/pidgin/main: 8564519d01c0: Don't pass incorrectly sized blocks ...

[Andrew Victor]

Changeset: 8564519d01c0a370d513b2eaa487a0d95cf9e2fc
Author:	 Andrew Victor <andrew.victor at mxit.com>
Date:	 2012-12-18 17:31 +0200
Branch:	 default
URL: http://hg.pidgin.im/pidgin/main/rev/8564519d01c0

Description:

Don't pass incorrectly sized blocks of encrypted data to the AES library.

diffstat:

 libpurple/protocols/mxit/cipher.c |  4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diffs (14 lines):

diff --git a/libpurple/protocols/mxit/cipher.c b/libpurple/protocols/mxit/cipher.c
--- a/libpurple/protocols/mxit/cipher.c
+++ b/libpurple/protocols/mxit/cipher.c
@@ -163,6 +163,10 @@ char* mxit_decrypt_message( struct MXitS
 	/* base64 decode the message */
 	raw_message = purple_base64_decode( message, &raw_len );
 
+	/* AES-encrypted data is always blocks of 16 bytes */
+	if ( ( raw_len == 0 ) || ( raw_len % 16 != 0 ) )
+		return NULL;
+
 	/* build the AES key */
 	ExpandKey( (unsigned char*) transport_layer_key( session ), (unsigned char*) exkey );