linux-kernel - [PATCH 3.2 04/70] crypto: skcipher - Copy iv from desc even for 0-len walks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <lsq.1453087115.428829142@decadent.org.uk>
Date:	Mon, 18 Jan 2016 03:18:35 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Jason A. Donenfeld" <Jason@...c4.com>,
	"Herbert Xu" <herbert@...dor.apana.org.au>
Subject: [PATCH 3.2 04/70] crypto: skcipher - Copy iv from desc even for
 0-len walks

3.2.76-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: "Jason A. Donenfeld" <Jason@...c4.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@...c4.com>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 crypto/ablkcipher.c | 2 +-
 crypto/blkcipher.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -280,12 +280,12 @@ 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);
 		if (err)
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -329,12 +329,12 @@ 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 & alignmask))) {
 		int err = blkcipher_copy_iv(walk, tfm, alignmask);
 		if (err)