practice a patent or covenant not to 491 | sue for patent infringement). To "grant" such a patent license to a 492 | party means to make such an agreement or commitment not to enforce a 493 | patent against the party. 494 | 495 | If you convey a covered work, knowingly relying on a patent license, 496 | and the Corresponding Source of the work is not available for anyone 497 | to copy, free of charge and under the terms of this License, through a 498 | publicly available network server or other readily accessible means, 499 | then you must either (1) cause the Corresponding Source to be so 500 | available, or (2) arrange to deprive yourself of the benefit of the 501 | patent license for this particular work, or (3) arrange, in a manner 502 | consistent with the requirements of this License, to extend the patent 503 | license to downstream recipients. "Knowingly relying" means you have 504 | actual knowledge that, but for the patent license, your conveying the 505 | covered work in a country, or your recipient's use of the covered work 506 | in a country, would infringe one or more identifiable patents in that 507 | country that you have reason to believe are valid. 508 | 509 | If, pursuant to or in connection with a single transaction or 510 | arrangement, you convey, or propagate by procuring conveyance of, a 511 | covered work, and grant a patent license to some of the parties 512 | receiving the covered work authorizing them to use, propagate, modify 513 | or convey a specific copy of the covered work, then the patent license 514 | you grant is automatically extended to all recipients of the covered 515 | work and works based on it. 516 | 517 | A patent license is "discriminatory" if it does not include within the 518 | scope of its coverage, prohibits the exercise of, or is conditioned on 519 | the non-exercise of one or more of the rights that are specifically 520 | granted under this License. You may not convey a covered work if you 521 | are a party to an arrangement with a third party that is in the 522 | business of distributing software, under which you make payment to the 523 | third party based on the extent of your activity of conveying the 524 | work, and under which the third party grants, to any of the parties 525 | who would receive the covered work from you, a discriminatory patent 526 | license (a) in connection with copies of the covered work conveyed by 527 | you (or copies made from those copies), or (b) primarily for and in 528 | connection with specific products or compilations that contain the 529 | covered work, unless you entered into that arrangement, or that patent 530 | license was granted, prior to 28 March 2007. 531 | 532 | Nothing in this License shall be construed as excluding or limiting 533 | any implied license or other defenses to infringement that may 534 | otherwise be available to you under applicable patent law. 535 | 536 | #### 12. No Surrender of Others' Freedom. 537 | 538 | If conditions are imposed on you (whether by court order, agreement or 539 | otherwise) that contradict the conditions of this License, they do not 540 | excuse you from the conditions of this License. If you cannot convey a 541 | covered work so as to satisfy simultaneously your obligations under 542 | this License and any other pertinent obligations, then as a 543 | consequence you may not convey it at all. For example, if you agree to 544 | terms that obligate you to collect a royalty for further conveying 545 | from those to whom you convey the Program, the only way you could 546 | satisfy both those terms and this License would be to refrain entirely 547 | from conveying the Program. 548 | 549 | #### 13. Use with the GNU Affero General Public License. 550 | 551 | Notwithstanding any other provision of this License, you have 552 | permission to link or combine any covered work with a work licensed 553 | under version 3 of the GNU Affero General Public License into a single 554 | combined work, and to convey the resulting work. The terms of this 555 | License will continue to apply to the part which is the covered work, 556 | but the special requirements of the GNU Affero General Public License, 557 | section 13, concerning interaction through a network will apply to the 558 | combination as such. 559 | 560 | #### 14. Revised Versions of this License. 561 | 562 | The Free Software Foundation may publish revised and/or new versions 563 | of the GNU General Public License from time to time. Such new versions 564 | will be similar in spirit to the present version, but may differ in 565 | detail to address new problems or concerns. 566 | 567 | Each version is given a distinguishing version number. If the Program 568 | specifies that a certain numbered version of the GNU General Public 569 | License "or any later version" applies to it, you have the option of 570 | following the terms and conditions either of that numbered version or 571 | of any later version published by the Free Software Foundation. If the 572 | Program does not specify a version number of the GNU General Public 573 | License, you may choose any version ever published by the Free 574 | Software Foundation. 575 | 576 | If the Program specifies that a proxy can decide which future versions 577 | of the GNU General Public License can be used, that proxy's public 578 | statement of acceptance of a version permanently authorizes you to 579 | choose that version for the Program. 580 | 581 | Later license versions may give you additional or different 582 | permissions. However, no additional obligations are imposed on any 583 | author or copyright holder as a result of your choosing to follow a 584 | later version. 585 | 586 | #### 15. Disclaimer of Warranty. 587 | 588 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 589 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 590 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT 591 | WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT 592 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 593 | A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND 594 | PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE 595 | DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR 596 | CORRECTION. 597 | 598 | #### 16. Limitation of Liability. 599 | 600 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 601 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR 602 | CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, 603 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES 604 | ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT 605 | NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR 606 | LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM 607 | TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER 608 | PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 609 | 610 | #### 17. Interpretation of Sections 15 and 16. 611 | 612 | If the disclaimer of warranty and limitation of liability provided 613 | above cannot be given local legal effect according to their terms, 614 | reviewing courts shall apply local law that most closely approximates 615 | an absolute waiver of all civil liability in connection with the 616 | Program, unless a warranty or assumption of liability accompanies a 617 | copy of the Program in return for a fee. 618 | 619 | END OF TERMS AND CONDITIONS 620 | 621 | ### How to Apply These Terms to Your New Programs 622 | 623 | If you develop a new program, and you want it to be of the greatest 624 | possible use to the public, the best way to achieve this is to make it 625 | free software which everyone can redistribute and change under these 626 | terms. 627 | 628 | To do so, attach the following notices to the program. It is safest to 629 | attach them to the start of each source file to most effectively state 630 | the exclusion of warranty; and each file should have at least the 631 | "copyright" line and a pointer to where the full notice is found. 632 | 633 | 634 | Copyright (C) 635 | 636 | This program is free software: you can redistribute it and/or modify 637 | it under the terms of the GNU General Public License as published by 638 | the Free Software Foundation, either version 3 of the License, or 639 | (at your option) any later version. 640 | 641 | This program is distributed in the hope that it will be useful, 642 | but WITHOUT ANY WARRANTY; without even the implied warranty of 643 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 644 | GNU General Public License for more details. 645 | 646 | You should have received a copy of the GNU General Public License 647 | along with this program. If not, see . 648 | 649 | Also add information on how to contact you by electronic and paper 650 | mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands \`show w' and \`show c' should show the 661 | appropriate parts of the General Public License. Of course, your 662 | program's commands might be different; for a GUI interface, you would 663 | use an "about box". 664 | 665 | You should also get your employer (if you work as a programmer) or 666 | school, if any, to sign a "copyright disclaimer" for the program, if 667 | necessary. For more information on this, and how to apply and follow 668 | the GNU GPL, see . 669 | 670 | The GNU General Public License does not permit incorporating your 671 | program into proprietary programs. If your program is a subroutine 672 | library, you may consider it more useful to permit linking proprietary 673 | applications with the library. If this is what you want to do, use the 674 | GNU Lesser General Public License instead of this License. But first, 675 | please read . -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | [![Code Coverage](https://img.shields.io/codecov/c/github/AdguardTeam/gomitmproxy/master.svg)](https://codecov.io/github/AdguardTeam/gomitmproxy?branch=master) 2 | [![Go Report Card](https://goreportcard.com/badge/github.com/AdguardTeam/gomitmproxy)](https://goreportcard.com/report/AdguardTeam/gomitmproxy) 3 | [![GolangCI](https://golangci.com/badges/github.com/AdguardTeam/gomitmproxy.svg)](https://golangci.com/r/github.com/AdguardTeam/gomitmproxy) 4 | [![Go Doc](https://godoc.org/github.com/AdguardTeam/gomitmproxy?status.svg)](https://godoc.org/github.com/AdguardTeam/gomitmproxy) 5 | 6 | # gomitmproxy 7 | 8 | This is a customizable HTTP proxy with TLS interception support. 9 | It was created as a part of [AdGuard Home](https://github.com/AdguardTeam/AdGuardHome). 10 | However, it can be used for different purposes so we decided to make it a separate project. 11 | 12 | ## Features 13 | 14 | * HTTP proxy 15 | * HTTP over TLS (HTTPS) proxy 16 | * Proxy authorization 17 | * TLS termination 18 | 19 | ## How to use gomitmproxy 20 | 21 | ### Simple HTTP proxy 22 | 23 | ```go 24 | package main 25 | 26 | import ( 27 | "log" 28 | "net" 29 | "os" 30 | "os/signal" 31 | "syscall" 32 | 33 | "github.com/AdguardTeam/gomitmproxy" 34 | ) 35 | 36 | func main() { 37 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 38 | ListenAddr: &net.TCPAddr{ 39 | IP: net.IPv4(0, 0, 0, 0), 40 | Port: 8080, 41 | }, 42 | }) 43 | err := proxy.Start() 44 | if err != nil { 45 | log.Fatal(err) 46 | } 47 | 48 | signalChannel := make(chan os.Signal, 1) 49 | signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM) 50 | <-signalChannel 51 | 52 | // Clean up 53 | proxy.Close() 54 | } 55 | ``` 56 | 57 | ### Modifying requests and responses 58 | 59 | You can modify requests and responses using `OnRequest` and `OnResponse` handlers. 60 | 61 | The example below will block requests to `example.net` and add a short comment to 62 | the end of every HTML response. 63 | 64 | ```go 65 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 66 | ListenAddr: &net.TCPAddr{ 67 | IP: net.IPv4(0, 0, 0, 0), 68 | Port: 8080, 69 | }, 70 | OnRequest: func(session *gomitmproxy.Session) (request *http.Request, response *http.Response) { 71 | req := session.Request() 72 | 73 | log.Printf("onRequest: %s %s", req.Method, req.URL.String()) 74 | 75 | if req.URL.Host == "example.net" { 76 | body := strings.NewReader("

Replaced response

") 77 | res := proxyutil.NewResponse(http.StatusOK, body, req) 78 | res.Header.Set("Content-Type", "text/html") 79 | 80 | // Use session props to pass the information about request being blocked 81 | session.SetProp("blocked", true) 82 | return nil, res 83 | } 84 | 85 | return nil, nil 86 | }, 87 | OnResponse: func(session *gomitmproxy.Session) *http.Response { 88 | log.Printf("onResponse: %s", session.Request().URL.String()) 89 | 90 | if _, ok := session.GetProp("blocked"); ok { 91 | log.Printf("onResponse: was blocked") 92 | } 93 | 94 | res := session.Response() 95 | req := session.Request() 96 | 97 | if strings.Index(res.Header.Get("Content-Type"), "text/html") != 0 { 98 | // Do nothing with non-HTML responses 99 | return nil 100 | } 101 | 102 | b, err := proxyutil.ReadDecompressedBody(res) 103 | // Close the original body 104 | _ = res.Body.Close() 105 | if err != nil { 106 | return proxyutil.NewErrorResponse(req, err) 107 | } 108 | 109 | // Use latin1 before modifying the body 110 | // Using this 1-byte encoding will let us preserve all original characters 111 | // regardless of what exactly is the encoding 112 | body, err := proxyutil.DecodeLatin1(bytes.NewReader(b)) 113 | if err != nil { 114 | return proxyutil.NewErrorResponse(session.Request(), err) 115 | } 116 | 117 | // Modifying the original body 118 | modifiedBody, err := proxyutil.EncodeLatin1(body + "") 119 | if err != nil { 120 | return proxyutil.NewErrorResponse(session.Request(), err) 121 | } 122 | 123 | res.Body = ioutil.NopCloser(bytes.NewReader(modifiedBody)) 124 | res.Header.Del("Content-Encoding") 125 | res.ContentLength = int64(len(modifiedBody)) 126 | return res 127 | }, 128 | }) 129 | ``` 130 | 131 | ### Proxy authorization 132 | 133 | If you want to protect your proxy with Basic authentication, set `Username` and `Password` 134 | fields in the proxy configuration. 135 | 136 | ```go 137 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 138 | ListenAddr: &net.TCPAddr{ 139 | IP: net.IPv4(0, 0, 0, 0), 140 | Port: 8080, 141 | }, 142 | Username: "user", 143 | Password: "pass", 144 | }) 145 | ``` 146 | 147 | ### HTTP over TLS (HTTPS) proxy 148 | 149 | If you want to protect yourself from eavesdropping on your traffic to proxy, you can configure 150 | it to work over a TLS tunnel. This is really simple to do, just set a `*tls.Config` instance 151 | in your proxy configuration. 152 | 153 | ```go 154 | tlsConfig := &tls.Config{ 155 | Certificates: []tls.Certificate{*proxyCert}, 156 | } 157 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 158 | ListenAddr: addr, 159 | TLSConfig: tlsConfig, 160 | }) 161 | ``` 162 | 163 | ### TLS interception 164 | 165 | If you want to do TLS termination, you first need to prepare a self-signed certificate 166 | that will be used as a certificates authority. Use the following `openssl` commands to do this. 167 | 168 | ```bash 169 | openssl genrsa -out demo.key 2048 170 | openssl req -new -x509 -key demo.key -out demo.crt -days 3650 -addext subjectAltName=DNS:,IP: 171 | ``` 172 | 173 | Now you can use it to initialize `MITMConfig`: 174 | ```go 175 | tlsCert, err := tls.LoadX509KeyPair("demo.crt", "demo.key") 176 | if err != nil { 177 | log.Fatal(err) 178 | } 179 | privateKey := tlsCert.PrivateKey.(*rsa.PrivateKey) 180 | 181 | x509c, err := x509.ParseCertificate(tlsCert.Certificate[0]) 182 | if err != nil { 183 | log.Fatal(err) 184 | } 185 | 186 | mitmConfig, err := mitm.NewConfig(x509c, privateKey, nil) 187 | if err != nil { 188 | log.Fatal(err) 189 | } 190 | 191 | mitmConfig.SetValidity(time.Hour * 24 * 7) // generate certs valid for 7 days 192 | mitmConfig.SetOrganization("gomitmproxy") // cert organization 193 | ``` 194 | 195 | Please note that you can set `MITMExceptions` to a list of hostnames, 196 | which will be excluded from TLS interception. 197 | 198 | ```go 199 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 200 | ListenAddr: &net.TCPAddr{ 201 | IP: net.IPv4(0, 0, 0, 0), 202 | Port: 3333, 203 | }, 204 | MITMConfig: mitmConfig, 205 | MITMExceptions: []string{"example.com"}, 206 | }) 207 | ``` 208 | 209 | If you configure the `APIHost`, you'll be able to download the CA certificate 210 | from `http://[APIHost]/cert.crt` when the proxy is configured. 211 | 212 | ```go 213 | // Navigate to http://gomitmproxy/cert.crt to download the CA certificate 214 | proxy.APIHost = "gomitmproxy" 215 | ``` 216 | 217 | ### Custom certs storage 218 | 219 | By default, `gomitmproxy` uses an in-memory map-based storage for the certificates, 220 | generated while doing TLS interception. It is often necessary to use a different kind 221 | of certificates storage. If this is your case, you can supply your own implementation 222 | of the `CertsStorage` interface. 223 | 224 | ```go 225 | // CustomCertsStorage - an example of a custom cert storage 226 | type CustomCertsStorage struct { 227 | certsCache map[string]*tls.Certificate // cache with the generated certificates 228 | } 229 | 230 | // Get gets the certificate from the storage 231 | func (c *CustomCertsStorage) Get(key string) (*tls.Certificate, bool) { 232 | v, ok := c.certsCache[key] 233 | return v, ok 234 | } 235 | 236 | // Set saves the certificate to the storage 237 | func (c *CustomCertsStorage) Set(key string, cert *tls.Certificate) { 238 | c.certsCache[key] = cert 239 | } 240 | ``` 241 | 242 | Then pass it to the `NewConfig` function. 243 | 244 | ```go 245 | mitmConfig, err := mitm.NewConfig(x509c, privateKey, &CustomCertsStorage{ 246 | certsCache: map[string]*tls.Certificate{}}, 247 | ) 248 | ``` 249 | 250 | ## Notable alternatives 251 | 252 | * [martian](https://github.com/google/martian) - an awesome debugging proxy with TLS interception support. 253 | * [goproxy](https://github.com/elazarl/goproxy) - also supports TLS interception and requests. 254 | 255 | ## TODO 256 | 257 | * [X] Basic HTTP proxy without MITM 258 | * [ ] Proxy 259 | * [X] Expose APIs for the library users 260 | * [X] How-to doc 261 | * [X] Travis configuration 262 | * [X] Proxy-Authorization 263 | * [X] WebSockets support (see [this](https://github.com/google/martian/issues/31)) 264 | * [X] `certsCache` -- allow custom implementations 265 | * [X] Support HTTP CONNECT over TLS 266 | * [X] Test plain HTTP requests inside HTTP CONNECT 267 | * [X] Test memory leaks 268 | * [X] Editing response body in a callback 269 | * [X] Handle unknown content-encoding values 270 | * [X] Handle CONNECT to APIHost properly (without trying to actually connect anywhere) 271 | * [X] Allow hijacking connections (!) 272 | * [X] Multiple listeners 273 | * [ ] Unit tests 274 | * [ ] Check & fix TODOs 275 | * [ ] Allow specifying net.Dialer 276 | * [ ] Specify timeouts for http.Transport 277 | * [ ] MITM 278 | * [X] Basic MITM 279 | * [X] MITM exceptions 280 | * [X] Handle invalid server certificates properly (not just reset connections) 281 | * [X] Pass the most important tests on badssl.com/dashboard 282 | * [X] Handle certificate authentication 283 | * [ ] Allow configuring minimum supported TLS version 284 | * [ ] OCSP check (see [example](https://stackoverflow.com/questions/46626963/golang-sending-ocsp-request-returns)) 285 | * [ ] (?) HPKP (see [example](https://github.com/tam7t/hpkp)) 286 | * [ ] (?) CT logs (see [example](https://github.com/google/certificate-transparency-go)) 287 | * [ ] (?) CRLSets (see [example](https://github.com/agl/crlset-tools)) 288 | -------------------------------------------------------------------------------- /auth.go: -------------------------------------------------------------------------------- 1 | package gomitmproxy 2 | 3 | import ( 4 | "encoding/base64" 5 | "net/http" 6 | "strings" 7 | 8 | "github.com/AdguardTeam/gomitmproxy/proxyutil" 9 | ) 10 | 11 | // basicAuth returns an HTTP authorization header value according to RFC2617. 12 | // See 2 (end of page 4) https://www.ietf.org/rfc/rfc2617.txt: 13 | // "To receive authorization, the client sends the userid and password, 14 | // separated by a single colon (":") character, within a base64 encoded string 15 | // in the credentials." 16 | // It is not meant to be urlencoded. 17 | func basicAuth(username, password string) string { 18 | auth := username + ":" + password 19 | return base64.StdEncoding.EncodeToString([]byte(auth)) 20 | } 21 | 22 | // newNotAuthorizedResponse creates a new "407 (Proxy Authentication Required)" 23 | // response. 24 | func newNotAuthorizedResponse(session *Session) *http.Response { 25 | res := proxyutil.NewResponse(http.StatusProxyAuthRequired, nil, session.req) 26 | 27 | // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Proxy-Authenticate. 28 | res.Header.Set("Proxy-Authenticate", "Basic") 29 | 30 | return res 31 | } 32 | 33 | // authorize checks the "Proxy-Authorization" header and returns true if the 34 | // request is authorized. If it returns false, it also returns the response that 35 | // should be written to the client. 36 | func (p *Proxy) authorize(session *Session) (bool, *http.Response) { 37 | if session.ctx.parent != nil { 38 | // If we're here, it means the connection is authorized already. 39 | return true, nil 40 | } 41 | 42 | if p.Username == "" { 43 | return true, nil 44 | } 45 | 46 | // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Proxy-Authorization. 47 | proxyAuth := session.req.Header.Get("Proxy-Authorization") 48 | if strings.Index(proxyAuth, "Basic ") != 0 { 49 | return false, newNotAuthorizedResponse(session) 50 | } 51 | 52 | authHeader := proxyAuth[len("Basic "):] 53 | if authHeader != basicAuth(p.Username, p.Password) { 54 | return false, newNotAuthorizedResponse(session) 55 | } 56 | 57 | return true, nil 58 | } 59 | -------------------------------------------------------------------------------- /config.go: -------------------------------------------------------------------------------- 1 | package gomitmproxy 2 | 3 | import ( 4 | "crypto/tls" 5 | "net" 6 | "net/http" 7 | 8 | "github.com/AdguardTeam/gomitmproxy/mitm" 9 | ) 10 | 11 | // OnConnectFunc is a declaration of the Config.OnConnect handler. 12 | type OnConnectFunc func(session *Session, proto string, addr string) (conn net.Conn) 13 | 14 | // OnRequestFunc is a declaration of the Config.OnRequest handler. 15 | type OnRequestFunc func(session *Session) (req *http.Request, resp *http.Response) 16 | 17 | // OnResponseFunc is a declaration of the Config.OnResponse handler. 18 | type OnResponseFunc func(session *Session) (resp *http.Response) 19 | 20 | // OnErrorFunc is a declaration of the Config.OnError handler. 21 | type OnErrorFunc func(session *Session, err error) 22 | 23 | // Config is the configuration of the Proxy. 24 | type Config struct { 25 | // ListenAddr is the TCP address the proxy should listen to. 26 | ListenAddr *net.TCPAddr 27 | 28 | // TLSConfig is a *tls.Config to use for the HTTP over TLS proxy. If not set 29 | // the proxy will work as a simple plain HTTP proxy. 30 | TLSConfig *tls.Config 31 | 32 | // Username is the username to be used in the "Proxy-Authorization" header. 33 | Username string 34 | 35 | // Password is the password to be used in the "Proxy-Authorization" header. 36 | Password string 37 | 38 | // MITMConfig defines the MITM configuration of the proxy. If it is not set 39 | // MITM won't be enabled for this proxy instance. 40 | MITMConfig *mitm.Config 41 | 42 | // MITMExceptions is a list of hostnames for which MITM will be disabled. 43 | MITMExceptions []string 44 | 45 | // APIHost is a name of the gomitmproxy API hostname. If it is not set, the 46 | // API won't be exposed via HTTP. 47 | // 48 | // Here are the methods exposed: 49 | // 1. apihost/cert.crt - serves the authority cert if MITMConfig is 50 | // configured. 51 | APIHost string 52 | 53 | // OnConnect is called when the proxy tries to open a new net.Conn. This 54 | // function allows hijacking the remote connection and replacing it with a 55 | // different one. 56 | // 57 | // 1. When the proxy handles the HTTP CONNECT. 58 | // IMPORTANT: In this case we don't actually use the remote connections. 59 | // It is only used to check if the remote endpoint is available. 60 | // 2. When the proxy bypasses data from the client to the remote endpoint. 61 | // For instance, it could happen when there's a WebSocket connection. 62 | OnConnect OnConnectFunc 63 | 64 | // OnRequest is called when the request has been just received, but has not 65 | // been sent to the remote server. 66 | // 67 | // At this stage, it is possible to do the following things: 68 | // 1. Modify or even replace the request. 69 | // 2. Supply an HTTP response to be written to the client. 70 | // 71 | // Return nil instead of *http.Request or *http.Response to keep the 72 | // original request / response. 73 | // 74 | // Note that even if you supply your own HTTP response here, the OnResponse 75 | // handler will be called anyway! 76 | OnRequest OnRequestFunc 77 | 78 | // OnResponse is called when the response has been just received, but has 79 | // not been sent to the local client. At this stage you can either keep the 80 | // original response, or you can replace it with a new one. 81 | OnResponse OnResponseFunc 82 | 83 | // OnError is called if there's an issue with retrieving the response from 84 | // the remote server. 85 | OnError OnErrorFunc 86 | } 87 | -------------------------------------------------------------------------------- /context.go: -------------------------------------------------------------------------------- 1 | package gomitmproxy 2 | 3 | import ( 4 | "bufio" 5 | "crypto/tls" 6 | "fmt" 7 | "net" 8 | "net/http" 9 | "sync/atomic" 10 | "time" 11 | ) 12 | 13 | var ( 14 | // currentContextID is an auto-incremented value, used for every new 15 | // Context instance. 16 | currentContextID = int64(100000) 17 | ) 18 | 19 | // Context contains all the necessary information about the connection that is 20 | // currently being processed by the proxy. 21 | type Context struct { 22 | // id is the connection identifier. 23 | id int64 24 | 25 | // lastSessionID is the number of the last session processed via the 26 | // connection. This is an auto-incremented field. 27 | lastSessionID int64 28 | 29 | // parent session makes sense in the case of handling HTTP CONNECT tunnels. 30 | // Also, it may become useful in the future when HTTP/2 support is added. 31 | parent *Session 32 | 33 | // conn is the local network connection. 34 | conn net.Conn 35 | 36 | // localRW is a buffered read/writer to conn. 37 | localRW *bufio.ReadWriter 38 | 39 | // props is a map with custom properties that can be used by gomitmproxy to 40 | // store additional context properties. 41 | props map[string]interface{} 42 | } 43 | 44 | // newContext creates a new Context instance. 45 | func newContext(conn net.Conn, localRW *bufio.ReadWriter, parent *Session) (ctx *Context) { 46 | var contextID int64 47 | if parent == nil { 48 | contextID = atomic.AddInt64(¤tContextID, 1) 49 | } else { 50 | contextID = atomic.AddInt64(&parent.lastChildID, 1) 51 | } 52 | 53 | return &Context{ 54 | id: contextID, 55 | parent: parent, 56 | conn: conn, 57 | localRW: localRW, 58 | props: map[string]interface{}{}, 59 | } 60 | } 61 | 62 | // ID is the context's unique ID. 63 | func (c *Context) ID() (id string) { 64 | if c.parent != nil { 65 | return fmt.Sprintf("%s-%d", c.parent.ID(), c.id) 66 | } 67 | 68 | return fmt.Sprintf("%d", c.id) 69 | } 70 | 71 | // IsMITM returns true if this context is for a MITMed connection. 72 | func (c *Context) IsMITM() (ok bool) { 73 | if _, ok = c.conn.(*tls.Conn); c.parent != nil && ok { 74 | return true 75 | } 76 | 77 | return false 78 | } 79 | 80 | // SetDeadline sets the read and write deadlines associated with the connection. 81 | // 82 | // The difference is that our contexts can be nested, so we search for the 83 | // topmost parent context recursively and call SetDeadline for its connection 84 | // only as this is the real underlying network connection. 85 | func (c *Context) SetDeadline(t time.Time) (err error) { 86 | if c.parent == nil { 87 | return c.conn.SetDeadline(t) 88 | } 89 | 90 | return c.parent.ctx.SetDeadline(t) 91 | } 92 | 93 | // GetProp gets context property (previously saved using SetProp). 94 | func (c *Context) GetProp(key string) (v interface{}, ok bool) { 95 | v, ok = c.props[key] 96 | 97 | return v, ok 98 | } 99 | 100 | // SetProp sets the context's property. 101 | func (c *Context) SetProp(key string, val interface{}) { 102 | c.props[key] = val 103 | } 104 | 105 | // Session contains all the necessary information about the request-response 106 | // pair that is currently being processed. 107 | type Session struct { 108 | // id is a session identifier. 109 | id int64 110 | // lastChildID is the last child context's identifier. This field is 111 | // automatically incremented. 112 | lastChildID int64 113 | 114 | // ctx is a context of the connection this session belongs to. 115 | ctx *Context 116 | 117 | // req is the *http.Request that's being processed in this session. 118 | req *http.Request 119 | 120 | // res is the *http.Response that's being processed in this session. 121 | res *http.Response 122 | 123 | // props is a map with custom properties that can be used by gomitmproxy to 124 | // store additional session properties. 125 | props map[string]interface{} 126 | } 127 | 128 | // newSession creates a new Session instance. 129 | func newSession(ctx *Context, req *http.Request) (sess *Session) { 130 | sessionID := atomic.AddInt64(&ctx.lastSessionID, 1) 131 | 132 | return &Session{ 133 | id: sessionID, 134 | ctx: ctx, 135 | req: req, 136 | props: map[string]interface{}{}, 137 | } 138 | } 139 | 140 | // ID returns a unique session identifier. 141 | func (s *Session) ID() (id string) { 142 | return fmt.Sprintf("%s-%d", s.ctx.ID(), s.id) 143 | } 144 | 145 | // Request returns the HTTP request of this session. 146 | func (s *Session) Request() (req *http.Request) { 147 | return s.req 148 | } 149 | 150 | // Response returns the HTTP response of this session. 151 | func (s *Session) Response() (resp *http.Response) { 152 | return s.res 153 | } 154 | 155 | // Ctx returns this session's context. 156 | func (s *Session) Ctx() (ctx *Context) { 157 | return s.ctx 158 | } 159 | 160 | // GetProp gets session property (previously saved using SetProp). 161 | func (s *Session) GetProp(key string) (v interface{}, ok bool) { 162 | v, ok = s.props[key] 163 | 164 | return v, ok 165 | } 166 | 167 | // SetProp sets a session's property. 168 | func (s *Session) SetProp(key string, val interface{}) { 169 | s.props[key] = val 170 | } 171 | 172 | // RemoteAddr returns this session's remote address. 173 | func (s *Session) RemoteAddr() (addr string) { 174 | if s.ctx.IsMITM() { 175 | return s.ctx.parent.RemoteAddr() 176 | } 177 | 178 | host := s.req.URL.Host 179 | if _, _, err := net.SplitHostPort(host); err == nil { 180 | return host 181 | } 182 | 183 | if s.req.URL.Scheme == "https" { 184 | return fmt.Sprintf("%s:443", host) 185 | } 186 | 187 | return fmt.Sprintf("%s:80", host) 188 | } 189 | -------------------------------------------------------------------------------- /examples/auth/README.md: -------------------------------------------------------------------------------- 1 | # Auth proxy demo 2 | 3 | Runs an HTTPS proxy on `localhost:3333` with authorization: 4 | 5 | * Username: `user` 6 | * Password: `pass` 7 | -------------------------------------------------------------------------------- /examples/auth/main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "net" 5 | "net/http" 6 | "os" 7 | "os/signal" 8 | "syscall" 9 | 10 | "github.com/AdguardTeam/golibs/log" 11 | "github.com/AdguardTeam/gomitmproxy" 12 | ) 13 | 14 | func main() { 15 | log.SetLevel(log.DEBUG) 16 | 17 | go func() { 18 | log.Println(http.ListenAndServe("localhost:6060", nil)) 19 | }() 20 | 21 | // Prepare the proxy. 22 | addr := &net.TCPAddr{ 23 | IP: net.IPv4(0, 0, 0, 0), 24 | Port: 3333, 25 | } 26 | 27 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 28 | ListenAddr: addr, 29 | 30 | Username: "user", 31 | Password: "pass", 32 | APIHost: "gomitmproxy", 33 | }) 34 | 35 | err := proxy.Start() 36 | if err != nil { 37 | log.Fatal(err) 38 | } 39 | 40 | signalChannel := make(chan os.Signal, 1) 41 | signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM) 42 | <-signalChannel 43 | 44 | // Stop the proxy. 45 | proxy.Close() 46 | } 47 | -------------------------------------------------------------------------------- /examples/mitm/README.md: -------------------------------------------------------------------------------- 1 | # MITM demo 2 | 3 | Runs an HTTPS proxy on `localhost:3333` with authorization: 4 | 5 | * Username: `user` 6 | * Password: `pass` 7 | 8 | Can be tested in Chrome using SwitchyOmega. 9 | 10 | Note, that you need to install `demo.crt` to the trusted roots storage. 11 | -------------------------------------------------------------------------------- /examples/mitm/demo.crt: -------------------------------------------------------------------------------- 1 | -----BEGIN CERTIFICATE----- 2 | MIIDGTCCAgGgAwIBAgIUS/F/3DxviRqvtvuzkSTwmPdn+PIwDQYJKoZIhvcNAQEL 3 | BQAwHDEaMBgGA1UEAwwRRE9fTk9UX1RSVVNUX0NFUlQwHhcNMjIxMTA2MTgyMTMw 4 | WhcNMjMxMDI4MTgyMTMwWjAcMRowGAYDVQQDDBFET19OT1RfVFJVU1RfQ0VSVDCC 5 | ASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAI4SU1jm74ih7YGJB+TQUUQ6 6 | +Kt32zk0TrYLcslj6igiuyZf1XvKJvHdhGBzSCA6KjgwpqazVBoMOtV48n3GJZFf 7 | R10joBdOqaMphcPBk+0hm97QNgawqquUE2PwEaaoWzBtpUJLOsA8yRXUl2+nzGcj 8 | mIIeAePRVc1xk8gEpn/tzca1806mDEJ90jFHJEij4Ps79RosGsPzuP51l/5mIcNp 9 | EE1oYN49Q1VpShxNZBbUB9dCaDUZiZbgp3Hyl6BvjpzJwtDEhHmfn9LK457R/Swr 10 | 3y5DsXqK6VCPeT37O/+gHfNtZWBieLW6M6eIEeertJcpQRZQWPAuFyykIoyD3oMC 11 | AwEAAaNTMFEwHQYDVR0OBBYEFK+9ZFY6OhSLdXF3MSUoPGT17pq8MB8GA1UdIwQY 12 | MBaAFK+9ZFY6OhSLdXF3MSUoPGT17pq8MA8GA1UdEwEB/wQFMAMBAf8wDQYJKoZI 13 | hvcNAQELBQADggEBACXtY1/HyLKCj7wFV97dceEyC0pzYV6NZ9NnYcQ2m6WDe8+L 14 | qNRoe5UOKR+xRN9CTp095EFDfhI/iqLfrdSIKldz/a1Dvnuyk7k+sN+FIex0bGuQ 15 | ZRKOp53HDGQN6Z+3k2dGXTE1HbF5CLbp3y/N9pAqkTHIN85FUU5vbr/gdYuQiBg+ 16 | N9lk7yYHppQCBikG2Q1uVpcg4RuawbsSPPMBgf5RZ2PhO8VDlBUWAGXSedZO/hbt 17 | U+FJGqdxlXS3HYwDlnW4d5PqLG3+VDDcIX2qD6gqorwrJS1VEFNgiZoxeFSV4rjb 18 | KmWrWMmj3/mlJ0tapRlSdMh6yuDWa77dtel9N94= 19 | -----END CERTIFICATE----- 20 | -------------------------------------------------------------------------------- /examples/mitm/demo.key: -------------------------------------------------------------------------------- 1 | -----BEGIN PRIVATE KEY----- 2 | MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCOElNY5u+Ioe2B 3 | iQfk0FFEOvird9s5NE62C3LJY+ooIrsmX9V7yibx3YRgc0ggOio4MKams1QaDDrV 4 | ePJ9xiWRX0ddI6AXTqmjKYXDwZPtIZve0DYGsKqrlBNj8BGmqFswbaVCSzrAPMkV 5 | 1Jdvp8xnI5iCHgHj0VXNcZPIBKZ/7c3GtfNOpgxCfdIxRyRIo+D7O/UaLBrD87j+ 6 | dZf+ZiHDaRBNaGDePUNVaUocTWQW1AfXQmg1GYmW4Kdx8pegb46cycLQxIR5n5/S 7 | yuOe0f0sK98uQ7F6iulQj3k9+zv/oB3zbWVgYni1ujOniBHnq7SXKUEWUFjwLhcs 8 | pCKMg96DAgMBAAECggEAMM06tB8fyN9Wplhbzc2BHN7k7IGPXGcLYp0sIOGhXYgQ 9 | oW3p90vJdOuSvU7cR7WzKvoLRNf02723t/yDz5Bw9y6zZNsH8vmia9mniUbFeX9B 10 | +5ep90JYXffPcVTVu1m5eTkwu0T8OWyn5kfQfRo2rHcdvBRysb8GqjuJd/ug9fBG 11 | wDHaDKrj4fsVeuuAtebHOEZhh59cXNWjn30nnsfJv+ePXgHZ9RtMtNp70uD5gLBr 12 | gCGdN9uNqKzaqwnZc5Zyv00AEFkQ/ZwsHPNoFTtZIHovYLBwPK5LtMNH3Pz+QaUE 13 | d0R7e2cNHw4ouEGNy9i2QV514ztEC8DWYeRu+unBAQKBgQDIeh3eFzNXQmls7Z40 14 | iFfEi8rRcjMpcqNONSSYwmrNGPvT3yHA0cnt73hFA91plZd1vBcOlmpADT7FqDe+ 15 | LWSXI/Xx23FgADijo3su54SUWZ/4Bt01L0KcfUebWHZRkRb5R2+Lga1Ycwqa+jsg 16 | kcn/5HWdsBPKL38RtiwZjwBcWQKBgQC1az7P6VYikXenbMTS/Mz2a0jRQbU2gDva 17 | FHOrCfP0sSTUSyVrkZOEhVYsyjyHUC4O6nCzwhCQ/q/amjCzRQLjkwfcROn2LwSf 18 | eEcY3u2Ktk6WnAfcwkrvFm5Lyiv/Xwhv2730zKp55CB/UDVnFcMdYpdameWBBtwe 19 | uPBK3NiGOwKBgAtOV8DerhaNuERcYj+0ML7040tMlXYQ8QTIGnhC/qLydcFNJCor 20 | qqewiafav/HkbdZF9UbtVLCoDpI3Gm2vQa0Eaipppcs0N/2Cir/qbp+vLkZenLsT 21 | Hz6UEiXAp2uSMyl7zd6gQZZrZn22/v6nOi0kRT3PYE5Wv2PQUkxetDaBAoGBAKTo 22 | 0NcDnwWbP64URDIaFGInEbENzqC1HjLVhnNCf9y8reLAUEqgsPy0i6n5R94kd0md 23 | uEbesFps+QN4R66dm8usWmfSyO28vbIMDmzAMCN4JqXnPYphnuYIeMgyBZ6ED1JG 24 | 6Dw/UvOr+BJiobiL4qmydiyoWiPYTX0r1VnnuHcDAoGAJ2DTMFEtSCzoxgisA0vv 25 | C/4csyH04hDn4M9J9XXufiHDjvFjOYhR0rB4NLHzzc+D+qjolMfwuyZ9rFO17u5C 26 | eRpmLc4toMUVuNl5+mprNYrcWsArsisTeOS+isz7Pi3jKWnCjzrwYda7Wslu7kL8 27 | 85NjxgzM9+PeSHHnOLy3L8U= 28 | -----END PRIVATE KEY----- 29 | -------------------------------------------------------------------------------- /examples/mitm/main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "bytes" 5 | "crypto/rsa" 6 | "crypto/tls" 7 | "crypto/x509" 8 | "io" 9 | "net" 10 | "net/http" 11 | "os" 12 | "os/signal" 13 | "strings" 14 | "syscall" 15 | "time" 16 | 17 | "github.com/AdguardTeam/golibs/log" 18 | "github.com/AdguardTeam/gomitmproxy" 19 | "github.com/AdguardTeam/gomitmproxy/mitm" 20 | "github.com/AdguardTeam/gomitmproxy/proxyutil" 21 | 22 | _ "net/http/pprof" 23 | ) 24 | 25 | func main() { 26 | log.SetLevel(log.DEBUG) 27 | 28 | go func() { 29 | log.Println(http.ListenAndServe("localhost:6060", nil)) 30 | }() 31 | 32 | // Read the MITM cert and key. 33 | tlsCert, err := tls.LoadX509KeyPair("demo.crt", "demo.key") 34 | if err != nil { 35 | log.Fatal(err) 36 | } 37 | privateKey := tlsCert.PrivateKey.(*rsa.PrivateKey) 38 | 39 | x509c, err := x509.ParseCertificate(tlsCert.Certificate[0]) 40 | if err != nil { 41 | log.Fatal(err) 42 | } 43 | 44 | mitmConfig, err := mitm.NewConfig(x509c, privateKey, &CustomCertsStorage{ 45 | certsCache: map[string]*tls.Certificate{}}, 46 | ) 47 | 48 | if err != nil { 49 | log.Fatal(err) 50 | } 51 | 52 | // Generate certs valid for 7 days. 53 | mitmConfig.SetValidity(time.Hour * 24 * 7) 54 | // Set certs organization. 55 | mitmConfig.SetOrganization("gomitmproxy") 56 | 57 | // Generate a cert-key pair for the HTTP-over-TLS proxy. 58 | proxyCert, err := mitmConfig.GetOrCreateCert("127.0.0.1") 59 | if err != nil { 60 | panic(err) 61 | } 62 | tlsConfig := &tls.Config{ 63 | Certificates: []tls.Certificate{*proxyCert}, 64 | } 65 | 66 | // Prepare the proxy. 67 | addr := &net.TCPAddr{ 68 | IP: net.IPv4(0, 0, 0, 0), 69 | Port: 3333, 70 | } 71 | 72 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 73 | ListenAddr: addr, 74 | TLSConfig: tlsConfig, 75 | 76 | Username: "user", 77 | Password: "pass", 78 | APIHost: "gomitmproxy", 79 | 80 | MITMConfig: mitmConfig, 81 | MITMExceptions: []string{"example.com"}, 82 | 83 | OnRequest: onRequest, 84 | OnResponse: onResponse, 85 | OnConnect: onConnect, 86 | }) 87 | 88 | err = proxy.Start() 89 | if err != nil { 90 | log.Fatal(err) 91 | } 92 | 93 | signalChannel := make(chan os.Signal, 1) 94 | signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM) 95 | <-signalChannel 96 | 97 | // Stop the proxy. 98 | proxy.Close() 99 | } 100 | 101 | func onRequest(session *gomitmproxy.Session) (*http.Request, *http.Response) { 102 | req := session.Request() 103 | 104 | log.Printf("onRequest: %s %s", req.Method, req.URL.String()) 105 | 106 | if req.URL.Host == "example.net" { 107 | body := strings.NewReader("

Replaced response

") 108 | res := proxyutil.NewResponse(http.StatusOK, body, req) 109 | res.Header.Set("Content-Type", "text/html") 110 | session.SetProp("blocked", true) 111 | return nil, res 112 | } 113 | 114 | if req.URL.Host == "testgomitmproxy" { 115 | body := strings.NewReader("

Served by gomitmproxy

") 116 | res := proxyutil.NewResponse(http.StatusOK, body, req) 117 | res.Header.Set("Content-Type", "text/html") 118 | return nil, res 119 | } 120 | 121 | return nil, nil 122 | } 123 | 124 | func onResponse(session *gomitmproxy.Session) *http.Response { 125 | log.Printf("onResponse: %s", session.Request().URL.String()) 126 | 127 | if _, ok := session.GetProp("blocked"); ok { 128 | log.Printf("onResponse: was blocked") 129 | return nil 130 | } 131 | 132 | res := session.Response() 133 | req := session.Request() 134 | 135 | if strings.Index(res.Header.Get("Content-Type"), "text/html") != 0 { 136 | // Do nothing with non-HTML responses 137 | return nil 138 | } 139 | 140 | b, err := proxyutil.ReadDecompressedBody(res) 141 | // Close the original body. 142 | _ = res.Body.Close() 143 | if err != nil { 144 | return proxyutil.NewErrorResponse(req, err) 145 | } 146 | 147 | // Use latin1 before modifying the body. Using this 1-byte encoding will 148 | // let us preserve all original characters regardless of what exactly is 149 | // the encoding. 150 | body, err := proxyutil.DecodeLatin1(bytes.NewReader(b)) 151 | if err != nil { 152 | return proxyutil.NewErrorResponse(session.Request(), err) 153 | } 154 | 155 | // Modifying the original body. 156 | modifiedBody, err := proxyutil.EncodeLatin1(body + "") 157 | if err != nil { 158 | return proxyutil.NewErrorResponse(session.Request(), err) 159 | } 160 | 161 | res.Body = io.NopCloser(bytes.NewReader(modifiedBody)) 162 | res.Header.Del("Content-Encoding") 163 | res.ContentLength = int64(len(modifiedBody)) 164 | 165 | return res 166 | } 167 | 168 | func onConnect(_ *gomitmproxy.Session, _ string, addr string) (conn net.Conn) { 169 | host, _, err := net.SplitHostPort(addr) 170 | 171 | if err == nil && host == "testgomitmproxy" { 172 | // Don't let it connecting there, we'll serve it by ourselves. 173 | return &proxyutil.NoopConn{} 174 | } 175 | 176 | return nil 177 | } 178 | 179 | // CustomCertsStorage is an example of a custom cert storage. 180 | type CustomCertsStorage struct { 181 | // certsCache is a cache with the generated certificates. 182 | certsCache map[string]*tls.Certificate 183 | } 184 | 185 | // Get gets the certificate from the storage. 186 | func (c *CustomCertsStorage) Get(key string) (cert *tls.Certificate, ok bool) { 187 | cert, ok = c.certsCache[key] 188 | 189 | return cert, ok 190 | } 191 | 192 | // Set saves the certificate to the storage. 193 | func (c *CustomCertsStorage) Set(key string, cert *tls.Certificate) { 194 | c.certsCache[key] = cert 195 | } 196 | -------------------------------------------------------------------------------- /examples/simple/main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "net" 5 | "os" 6 | "os/signal" 7 | "syscall" 8 | 9 | "github.com/AdguardTeam/golibs/log" 10 | "github.com/AdguardTeam/gomitmproxy" 11 | ) 12 | 13 | func main() { 14 | proxy := gomitmproxy.NewProxy(gomitmproxy.Config{ 15 | ListenAddr: &net.TCPAddr{ 16 | IP: net.IPv4(0, 0, 0, 0), 17 | Port: 8080, 18 | }, 19 | }) 20 | err := proxy.Start() 21 | if err != nil { 22 | log.Fatal(err) 23 | } 24 | 25 | signalChannel := make(chan os.Signal, 1) 26 | signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM) 27 | <-signalChannel 28 | 29 | // Clean up. 30 | proxy.Close() 31 | } 32 | -------------------------------------------------------------------------------- /go.mod: -------------------------------------------------------------------------------- 1 | module github.com/AdguardTeam/gomitmproxy 2 | 3 | go 1.20 4 | 5 | require ( 6 | github.com/AdguardTeam/golibs v0.13.2 7 | github.com/pkg/errors v0.9.1 8 | github.com/stretchr/testify v1.8.2 9 | golang.org/x/text v0.8.0 10 | ) 11 | 12 | require ( 13 | github.com/davecgh/go-spew v1.1.1 // indirect 14 | github.com/kr/text v0.2.0 // indirect 15 | github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect 16 | github.com/pmezard/go-difflib v1.0.0 // indirect 17 | gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect 18 | gopkg.in/yaml.v3 v3.0.1 // indirect 19 | ) 20 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- 1 | github.com/AdguardTeam/golibs v0.13.2 h1:BPASsyQKmb+b8VnvsNOHp7bKfcZl9Z+Z2UhPjOiupSc= 2 | github.com/AdguardTeam/golibs v0.13.2/go.mod h1:7ylQLv2Lqsc3UW3jHoITynYk6Y1tYtgEMkR09ppfsN8= 3 | github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E= 4 | github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= 5 | github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= 6 | github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= 7 | github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ= 8 | github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI= 9 | github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY= 10 | github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE= 11 | github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs= 12 | github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno= 13 | github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4= 14 | github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0= 15 | github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= 16 | github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= 17 | github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= 18 | github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw= 19 | github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo= 20 | github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg= 21 | github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU= 22 | github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8= 23 | github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4= 24 | golang.org/x/text v0.8.0 h1:57P1ETyNKtuIjB4SRd15iJxuhj8Gc416Y78H3qgMh68= 25 | golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8= 26 | gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= 27 | gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU= 28 | gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= 29 | gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= 30 | gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA= 31 | gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= 32 | -------------------------------------------------------------------------------- /helper.go: -------------------------------------------------------------------------------- 1 | package gomitmproxy 2 | 3 | import ( 4 | "errors" 5 | "io" 6 | "net" 7 | ) 8 | 9 | var errShutdown = errors.New("proxy is shutting down") 10 | var errClose = errors.New("closing connection") 11 | 12 | // isCloseable checks if the error signals about connection being closed 13 | // or the proxy shutting down. 14 | func isCloseable(err error) (ok bool) { 15 | // TODO(ameshkov): use errors.Is. 16 | if netErr, ok := err.(net.Error); ok && netErr.Timeout() { 17 | return true 18 | } 19 | 20 | switch err { 21 | case io.EOF, io.ErrClosedPipe, errClose, errShutdown: 22 | return true 23 | } 24 | 25 | return false 26 | } 27 | 28 | // A peekedConn subverts the net.Conn.Read implementation, primarily so that 29 | // sniffed bytes can be transparently prepended. 30 | type peekedConn struct { 31 | net.Conn 32 | r io.Reader 33 | } 34 | 35 | // Read allows control over the embedded net.Conn's read data. By using an 36 | // io.MultiReader one can read from a conn, and then replace what they read, to 37 | // be read again. 38 | func (c *peekedConn) Read(buf []byte) (int, error) { return c.r.Read(buf) } 39 | -------------------------------------------------------------------------------- /hopbyhop.go: -------------------------------------------------------------------------------- 1 | package gomitmproxy 2 | 3 | import ( 4 | "net/http" 5 | "strings" 6 | ) 7 | 8 | // Hop-by-hop headers as defined by RFC2616. 9 | // 10 | // http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3.1 11 | var hopByHopHeaders = []string{ 12 | "Connection", 13 | "Keep-Alive", 14 | "Proxy-Authenticate", 15 | "Proxy-Authorization", 16 | "Proxy-Connection", // Non-standard, but required for HTTP/2. 17 | "Te", 18 | "Trailer", 19 | "Transfer-Encoding", 20 | "Upgrade", 21 | } 22 | 23 | // removeHopByHopHeaders removes hop-by-hop headers. 24 | func removeHopByHopHeaders(header http.Header) { 25 | // Additional hop-by-hop headers may be specified in `Connection` headers. 26 | // http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-9.1 27 | for _, vs := range header["Connection"] { 28 | for _, v := range strings.Split(vs, ",") { 29 | k := http.CanonicalHeaderKey(strings.TrimSpace(v)) 30 | header.Del(k) 31 | } 32 | } 33 | 34 | for _, k := range hopByHopHeaders { 35 | header.Del(k) 36 | } 37 | } 38 | -------------------------------------------------------------------------------- /mitm/mitm.go: -------------------------------------------------------------------------------- 1 | // Package mitm implements methods for working with certificates and TLS configurations 2 | // that are used for MITMing connections. 3 | package mitm 4 | 5 | import ( 6 | "crypto/rand" 7 | "crypto/rsa" 8 | "crypto/sha1" 9 | "crypto/tls" 10 | "crypto/x509" 11 | "crypto/x509/pkix" 12 | "math/big" 13 | "net" 14 | "sync" 15 | "sync/atomic" 16 | "time" 17 | 18 | "github.com/AdguardTeam/golibs/log" 19 | ) 20 | 21 | // While generating a new certificate, in order to get a unique serial 22 | // number every time we increment this value. 23 | var currentSerialNumber = time.Now().Unix() 24 | 25 | // Config is a set of configuration values that are used to build TLS configs 26 | // capable of MITM. 27 | type Config struct { 28 | ca *x509.Certificate // Root certificate authority 29 | caPrivateKey *rsa.PrivateKey // CA private key 30 | 31 | // roots is a CertPool that contains the root CA GetOrCreateCert 32 | // it serves a single purpose -- to verify the cached domain certs 33 | roots *x509.CertPool 34 | 35 | // privateKey is the private key that will be used to generate leaf certificates 36 | // TODO: insecure approach, generating a new key would be better 37 | privateKey *rsa.PrivateKey 38 | 39 | validity time.Duration // Validity of the generated certificates 40 | keyID []byte // SKI to use in generated certificates (https://tools.ietf.org/html/rfc3280#section-4.2.1.2) 41 | organization string // Organization (will be used for generated certificates) 42 | 43 | certsStorage CertsStorage // cache with the generated certificates 44 | certsStorageMu sync.RWMutex 45 | } 46 | 47 | // CertsStorage is an interface for generated tls certificates storage 48 | type CertsStorage interface { 49 | // Get gets the certificate from the storage 50 | Get(key string) (*tls.Certificate, bool) 51 | // Set saves the certificate to the storage 52 | Set(key string, cert *tls.Certificate) 53 | } 54 | 55 | // CertsCache is a simple map-based CertsStorage implementation 56 | type CertsCache struct { 57 | certsCache map[string]*tls.Certificate // cache with the generated certificates 58 | } 59 | 60 | // Get gets the certificate from the storage 61 | func (c *CertsCache) Get(key string) (*tls.Certificate, bool) { 62 | v, ok := c.certsCache[key] 63 | return v, ok 64 | } 65 | 66 | // Set saves the certificate to the storage 67 | func (c *CertsCache) Set(key string, cert *tls.Certificate) { 68 | c.certsCache[key] = cert 69 | } 70 | 71 | // NewAuthority creates a new CA certificate and associated private key. 72 | // name -- certificate subject name 73 | // organization -- certificate organization 74 | // validity -- time for which the certificate is valid 75 | func NewAuthority(name, organization string, validity time.Duration) (*x509.Certificate, *rsa.PrivateKey, error) { 76 | priv, err := rsa.GenerateKey(rand.Reader, 2048) 77 | if err != nil { 78 | return nil, nil, err 79 | } 80 | pub := priv.Public() 81 | 82 | // Subject Key Identifier support for end entity certificate. 83 | // https://tools.ietf.org/html/rfc3280#section-4.2.1.2 84 | pkixpub, err := x509.MarshalPKIXPublicKey(pub) 85 | if err != nil { 86 | return nil, nil, err 87 | } 88 | h := sha1.New() 89 | _, err = h.Write(pkixpub) 90 | if err != nil { 91 | return nil, nil, err 92 | } 93 | keyID := h.Sum(nil) 94 | 95 | // Increment the serial number 96 | serial := atomic.AddInt64(¤tSerialNumber, 1) 97 | 98 | tmpl := &x509.Certificate{ 99 | SerialNumber: big.NewInt(serial), 100 | Subject: pkix.Name{ 101 | CommonName: name, 102 | Organization: []string{organization}, 103 | }, 104 | SubjectKeyId: keyID, 105 | KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign, 106 | ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}, 107 | BasicConstraintsValid: true, 108 | NotBefore: time.Now().Add(-validity), 109 | NotAfter: time.Now().Add(validity), 110 | DNSNames: []string{name}, 111 | IsCA: true, 112 | } 113 | 114 | raw, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, pub, priv) 115 | if err != nil { 116 | return nil, nil, err 117 | } 118 | 119 | // Parse certificate bytes so that we have a leaf certificate. 120 | x509c, err := x509.ParseCertificate(raw) 121 | if err != nil { 122 | return nil, nil, err 123 | } 124 | 125 | return x509c, priv, nil 126 | } 127 | 128 | // NewConfig creates a new MITM configuration 129 | // ca -- root certificate authority to use for generating domain certs 130 | // privateKey -- private key of this CA GetOrCreateCert 131 | // storage -- a custom certs storage or null if you want to use the default implementation 132 | func NewConfig(ca *x509.Certificate, privateKey *rsa.PrivateKey, storage CertsStorage) (*Config, error) { 133 | roots := x509.NewCertPool() 134 | roots.AddCert(ca) 135 | 136 | // Generating the private key that will be used for domain certificates 137 | priv, err := rsa.GenerateKey(rand.Reader, 2048) 138 | if err != nil { 139 | return nil, err 140 | } 141 | pub := priv.Public() 142 | 143 | // Subject Key Identifier support for end entity certificate. 144 | // https://tools.ietf.org/html/rfc3280#section-4.2.1.2 145 | pkixpub, err := x509.MarshalPKIXPublicKey(pub) 146 | if err != nil { 147 | return nil, err 148 | } 149 | h := sha1.New() 150 | _, err = h.Write(pkixpub) 151 | if err != nil { 152 | return nil, err 153 | } 154 | keyID := h.Sum(nil) 155 | 156 | if storage == nil { 157 | storage = &CertsCache{certsCache: make(map[string]*tls.Certificate)} 158 | } 159 | 160 | return &Config{ 161 | ca: ca, 162 | caPrivateKey: privateKey, 163 | privateKey: priv, 164 | keyID: keyID, 165 | validity: time.Hour, 166 | organization: "gomitmproxy", 167 | certsStorage: storage, 168 | roots: roots, 169 | }, nil 170 | } 171 | 172 | // GetCA returns the authority cert 173 | func (c *Config) GetCA() *x509.Certificate { 174 | return c.ca 175 | } 176 | 177 | // SetOrganization sets the organization name that 178 | // will be used in generated certs 179 | func (c *Config) SetOrganization(organization string) { 180 | c.organization = organization 181 | } 182 | 183 | // SetValidity sets validity period for the generated certs 184 | func (c *Config) SetValidity(validity time.Duration) { 185 | c.validity = validity 186 | } 187 | 188 | // NewTLSConfigForHost creates a *tls.Config that will generate 189 | // domain certificates on-the-fly using the SNI extension (if specified) 190 | // or the hostname 191 | func (c *Config) NewTLSConfigForHost(hostname string) *tls.Config { 192 | tlsConfig := &tls.Config{ 193 | GetCertificate: func(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) { 194 | host := clientHello.ServerName 195 | if host == "" { 196 | host = hostname 197 | } 198 | 199 | return c.GetOrCreateCert(host) 200 | }, 201 | NextProtos: []string{"http/1.1"}, 202 | } 203 | 204 | // Accept client certs without verifying them 205 | // Note that we will still verify remote server certs 206 | // nolint:gosec 207 | tlsConfig.InsecureSkipVerify = true 208 | 209 | return tlsConfig 210 | } 211 | 212 | // GetOrCreateCert gets or creates a certificate for the specified hostname 213 | func (c *Config) GetOrCreateCert(hostname string) (cert *tls.Certificate, err error) { 214 | // Remove the port if it exists. 215 | host, _, err := net.SplitHostPort(hostname) 216 | if err == nil { 217 | hostname = host 218 | } 219 | 220 | c.certsStorageMu.RLock() 221 | cert, ok := c.certsStorage.Get(hostname) 222 | c.certsStorageMu.RUnlock() 223 | 224 | if ok { 225 | log.Debug("mitm: cache hit for %s", hostname) 226 | 227 | // Check validity of the certificate for hostname match, expiry, etc. In 228 | // particular, if the cached certificate has expired, create a new one. 229 | if _, err = cert.Leaf.Verify(x509.VerifyOptions{ 230 | DNSName: hostname, 231 | Roots: c.roots, 232 | }); err == nil { 233 | return cert, nil 234 | } 235 | 236 | log.Debug("mitm: invalid certificate in the cache for %s", hostname) 237 | } 238 | 239 | log.Debug("mitm: cache miss for %s", hostname) 240 | 241 | // Increment the serial number 242 | serial := atomic.AddInt64(¤tSerialNumber, 1) 243 | 244 | tmpl := &x509.Certificate{ 245 | SerialNumber: big.NewInt(serial), 246 | Subject: pkix.Name{ 247 | CommonName: hostname, 248 | Organization: []string{c.organization}, 249 | }, 250 | SubjectKeyId: c.keyID, 251 | KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature, 252 | ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}, 253 | BasicConstraintsValid: true, 254 | NotBefore: time.Now().Add(-c.validity), 255 | NotAfter: time.Now().Add(c.validity), 256 | } 257 | 258 | if ip := net.ParseIP(hostname); ip != nil { 259 | tmpl.IPAddresses = []net.IP{ip} 260 | } else { 261 | tmpl.DNSNames = []string{hostname} 262 | } 263 | 264 | raw, err := x509.CreateCertificate(rand.Reader, tmpl, c.ca, c.privateKey.Public(), c.caPrivateKey) 265 | if err != nil { 266 | return nil, err 267 | } 268 | 269 | // Parse certificate bytes so that we have a leaf certificate. 270 | x509c, err := x509.ParseCertificate(raw) 271 | if err != nil { 272 | return nil, err 273 | } 274 | 275 | cert = &tls.Certificate{ 276 | Certificate: [][]byte{raw, c.ca.Raw}, 277 | PrivateKey: c.privateKey, 278 | Leaf: x509c, 279 | } 280 | 281 | c.certsStorageMu.Lock() 282 | c.certsStorage.Set(hostname, cert) 283 | c.certsStorageMu.Unlock() 284 | 285 | return cert, nil 286 | } 287 | -------------------------------------------------------------------------------- /mitm/mitm_test.go: -------------------------------------------------------------------------------- 1 | package mitm 2 | 3 | import ( 4 | "crypto/tls" 5 | "crypto/x509" 6 | "net" 7 | "testing" 8 | "time" 9 | 10 | "github.com/stretchr/testify/assert" 11 | ) 12 | 13 | func TestMITM(t *testing.T) { 14 | ca, privateKey, err := NewAuthority("gomitmproxy ca", "gomitmproxy", 24*time.Hour) 15 | 16 | assert.Nil(t, err) 17 | assert.NotNil(t, ca) 18 | assert.NotNil(t, privateKey) 19 | 20 | c, err := NewConfig(ca, privateKey, nil) 21 | assert.Nil(t, err) 22 | 23 | c.SetValidity(20 * time.Hour) 24 | c.SetOrganization("Test Organization") 25 | 26 | conf := c.NewTLSConfigForHost("example.org") 27 | assert.Equal(t, []string{"http/1.1"}, conf.NextProtos) 28 | assert.True(t, conf.InsecureSkipVerify) 29 | 30 | // Test generating a certificate 31 | clientHello := &tls.ClientHelloInfo{ 32 | ServerName: "example.org", 33 | } 34 | tlsCert, err := conf.GetCertificate(clientHello) 35 | assert.Nil(t, err) 36 | assert.NotNil(t, tlsCert) 37 | 38 | // Assert certificate details 39 | x509c := tlsCert.Leaf 40 | assert.Equal(t, "example.org", x509c.Subject.CommonName) 41 | assert.Nil(t, x509c.VerifyHostname("example.org")) 42 | assert.Equal(t, []string{"Test Organization"}, x509c.Subject.Organization) 43 | assert.NotNil(t, x509c.SubjectKeyId) 44 | assert.True(t, x509c.BasicConstraintsValid) 45 | assert.True(t, x509c.KeyUsage&x509.KeyUsageKeyEncipherment == x509.KeyUsageKeyEncipherment) 46 | assert.True(t, x509c.KeyUsage&x509.KeyUsageDigitalSignature == x509.KeyUsageDigitalSignature) 47 | assert.Equal(t, []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}, x509c.ExtKeyUsage) 48 | assert.Equal(t, []string{"example.org"}, x509c.DNSNames) 49 | assert.True(t, x509c.NotBefore.Before(time.Now().Add(-2*time.Hour))) 50 | assert.True(t, x509c.NotAfter.After(time.Now().Add(2*time.Hour))) 51 | 52 | // Check that certificate is cached 53 | tlsCert2, err := c.GetOrCreateCert("example.org") 54 | assert.Nil(t, err) 55 | assert.True(t, tlsCert == tlsCert2) 56 | 57 | // Check the certificate for an IP 58 | tlsCertForIP, err := c.GetOrCreateCert("192.168.0.1:443") 59 | assert.Nil(t, err) 60 | x509c = tlsCertForIP.Leaf 61 | assert.Equal(t, 1, len(x509c.IPAddresses)) 62 | assert.True(t, net.ParseIP("192.168.0.1").Equal(x509c.IPAddresses[0])) 63 | } 64 | -------------------------------------------------------------------------------- /proxy.go: -------------------------------------------------------------------------------- 1 | // Package gomitmproxy implements a configurable mitm proxy wring purely in go. 2 | package gomitmproxy 3 | 4 | import ( 5 | "bufio" 6 | "bytes" 7 | "crypto/tls" 8 | "encoding/pem" 9 | "io" 10 | "net" 11 | "net/http" 12 | "strings" 13 | "sync" 14 | "time" 15 | 16 | "github.com/AdguardTeam/golibs/log" 17 | "github.com/AdguardTeam/gomitmproxy/proxyutil" 18 | "github.com/pkg/errors" 19 | ) 20 | 21 | var errClientCertRequested = errors.New("tls: client cert authentication unsupported") 22 | 23 | // defaultTimeout is the default value for reading from local connections. 24 | // By default we have no timeout. 25 | // 26 | // TODO(ameshkov): rework deadlines (see #13 for example). 27 | const defaultTimeout = 0 28 | const dialTimeout = 30 * time.Second 29 | const tlsHandshakeTimeout = 10 * time.Second 30 | 31 | // Proxy is a structure with the proxy server configuration and current state. 32 | type Proxy struct { 33 | // addr is the address the proxy listens to. 34 | addr net.Addr 35 | 36 | // transport is an http.RoundTripper instance that we use for plain HTTP 37 | // requests. 38 | transport http.RoundTripper 39 | 40 | // listener is used to accept incoming connections to this proxy. 41 | listener net.Listener 42 | 43 | // dial is a function for creating net.Conn. Can be useful to override in 44 | // unit-tests. 45 | dial func(string, string) (net.Conn, error) 46 | 47 | // timeout is the remote connection's read/write timeout. 48 | timeout time.Duration 49 | 50 | // closing is the channel that signals that proxy is closing. 51 | closing chan bool 52 | 53 | // connsWg is a wait group that's used to keep track of active connections. 54 | connsWg sync.WaitGroup 55 | 56 | // The proxy will not attempt MITM for these hostnames. A hostname can be 57 | // added to this list in runtime if proxy fails to verify the certificate. 58 | invalidTLSHosts map[string]bool 59 | invalidTLSHostsMu sync.RWMutex 60 | 61 | // Config is the proxy's configuration. 62 | // TODO(ameshkov): make it a field. 63 | Config 64 | } 65 | 66 | // NewProxy creates a new instance of the Proxy. 67 | func NewProxy(config Config) *Proxy { 68 | proxy := &Proxy{ 69 | Config: config, 70 | transport: &http.Transport{ 71 | // This forces http.Transport to not upgrade requests to HTTP/2. 72 | // TODO: Remove when HTTP/2 can be supported. 73 | TLSNextProto: make(map[string]func(string, *tls.Conn) http.RoundTripper), 74 | Proxy: http.ProxyFromEnvironment, 75 | TLSHandshakeTimeout: tlsHandshakeTimeout, 76 | ExpectContinueTimeout: time.Second, 77 | TLSClientConfig: &tls.Config{ 78 | GetClientCertificate: func(info *tls.CertificateRequestInfo) (certificate *tls.Certificate, e error) { 79 | // We purposefully cause an error here so that the 80 | // http.Transport.RoundTrip method failed. In this case 81 | // we'll receive the error and will be able to add the host 82 | // to invalidTLSHosts. 83 | return nil, errClientCertRequested 84 | }, 85 | }, 86 | }, 87 | timeout: defaultTimeout, 88 | invalidTLSHosts: map[string]bool{}, 89 | closing: make(chan bool), 90 | } 91 | proxy.dial = (&net.Dialer{ 92 | Timeout: dialTimeout, 93 | KeepAlive: dialTimeout, 94 | }).Dial 95 | 96 | if len(config.MITMExceptions) > 0 { 97 | for _, hostname := range config.MITMExceptions { 98 | proxy.invalidTLSHosts[hostname] = true 99 | } 100 | } 101 | 102 | return proxy 103 | } 104 | 105 | // Addr returns the address this proxy listens to. 106 | func (p *Proxy) Addr() (addr net.Addr) { 107 | return p.addr 108 | } 109 | 110 | // Closing returns true if the proxy is in the closing state. 111 | func (p *Proxy) Closing() (ok bool) { 112 | select { 113 | case <-p.closing: 114 | return true 115 | default: 116 | return false 117 | } 118 | } 119 | 120 | // Start starts the proxy server in a separate goroutine. 121 | func (p *Proxy) Start() (err error) { 122 | l, err := net.ListenTCP("tcp", p.ListenAddr) 123 | if err != nil { 124 | return err 125 | } 126 | p.addr = l.Addr() 127 | 128 | var listener net.Listener 129 | listener = l 130 | if p.TLSConfig != nil { 131 | listener = tls.NewListener(l, p.TLSConfig) 132 | } 133 | 134 | p.listener = listener 135 | go p.Serve(listener) 136 | return nil 137 | } 138 | 139 | // Serve starts reading and processing requests from the specified listener. 140 | // Please note, that it will close the listener in the end. 141 | func (p *Proxy) Serve(l net.Listener) { 142 | log.Printf("start listening to %s", l.Addr()) 143 | err := p.serve(l) 144 | if err != nil { 145 | log.Printf("finished serving due to: %v", err) 146 | } 147 | _ = l.Close() 148 | } 149 | 150 | // Close sets the proxy to the closing state so it stops receiving new 151 | // connections, finishes processing any inflight requests, and closes existing 152 | // connections without reading anymore requests from them. 153 | // 154 | // TODO(ameshkov): make it return an error. 155 | func (p *Proxy) Close() { 156 | log.Printf("Closing proxy") 157 | 158 | log.OnCloserError(p.listener, log.DEBUG) 159 | 160 | // This will prevent waiting for the proxy.timeout until an incoming 161 | // request has been read. 162 | close(p.closing) 163 | 164 | log.Printf("Waiting for all active connections to close") 165 | p.connsWg.Wait() 166 | log.Printf("All connections closed") 167 | } 168 | 169 | // serve accepts connections from the specified listener and passes them further 170 | // to Proxy.handleConnection. 171 | func (p *Proxy) serve(l net.Listener) (err error) { 172 | for { 173 | if p.Closing() { 174 | return nil 175 | } 176 | 177 | conn, err := l.Accept() 178 | if err != nil { 179 | return err 180 | } 181 | 182 | localRW := bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)) 183 | ctx := newContext(conn, localRW, nil) 184 | log.Debug("id=%s: accepted connection from %s", ctx.ID(), ctx.conn.RemoteAddr()) 185 | 186 | if tcpConn, ok := conn.(*net.TCPConn); ok { 187 | _ = tcpConn.SetKeepAlive(true) 188 | _ = tcpConn.SetKeepAlivePeriod(3 * time.Minute) 189 | } 190 | 191 | go p.handleConnection(ctx) 192 | } 193 | } 194 | 195 | // handleConnection starts processing a new network connection. 196 | func (p *Proxy) handleConnection(ctx *Context) { 197 | // Increment the active connections count. 198 | p.connsWg.Add(1) 199 | 200 | // Clean up on exit. 201 | defer p.connsWg.Done() 202 | defer log.OnCloserError(ctx.conn, log.DEBUG) 203 | 204 | if p.Closing() { 205 | return 206 | } 207 | 208 | p.handleLoop(ctx) 209 | } 210 | 211 | // handleLoop processes requests in a loop. 212 | func (p *Proxy) handleLoop(ctx *Context) { 213 | for { 214 | if p.timeout > 0 { 215 | // TODO(ameshkov): rework deadlines (see #13 for example). 216 | deadline := time.Now().Add(p.timeout) 217 | _ = ctx.SetDeadline(deadline) 218 | } 219 | 220 | if err := p.handleRequest(ctx); err != nil { 221 | log.Debug("id=%s: closing connection due to: %v", ctx.ID(), err) 222 | 223 | return 224 | } 225 | } 226 | } 227 | 228 | // handleRequest reads an incoming request and processes it. 229 | func (p *Proxy) handleRequest(ctx *Context) (err error) { 230 | origReq, err := p.readRequest(ctx) 231 | if err != nil { 232 | return err 233 | } 234 | 235 | defer log.OnCloserError(origReq.Body, log.DEBUG) 236 | 237 | session := newSession(ctx, origReq) 238 | p.prepareRequest(origReq, session) 239 | log.Debug("id=%s: handle request %s %s", session.ID(), origReq.Method, origReq.URL.String()) 240 | 241 | customRes := false 242 | if p.OnRequest != nil { 243 | newReq, newRes := p.OnRequest(session) 244 | if newReq != nil { 245 | log.Debug("id=%s: request was overridden by: %s", session.ID(), newReq.URL.String()) 246 | session.req = newReq 247 | } 248 | if newRes != nil { 249 | log.Debug("id=%s: response was overridden by: %s", session.ID(), newRes.Status) 250 | session.res = newRes 251 | customRes = true 252 | } 253 | } 254 | 255 | if session.req.Host == p.APIHost { 256 | return p.handleAPIRequest(session) 257 | } 258 | 259 | if !customRes { 260 | // check proxy authorization first. 261 | if p.Username != "" { 262 | auth, res := p.authorize(session) 263 | if !auth { 264 | log.Debug("id=%s: proxy auth required", session.ID()) 265 | session.res = res 266 | 267 | defer log.OnCloserError(res.Body, log.DEBUG) 268 | 269 | _ = p.writeResponse(session) 270 | 271 | // Do not return any error here as we must keep the connection 272 | // alive. When the client receives 407 error, it can write 273 | // another request with user credentials to the same connection. 274 | // See https://github.com/AdguardTeam/gomitmproxy/pull/19. 275 | return nil 276 | } 277 | } 278 | 279 | if session.req.Header.Get("Upgrade") == "websocket" { 280 | // connection protocol will be upgraded. 281 | return p.handleTunnel(session) 282 | } 283 | 284 | // connection, proxy-connection, etc, etc. 285 | removeHopByHopHeaders(session.req.Header) 286 | 287 | if session.req.Method == http.MethodConnect { 288 | return p.handleConnect(session) 289 | } 290 | 291 | // not a CONNECT request, processing a plain HTTP request. 292 | res, err := p.transport.RoundTrip(session.req) 293 | if err != nil { 294 | log.Error("id=%s: failed to round trip: %v", session.ID(), err) 295 | p.raiseOnError(session, err) 296 | 297 | res = proxyutil.NewErrorResponse(session.req, err) 298 | 299 | if strings.Contains(err.Error(), "x509: ") || 300 | strings.Contains(err.Error(), errClientCertRequested.Error()) { 301 | log.Printf("id=%s: adding %s to invalid TLS hosts due to: %v", session.ID(), session.req.Host, err) 302 | p.invalidTLSHostsMu.Lock() 303 | p.invalidTLSHosts[session.req.Host] = true 304 | p.invalidTLSHostsMu.Unlock() 305 | } 306 | } 307 | 308 | log.Debug("id=%s: received response %s", session.ID(), res.Status) 309 | removeHopByHopHeaders(res.Header) 310 | session.res = res 311 | } 312 | 313 | // Make sure the response body is always closed. 314 | defer log.OnCloserError(session.res.Body, log.DEBUG) 315 | 316 | err = p.writeResponse(session) 317 | if err != nil { 318 | return err 319 | } 320 | 321 | // TODO(ameshkov): Think about refactoring this, looks not good 322 | if p.isClosing(session) { 323 | return errClose 324 | } 325 | 326 | if p.Closing() { 327 | log.Debug("id=%s: proxy is shutting down, closing response", session.ID()) 328 | return errShutdown 329 | } 330 | 331 | return nil 332 | } 333 | 334 | // handleAPIRequest handles a request to gomitmproxy's API. 335 | func (p *Proxy) handleAPIRequest(session *Session) (err error) { 336 | if session.req.URL.Path == "/cert.crt" && p.MITMConfig != nil { 337 | // serve ca 338 | b := pem.EncodeToMemory(&pem.Block{ 339 | Type: "CERTIFICATE", 340 | Bytes: p.MITMConfig.GetCA().Raw, 341 | }) 342 | 343 | session.res = proxyutil.NewResponse(http.StatusOK, bytes.NewReader(b), session.req) 344 | defer log.OnCloserError(session.res.Body, log.DEBUG) 345 | 346 | session.res.Close = true 347 | session.res.Header.Set("Content-Type", "application/x-x509-ca-cert") 348 | session.res.ContentLength = int64(len(b)) 349 | 350 | return p.writeResponse(session) 351 | } 352 | 353 | session.res = proxyutil.NewErrorResponse(session.req, errors.Errorf("wrong API method")) 354 | defer log.OnCloserError(session.res.Body, log.DEBUG) 355 | 356 | session.res.Close = true 357 | 358 | return p.writeResponse(session) 359 | } 360 | 361 | // isClosing returns true if this session's response or request signals that 362 | // the connection must be closed. 363 | func (p *Proxy) isClosing(session *Session) (ok bool) { 364 | // See http.Response.Write implementation for the details on this. 365 | // 366 | // If we're sending a non-chunked HTTP/1.1 response without a 367 | // content-length, the only way to do that is the old HTTP/1.0 way, by 368 | // noting the EOF with a connection close, so we need to set Close. 369 | if (session.res.ContentLength == 0 || session.res.ContentLength == -1) && 370 | !session.res.Close && 371 | session.res.ProtoAtLeast(1, 1) && 372 | !session.res.Uncompressed && 373 | (len(session.res.TransferEncoding) == 0 || session.res.TransferEncoding[0] != "chunked") { 374 | log.Debug("id=%s: received close request (http/1.0 way)", session.ID()) 375 | 376 | return true 377 | } 378 | 379 | if session.req.Close || session.res.Close { 380 | log.Debug("id=%s: received close request", session.ID()) 381 | 382 | return true 383 | } 384 | 385 | return false 386 | } 387 | 388 | // handleTunnel tunnels data to the remote connection. 389 | func (p *Proxy) handleTunnel(session *Session) (err error) { 390 | log.Debug("id=%s: handling connection to host: %s", session.ID(), session.req.URL.Host) 391 | 392 | conn, err := p.connect(session, "tcp", session.RemoteAddr()) 393 | if err != nil { 394 | log.Error("id=%s: failed to connect to %s: %v", session.ID(), session.req.URL.Host, err) 395 | p.raiseOnError(session, err) 396 | session.res = proxyutil.NewErrorResponse(session.req, err) 397 | _ = p.writeResponse(session) 398 | log.OnCloserError(session.res.Body, log.DEBUG) 399 | 400 | return err 401 | } 402 | 403 | remoteConn := conn 404 | defer log.OnCloserError(remoteConn, log.DEBUG) 405 | 406 | // If we're inside a MITMed connection, we should open a TLS connection 407 | // instead. 408 | if session.ctx.IsMITM() { 409 | getClientCert := func( 410 | info *tls.CertificateRequestInfo, 411 | ) (certificate *tls.Certificate, e error) { 412 | // We purposefully cause an error here so that the 413 | // http.Transport.RoundTrip method failed. In this case we'll 414 | // receive the error and will be able to add the host to 415 | // invalidTLSHosts. 416 | return nil, errClientCertRequested 417 | } 418 | 419 | tlsConn := tls.Client(conn, &tls.Config{ 420 | ServerName: session.req.URL.Host, 421 | GetClientCertificate: getClientCert, 422 | }) 423 | 424 | // Handshake with the remote server. 425 | if err = tlsConn.Handshake(); err != nil { 426 | // TODO(ameshkov): Consider adding to invalidTLSHosts. 427 | // We should do this if this happens a couple of times in a short 428 | // period of time. 429 | log.Error("id=%s: failed to handshake with the server: %v", session.ID(), err) 430 | 431 | return err 432 | } 433 | 434 | // Prepare to process the data. 435 | remoteConn = tlsConn 436 | } 437 | 438 | // Write the original request to the connection. 439 | err = session.req.Write(remoteConn) 440 | if err != nil { 441 | log.Error("id=%s: failed to write request: %v", session.ID(), err) 442 | 443 | return err 444 | } 445 | 446 | // Note that we don't use buffered reader/writer for local connection as it 447 | // causes a noticeable delay when we work as an HTTP over TLS proxy. 448 | donec := make(chan bool, 2) 449 | go copyConnectTunnel(session, remoteConn, session.ctx.conn, donec) 450 | go copyConnectTunnel(session, session.ctx.conn, remoteConn, donec) 451 | 452 | log.Debug("id=%s: established tunnel, proxying traffic", session.ID()) 453 | <-donec 454 | <-donec 455 | log.Debug("id=%s: closed tunnel", session.ID()) 456 | 457 | return errClose 458 | } 459 | 460 | // handleConnect processes HTTP CONNECT requests. 461 | func (p *Proxy) handleConnect(session *Session) (err error) { 462 | log.Debug("id=%s: connecting to host: %s", session.ID(), session.req.URL.Host) 463 | 464 | // TODO(ameshkov): find a way to use remoteConn when the request is MITMed. 465 | remoteConn, err := p.connect(session, "tcp", session.RemoteAddr()) 466 | if remoteConn != nil { 467 | defer log.OnCloserError(remoteConn, log.DEBUG) 468 | } 469 | 470 | if err != nil { 471 | log.Error("id=%s: failed to connect to %s: %v", session.ID(), session.req.URL.Host, err) 472 | p.raiseOnError(session, err) 473 | 474 | session.res = proxyutil.NewErrorResponse(session.req, err) 475 | _ = p.writeResponse(session) 476 | defer log.OnCloserError(session.res.Body, log.DEBUG) 477 | 478 | return err 479 | } 480 | 481 | if p.canMITM(session.req.URL.Host) { 482 | log.Debug("id=%s: attempting MITM for connection", session.ID()) 483 | session.res = proxyutil.NewResponse(http.StatusOK, nil, session.req) 484 | err = p.writeResponse(session) 485 | 486 | log.OnCloserError(session.res.Body, log.DEBUG) 487 | 488 | if err != nil { 489 | return err 490 | } 491 | 492 | b := make([]byte, 1) 493 | if _, err = session.ctx.localRW.Read(b); err != nil { 494 | log.Error("id=%s: error peeking message through CONNECT tunnel to determine type: %v", session.ID(), err) 495 | return err 496 | } 497 | 498 | // Drain all of the rest of the buffered data. 499 | buf := make([]byte, session.ctx.localRW.Reader.Buffered()) 500 | _, _ = session.ctx.localRW.Read(buf) 501 | 502 | // Prepend the previously read data to be read again by 503 | // http.ReadRequest. 504 | pc := &peekedConn{ 505 | session.ctx.conn, 506 | io.MultiReader(bytes.NewReader(b), bytes.NewReader(buf), session.ctx.conn), 507 | } 508 | 509 | // 22 is the TLS handshake. 510 | // https://tools.ietf.org/html/rfc5246#section-6.2.1 511 | if b[0] == 22 { 512 | tlsConn := tls.Server(pc, p.MITMConfig.NewTLSConfigForHost(session.req.URL.Host)) 513 | 514 | // Handshake with the local client. 515 | if err = tlsConn.Handshake(); err != nil { 516 | // TODO(ameshkov): Consider adding to invalidTLSHosts. 517 | // We should do this if this happens a couple of times in a 518 | // short period of time. 519 | log.Error("id=%s: failed to handshake with the client: %v", session.ID(), err) 520 | 521 | return err 522 | } 523 | 524 | newLocalRW := bufio.NewReadWriter(bufio.NewReader(tlsConn), bufio.NewWriter(tlsConn)) 525 | newCtx := newContext(tlsConn, newLocalRW, session) 526 | p.handleLoop(newCtx) 527 | 528 | return errClose 529 | } 530 | 531 | newLocalRW := bufio.NewReadWriter(bufio.NewReader(pc), bufio.NewWriter(pc)) 532 | newCtx := newContext(pc, newLocalRW, session) 533 | p.handleLoop(newCtx) 534 | 535 | return errClose 536 | } 537 | 538 | session.res = proxyutil.NewResponse(http.StatusOK, nil, session.req) 539 | defer log.OnCloserError(session.res.Body, log.DEBUG) 540 | 541 | session.res.ContentLength = -1 542 | err = p.writeResponse(session) 543 | if err != nil { 544 | return err 545 | } 546 | 547 | // Note that we don't use buffered reader/writer for local connection 548 | // as it causes a noticeable delay when we work as an HTTP over TLS proxy 549 | donec := make(chan bool, 2) 550 | go copyConnectTunnel(session, remoteConn, session.ctx.conn, donec) 551 | go copyConnectTunnel(session, session.ctx.conn, remoteConn, donec) 552 | 553 | log.Debug("id=%s: established CONNECT tunnel, proxying traffic", session.ID()) 554 | <-donec 555 | <-donec 556 | log.Debug("id=%s: closed CONNECT tunnel", session.ID()) 557 | 558 | return errClose 559 | } 560 | 561 | // copyConnectTunnel copies data from reader to writer and then signals about 562 | // finishing to the "donec" channel. 563 | func copyConnectTunnel(session *Session, w io.Writer, r io.Reader, donec chan<- bool) { 564 | if _, err := io.Copy(w, r); err != nil && !isCloseable(err) { 565 | log.Error("id=%s: failed to tunnel: %v", session.ID(), err) 566 | } 567 | 568 | log.Debug("id=%s: tunnel finished copying", session.ID()) 569 | donec <- true 570 | } 571 | 572 | // readRequest reads incoming http request. 573 | func (p *Proxy) readRequest(ctx *Context) (req *http.Request, err error) { 574 | log.Debug("id=%s: waiting for request", ctx.ID()) 575 | 576 | reqc := make(chan *http.Request, 1) 577 | errc := make(chan error, 1) 578 | 579 | // Try reading the HTTP request in a separate goroutine. The idea is to make 580 | // this process cancelable. When reading the request is finished, it will 581 | // write the results to one of the channels, either reqc or errc. At the 582 | // same time we'll be reading from the "closing" channel. When the proxy is 583 | // shutting down, the "closing" channel is closed so we'll immediately 584 | // return. 585 | go func() { 586 | r, readErr := http.ReadRequest(ctx.localRW.Reader) 587 | if readErr != nil { 588 | if isCloseable(readErr) { 589 | log.Debug("id=%s: connection closed prematurely: %v", ctx.ID(), readErr) 590 | } else { 591 | log.Debug("id=%s: failed to read request: %v", ctx.ID(), readErr) 592 | } 593 | 594 | errc <- readErr 595 | return 596 | } 597 | reqc <- r 598 | }() 599 | 600 | // Waiting for the result or for proxy to shutdown 601 | select { 602 | case err = <-errc: 603 | return nil, err 604 | case req = <-reqc: 605 | case <-p.closing: 606 | return nil, errShutdown 607 | } 608 | 609 | return req, nil 610 | } 611 | 612 | // writeResponse writes the response from session.res to the local client. 613 | func (p *Proxy) writeResponse(session *Session) (err error) { 614 | if p.OnResponse != nil { 615 | res := p.OnResponse(session) 616 | if res != nil { 617 | origBody := res.Body 618 | defer log.OnCloserError(origBody, log.DEBUG) 619 | log.Debug("id=%s: response was overridden by: %s", session.ID(), res.Status) 620 | session.res = res 621 | } 622 | } 623 | 624 | if err = session.res.Write(session.ctx.localRW); err != nil { 625 | log.Error( 626 | "id=%s: got error while writing response back to client: %v", 627 | session.ID(), 628 | err, 629 | ) 630 | } 631 | 632 | if err = session.ctx.localRW.Flush(); err != nil { 633 | log.Error( 634 | "id=%s: got error while flushing response back to client: %v", 635 | session.ID(), 636 | err, 637 | ) 638 | } 639 | 640 | return err 641 | } 642 | 643 | // connect opens a network connection to the specified remote address. 644 | // 645 | // This method can be called in two cases: 646 | // 1. When the proxy handles the HTTP CONNECT. 647 | // IMPORTANT: In this case we don't actually use the remote connections. 648 | // It is only used to check if the remote endpoint is available 649 | // 2. When the proxy bypasses data from the client to the remote endpoint. 650 | // For instance, it could happen when there's a WebSocket connection. 651 | func (p *Proxy) connect(session *Session, proto string, addr string) (conn net.Conn, err error) { 652 | log.Debug("id=%s: connecting to %s://%s", session.ID(), proto, addr) 653 | 654 | if p.OnConnect != nil { 655 | conn = p.OnConnect(session, proto, addr) 656 | if conn != nil { 657 | log.Debug("id=%s: connection was overridden", session.ID()) 658 | 659 | return conn, nil 660 | } 661 | } 662 | 663 | host, _, err := net.SplitHostPort(addr) 664 | if err == nil && host == p.APIHost { 665 | log.Debug("id=%s: connecting to the API host, return dummy connection", session.ID()) 666 | 667 | return &proxyutil.NoopConn{}, nil 668 | } 669 | 670 | return p.dial(proto, addr) 671 | } 672 | 673 | // prepareRequest prepares an HTTP request to be sent to the remote server. 674 | func (p *Proxy) prepareRequest(req *http.Request, session *Session) { 675 | if req.URL.Host == "" { 676 | req.URL.Host = req.Host 677 | } 678 | // http by default. 679 | req.URL.Scheme = "http" 680 | 681 | // Check if this is an HTTPS connection inside an HTTP CONNECT tunnel. 682 | if session.ctx.IsMITM() { 683 | tlsConn := session.ctx.conn.(*tls.Conn) 684 | cs := tlsConn.ConnectionState() 685 | req.TLS = &cs 686 | 687 | // Force HTTPS for secure sessions. 688 | req.URL.Scheme = "https" 689 | } 690 | req.RemoteAddr = session.ctx.conn.RemoteAddr().String() 691 | 692 | // Remove unsupported encodings. 693 | if req.Header.Get("Accept-Encoding") != "" { 694 | req.Header.Set("Accept-Encoding", "gzip") 695 | } 696 | } 697 | 698 | // raiseOnError calls Proxy.OnError callback if needed. 699 | func (p *Proxy) raiseOnError(session *Session, err error) { 700 | if p.OnError != nil { 701 | p.OnError(session, err) 702 | } 703 | } 704 | 705 | // canMITM checks if we can perform MITM for this host. 706 | func (p *Proxy) canMITM(hostname string) (ok bool) { 707 | if p.MITMConfig == nil { 708 | return false 709 | } 710 | 711 | // Remove the port if it exists. 712 | host, port, err := net.SplitHostPort(hostname) 713 | if err == nil { 714 | hostname = host 715 | } 716 | 717 | // TODO(ameshkov): change this, should be exposed via a callback. 718 | if port != "443" { 719 | log.Debug("do not attempt to MITM connections to a port different from 443") 720 | 721 | return false 722 | } 723 | 724 | p.invalidTLSHostsMu.RLock() 725 | _, found := p.invalidTLSHosts[hostname] 726 | p.invalidTLSHostsMu.RUnlock() 727 | 728 | return !found 729 | } 730 | -------------------------------------------------------------------------------- /proxyutil/util.go: -------------------------------------------------------------------------------- 1 | // Package proxyutil contains different utility methods that will be helpful to 2 | // gomitmproxy users. 3 | package proxyutil 4 | 5 | import ( 6 | "bytes" 7 | "compress/gzip" 8 | "fmt" 9 | "io" 10 | "net" 11 | "net/http" 12 | "time" 13 | 14 | "github.com/AdguardTeam/golibs/log" 15 | "golang.org/x/text/encoding/charmap" 16 | "golang.org/x/text/transform" 17 | ) 18 | 19 | // NewResponse builds a new HTTP response. If body is nil, an empty byte.Buffer 20 | // will be provided to be consistent with the guarantees provided by 21 | // http.Transport and http.Client. 22 | func NewResponse(code int, body io.Reader, req *http.Request) (resp *http.Response) { 23 | if body == nil { 24 | body = &bytes.Buffer{} 25 | } 26 | 27 | rc, ok := body.(io.ReadCloser) 28 | if !ok { 29 | rc = io.NopCloser(body) 30 | } 31 | 32 | res := &http.Response{ 33 | StatusCode: code, 34 | Status: fmt.Sprintf("%d %s", code, http.StatusText(code)), 35 | Proto: "HTTP/1.1", 36 | ProtoMajor: 1, 37 | ProtoMinor: 1, 38 | Header: http.Header{}, 39 | Body: rc, 40 | Request: req, 41 | } 42 | 43 | if req != nil { 44 | res.Close = req.Close 45 | res.Proto = req.Proto 46 | res.ProtoMajor = req.ProtoMajor 47 | res.ProtoMinor = req.ProtoMinor 48 | } 49 | 50 | return res 51 | } 52 | 53 | // NewErrorResponse creates a new HTTP response with status code 54 | // "502 Bad Gateway". "Warning" header is populated with the error details. 55 | // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Warning. 56 | func NewErrorResponse(req *http.Request, err error) (resp *http.Response) { 57 | resp = NewResponse(http.StatusBadGateway, nil, req) 58 | resp.Close = true 59 | 60 | date := resp.Header.Get("Date") 61 | if date == "" { 62 | date = time.Now().Format(http.TimeFormat) 63 | } 64 | 65 | w := fmt.Sprintf(`199 "gomitmproxy" %q %q`, err.Error(), date) 66 | resp.Header.Add("Warning", w) 67 | return resp 68 | } 69 | 70 | // ReadDecompressedBody reads full response body and decompresses it if 71 | // necessary. 72 | func ReadDecompressedBody(res *http.Response) (b []byte, err error) { 73 | rBody := res.Body 74 | if res.Header.Get("Content-Encoding") == "gzip" { 75 | var gzReader io.ReadCloser 76 | gzReader, err = gzip.NewReader(rBody) 77 | if err != nil { 78 | return nil, err 79 | } 80 | 81 | rBody = gzReader 82 | 83 | defer log.OnCloserError(gzReader, log.DEBUG) 84 | } 85 | 86 | return io.ReadAll(rBody) 87 | } 88 | 89 | // DecodeLatin1 decodes Latin1 string from the reader. This method is useful 90 | // for editing response bodies when you don't want to handle different 91 | // encodings. 92 | func DecodeLatin1(reader io.Reader) (str string, err error) { 93 | r := transform.NewReader(reader, charmap.ISO8859_1.NewDecoder()) 94 | b, err := io.ReadAll(r) 95 | if err != nil { 96 | return "", err 97 | } 98 | 99 | return string(b), nil 100 | } 101 | 102 | // EncodeLatin1 encodes the string as a byte array using Latin1. 103 | func EncodeLatin1(str string) ([]byte, error) { 104 | return charmap.ISO8859_1.NewEncoder().Bytes([]byte(str)) 105 | } 106 | 107 | // NoopConn is a struct that implements net.Conn and does nothing. 108 | type NoopConn struct{} 109 | 110 | // LocalAddr always returns 0.0.0.0:0. 111 | func (NoopConn) LocalAddr() net.Addr { return &net.TCPAddr{} } 112 | 113 | // RemoteAddr always returns 0.0.0.0:0. 114 | func (NoopConn) RemoteAddr() net.Addr { return &net.TCPAddr{} } 115 | 116 | // SetDeadline does nothing, returns nil. 117 | func (NoopConn) SetDeadline(time.Time) error { return nil } 118 | 119 | // SetReadDeadline does nothing, returns nil. 120 | func (NoopConn) SetReadDeadline(time.Time) error { return nil } 121 | 122 | // SetWriteDeadline does nothing, returns nil. 123 | func (NoopConn) SetWriteDeadline(time.Time) error { return nil } 124 | 125 | // Read does nothing, returns io.EOF. 126 | func (NoopConn) Read([]byte) (int, error) { return 0, io.EOF } 127 | 128 | // Write does nothing, returns len(b). 129 | func (NoopConn) Write(b []byte) (int, error) { return len(b), nil } 130 | 131 | // Close does nothing, returns nil. 132 | func (NoopConn) Close() error { return nil } 133 | --------------------------------------------------------------------------------