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%3Ba=su...

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 stable@vger.kernel.org know about it.

From 441f99c90497e15aa3ad1dbabd56187e29614348 Mon Sep 17 00:00:00 2001

From: Romain Izard romain.izard.pro@gmail.com Date: Tue, 31 Oct 2017 15:42:35 +0100 Subject: crypto: ccm - preserve the IV buffer

From: Romain Izard romain.izard.pro@gmail.com

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.

Signed-off-by: Romain Izard romain.izard.pro@gmail.com Reviewed-by: Tudor Ambarus tudor.ambarus@microchip.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

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

--- a/crypto/ccm.c +++ b/crypto/ccm.c @@ -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 romain.izard.pro@gmail.com are

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