├── requirements.txt ├── .gitignore ├── seguranca.py ├── README.md └── LICENSE /requirements.txt: -------------------------------------------------------------------------------- 1 | argon2-cffi==16.1.0 2 | cffi==1.7.0 3 | cryptography==3.3.2 4 | google-api-python-client==1.5.1 5 | httplib2==0.19.0 6 | idna==2.1 7 | oauth2client==3.0.0 8 | otpauth==1.0.1 9 | pyasn1==0.1.9 10 | pyasn1-modules==0.0.8 11 | pycparser==2.14 12 | pycrypto==2.6.1 13 | PyDrive3==1.0.0 14 | PyNaCl==1.0.1 15 | pyOpenSSL==17.5.0 16 | PyYAML==5.4 17 | rsa==4.7 18 | simplejson==3.8.2 19 | six==1.10.0 20 | uritemplate==0.6 21 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # Byte-compiled / optimized / DLL files 2 | __pycache__/ 3 | *.py[cod] 4 | *$py.class 5 | 6 | # C extensions 7 | *.so 8 | 9 | # Distribution / packaging 10 | .Python 11 | env/ 12 | build/ 13 | develop-eggs/ 14 | dist/ 15 | downloads/ 16 | eggs/ 17 | .eggs/ 18 | lib/ 19 | lib64/ 20 | parts/ 21 | sdist/ 22 | var/ 23 | *.egg-info/ 24 | .installed.cfg 25 | *.egg 26 | 27 | # PyInstaller 28 | # Usually these files are written by a python script from a template 29 | # before PyInstaller builds the exe, so as to inject date/other infos into it. 30 | *.manifest 31 | *.spec 32 | 33 | # Installer logs 34 | pip-log.txt 35 | pip-delete-this-directory.txt 36 | 37 | # Unit test / coverage reports 38 | htmlcov/ 39 | .tox/ 40 | .coverage 41 | .coverage.* 42 | .cache 43 | nosetests.xml 44 | coverage.xml 45 | *,cover 46 | .hypothesis/ 47 | 48 | # Translations 49 | *.mo 50 | *.pot 51 | 52 | # Django stuff: 53 | *.log 54 | local_settings.py 55 | 56 | # Flask stuff: 57 | instance/ 58 | .webassets-cache 59 | 60 | # Scrapy stuff: 61 | .scrapy 62 | 63 | # Sphinx documentation 64 | docs/_build/ 65 | 66 | # PyBuilder 67 | target/ 68 | 69 | # IPython Notebook 70 | .ipynb_checkpoints 71 | 72 | # pyenv 73 | .python-version 74 | 75 | # celery beat schedule file 76 | celerybeat-schedule 77 | 78 | # dotenv 79 | .env 80 | 81 | # virtualenv 82 | venv/ 83 | ENV/ 84 | 85 | # Spyder project settings 86 | .spyderproject 87 | 88 | # Rope project settings 89 | .ropeproject 90 | -------------------------------------------------------------------------------- /seguranca.py: -------------------------------------------------------------------------------- 1 | # Cuidado ao importar módulos! Tente usar apenas a biblioteca 2 | # padrão da linguagem e módulos bem conhecidos, obtidos de 3 | # fontes confiáveis. 4 | from hashlib import pbkdf2_hmac 5 | from base64 import b64encode, b64decode 6 | 7 | import nacl.utils 8 | from Crypto import Random 9 | from Crypto.Cipher import AES 10 | from Crypto.Hash import HMAC, SHA256 11 | from nacl.secret import SecretBox 12 | from argon2 import PasswordHasher 13 | from otpauth import OtpAuth 14 | from logging import basicConfig, warning 15 | from OpenSSL.crypto import load_pkcs12, dump_certificate, FILETYPE_TEXT 16 | from pydrive.auth import GoogleAuth 17 | from pydrive.drive import GoogleDrive 18 | 19 | 20 | class Criptografia(object): 21 | def __init__(self): 22 | """ 23 | PYCRYPTO 24 | O PyCrypto provê um ótimo conjunto de funções criptográficas. Para dar 25 | mais liberdade ao programador, essa biblioteca não entrega soluções 26 | prontas, o que exige do seu utilizador bons conhecimentos em 27 | criptografia e codificação segura. 28 | 29 | As funções pycrypto_enc e pycrypto_dec, por exemplo, utilizam o AES 30 | para [de]cifrar mensagens, mas exigem funções adicionais, para garantir 31 | que o tamanho total da mensagem seja múltiplo do tamanho de bloco 32 | usado --pad e unpad. 33 | 34 | Essas funções são aqui implementadas seguindo o padrão PKCS7, o que 35 | significa que são vulneráveis ao padding oracle attack. 36 | 37 | PYNACL 38 | Exemplos mais seguros ainda do uso de criptografia são mostrados nas 39 | funções pynacl_enc e pynacl_dec, que usam a biblioteca NaCl para 40 | [de]criptografar mensagens. É importante perceber como é mais fácil 41 | usar essa biblioteca que a anterior, o que ajuda na segurança, mas 42 | diminui a liberdade do programador. Apesar disso, é importante saber 43 | como essa biblioteca funciona, quais algoritmos ela utiliza e como 44 | eles estão implementados, visto que praticamente nada é exposto --o 45 | que é ótimo do ponto de vista de segurança. 46 | 47 | """ 48 | # Adiciona dados no fim da mensagem, para completar o tamanho do bloco. 49 | self.pad = lambda s: s + (AES.block_size - len(s) % AES.block_size) * \ 50 | chr(AES.block_size - len(s) % AES.block_size) 51 | 52 | # Retira os dados adicionados pela função anterior no fim da mensagem. 53 | self.unpad = lambda s: s[:-ord(s[-1:])] 54 | 55 | # Sal usado nas funções do PyNaCl - escolhi uma string e fiz o hash 56 | self.pynacl_sal = pbkdf2_hmac('sha256', b'Aquele S4l _ULTR4_ Sekr3t0!', 57 | b'Aquele S4l _ULTR4_ Sekr3t0!', 100000, SecretBox.KEY_SIZE) 58 | 59 | def pycrypto_enc(self, msg, chave): 60 | """ 61 | Criptografa uma mensagem usando AES no modo CBC com PyCryto. 62 | 63 | ARGS: 64 | - msg (string): mensagem em si. 65 | - chave (string): chave para criptografar a mensagem. 66 | 67 | """ 68 | chave = pbkdf2_hmac('sha256', chave.encode('utf8'), self.pynacl_sal, 69 | 100000, SecretBox.KEY_SIZE) 70 | vi = Random.new().read(AES.block_size) 71 | cifra = AES.new(chave, AES.MODE_CBC, vi) 72 | return b64encode(vi + cifra.encrypt(self.pad(msg))).decode() 73 | 74 | def pycrypto_dec(self, cifrada, chave): 75 | """ 76 | Decriptografa uma mensagem criptografada com o método anterior. 77 | 78 | ARGS: 79 | - cifrada (string): mensagem cifrada. 80 | - chave (string): chave para decriptografar a mensagem cifrada. 81 | 82 | """ 83 | chave = pbkdf2_hmac('sha256', chave.encode('utf8'), self.pynacl_sal, 84 | 100000, SecretBox.KEY_SIZE) 85 | cifrada = b64decode(cifrada) 86 | vi = cifrada[:16] 87 | cifra = AES.new(chave, AES.MODE_CBC, vi) 88 | return self.unpad(cifra.decrypt(cifrada[16:])).decode('utf8') 89 | 90 | def pynacl_enc(self, msg, chave): 91 | """ 92 | Criptografa uma mensagem usando a biblioteca NaCl. 93 | 94 | ARGS: 95 | - msg (string): mensagem em si. 96 | - chave (string): chave para criptografar a mensagem. 97 | 98 | """ 99 | chave = pbkdf2_hmac('sha256', chave.encode('utf8'), self.pynacl_sal, 100 | 100000, SecretBox.KEY_SIZE) 101 | nonce = nacl.utils.random(SecretBox.NONCE_SIZE) 102 | return b64encode(SecretBox(chave).encrypt(msg.encode('utf8'), 103 | nonce)).decode() 104 | 105 | def pynacl_dec(self, cifrada, chave): 106 | """ 107 | Decriptografa uma mensagem usando a NaCl. 108 | 109 | ARGS: 110 | - cifrada (string): mensagem cifrada. 111 | - chave (string): chave para decriptograr a mensagem cifrada. 112 | 113 | """ 114 | chave = pbkdf2_hmac('sha256', chave.encode('utf8'), self.pynacl_sal, 115 | 100000, SecretBox.KEY_SIZE) 116 | cifrada = b64decode(cifrada.encode('utf8')) 117 | return SecretBox(chave).decrypt(cifrada).decode() 118 | 119 | 120 | class Senhas(object): 121 | def protege_senha_hmac_sha256(self, senha, sal, chave): 122 | """ 123 | Protege a senha usando HMAC + SHA-256 + salt, como indicado pelo OWASP 124 | [1]. 125 | 126 | ARGS: 127 | - senha (string): senha digitada pelo usuário. 128 | - sal (string): usada para "temperar" a senha, evitando ataques de 129 | dicionário. 130 | Ex.: 6b3a55e0261b030$143f805a24924dOc1c44524821305f31d927743b8a10f 131 | - chave (string): a chave usada para criptografar o hash. 132 | Ex.: a7998f247bd965694ff227fa325c81&69a07471a8B6808d3e002a486c4e65 133 | 134 | """ 135 | # Crypto.Hash.HMAC exige o uso de bytes em vez de 136 | # strings --uma especificidade do Python 3. 137 | senha = senha.encode() 138 | chave = chave.encode() 139 | return sal + HMAC.new(sal.encode() + chave, senha, SHA256).hexdigest() 140 | 141 | def protege_senha_pbkdf2(self, senha, sal, iter): 142 | """ 143 | Protege a senha usando o PBKDF2. 144 | 145 | ARGS: 146 | - senha (string): senha digitada pelo usuário. 147 | - sal (string): usada para "temperar a senha". 148 | - iter (integer): quantidade de iterações --o manual 149 | (hashlib.pbkdf2()), de 2013, recomenda, no mínimo, 100000. 150 | 151 | NOTA 152 | Em ambientes de produção, o parâmetro de iterações do PBKDF2 pode ser 153 | alterado, para garantir mais segurança --o manual da biblioteca usada 154 | aqui sugere valores maiores que 100000 (cem mil). 155 | 156 | """ 157 | return b64encode(pbkdf2_hmac('sha256', senha.encode('utf8'), 158 | sal.encode('utf8'), iter)).decode('utf8') 159 | 160 | def protege_senha_argon2(self, senha): 161 | """ 162 | O Argon2 foi vencedor da edição 2015 da 'Password Hashing Competition' 163 | e é indicado por muitos especialistas 164 | como a melhor solução para hash de senhas. 165 | 166 | ARGS: 167 | - senha (string): senha digitada pelo usuário. 168 | 169 | NOTAS 170 | 1. O resultado de um hash Argon2 informa os parâmetros usados para 171 | obter aquele hash, além do próprio hash. 172 | 2. Em ambientes de produção, esses parâmetros podem ser melhor 173 | configurados, como o tempo e a memória utilizados. 174 | 175 | """ 176 | return PasswordHasher().hash(senha) 177 | 178 | 179 | class Autenticacao(object): 180 | def segundo_fator(self, metodo, chave): 181 | """ 182 | Calcula e retorna one-time passwords para uso como segundo fator de 183 | autenticação baseados em tempo ou hashes criptografados. 184 | 185 | ARGS: 186 | - metodo (string): pode ser 'time' ou 'hmac'. 187 | - chave (string): a chave privada usada para gerar os códigos. 188 | 189 | """ 190 | au = OtpAuth(chave) 191 | 192 | if metodo == 'time': 193 | return au.totp() 194 | elif metodo == 'hmac': 195 | return au.hotp() 196 | else: 197 | raise ValueError('método não identificado') 198 | 199 | 200 | class Validacao(object): 201 | def codifica_b64(self, entrada): 202 | """ 203 | Codifica a entrada do usuário em Base 64, para armazenagem segura. 204 | Retorna uma string com a representação hexadecimal da entrada. 205 | 206 | ARGS: 207 | - entrada (string): a string informada pelo usuário. 208 | 209 | """ 210 | return b64encode(entrada.encode()).decode() 211 | 212 | def decodifica_b64(self, codificados): 213 | """ 214 | Decodifica um dado que foi armazenado de forma codificada. Retorna 215 | uma string com os dados decodificados. 216 | 217 | PARÂMETROS 218 | - codificados (string): string na sua representação Base 64. 219 | 220 | """ 221 | return b64decode(codificados.encode()).decode() 222 | 223 | 224 | class Transferencias(object): 225 | pass 226 | 227 | 228 | class Logs(object): 229 | def __init__(self): 230 | basicConfig(format='%(asctime)s %(levelname)s: %(message)s') 231 | 232 | def log_aviso(self, msg): 233 | """ 234 | Cria um log de aviso. 235 | 236 | ARGS: 237 | - msg (string): a mensagem a ser "logada". 238 | 239 | """ 240 | warning(msg) 241 | 242 | def tamanho_log(self, eventos_dia, tamanho): 243 | """ 244 | Calcula o tamanho médio para armazenagem dos logs de uma aplicação. 245 | 246 | ARGS: 247 | - eventos_dia (integer): média de eventos diários. 248 | - tamanho (integer): tamanho médio (bytes) do log de cada evento --1 249 | (um) caractere == 1 byte. 250 | 251 | """ 252 | # 30 dias no mês + 10% do tamanho especificado; resultado em GB 253 | tamanho_mes = eventos_dia * 30 * (tamanho + (10 * tamanho / 254 | 100)) * 10 ** -9 255 | 256 | return 'Tamanho em 1 mês..: {0:6.2f} GB\n'\ 257 | 'Tamanho em 6 meses: {1:6.2f} GB\n'\ 258 | 'Tamanho em 1 ano..: {2:6.2f} GB\n'\ 259 | 'Tamanho em 1,5 ano: {3:6.2f} GB\n'\ 260 | 'Tamanho em 2 anos.: {4:6.2f} GB\n'\ 261 | 'Tamanho em 5 anos.: {5:6.2f} GB'.format(tamanho_mes, 262 | tamanho_mes*6, tamanho_mes*12, tamanho_mes*18, tamanho_mes*24, 263 | tamanho_mes*60) 264 | 265 | 266 | class CertificadosDigitais(object): 267 | def le_cert_p12(self, caminho, senha): 268 | p12 = load_pkcs12(open(caminho, 'rb').read(), senha) 269 | return dump_certificate(FILETYPE_TEXT, p12.get_certificate()).decode() 270 | 271 | 272 | class SegregacaoFuncoes(object): 273 | pass 274 | 275 | 276 | class Nuvem(object): 277 | def upload_para_gdrive(self, caminho): 278 | """ 279 | Este método faz o upload de um arquivo para o Google Drive. Para que 280 | funcione, siga os passos a seguir: 281 | 282 | a. Entre no Google Developers Console 283 | , com a sua conta no Google, 284 | crie um novo projeto e habilite o Google Drive. 285 | b. Após configurar o projeto e tê-lo criado, entre em 'Credentials', 286 | selecione o projeto recém criado, e em 'Download JSON'. 287 | c. Renomeie o arquivo baixado para 'client_secrets.json' e coloque-o 288 | no mesmo diretório deste script. 289 | d. Ao ser executado, este script usará os parâmetros definidos no 290 | arquivo JSON para autenticar essa aplicação; em seguida, será 291 | aberto um navegador, para que o usuário acesse sua conta no Google 292 | e dê permissões de acesso a esta aplicação. 293 | 294 | ARGS: 295 | - path (string): caminho do arquivo a ser 'subido' para o Google Drive. 296 | 297 | """ 298 | f = GoogleDrive(GoogleAuth()).CreateFile() 299 | f.SetContentFile(caminho) 300 | f.Upload() 301 | 302 | 303 | class TestesAnalisesVulnerabilidade(object): 304 | pass 305 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # O Tao do Desenvolvimento Seguro 2 | Este guia apresenta práticas de desenvolvimento seguro. Cada tópico possui boas práticas de segurança pertinentes àquele assunto. Além disso, para cada tópico há --ou deveria haver :P-- uma classe implementada no arquivo `seguranca.py`, com exemplos práticos. O mais interessante a se notar é que, normalmente, é muito fácil implementar as boas práticas de segurança no código, o que deve servir como motivador para sua adoção. 3 | 4 | O guia é dividido em vários tópicos, cada um tratando de um assunto específico, que agrega as suas boas práticas. Cada prática utiliza um verbo que indica a ação esperada do programador, como 'use', 'implemente' ou '[nunca] faça'. Dado o grau de abstração deste guia, ele deve se encaixar em vários projetos e linguagens de programação, mas precisa ser adaptado a cada situação, i.e., poderá haver situações onde o programador precisará usar senhas curtas ou usar SMB para transferir arquivos. Entretanto, casos específicos devem ser tratados como aquilo que são --exceções-- e, **principalmente**, [para quebrar regras, deve-se dominá-las primeiro](https://c1.staticflickr.com/9/8550/8711954278_667f63b745_z.jpg). Em todo caso, a não-adoção de uma boa prática deve ser documentada e seguida de medidas de mitigação dos riscos associados. 5 | 6 | ### Dependências 7 | Pacotes no [Ubuntu](http://www.ubuntu.com/) --os dois últimos são requisitos do pyopenssl: `python3`, `libffi-dev`, `python-dev` e `libpq-dev`. 8 | 9 | Além deles, o arquivo `requirements.txt` tem a lista completa de dependências para execução do `seguranca.py`. 10 | 11 | 12 | ## Lista de Abreviaturas 13 | ``` 14 | AES Advanced Encryption Standard 15 | API Application Programming Interface 16 | CBC Cipher Block Chaining 17 | CRL Certificate Revocation List --o mesmo que LCR 18 | CTR Counter --modo de criptografia de bloco 19 | DAST Dynamic Application Security Testing 20 | ECB Electronic Codebook 21 | ECC Elliptic Curve Cryptography 22 | ECDSA Elliptic Curve Digital Signature Algorithm 23 | FTP File Transfer Protocol 24 | GMT Greenwich Mean Time 25 | HTTP Hypertext Transfer Protocol 26 | HTTPS Hypertext Transfer Protocol Secure 27 | IAST Interactive Application Security Testing 28 | LCR Lista de Certificados Revogados 29 | LDAP Lightweight Directory Access Protocol 30 | LDAPS Lightweight Directory Access Protocol Secure 31 | MD Message Digest 32 | ORM Object-relational Mapping 33 | PBKDF2 Password-Based Key Derivation Function 2 34 | RASP Runtime Application Self-protection 35 | RFC Request for Comments 36 | RSA Rivest, Shamir, Adleman 37 | SAST Static Application Security Testing 38 | SHA Secure Hash 39 | SIEM Security Information and Event Management 40 | SMB Server Message Block 41 | SNMP Simple Network Management Protocol 42 | SQL Structured Query Language 43 | SSH Secure Shell 44 | SSL Secure Sockets Layer 45 | TLS Transport Layer Security 46 | ``` 47 | 48 | 49 | ## 0. Criptografia 50 | 0. **NUNCA** crie seu sistema criptográfico: use aqueles já existentes. 51 | 1. Entenda o que são as criptografias [simétrica](https://en.wikipedia.org/wiki/Symmetric-key_algorithm) e [assimétrica](https://en.wikipedia.org/wiki/Public-key_cryptography). 52 | 2. Na criptografia simétrica, prefira usar o [AES](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard). 53 | 3. Na criptografia assimétrica, prefira usar o [RSA](https://en.wikipedia.org/wiki/RSA_(cryptosystem)) ou algum algoritmo baseado em [ECC](https://en.wikipedia.org/wiki/Elliptic_curve_cryptography), como [ECDSA](https://wiki.openssl.org/index.php/Elliptic_Curve_Cryptography) ou [Ed25519](https://ed25519.cr.yp.to/). 54 | 4. Entenda o que são [*hashes*](https://en.wikipedia.org/wiki/Hash_function) e [*hashes* autenticados](https://en.wikipedia.org/wiki/Hash-based_message_authentication_code). 55 | 5. Prefira usar o algoritmo de *hash* [SHA-2](https://en.wikipedia.org/wiki/SHA-2) --*digest* >= 256 bits-- em vez do [MD5](https://en.wikipedia.org/wiki/MD5#Overview_of_security_issues) ou [SHA-1](https://en.wikipedia.org/wiki/SHA-1#Attacks). 56 | 6. Nas cifras de bloco, prefira os modos [CBC](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_Block_Chaining_.28CBC.29) ou [CTR](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Counter_.28CTR.29) em vez do [ECB](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Electronic_Codebook_.28ECB.29). 57 | 7. Entenda que [criptografia é diferente de codificação](https://danielmiessler.com/study/encoding-encryption-hashing-obfuscation/). 58 | 8. Use implementações de código-aberto1 e amplamente testadas dos algoritmos criptográficos, em vez de fazê-las por conta própria. 59 | 9. Utilize bibliotecas que requeiram o mínimo de intervenção do programador, como a [NaCl](https://nacl.cr.yp.to/), para evitar erros de programação. 60 | 61 | ### 0.1. Exemplos 62 | A classe `Criptografia` implementa exemplos pertinentes a este tópico. Veja como usá-la: 63 | 64 | ```python 65 | >>> from seguranca import Criptografia 66 | >>> c = Criptografia() 67 | >>> c.pycrypto_enc('ataque ao amanhecer', ')s3nh4+mu1t0_S3kreT4&') 68 | 'zTztObz5VNexu8OWc+ZN6qlwPTgbC14MhC2cGpKmL2S5kI+VivbSpjDosXOSktIp' 69 | >>> c.pycrypto_dec('zTztObz5VNexu8OWc+ZN6qlwPTgbC14MhC2cGpKmL2S5kI+VivbSpjDosXOSktIp', ')s3nh4+mu1t0_S3kreT4&') 70 | 'ataque ao amanhecer' 71 | >>> c.pynacl_enc('ataque ao amanhecer', ')s3nh4+mu1t0_S3kreT4&') 72 | 'mjBjla9rVR4314t2YMRP+qYlY1VRn206EjzCdx+kPavgMklsveGoMFDdeq09B0MN4vcy0aH85Fiw0wY=' 73 | >>> c.pynacl_dec('mjBjla9rVR4314t2YMRP+qYlY1VRn206EjzCdx+kPavgMklsveGoMFDdeq09B0MN4vcy0aH85Fiw0wY=', ')s3nh4+mu1t0_S3kreT4&') 74 | 'ataque ao amanhecer' 75 | ``` 76 | 77 | 78 | ## 1. Senhas 79 | 1. Não limite o conjunto de caracteres das senhas. 80 | 2. Permita senhas realmente longas --e.g., 160 caracteres. 81 | 3. Proteja as senhas antes de armazená-las --e.g., usando [*salt*](https://en.wikipedia.org/wiki/Salt_(cryptography)). 82 | 4. Considere usar *hashes* autenticados na proteção da senha. 83 | 5. Trate os *salts* e as credenciais de *hashes* autenticados como chaves privadas. 84 | 6. Crie parâmetros mínimos de senha --e.g., 12 caracteres, com letras minúsculas `[a-z]`, maiúsculas `[A-Z]`, números `[0-9]` e não-alfanuméricos `[!@#$%~^...]`. 85 | 7. Use algoritmos de *hash* cujo tempo de processamento possa ser configurado, pois eles tendem a ser mais seguros para essa finalidade --e.g., [PBKDF2](https://en.wikipedia.org/wiki/PBKDF2) e [Argon2](https://en.wikipedia.org/wiki/Argon2). 86 | 87 | ### 1.1. Exemplos 88 | Exemplos deste tópico são implementados na classe `Senhas`, que pode ser usada da seguinte forma: 89 | 90 | ```python 91 | >>> from seguranca import Senhas 92 | >>> s = Senhas() 93 | >>> s.protege_senha_hmac_sha256('senha super secreta', 'sal super secreto', 'chave do hmac [super secreta]') 94 | 'sal super secretoc4cd44c5487f0085e8a95e12ec627af7417ed43cf7e27d52f9a187cbfbbecc6d' 95 | >>> s.protege_senha_pbkdf2('senha super secreta', 'sal super secreto', 100001) 96 | 'qjFxmVO0TJvCz5WLSFOI/cRAjvOYXp8r2+KA+yXUp1w=' 97 | >>> s.protege_senha_argon2('senha super secreta') 98 | '$argon2i$v=19$m=512,t=2,p=2$RY6X+K5gL3W0c954OdJjpw$OwNj9fvVV31WBW6MxeA4UQ' 99 | ``` 100 | 101 | 102 | ## 2. Autenticação e Autorização 103 | 1. Sempre faça autenticação negativa: variáveis que permitirão a entrada no sistema devem ser inicializadas para negar o acesso --cabe ao usuário provar que ele pode entrar. 104 | 2. Prefira usar sistemas de autenticação existentes em vez de criar um novo --e.g., [LDAP](https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol) e [OAuth](https://oauth.net/). 105 | 3. Mensagens de erro de autenticação devem informar o problema sem expor dados sensíveis, como nomes de usuário e versões de software. 106 | 4. Sempre que possível, implemente o duplo fator de autenticação --RFCs [4226](https://www.ietf.org/rfc/rfc4226.txt) ou [6238](https://www.ietf.org/rfc/rfc6238.txt). 107 | 5. Atenção ao usar certificados digitais para autenticação: um sistema que use essa técnica deveria abrir o certificado, baixar a CRL relacionada, verificar se o certificado em questão está lá, verificar a cadeia de emissão do certificado, determinar se a cadeia é acreditada no sistema, obter o identificador do usuário gravado no certificado, verificar se aquele identificador está permitido a acessar o sistema e, só então, permitir o acesso. 108 | 6. Estude a utilização de um método bem definido de acesso às informações dentro do programa, como [RBAC](https://en.wikipedia.org/wiki/Role-based_access_control), [DAC](https://en.wikipedia.org/wiki/Discretionary_access_control), [MAC](https://en.wikipedia.org/wiki/Mandatory_access_control) ou [ACL](https://en.wikipedia.org/wiki/Access_control_list). 109 | 110 | ### 2.1. Exemplos 111 | Exemplos implementados na classe `Autenticacao`. Uso: 112 | 113 | ```python 114 | >>> from seguranca import Autenticacao 115 | >>> a = Autenticacao() 116 | >>> a.segundo_fator('time', 'O}PIk7*9') 117 | 613083 118 | >>> a.segundo_fator('hmac', 'O}PIk7*9') 119 | 236466 120 | ``` 121 | 122 | 123 | ## 3. Validação 124 | 1. Valide todos os dados de entrada adequadamente, tratando com atenção caracteres especiais, como aspas simples e duplas. 125 | 2. Limite os *ranges* nos campos de entrada de dados do programa --e.g., um campo para CPF não deveria permitir o envio de 1024 caracteres. 126 | 3. Em aplicações web, validações no lado cliente devem ser refeitas no servidor. 127 | 4. Parametrize consultas SQL, use um [ORM](https://en.wikipedia.org/wiki/Object-relational_mapping) ou utilize de [*stored procedures*](https://en.wikipedia.org/wiki/Stored_procedure). 128 | 5. Considere como dados de entrada: cabeçalhos HTTP, parâmetros para métodos [GET/POST](http://www.w3schools.com/tags/ref_httpmethods.asp), [*cookies*](https://en.wikipedia.org/wiki/HTTP_cookie) e arquivos, por exemplo. 129 | 6. Atenção aos *cookies*: evite armazenar dados sensíveis neles, como senhas, e defina datas para expiração das sessões. 130 | 131 | ### 3.1. Exemplos 132 | A classe `Validacao` implementa exemplos desse tópico. Uso: 133 | 134 | ```python 135 | >>> from seguranca import Validacao 136 | >>> v = Validacao() 137 | >>> v.codifica_b64('entrada duvidosa do usuário') 138 | 'ZW50cmFkYSBkdXZpZG9zYSBkbyB1c3XDoXJpbw==' 139 | >>> v.decodifica_b64('ZW50cmFkYSBkdXZpZG9zYSBkbyB1c3XDoXJpbw==') 140 | 'entrada duvidosa do usuário' 141 | ``` 142 | 143 | 144 | ## 4. Transferências 145 | 1. Em aplicações web, use [HTTPS](https://en.wikipedia.org/wiki/HTTPS) em vez do [HTTP](https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol). 146 | 2. Prefira transferir arquivos via [SSH](https://en.wikipedia.org/wiki/Secure_Shell); evite [FTP](https://en.wikipedia.org/wiki/File_Transfer_Protocol) ou [SMB](https://en.wikipedia.org/wiki/Server_Message_Block). 147 | 3. No servidor, [desabilite](http://disablessl3.com/) versões inseguras de protocolos de criptografia --e.g., SSLv2 e SSLv3. 148 | 4. Crie senhas fortes para cada serviço e evite compartilhá-las entre eles. 149 | 5. Considere criptografar todas as conexões que forem feitas pela aplicação --e.g., HTTPS, LDAP over TLS/SSL (LDAPS) e SNMPv3. 150 | 151 | 152 | ## 5. Logs 153 | 1. Defina informações importantes que precisam ser armazenadas para fins de auditoria. 154 | 2. Considere usar bibliotecas específicas para a geração de logs. 155 | 3. Estruture os logs de acordo com algum padrão; evite criar novos --e.g., [syslog-ng](https://en.wikipedia.org/wiki/Syslog-ng) e [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) para datas. 156 | 4. Projete seu sistema de logs considerando que ele eventualmente será exportado para um [SIEM](https://en.wikipedia.org/wiki/Security_information_and_event_management). 157 | 5. **NUNCA** exponha informações sensíveis em logs --e.g., senhas. 158 | 6. Defina os logs de forma que sejam facilmente integráveis com outros sistemas --e.g., gravar o endereço IP/MAC usado pelo usuário para entrar no programa, as ações realizadas pela conta durante a sessão e quando foi feito o *logout*; mais informações poderiam ser obtidas com o cruzamento de dados com outros sistemas de log. 159 | 7. Mantenha o tempo dos servidores atualizados de acordo com um serviço confiável e único dentro do domínio, para manter o padrão nos logs --e.g., [NTP.br](http://ntp.br). 160 | 8. Prefira armazenar datas de logs com o fuso GMT+0, ajustando o fuso apenas na apresentação para o auditor. 161 | 9. Para facilitar futuras pesquisas, defina níveis de log padrões para a aplicação --e.g., *debug*, *info*, *warning*, *error* e *critical*. 162 | 163 | ### 5.1. Exemplos 164 | Exemplos de uso --classe `Logs`: 165 | 166 | ```python 167 | >>> from seguranca import Logs 168 | >>> l = Logs() 169 | >>> u = input('Nome de usuário: ') 170 | Nome de usuário: cemig 171 | >>> l.log_aviso('usuário inválido: {}'.format(u)) 172 | 2016-08-09 11:03:00,586 WARNING: usuário inválido: cemig 173 | >>> print(l.tamanho_log(1000, 60)) 174 | ... 175 | ``` 176 | 177 | 178 | ## 6. Certificados Digitais 179 | 1. Ao usar certificados em software, tenha atenção a quem tem acesso ao servidor onde ele está instalado. 180 | 2. De forma segura, remova do servidor certificados vencidos, revogados ou inutilizados por quaisquer outros motivos. 181 | 3. Mantenha algum tipo de controle de validade de certificados digitais, considerando que leva-se um tempo entre o pedido de renovação e a emissão do novo certificado --dependendo da morosidade do processo de aquisição do certificado, da criticidade e período de validade dele, considere renovar com 6 meses de antecedência. 182 | 4. Evite usar um certificado para mais de uma finalidade. 183 | 5. Certificados *wildcard* devem receber atenção especial: o ideal é que seu 'instalador' seja restrito a poucas pessoas e servidores; o uso ideal dele seria em um proxy reverso, fechando conexões seguras com clientes e esse proxy fechando conexões seguras com os servidores usando outros certificados. 184 | 6. Revogue o certificado a qualquer evidência de comprometimento do mesmo --lembre-se que, em posse dele, qualquer pessoa pode decriptografar informações, forjar serviços 'seguros' ou assinar documentos como o dono do certificado. 185 | 7. Defina políticas para gestão de cada tipo de certificados, como requisição, instalação, uso, renovação, revogação e descarte. 186 | 187 | ### 6.1. Exemplos 188 | A classe `CertificadosDigitais` tem alguns exemplos de uso e pode ser usada como neste exemplo: 189 | 190 | ```python 191 | >>> from seguranca import CertificadosDigitais 192 | >>> c = CertificadosDigitais() 193 | >>> print(c.le_cert_p12('/home/forkd/Downloads/certest.p12')) 194 | ... 195 | ``` 196 | 197 | 198 | ## 7. Segregação de Funções 199 | 1. Crie contas administrativas separadas das de usuários comuns. 200 | 2. Restrinja o acesso de contas administrativas em redes ou endereços IP específicos. 201 | 3. Aumente o nível de segurança para contas administrativas --e.g., senhas realmente longas (> 40 caracteres), duplo fator de autenticação e, possivelmente, com certificado digital (*token* ou *smart card*). 202 | 4. Mantenha o princípio do menor privilégio, i.e., o usuário deve possuir permissões mínimas para realizar seu trabalho e a aplicação deve garantir que isso possa ser configurado. 203 | 5. Crie usuários específicos para executar tarefas da aplicação --e.g., banco de dados e sistema operacional. 204 | 6. Evite no sistema situações onde um usuário executar ações especiais e ele mesmo auditá-las --e.g., usuário executa a compra de um item e ele mesmo aprova a compra. 205 | 206 | 207 | ## 8. Nuvem 208 | 0. Entenda que *nuvem*, no fundo, significa um servidor alocado em algum local remoto. 209 | 1. Ao usar serviços 'na nuvem', procure saber mais sobre o seu provedor: casos de sucesso, clientes, garantias de segurança, backup, recuperação de desastres etc. 210 | 2. Descubra onde, de fato, os dados serão armazenados ou processados; não se esqueça que cada país possui a sua legislação e ela pode afetar o seu serviço. 211 | 3. Leia e entenda os termos de serviço do provedor; atenção especial à cláusulas de confidencialidade das informações que serão armazenadas/processadas e ao que acontecerá com elas em caso de cancelamento do serviço --lembre-se que muitas empresas poderão nunca deletar realmente tais informações e outras poderão usá-las ou vendê-las em parte ou na totalidade. 212 | 4. Preveja um cenário de migração do serviço para outro provedor ou até para servidores internos; procure saber como o provedor a ser contratado trata essa possibilidade. 213 | 5. Avalie os riscos de expor as informações na nuvem; essa avaliação deve levar em consideração a classificação das informações que serão enviadas para o provedor contratado. 214 | 6. Considere fortemente as práticas do item 4, Transferências, ao trafegar dados locais para a nuvem e vice-versa. 215 | 216 | ### 8.1. Exemplos 217 | Exemplos na classe `Nuvem`. Uso: 218 | 219 | ```python 220 | >>> from seguranca import Nuvem 221 | >>> n = Nuvem() 222 | >>> n.upload_para_gdrive('/home/forkd/Downloads/certest.p12') 223 | ... 224 | ``` 225 | 226 | 227 | ## 9. Testes e Análises de Vulnerabilidade 228 | 1. Realize análises de vulnerabilidade periodicamente nas aplicações. 229 | 2. Adicione uma etapa de análise de vulnerabilidades ao processo de desenvolvimento de software. 230 | 3. Publique aplicações apenas após tratar todas as vulnerabilidades listadas nas análises. 231 | 4. Lembre-se que é mais fácil tratar vulnerabilidades em ambientes de homologação do que nos pares de produção. 232 | 5. Separe fisica e logicamente os ambientes de homologação e produção. 233 | 6. Crie ambientes de homologação o mais parecidos possível dos seus pares de produção. 234 | 7. Proteja os ambientes de homologação com o mesmo nível dos de produção; caso eles tenham de ser expostos a partes não confiáveis, considere utilizar rotinas de mascaramento de dados --e.g., trocar números de CPF, embaralhar nomes e alterar endereços de email. 235 | 8. Considere o uso de alguma ferramenta de análise de código, seja [SAST](http://www.gartner.com/it-glossary/static-application-security-testing-sast/), [DAST](http://www.gartner.com/it-glossary/dynamic-application-security-testing-dast/), [IAST](http://blogs.gartner.com/neil_macdonald/2012/01/30/interactive-application-security-testing/) ou [RAST](http://www.gartner.com/it-glossary/runtime-application-self-protection-rasp/). 236 | 237 | 238 | ## 10. Outros 239 | 1. Garanta que o sistema esteja alinhado com a legislação local --e.g., [Marco Civil da Internet](https://www.planalto.gov.br/ccivil_03/_ato2011-2014/2014/lei/l12965.htm) e [SOX](https://en.wikipedia.org/wiki/Sarbanes%E2%80%93Oxley_Act). 240 | 2. Crie um processo formal para implantação de sistemas, que deverá garantir, entre outras coisas, que apenas os arquivos essenciais sejam colocados em produção --e.g., estruturas de controle de versão (e.g., diretórios .git) deveriam ser apagados. 241 | 3. Mantenha uma rotina de atualização do software e suas dependências, como APIs e sistemas operacionais. 242 | 4. Mantenha atualizada a documentação, seja ela qual for, da aplicação, pois em caso de problemas, ela será uma das primeiras fontes de consulta. 243 | 5. Documente todas as mudanças no software, preferencialmente usando um sistema de controle de versões de código. 244 | 6. Mudanças na infraestrutura deveriam ser documentadas, para facilitar o rastreio de problemas --e.g., atualização do servidor e entrada em produção de uma nova versão de determinado serviço. 245 | 246 | 247 | ## Notas 248 | 1. Dos [princípios de Kerckhoff](https://en.wikipedia.org/wiki/Kerckhoffs%27s_principle) (1835-1903): os algoritmos devem ser abertos e as chaves, secretas --por extensão pode-se inferir que as implentações dos algoritmos deveriam ser igualmente abertas e o programador deveria ter conhecimento completo do código utilizado. 249 | 250 | 251 | ## Referências 252 | 1. Open Web Application Security Project (OWASP). Password Storage Cheat Sheet. Disponível em: [https://www.owasp.org/index.php/Password_Storage_Cheat_Sheet](https://www.owasp.org/index.php/Password_Storage_Cheat_Sheet). 253 | 2. National Institute of Standards and Technology (NIST). Recommendation for Block Cipher Modes of Operation. NIST Special Publication 800-38A. 2001. Disponível em: [http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf](http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf). 254 | 3. Open Web Application Security Project (OWASP). OWASP Proactive Controls. Disponível em: [https://www.owasp.org/index.php/OWASP_Proactive_Controls](https://www.owasp.org/index.php/OWASP_Proactive_Controls). 255 | 4. Open Web Application Security Project (OWASP). SQL Injection Prevention Cheat Sheet. Disponível em: [https://www.owasp.org/index.php/SQL_Injection_Prevention_Cheat_Sheet](https://www.owasp.org/index.php/SQL_Injection_Prevention_Cheat_Sheet). 256 | 5. Open Web Application Security Project (OWASP). Session Management Cheat Sheet. Disponível em: [https://www.owasp.org/index.php/Session_Management_Cheat_Sheet](https://www.owasp.org/index.php/Session_Management_Cheat_Sheet). 257 | 6. Open Web Application Project (OWASP). Secure Coding Principles. Disponível em: [https://www.owasp.org/index.php/Secure_Coding_Principles](https://www.owasp.org/index.php/Secure_Coding_Principles). 258 | 7. International Information System Security Certification Consortium (ISC)². The Ten Best Practices for Secure Software Development. 259 | 8. Hynek Schlawack. Storing Passwords in a Highly Parallelized World. [https://hynek.me/articles/storing-passwords](https://hynek.me/articles/storing-passwords) 260 | 9. National Institute of Standards and Technology (NIST). NISTIR 8151: Dramatically Reducing Software Vulnerabilities. Disponível em: [https://doi.org/10.6028/NIST.IR.8151](https://doi.org/10.6028/NIST.IR.8151). 261 | 262 | 263 | ## Sobre 264 | Criado por José Lopes de Oliveira Jr. e licenciado sob a [GNU General Public License v3 ou posterior](https://github.com/forkd/seguranca/blob/master/LICENSE) --leia o arquivo `LICENSE` para mais informações. 265 | 266 | ### Contribuições 267 | * Encontrou algum erro? 268 | * Quer sugerir outra prática ou outro tópico? 269 | * Quer relatar um caso de uso? 270 | * Pintou alguma dúvida? 271 | 272 | Entre em contato: `joselopes (a) cemig.com.br` **ou** submeta um *pull request* **ou** abra uma nova *issue* aqui. 273 | 274 | *Apenas a mudança é permanente.* 275 | 276 | ### Agradecimentos 277 | * [Cemig](http://www.cemig.com.br) 278 | * [Comunidade Python Brasil](http://python.org.br) 279 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. We, the Free Software Foundation, use the 18 | GNU General Public License for most of our software; it applies also to 19 | any other work released this way by its authors. You can apply it to 20 | your programs, too. 21 | 22 | When we speak of free software, we are referring to freedom, not 23 | price. Our General Public Licenses are designed to make sure that you 24 | have the freedom to distribute copies of free software (and charge for 25 | them if you wish), that you receive source code or can get it if you 26 | want it, that you can change the software or use pieces of it in new 27 | free programs, and that you know you can do these things. 28 | 29 | To protect your rights, we need to prevent others from denying you 30 | these rights or asking you to surrender the rights. Therefore, you have 31 | certain responsibilities if you distribute copies of the software, or if 32 | you modify it: responsibilities to respect the freedom of others. 33 | 34 | For example, if you distribute copies of such a program, whether 35 | gratis or for a fee, you must pass on to the recipients the same 36 | freedoms that you received. You must make sure that they, too, receive 37 | or can get the source code. And you must show them these terms so they 38 | know their rights. 39 | 40 | Developers that use the GNU GPL protect your rights with two steps: 41 | (1) assert copyright on the software, and (2) offer you this License 42 | giving you legal permission to copy, distribute and/or modify it. 43 | 44 | For the developers' and authors' protection, the GPL clearly explains 45 | that there is no warranty for this free software. For both users' and 46 | authors' sake, the GPL requires that modified versions be marked as 47 | changed, so that their problems will not be attributed erroneously to 48 | authors of previous versions. 49 | 50 | Some devices are designed to deny users access to install or run 51 | modified versions of the software inside them, although the manufacturer 52 | can do so. This is fundamentally incompatible with the aim of 53 | protecting users' freedom to change the software. The systematic 54 | pattern of such abuse occurs in the area of products for individuals to 55 | use, which is precisely where it is most unacceptable. Therefore, we 56 | have designed this version of the GPL to prohibit the practice for those 57 | products. If such problems arise substantially in other domains, we 58 | stand ready to extend this provision to those domains in future versions 59 | of the GPL, as needed to protect the freedom of users. 60 | 61 | Finally, every program is threatened constantly by software patents. 62 | States should not allow patents to restrict development and use of 63 | software on general-purpose computers, but in those that do, we wish to 64 | avoid the special danger that patents applied to a free program could 65 | make it effectively proprietary. To prevent this, the GPL assures that 66 | patents cannot be used to render the program non-free. 67 | 68 | The precise terms and conditions for copying, distribution and 69 | modification follow. 70 | 71 | TERMS AND CONDITIONS 72 | 73 | 0. Definitions. 74 | 75 | "This License" refers to version 3 of the GNU General Public License. 76 | 77 | "Copyright" also means copyright-like laws that apply to other kinds of 78 | works, such as semiconductor masks. 79 | 80 | "The Program" refers to any copyrightable work licensed under this 81 | License. Each licensee is addressed as "you". "Licensees" and 82 | "recipients" may be individuals or organizations. 83 | 84 | To "modify" a work means to copy from or adapt all or part of the work 85 | in a fashion requiring copyright permission, other than the making of an 86 | exact copy. The resulting work is called a "modified version" of the 87 | earlier work or a work "based on" the earlier work. 88 | 89 | A "covered work" means either the unmodified Program or a work based 90 | on the Program. 91 | 92 | To "propagate" a work means to do anything with it that, without 93 | permission, would make you directly or secondarily liable for 94 | infringement under applicable copyright law, except executing it on a 95 | computer or modifying a private copy. Propagation includes copying, 96 | distribution (with or without modification), making available to the 97 | public, and in some countries other activities as well. 98 | 99 | To "convey" a work means any kind of propagation that enables other 100 | parties to make or receive copies. Mere interaction with a user through 101 | a computer network, with no transfer of a copy, is not conveying. 102 | 103 | An interactive user interface displays "Appropriate Legal Notices" 104 | to the extent that it includes a convenient and prominently visible 105 | feature that (1) displays an appropriate copyright notice, and (2) 106 | tells the user that there is no warranty for the work (except to the 107 | extent that warranties are provided), that licensees may convey the 108 | work under this License, and how to view a copy of this License. If 109 | the interface presents a list of user commands or options, such as a 110 | menu, a prominent item in the list meets this criterion. 111 | 112 | 1. Source Code. 113 | 114 | The "source code" for a work means the preferred form of the work 115 | for making modifications to it. "Object code" means any non-source 116 | form of a work. 117 | 118 | A "Standard Interface" means an interface that either is an official 119 | standard defined by a recognized standards body, or, in the case of 120 | interfaces specified for a particular programming language, one that 121 | is widely used among developers working in that language. 122 | 123 | The "System Libraries" of an executable work include anything, other 124 | than the work as a whole, that (a) is included in the normal form of 125 | packaging a Major Component, but which is not part of that Major 126 | Component, and (b) serves only to enable use of the work with that 127 | Major Component, or to implement a Standard Interface for which an 128 | implementation is available to the public in source code form. A 129 | "Major Component", in this context, means a major essential component 130 | (kernel, window system, and so on) of the specific operating system 131 | (if any) on which the executable work runs, or a compiler used to 132 | produce the work, or an object code interpreter used to run it. 133 | 134 | The "Corresponding Source" for a work in object code form means all 135 | the source code needed to generate, install, and (for an executable 136 | work) run the object code and to modify the work, including scripts to 137 | control those activities. However, it does not include the work's 138 | System Libraries, or general-purpose tools or generally available free 139 | programs which are used unmodified in performing those activities but 140 | which are not part of the work. For example, Corresponding Source 141 | includes interface definition files associated with source files for 142 | the work, and the source code for shared libraries and dynamically 143 | linked subprograms that the work is specifically designed to require, 144 | such as by intimate data communication or control flow between those 145 | subprograms and other parts of the work. 146 | 147 | The Corresponding Source need not include anything that users 148 | can regenerate automatically from other parts of the Corresponding 149 | Source. 150 | 151 | The Corresponding Source for a work in source code form is that 152 | same work. 153 | 154 | 2. Basic Permissions. 155 | 156 | All rights granted under this License are granted for the term of 157 | copyright on the Program, and are irrevocable provided the stated 158 | conditions are met. This License explicitly affirms your unlimited 159 | permission to run the unmodified Program. The output from running a 160 | covered work is covered by this License only if the output, given its 161 | content, constitutes a covered work. This License acknowledges your 162 | rights of fair use or other equivalent, as provided by copyright law. 163 | 164 | You may make, run and propagate covered works that you do not 165 | convey, without conditions so long as your license otherwise remains 166 | in force. You may convey covered works to others for the sole purpose 167 | of having them make modifications exclusively for you, or provide you 168 | with facilities for running those works, provided that you comply with 169 | the terms of this License in conveying all material for which you do 170 | not control copyright. Those thus making or running the covered works 171 | for you must do so exclusively on your behalf, under your direction 172 | and control, on terms that prohibit them from making any copies of 173 | your copyrighted material outside their relationship with you. 174 | 175 | Conveying under any other circumstances is permitted solely under 176 | the conditions stated below. Sublicensing is not allowed; section 10 177 | makes it unnecessary. 178 | 179 | 3. Protecting Users' Legal Rights From Anti-Circumvention Law. 180 | 181 | No covered work shall be deemed part of an effective technological 182 | measure under any applicable law fulfilling obligations under article 183 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or 184 | similar laws prohibiting or restricting circumvention of such 185 | measures. 186 | 187 | When you convey a covered work, you waive any legal power to forbid 188 | circumvention of technological measures to the extent such circumvention 189 | is effected by exercising rights under this License with respect to 190 | the covered work, and you disclaim any intention to limit operation or 191 | modification of the work as a means of enforcing, against the work's 192 | users, your or third parties' legal rights to forbid circumvention of 193 | technological measures. 194 | 195 | 4. Conveying Verbatim Copies. 196 | 197 | You may convey verbatim copies of the Program's source code as you 198 | receive it, in any medium, provided that you conspicuously and 199 | appropriately publish on each copy an appropriate copyright notice; 200 | keep intact all notices stating that this License and any 201 | non-permissive terms added in accord with section 7 apply to the code; 202 | keep intact all notices of the absence of any warranty; and give all 203 | recipients a copy of this License along with the Program. 204 | 205 | You may charge any price or no price for each copy that you convey, 206 | and you may offer support or warranty protection for a fee. 207 | 208 | 5. Conveying Modified Source Versions. 209 | 210 | You may convey a work based on the Program, or the modifications to 211 | produce it from the Program, in the form of source code under the 212 | terms of section 4, provided that you also meet all of these conditions: 213 | 214 | a) The work must carry prominent notices stating that you modified 215 | it, and giving a relevant date. 216 | 217 | b) The work must carry prominent notices stating that it is 218 | released under this License and any conditions added under section 219 | 7. This requirement modifies the requirement in section 4 to 220 | "keep intact all notices". 221 | 222 | c) You must license the entire work, as a whole, under this 223 | License to anyone who comes into possession of a copy. This 224 | License will therefore apply, along with any applicable section 7 225 | additional terms, to the whole of the work, and all its parts, 226 | regardless of how they are packaged. This License gives no 227 | permission to license the work in any other way, but it does not 228 | invalidate such permission if you have separately received it. 229 | 230 | d) If the work has interactive user interfaces, each must display 231 | Appropriate Legal Notices; however, if the Program has interactive 232 | interfaces that do not display Appropriate Legal Notices, your 233 | work need not make them do so. 234 | 235 | A compilation of a covered work with other separate and independent 236 | works, which are not by their nature extensions of the covered work, 237 | and which are not combined with it such as to form a larger program, 238 | in or on a volume of a storage or distribution medium, is called an 239 | "aggregate" if the compilation and its resulting copyright are not 240 | used to limit the access or legal rights of the compilation's users 241 | beyond what the individual works permit. Inclusion of a covered work 242 | in an aggregate does not cause this License to apply to the other 243 | parts of the aggregate. 244 | 245 | 6. Conveying Non-Source Forms. 246 | 247 | You may convey a covered work in object code form under the terms 248 | of sections 4 and 5, provided that you also convey the 249 | machine-readable Corresponding Source under the terms of this License, 250 | in one of these ways: 251 | 252 | a) Convey the object code in, or embodied in, a physical product 253 | (including a physical distribution medium), accompanied by the 254 | Corresponding Source fixed on a durable physical medium 255 | customarily used for software interchange. 256 | 257 | b) Convey the object code in, or embodied in, a physical product 258 | (including a physical distribution medium), accompanied by a 259 | written offer, valid for at least three years and valid for as 260 | long as you offer spare parts or customer support for that product 261 | model, to give anyone who possesses the object code either (1) a 262 | copy of the Corresponding Source for all the software in the 263 | product that is covered by this License, on a durable physical 264 | medium customarily used for software interchange, for a price no 265 | more than your reasonable cost of physically performing this 266 | conveying of source, or (2) access to copy the 267 | Corresponding Source from a network server at no charge. 268 | 269 | c) Convey individual copies of the object code with a copy of the 270 | written offer to provide the Corresponding Source. This 271 | alternative is allowed only occasionally and noncommercially, and 272 | only if you received the object code with such an offer, in accord 273 | with subsection 6b. 274 | 275 | d) Convey the object code by offering access from a designated 276 | place (gratis or for a charge), and offer equivalent access to the 277 | Corresponding Source in the same way through the same place at no 278 | further charge. You need not require recipients to copy the 279 | Corresponding Source along with the object code. If the place to 280 | copy the object code is a network server, the Corresponding Source 281 | may be on a different server (operated by you or a third party) 282 | that supports equivalent copying facilities, provided you maintain 283 | clear directions next to the object code saying where to find the 284 | Corresponding Source. Regardless of what server hosts the 285 | Corresponding Source, you remain obligated to ensure that it is 286 | available for as long as needed to satisfy these requirements. 287 | 288 | e) Convey the object code using peer-to-peer transmission, provided 289 | you inform other peers where the object code and Corresponding 290 | Source of the work are being offered to the general public at no 291 | charge under subsection 6d. 292 | 293 | A separable portion of the object code, whose source code is excluded 294 | from the Corresponding Source as a System Library, need not be 295 | included in conveying the object code work. 296 | 297 | A "User Product" is either (1) a "consumer product", which means any 298 | tangible personal property which is normally used for personal, family, 299 | or household purposes, or (2) anything designed or sold for incorporation 300 | into a dwelling. In determining whether a product is a consumer product, 301 | doubtful cases shall be resolved in favor of coverage. For a particular 302 | product received by a particular user, "normally used" refers to a 303 | typical or common use of that class of product, regardless of the status 304 | of the particular user or of the way in which the particular user 305 | actually uses, or expects or is expected to use, the product. A product 306 | is a consumer product regardless of whether the product has substantial 307 | commercial, industrial or non-consumer uses, unless such uses represent 308 | the only significant mode of use of the product. 309 | 310 | "Installation Information" for a User Product means any methods, 311 | procedures, authorization keys, or other information required to install 312 | and execute modified versions of a covered work in that User Product from 313 | a modified version of its Corresponding Source. The information must 314 | suffice to ensure that the continued functioning of the modified object 315 | code is in no case prevented or interfered with solely because 316 | modification has been made. 317 | 318 | If you convey an object code work under this section in, or with, or 319 | specifically for use in, a User Product, and the conveying occurs as 320 | part of a transaction in which the right of possession and use of the 321 | User Product is transferred to the recipient in perpetuity or for a 322 | fixed term (regardless of how the transaction is characterized), the 323 | Corresponding Source conveyed under this section must be accompanied 324 | by the Installation Information. 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 updates 331 | for a work that has been modified or installed by the recipient, or for 332 | the User Product in which it has been modified or installed. Access to a 333 | network may be denied when the modification itself materially and 334 | adversely affects the operation of the network or violates the rules and 335 | protocols for communication across the network. 336 | 337 | Corresponding Source conveyed, and Installation Information provided, 338 | in accord with this section must be in a format that is publicly 339 | documented (and with an implementation available to the public in 340 | source code form), and must require no special password or key for 341 | unpacking, reading or copying. 342 | 343 | 7. Additional Terms. 344 | 345 | "Additional permissions" are terms that supplement the terms of this 346 | License by making exceptions from one or more of its conditions. 347 | Additional permissions that are applicable to the entire Program shall 348 | be treated as though they were included in this License, to the extent 349 | that they are valid under applicable law. If additional permissions 350 | apply only to part of the Program, that part may be used separately 351 | under those permissions, but the entire Program remains governed by 352 | this License without regard to the additional permissions. 353 | 354 | When you convey a copy of a covered work, you may at your option 355 | remove any additional permissions from that copy, or from any part of 356 | it. (Additional permissions may be written to require their own 357 | removal in certain cases when you modify the work.) You may place 358 | additional permissions on material, added by you to a covered work, 359 | for which you have or can give appropriate copyright permission. 360 | 361 | Notwithstanding any other provision of this License, for material you 362 | add to a covered work, you may (if authorized by the copyright holders of 363 | that material) supplement the terms of this License with terms: 364 | 365 | a) Disclaiming warranty or limiting liability differently from the 366 | terms of sections 15 and 16 of this License; or 367 | 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 | 372 | c) Prohibiting misrepresentation of the origin of that material, or 373 | requiring that modified versions of such material be marked in 374 | reasonable ways as different from the original version; or 375 | 376 | d) Limiting the use for publicity purposes of names of licensors or 377 | authors of the material; or 378 | 379 | e) Declining to grant rights under trademark law for use of some 380 | trade names, trademarks, or service marks; or 381 | 382 | f) Requiring indemnification of licensors and authors of that 383 | material by anyone who conveys the material (or modified versions of 384 | it) with contractual assumptions of liability to the recipient, for 385 | any liability that these contractual assumptions directly impose on 386 | those licensors and authors. 387 | 388 | All other non-permissive additional terms are considered "further 389 | restrictions" within the meaning of section 10. If the Program as you 390 | received it, or any part of it, contains a notice stating that it is 391 | governed by this License along with a term that is a further 392 | restriction, you may remove that term. If a license document contains 393 | a further restriction but permits relicensing or conveying under this 394 | License, you may add to a covered work material governed by the terms 395 | of that license document, provided that the further restriction does 396 | not survive such relicensing or conveying. 397 | 398 | If you add terms to a covered work in accord with this section, you 399 | must place, in the relevant source files, a statement of the 400 | additional terms that apply to those files, or a notice indicating 401 | where to find the applicable terms. 402 | 403 | Additional terms, permissive or non-permissive, may be stated in the 404 | form of a separately written license, or stated as exceptions; 405 | the above requirements apply either way. 406 | 407 | 8. Termination. 408 | 409 | You may not propagate or modify a covered work except as expressly 410 | provided under this License. Any attempt otherwise to propagate or 411 | modify it is void, and will automatically terminate your rights under 412 | this License (including any patent licenses granted under the third 413 | paragraph of section 11). 414 | 415 | However, if you cease all violation of this License, then your 416 | license from a particular copyright holder is reinstated (a) 417 | provisionally, unless and until the copyright holder explicitly and 418 | finally terminates your license, and (b) permanently, if the copyright 419 | holder fails to notify you of the violation by some reasonable means 420 | prior to 60 days after the cessation. 421 | 422 | Moreover, your license from a particular copyright holder is 423 | reinstated permanently if the copyright holder notifies you of the 424 | violation by some reasonable means, this is the first time you have 425 | received notice of violation of this License (for any work) from that 426 | copyright holder, and you cure the violation prior to 30 days after 427 | your receipt of the notice. 428 | 429 | Termination of your rights under this section does not terminate the 430 | licenses of parties who have received copies or rights from you under 431 | this License. If your rights have been terminated and not permanently 432 | reinstated, you do not qualify to receive new licenses for the same 433 | material under section 10. 434 | 435 | 9. Acceptance Not Required for Having Copies. 436 | 437 | You are not required to accept this License in order to receive or 438 | run a copy of the Program. Ancillary propagation of a covered work 439 | occurring solely as a consequence of using peer-to-peer transmission 440 | to receive a copy likewise does not require acceptance. However, 441 | nothing other than this License grants you permission to propagate or 442 | modify any covered work. These actions infringe copyright if you do 443 | not accept this License. Therefore, by modifying or propagating a 444 | covered work, you indicate your acceptance of this License to do so. 445 | 446 | 10. Automatic Licensing of Downstream Recipients. 447 | 448 | Each time you convey a covered work, the recipient automatically 449 | receives a license from the original licensors, to run, modify and 450 | propagate that work, subject to this License. You are not responsible 451 | for enforcing compliance by third parties with this License. 452 | 453 | An "entity transaction" is a transaction transferring control of an 454 | organization, or substantially all assets of one, or subdividing an 455 | organization, or merging organizations. If propagation of a covered 456 | work results from an entity transaction, each party to that 457 | transaction who receives a copy of the work also receives whatever 458 | licenses to the work the party's predecessor in interest had or could 459 | give under the previous paragraph, plus a right to possession of the 460 | Corresponding Source of the work from the predecessor in interest, if 461 | the predecessor has it or can get it with reasonable efforts. 462 | 463 | You may not impose any further restrictions on the exercise of the 464 | rights granted or affirmed under this License. For example, you may 465 | not impose a license fee, royalty, or other charge for exercise of 466 | rights granted under this License, and you may not initiate litigation 467 | (including a cross-claim or counterclaim in a lawsuit) alleging that 468 | any patent claim is infringed by making, using, selling, offering for 469 | sale, or importing the Program or any portion of it. 470 | 471 | 11. Patents. 472 | 473 | A "contributor" is a copyright holder who authorizes use under this 474 | License of the Program or a work on which the Program is based. The 475 | work thus licensed is called the contributor's "contributor version". 476 | 477 | A contributor's "essential patent claims" are all patent claims 478 | owned or controlled by the contributor, whether already acquired or 479 | hereafter acquired, that would be infringed by some manner, permitted 480 | by this License, of making, using, or selling its contributor version, 481 | but do not include claims that would be infringed only as a 482 | consequence of further modification of the contributor version. For 483 | purposes of this definition, "control" includes the right to grant 484 | patent sublicenses in a manner consistent with the requirements of 485 | this License. 486 | 487 | Each contributor grants you a non-exclusive, worldwide, royalty-free 488 | patent license under the contributor's essential patent claims, to 489 | make, use, sell, offer for sale, import and otherwise run, modify and 490 | propagate the contents of its contributor version. 491 | 492 | In the following three paragraphs, a "patent license" is any express 493 | agreement or commitment, however denominated, not to enforce a patent 494 | (such as an express permission to practice a patent or covenant not to 495 | sue for patent infringement). To "grant" such a patent license to a 496 | party means to make such an agreement or commitment not to enforce a 497 | patent against the party. 498 | 499 | If you convey a covered work, knowingly relying on a patent license, 500 | and the Corresponding Source of the work is not available for anyone 501 | to copy, free of charge and under the terms of this License, through a 502 | publicly available network server or other readily accessible means, 503 | then you must either (1) cause the Corresponding Source to be so 504 | available, or (2) arrange to deprive yourself of the benefit of the 505 | patent license for this particular work, or (3) arrange, in a manner 506 | consistent with the requirements of this License, to extend the patent 507 | license to downstream recipients. "Knowingly relying" means you have 508 | actual knowledge that, but for the patent license, your conveying the 509 | covered work in a country, or your recipient's use of the covered work 510 | in a country, would infringe one or more identifiable patents in that 511 | country that you have reason to believe are valid. 512 | 513 | If, pursuant to or in connection with a single transaction or 514 | arrangement, you convey, or propagate by procuring conveyance of, a 515 | covered work, and grant a patent license to some of the parties 516 | receiving the covered work authorizing them to use, propagate, modify 517 | or convey a specific copy of the covered work, then the patent license 518 | you grant is automatically extended to all recipients of the covered 519 | work and works based on it. 520 | 521 | A patent license is "discriminatory" if it does not include within 522 | the scope of its coverage, prohibits the exercise of, or is 523 | conditioned on the non-exercise of one or more of the rights that are 524 | specifically granted under this License. You may not convey a covered 525 | work if you are a party to an arrangement with a third party that is 526 | in the business of distributing software, under which you make payment 527 | to the third party based on the extent of your activity of conveying 528 | the work, and under which the third party grants, to any of the 529 | parties who would receive the covered work from you, a discriminatory 530 | patent license (a) in connection with copies of the covered work 531 | conveyed by you (or copies made from those copies), or (b) primarily 532 | for and in connection with specific products or compilations that 533 | contain the covered work, unless you entered into that arrangement, 534 | or that patent license was granted, prior to 28 March 2007. 535 | 536 | Nothing in this License shall be construed as excluding or limiting 537 | any implied license or other defenses to infringement that may 538 | otherwise be available to you under applicable patent law. 539 | 540 | 12. No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | {one line to give the program's name and a brief idea of what it does.} 635 | Copyright (C) {year} {name of author} 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper 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 | {project} Copyright (C) {year} {fullname} 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 appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | --------------------------------------------------------------------------------