Patch "crypto: mcryptd - Check mcryptd algorithm compatibility" has been added to the 4.8-stable tree

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

crypto: mcryptd - Check mcryptd algorithm compatibility

to the 4.8-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-mcryptd-check-mcryptd-algorithm-compatibility.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: tim <[email protected]>
Date: Mon, 5 Dec 2016 11:46:31 -0800
Subject: crypto: mcryptd - Check mcryptd algorithm compatibility

From: tim <[email protected]>

commit 48a992727d82cb7db076fa15d372178743b1f4cd upstream.

Algorithms not compatible with mcryptd could be spawned by mcryptd with a direct crypto_alloc_tfm invocation using a "mcryptd(alg)" name construct. This causes mcryptd to crash the kernel if an arbitrary "alg" is incompatible and not intended to be used with mcryptd. It is an issue if AF_ALG tries to spawn mcryptd(alg) to expose it externally. But such algorithms must be used internally and not be exposed.

We added a check to enforce that only internal algorithms are allowed with mcryptd at the time mcryptd is spawning an algorithm.

---
 crypto/mcryptd.c |   19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

@@ -254,18 +254,22 @@ out_free_inst:
 	goto out;
 }
 
-static inline void mcryptd_check_internal(struct rtattr **tb, u32 *type,
+static inline bool mcryptd_check_internal(struct rtattr **tb, u32 *type,
 					  u32 *mask)
 {
 	struct crypto_attr_type *algt;
 
 	algt = crypto_get_attr_type(tb);
 	if (IS_ERR(algt))
-		return;
-	if ((algt->type & CRYPTO_ALG_INTERNAL))
-		*type |= CRYPTO_ALG_INTERNAL;
-	if ((algt->mask & CRYPTO_ALG_INTERNAL))
-		*mask |= CRYPTO_ALG_INTERNAL;
+		return false;
+
+	*type |= algt->type & CRYPTO_ALG_INTERNAL;
+	*mask |= algt->mask & CRYPTO_ALG_INTERNAL;
+
+	if (*type & *mask & CRYPTO_ALG_INTERNAL)
+		return true;
+	else
+		return false;
 }
 
 static int mcryptd_hash_init_tfm(struct crypto_tfm *tfm)

@@ -492,7 +496,8 @@ static int mcryptd_create_hash(struct cr
 	u32 mask = 0;
 	int err;
 
-	mcryptd_check_internal(tb, &type, &mask);
+	if (!mcryptd_check_internal(tb, &type, &mask))
+		return -EINVAL;
 
 	halg = ahash_attr_alg(tb[1], type, mask);
 	if (IS_ERR(halg))

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/crypto-mcryptd-check-mcryptd-algorithm-compatibility.patch