gnu: python-pycrypto: Fix CVE-2013-7459.

* gnu/packages/patches/python-pycrypto-CVE-2013-7459.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/python.scm (python-pycrypto, python2-pycrypto)[source]: Use the
patch. Use pypi-uri.

2 files changed, 102 insertions, 7 deletions

diff --git a/gnu/packages/patches/python-pycrypto-CVE-2013-7459.patch b/gnu/packages/patches/python-pycrypto-CVE-2013-7459.patch
new file mode 100644
index 0000000000..3570b94e9b
--- /dev/null
+++ b/gnu/packages/patches/python-pycrypto-CVE-2013-7459.patch
@@ -0,0 +1,97 @@
+Fix CVE-2013-7459:
+
+https://github.com/dlitz/pycrypto/issues/176
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-7459
+
+Copied from Debian:
+
+https://anonscm.debian.org/cgit/collab-maint/python-crypto.git/commit/?id=0de2243837ed369a086f15c50cca2be85bdfab9d
+
+Debian adapts this upstream commit:
+
+https://github.com/dlitz/pycrypto/commit/8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4
+
+From 8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4 Mon Sep 17 00:00:00 2001
+From: Legrandin <helderijs@gmail.com>
+Date: Sun, 22 Dec 2013 22:24:46 +0100
+Subject: [PATCH] Throw exception when IV is used with ECB or CTR
+
+The IV parameter is currently ignored when initializing
+a cipher in ECB or CTR mode.
+
+For CTR mode, it is confusing: it takes some time to see
+that a different parameter is needed (the counter).
+
+For ECB mode, it is outright dangerous.
+
+This patch forces an exception to be raised.
+---
+ lib/Crypto/SelfTest/Cipher/common.py | 31 +++++++++++++++++++++++--------
+ src/block_template.c                 | 11 +++++++++++
+ 2 files changed, 34 insertions(+), 8 deletions(-)
+
+--- a/lib/Crypto/SelfTest/Cipher/common.py
++++ b/lib/Crypto/SelfTest/Cipher/common.py
+@@ -239,19 +239,34 @@ class RoundtripTest(unittest.TestCase):
+         return """%s .decrypt() output of .encrypt() should not be garbled""" % (self.module_name,)
+ 
+     def runTest(self):
+-        for mode in (self.module.MODE_ECB, self.module.MODE_CBC, self.module.MODE_CFB, self.module.MODE_OFB, self.module.MODE_OPENPGP):
++
++        ## ECB mode
++        mode = self.module.MODE_ECB
++        encryption_cipher = self.module.new(a2b_hex(self.key), mode)
++        ciphertext = encryption_cipher.encrypt(self.plaintext)
++        decryption_cipher = self.module.new(a2b_hex(self.key), mode)
++        decrypted_plaintext = decryption_cipher.decrypt(ciphertext)
++        self.assertEqual(self.plaintext, decrypted_plaintext)
++
++        ## OPENPGP mode
++        mode = self.module.MODE_OPENPGP
++        encryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv)
++        eiv_ciphertext = encryption_cipher.encrypt(self.plaintext)
++        eiv = eiv_ciphertext[:self.module.block_size+2]
++        ciphertext = eiv_ciphertext[self.module.block_size+2:]
++        decryption_cipher = self.module.new(a2b_hex(self.key), mode, eiv)
++        decrypted_plaintext = decryption_cipher.decrypt(ciphertext)
++        self.assertEqual(self.plaintext, decrypted_plaintext)
++
++        ## All other non-AEAD modes (but CTR)
++        for mode in (self.module.MODE_CBC, self.module.MODE_CFB, self.module.MODE_OFB):
+             encryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv)
+             ciphertext = encryption_cipher.encrypt(self.plaintext)
+-            
+-            if mode != self.module.MODE_OPENPGP:
+-                decryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv)
+-            else:
+-                eiv = ciphertext[:self.module.block_size+2]
+-                ciphertext = ciphertext[self.module.block_size+2:]
+-                decryption_cipher = self.module.new(a2b_hex(self.key), mode, eiv)
++            decryption_cipher = self.module.new(a2b_hex(self.key), mode, self.iv)
+             decrypted_plaintext = decryption_cipher.decrypt(ciphertext)
+             self.assertEqual(self.plaintext, decrypted_plaintext)
+ 
++
+ class PGPTest(unittest.TestCase):
+     def __init__(self, module, params):
+         unittest.TestCase.__init__(self)
+--- a/src/block_template.c
++++ b/src/block_template.c
+@@ -170,6 +170,17 @@ ALGnew(PyObject *self, PyObject *args, P
+ 				"Key cannot be the null string");
+ 		return NULL;
+ 	}
++	if (IVlen != 0 && mode == MODE_ECB)
++	{
++		PyErr_Format(PyExc_ValueError, "ECB mode does not use IV");
++		return NULL;
++	}
++	if (IVlen != 0 && mode == MODE_CTR)
++	{
++		PyErr_Format(PyExc_ValueError,
++			"CTR mode needs counter parameter, not IV");
++		return NULL;
++	}
+ 	if (IVlen != BLOCK_SIZE && mode != MODE_ECB && mode != MODE_CTR)
+ 	{
+ 		PyErr_Format(PyExc_ValueError,
diff --git a/gnu/packages/python.scm b/gnu/packages/python.scm
index 5faebae3d9..d8ca83d810 100644
--- a/gnu/packages/python.scm
+++ b/gnu/packages/python.scm
@@ -958,13 +958,11 @@ Python 3 support.")
 (define-public python2-setuptools
   (package-with-python2 python-setuptools))
 
-;;; Pycrypto is abandoned upstream [0] and contains at least one bug that can be
-;;; exploited to achieve arbitrary code execution [1].
+;;; Pycrypto is abandoned upstream:
 ;;;
-;;; TODO Remove this package from GNU Guix.
+;;; https://github.com/dlitz/pycrypto/issues/173
 ;;;
-;;; [0] https://github.com/dlitz/pycrypto/issues/173
-;;; [1] https://github.com/dlitz/pycrypto/issues/176
+;;; TODO Remove this package from GNU Guix.
 (define-public python-pycrypto
   (package
     (name "python-pycrypto")
@@ -972,8 +970,8 @@ Python 3 support.")
     (source
      (origin
       (method url-fetch)
-      (uri (string-append "https://pypi.python.org/packages/source/p/"
-                          "pycrypto/pycrypto-" version ".tar.gz"))
+      (uri (pypi-uri "pycrypto" version))
+      (patches (search-patches "python-pycrypto-CVE-2013-7459.patch"))
       (sha256
        (base32
         "0g0ayql5b9mkjam8hym6zyg6bv77lbh66rv1fyvgqb17kfc1xkpj"))))