| 1 | Fix CVE-2013-7459: |
| 2 | |
| 3 | https://github.com/dlitz/pycrypto/issues/176 |
| 4 | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-7459 |
| 5 | |
| 6 | Copied from Debian: |
| 7 | |
| 8 | https://anonscm.debian.org/cgit/collab-maint/python-crypto.git/commit/?id=0de2243837ed369a086f15c50cca2be85bdfab9d |
| 9 | |
| 10 | Debian adapts this upstream commit: |
| 11 | |
| 12 | https://github.com/dlitz/pycrypto/commit/8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4 |
| 13 | |
| 14 | From 8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4 Mon Sep 17 00:00:00 2001 |
| 15 | From: Legrandin <helderijs@gmail.com> |
| 16 | Date: Sun, 22 Dec 2013 22:24:46 +0100 |
| 17 | Subject: [PATCH] Throw exception when IV is used with ECB or CTR |
| 18 | |
| 19 | The IV parameter is currently ignored when initializing |
| 20 | a cipher in ECB or CTR mode. |
| 21 | |
| 22 | For CTR mode, it is confusing: it takes some time to see |
| 23 | that a different parameter is needed (the counter). |
| 24 | |
| 25 | For ECB mode, it is outright dangerous. |
| 26 | |
| 27 | This patch forces an exception to be raised. |
| 28 | --- |
| 29 | lib/Crypto/SelfTest/Cipher/common.py | 31 +++++++++++++++++++++++-------- |
| 30 | src/block_template.c | 11 +++++++++++ |
| 31 | 2 files changed, 34 insertions(+), 8 deletions(-) |
| 32 | |
| 33 | --- a/lib/Crypto/SelfTest/Cipher/common.py |
| 34 | +++ b/lib/Crypto/SelfTest/Cipher/common.py |
| 35 | @@ -239,19 +239,34 @@ class RoundtripTest(unittest.TestCase): |
| 36 | return """%s .decrypt() output of .encrypt() should not be garbled""" % (self.module_name,) |
| 37 | |
| 38 | def runTest(self): |
| 39 | - for mode in (self.module.MODE_ECB, self.module.MODE_CBC, self.module.MODE_CFB, self.module.MODE_OFB, self.module.MODE_OPENPGP): |
| 40 | + |
| 41 | + ## ECB mode |
| 42 | + mode = self.module.MODE_ECB |
| 43 | + encryption_cipher = self.module.new(a2b_hex(self.key), mode) |
| 44 | + ciphertext = encryption_cipher.encrypt(self.plaintext) |
| 45 | + decryption_cipher = self.module.new(a2b_hex(self.key), mode) |
| 46 | + decrypted_plaintext = decryption_cipher.decrypt(ciphertext) |
| 47 | + self.assertEqual(self.plaintext, decrypted_plaintext) |
| 48 | + |
| 49 | + ## OPENPGP mode |
| 50 | + mode = self.module.MODE_OPENPGP |
| 51 | + encryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv) |
| 52 | + eiv_ciphertext = encryption_cipher.encrypt(self.plaintext) |
| 53 | + eiv = eiv_ciphertext[:self.module.block_size+2] |
| 54 | + ciphertext = eiv_ciphertext[self.module.block_size+2:] |
| 55 | + decryption_cipher = self.module.new(a2b_hex(self.key), mode, eiv) |
| 56 | + decrypted_plaintext = decryption_cipher.decrypt(ciphertext) |
| 57 | + self.assertEqual(self.plaintext, decrypted_plaintext) |
| 58 | + |
| 59 | + ## All other non-AEAD modes (but CTR) |
| 60 | + for mode in (self.module.MODE_CBC, self.module.MODE_CFB, self.module.MODE_OFB): |
| 61 | encryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv) |
| 62 | ciphertext = encryption_cipher.encrypt(self.plaintext) |
| 63 | - |
| 64 | - if mode != self.module.MODE_OPENPGP: |
| 65 | - decryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv) |
| 66 | - else: |
| 67 | - eiv = ciphertext[:self.module.block_size+2] |
| 68 | - ciphertext = ciphertext[self.module.block_size+2:] |
| 69 | - decryption_cipher = self.module.new(a2b_hex(self.key), mode, eiv) |
| 70 | + decryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv) |
| 71 | decrypted_plaintext = decryption_cipher.decrypt(ciphertext) |
| 72 | self.assertEqual(self.plaintext, decrypted_plaintext) |
| 73 | |
| 74 | + |
| 75 | class PGPTest(unittest.TestCase): |
| 76 | def __init__(self, module, params): |
| 77 | unittest.TestCase.__init__(self) |
| 78 | --- a/src/block_template.c |
| 79 | +++ b/src/block_template.c |
| 80 | @@ -170,6 +170,17 @@ ALGnew(PyObject *self, PyObject *args, P |
| 81 | "Key cannot be the null string"); |
| 82 | return NULL; |
| 83 | } |
| 84 | + if (IVlen != 0 && mode == MODE_ECB) |
| 85 | + { |
| 86 | + PyErr_Format(PyExc_ValueError, "ECB mode does not use IV"); |
| 87 | + return NULL; |
| 88 | + } |
| 89 | + if (IVlen != 0 && mode == MODE_CTR) |
| 90 | + { |
| 91 | + PyErr_Format(PyExc_ValueError, |
| 92 | + "CTR mode needs counter parameter, not IV"); |
| 93 | + return NULL; |
| 94 | + } |
| 95 | if (IVlen != BLOCK_SIZE && mode != MODE_ECB && mode != MODE_CTR) |
| 96 | { |
| 97 | PyErr_Format(PyExc_ValueError, |