Patch "crypto: skcipher - Copy iv from desc even for 0-len walks" has been added to the 4.3-stable tree

Patch "crypto: skcipher - Copy iv from desc even for 0-len walks" has been added to the 4.3-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    crypto: skcipher - Copy iv from desc even for 0-len walks

to the 4.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-skcipher-copy-iv-from-desc-even-for-0-len-walks.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 70d906bc17500edfa9bdd8c8b7e59618c7911613 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 6 Dec 2015 02:51:37 +0100
Subject: crypto: skcipher - Copy iv from desc even for 0-len walks

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

commit 70d906bc17500edfa9bdd8c8b7e59618c7911613 upstream.

Some ciphers actually support encrypting zero length plaintexts. For
example, many AEAD modes support this. The resulting ciphertext for
those winds up being only the authentication tag, which is a result of
the key, the iv, the additional data, and the fact that the plaintext
had zero length. The blkcipher constructors won't copy the IV to the
right place, however, when using a zero length input, resulting in
some significant problems when ciphers call their initialization
routines, only to find that the ->iv parameter is uninitialized. One
such example of this would be using chacha20poly1305 with a zero length
input, which then calls chacha20, which calls the key setup routine,
which eventually OOPSes due to the uninitialized ->iv member.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 crypto/ablkcipher.c |    2 +-
 crypto/blkcipher.c  |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -277,12 +277,12 @@ static int ablkcipher_walk_first(struct
 	if (WARN_ON_ONCE(in_irq()))
 		return -EDEADLK;
 
+	walk->iv = req->info;
 	walk->nbytes = walk->total;
 	if (unlikely(!walk->total))
 		return 0;
 
 	walk->iv_buffer = NULL;
-	walk->iv = req->info;
 	if (unlikely(((unsigned long)walk->iv & alignmask))) {
 		int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -326,12 +326,12 @@ static int blkcipher_walk_first(struct b
 	if (WARN_ON_ONCE(in_irq()))
 		return -EDEADLK;
 
+	walk->iv = desc->info;
 	walk->nbytes = walk->total;
 	if (unlikely(!walk->total))
 		return 0;
 
 	walk->buffer = NULL;
-	walk->iv = desc->info;
 	if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
 		int err = blkcipher_copy_iv(walk);
 		if (err)


Patches currently in stable-queue which might be from Jason@zx2c4.com are

queue-4.3/crypto-skcipher-copy-iv-from-desc-even-for-0-len-walks.patch