From 18d8a55f0d5b2ce758126efc8a42c05efcb5f326 Mon Sep 17 00:00:00 2001 From: Romain Izard Date: Tue, 31 Oct 2017 15:42:35 +0100 Subject: [PATCH] crypto: ccm - preserve the IV buffer BugLink: http://bugs.launchpad.net/bugs/1732726 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 Reviewed-by: Tudor Ambarus Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Stefan Bader Signed-off-by: Thadeu Lima de Souza Cascardo --- crypto/ccm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/crypto/ccm.c b/crypto/ccm.c index 1ce37ae0ce56..0a083342ec8c 100644 --- a/crypto/ccm.c +++ b/crypto/ccm.c @@ -363,7 +363,7 @@ static int crypto_ccm_decrypt(struct aead_request *req) 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; @@ -379,6 +379,8 @@ static int crypto_ccm_decrypt(struct aead_request *req) 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); -- 2.39.5