python-pycrypto: Security fix CVE-2013-7459

CVE-2013-7459: Heap-based buffer overflow in the ALGnew function in
block_templace.c in Python Cryptography Toolkit (aka pycrypto) allows
remote attackers to execute arbitrary code as demonstrated by a crafted
iv parameter to cryptmsg.py.

Reference:
https://nvd.nist.gov/vuln/detail/CVE-2013-7459

Patch from:
https://github.com/dlitz/pycrypto/commit/8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
(cherry picked from commit e4af9cf961c70bb4a96eaafd995d0ff2c264cb8e)
Signed-off-by: Armin Kuster <akuster808@gmail.com>

2 files changed, 101 insertions, 1 deletions

diff --git a/meta-python/recipes-devtools/python/python-pycrypto/CVE-2013-7459.patch b/meta-python/recipes-devtools/python/python-pycrypto/CVE-2013-7459.patch
new file mode 100644
index 000000000..9006c5c35
--- /dev/null
+++ b/meta-python/recipes-devtools/python/python-pycrypto/CVE-2013-7459.patch
@@ -0,0 +1,98 @@
+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.
+
+Upstream-Status: Backport
+[https://github.com/dlitz/pycrypto/commit/8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4]
+
+CVE: CVE-2013-7459
+
+Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
+---
+ lib/Crypto/SelfTest/Cipher/common.py | 31 +++++++++++++++++++++++--------
+ src/block_template.c                 | 11 +++++++++++
+ 2 files changed, 34 insertions(+), 8 deletions(-)
+
+diff --git a/lib/Crypto/SelfTest/Cipher/common.py b/lib/Crypto/SelfTest/Cipher/common.py
+index 8bebed9..91ec743 100644
+--- 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)
+diff --git a/src/block_template.c b/src/block_template.c
+index c36b316..8746948 100644
+--- a/src/block_template.c
++++ b/src/block_template.c
+@@ -170,6 +170,17 @@ ALGnew(PyObject *self, PyObject *args, PyObject *kwdict)
+                                "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,
+-- 
+2.7.4
+
diff --git a/meta-python/recipes-devtools/python/python-pycrypto_2.6.1.bb b/meta-python/recipes-devtools/python/python-pycrypto_2.6.1.bb
index 06a0cc444..919f91ecb 100644
--- a/meta-python/recipes-devtools/python/python-pycrypto_2.6.1.bb
+++ b/meta-python/recipes-devtools/python/python-pycrypto_2.6.1.bb
@@ -1,7 +1,9 @@
 inherit distutils
 require python-pycrypto.inc
 
-SRC_URI += "file://cross-compiling.patch"
+SRC_URI += "file://cross-compiling.patch \
+            file://CVE-2013-7459.patch \
+           "
 
 # We explicitly call distutils_do_install, since we want it to run, but
 # *don't* want the autotools install to run, since this package doesn't