Patch "crypto: ccm - preserve the IV buffer" has been added to the 4.9-stable tree

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

crypto: ccm - preserve the IV buffer

to the 4.9-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-ccm-preserve-the-iv-buffer.patch
and it can be found in the queue-4.9 subdirectory.

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

From: Romain Izard <[email protected]>
Date: Tue, 31 Oct 2017 15:42:35 +0100
Subject: crypto: ccm - preserve the IV buffer

From: Romain Izard <[email protected]>

commit 441f99c90497e15aa3ad1dbabd56187e29614348 upstream.

The IV buffer used during CCM operations is used twice, during both the hashing step and the ciphering step.

When using a hardware accelerator that updates the contents of the IV buffer at the end of ciphering operations, the value will be modified. In the decryption case, the subsequent setup of the hashing algorithm will interpret the updated IV instead of the original value, which can lead to out-of-bounds writes.

Reuse the idata buffer, only used in the hashing step, to preserve the IV's value during the ciphering step in the decryption case.

---
 crypto/ccm.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -413,7 +413,7 @@ static int crypto_ccm_decrypt(struct aea
 	unsigned int cryptlen = req->cryptlen;
 	u8 *authtag = pctx->auth_tag;
 	u8 *odata = pctx->odata;
-	u8 *iv = req->iv;
+	u8 *iv = pctx->idata;
 	int err;
 
 	cryptlen -= authsize;

@@ -429,6 +429,8 @@ static int crypto_ccm_decrypt(struct aea
 	if (req->src != req->dst)
 		dst = pctx->dst;
 
+	memcpy(iv, req->iv, 16);
+
 	skcipher_request_set_tfm(skreq, ctx->ctr);
 	skcipher_request_set_callback(skreq, pctx->flags,
 				      crypto_ccm_decrypt_done, req);

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

queue-4.9/crypto-ccm-preserve-the-iv-buffer.patch