[3.19.y-ckt stable] Patch "crypto: ahash - ensure statesize is non-zero" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    crypto: ahash - ensure statesize is non-zero

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 7d3c73865cb6079a02a62117c8fb17788c6098bb Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel at arm.linux.org.uk>
Date: Fri, 9 Oct 2015 20:43:33 +0100
Subject: [PATCH 041/120] crypto: ahash - ensure statesize is non-zero

commit 8996eafdcbad149ac0f772fb1649fbb75c482a6a upstream.

Unlike shash algorithms, ahash drivers must implement export
and import as their descriptors may contain hardware state and
cannot be exported as is.  Unfortunately some ahash drivers did
not provide them and end up causing crashes with algif_hash.

This patch adds a check to prevent these drivers from registering
ahash algorithms until they are fixed.

Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 crypto/ahash.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crypto/ahash.c b/crypto/ahash.c
index f6a36a5..c1d8591 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -543,7 +543,8 @@ static int ahash_prepare_alg(struct ahash_alg *alg)
 	struct crypto_alg *base = &alg->halg.base;

 	if (alg->halg.digestsize > PAGE_SIZE / 8 ||
-	    alg->halg.statesize > PAGE_SIZE / 8)
+	    alg->halg.statesize > PAGE_SIZE / 8 ||
+	    alg->halg.statesize == 0)
 		return -EINVAL;

 	base->cra_type = &crypto_ahash_type;
--
1.9.1