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

[Luis Henriques]

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-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt20.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 59aff89435b9be17c5b53706c1550ea8aadbbb25 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: 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: Luis Henriques <luis.henriques 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 f2a5d8f656ff..d3e86a46ecea 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -537,7 +537,8 @@ 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;