Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/werkzeug/security.py: 23%

1from __future__ import annotations 

2 

3import hashlib 

4import hmac 

5import os 

6import posixpath 

7import secrets 

8 

9SALT_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" 

10DEFAULT_PBKDF2_ITERATIONS = 1_000_000 

11 

12_os_alt_seps: list[str] = list( 

13 sep for sep in [os.sep, os.path.altsep] if sep is not None and sep != "/" 

14) 

15# https://chrisdenton.github.io/omnipath/Special%20Dos%20Device%20Names.html 

16_windows_device_files = { 

17 "AUX", 

18 "CON", 

19 "CONIN$", 

20 "CONOUT$", 

21 *(f"COM{c}" for c in "123456789¹²³"), 

22 *(f"LPT{c}" for c in "123456789¹²³"), 

23 "NUL", 

24 "PRN", 

25} 

26 

27 

28def gen_salt(length: int) -> str: 

29 """Generate a random string of SALT_CHARS with specified ``length``.""" 

30 if length <= 0: 

31 raise ValueError("Salt length must be at least 1.") 

32 

33 return "".join(secrets.choice(SALT_CHARS) for _ in range(length)) 

34 

35 

36def _hash_internal(method: str, salt: str, password: str) -> tuple[str, str]: 

37 method, *args = method.split(":") 

38 salt_bytes = salt.encode() 

39 password_bytes = password.encode() 

40 

41 if method == "scrypt": 

42 if not args: 

43 n = 2**15 

44 r = 8 

45 p = 1 

46 else: 

47 try: 

48 n, r, p = map(int, args) 

49 except ValueError: 

50 raise ValueError("'scrypt' takes 3 arguments.") from None 

51 

52 maxmem = 132 * n * r * p # ideally 128, but some extra seems needed 

53 return ( 

54 hashlib.scrypt( 

55 password_bytes, salt=salt_bytes, n=n, r=r, p=p, maxmem=maxmem 

56 ).hex(), 

57 f"scrypt:{n}:{r}:{p}", 

58 ) 

59 elif method == "pbkdf2": 

60 len_args = len(args) 

61 

62 if len_args == 0: 

63 hash_name = "sha256" 

64 iterations = DEFAULT_PBKDF2_ITERATIONS 

65 elif len_args == 1: 

66 hash_name = args[0] 

67 iterations = DEFAULT_PBKDF2_ITERATIONS 

68 elif len_args == 2: 

69 hash_name = args[0] 

70 iterations = int(args[1]) 

71 else: 

72 raise ValueError("'pbkdf2' takes 2 arguments.") 

73 

74 return ( 

75 hashlib.pbkdf2_hmac( 

76 hash_name, password_bytes, salt_bytes, iterations 

77 ).hex(), 

78 f"pbkdf2:{hash_name}:{iterations}", 

79 ) 

80 else: 

81 raise ValueError(f"Invalid hash method '{method}'.") 

82 

83 

84def generate_password_hash( 

85 password: str, method: str = "scrypt", salt_length: int = 16 

86) -> str: 

87 """Securely hash a password for storage. A password can be compared to a stored hash 

88 using :func:`check_password_hash`. 

89 

90 The following methods are supported: 

91 

92 - ``scrypt``, the default. The parameters are ``n``, ``r``, and ``p``, the default 

93 is ``scrypt:32768:8:1``. See :func:`hashlib.scrypt`. 

94 - ``pbkdf2``, less secure. The parameters are ``hash_method`` and ``iterations``, 

95 the default is ``pbkdf2:sha256:600000``. See :func:`hashlib.pbkdf2_hmac`. 

96 

97 Default parameters may be updated to reflect current guidelines, and methods may be 

98 deprecated and removed if they are no longer considered secure. To migrate old 

99 hashes, you may generate a new hash when checking an old hash, or you may contact 

100 users with a link to reset their password. 

101 

102 :param password: The plaintext password. 

103 :param method: The key derivation function and parameters. 

104 :param salt_length: The number of characters to generate for the salt. 

105 

106 .. versionchanged:: 3.1 

107 The default iterations for pbkdf2 was increased to 1,000,000. 

108 

109 .. versionchanged:: 2.3 

110 Scrypt support was added. 

111 

112 .. versionchanged:: 2.3 

113 The default iterations for pbkdf2 was increased to 600,000. 

114 

115 .. versionchanged:: 2.3 

116 All plain hashes are deprecated and will not be supported in Werkzeug 3.0. 

117 """ 

118 salt = gen_salt(salt_length) 

119 h, actual_method = _hash_internal(method, salt, password) 

120 return f"{actual_method}${salt}${h}" 

121 

122 

123def check_password_hash(pwhash: str, password: str) -> bool: 

124 """Securely check that the given stored password hash, previously generated using 

125 :func:`generate_password_hash`, matches the given password. 

126 

127 Methods may be deprecated and removed if they are no longer considered secure. To 

128 migrate old hashes, you may generate a new hash when checking an old hash, or you 

129 may contact users with a link to reset their password. 

130 

131 :param pwhash: The hashed password. 

132 :param password: The plaintext password. 

133 

134 .. versionchanged:: 2.3 

135 All plain hashes are deprecated and will not be supported in Werkzeug 3.0. 

136 """ 

137 try: 

138 method, salt, hashval = pwhash.split("$", 2) 

139 except ValueError: 

140 return False 

141 

142 return hmac.compare_digest(_hash_internal(method, salt, password)[0], hashval) 

143 

144 

145def safe_join(directory: str, *pathnames: str) -> str | None: 

146 """Safely join zero or more untrusted path components to a base 

147 directory to avoid escaping the base directory. 

148 

149 :param directory: The trusted base directory. 

150 :param pathnames: The untrusted path components relative to the 

151 base directory. 

152 :return: A safe path, otherwise ``None``. 

153 

154 .. versionchanged:: 3.1.5 

155 More special device names, regardless of extension or trailing spaces, 

156 are not allowed on Windows. 

157 

158 .. versionchanged:: 3.1.4 

159 Special device names are not allowed on Windows. 

160 """ 

161 if not directory: 

162 # Ensure we end up with ./path if directory="" is given, 

163 # otherwise the first untrusted part could become trusted. 

164 directory = "." 

165 

166 parts = [directory] 

167 

168 for filename in pathnames: 

169 if filename != "": 

170 filename = posixpath.normpath(filename) 

171 

172 if ( 

173 any(sep in filename for sep in _os_alt_seps) 

174 or ( 

175 os.name == "nt" 

176 and filename.partition(".")[0].strip().upper() in _windows_device_files 

177 ) 

178 or os.path.isabs(filename) 

179 # ntpath.isabs doesn't catch this on Python < 3.11 

180 or filename.startswith("/") 

181 or filename == ".." 

182 or filename.startswith("../") 

183 ): 

184 return None 

185 

186 parts.append(filename) 

187 

188 return posixpath.join(*parts)