From mboxrd@z Thu Jan 1 00:00:00 1970 From: Herbert Xu Subject: [v4 PATCH 2/3] crypto: algif_skcipher - Do not dereference ctx without socket lock Date: Wed, 03 Feb 2016 21:39:26 +0800 Message-ID: References: <20160203133648.GA29251@gondor.apana.org.au> To: Tadeusz Struk , linux-crypto@vger.kernel.org Return-path: Received: from helcar.hengli.com.au ([209.40.204.226]:54435 "EHLO helcar.hengli.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752770AbcBCNj2 (ORCPT ); Wed, 3 Feb 2016 08:39:28 -0500 Sender: linux-crypto-owner@vger.kernel.org List-ID: Any access to non-constant bits of the private context must be done under the socket lock, in particular, this includes ctx->req. This patch moves such accesses under the lock, and fetches the tfm from the parent socket which is guaranteed to be constant, rather than from ctx->req. Signed-off-by: Herbert Xu --- crypto/algif_skcipher.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c index ec07a86..ef84353 100644 --- a/crypto/algif_skcipher.c +++ b/crypto/algif_skcipher.c @@ -295,8 +295,11 @@ static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg, { struct sock *sk = sock->sk; struct alg_sock *ask = alg_sk(sk); + struct sock *psk = ask->parent; + struct alg_sock *pask = alg_sk(psk); struct skcipher_ctx *ctx = ask->private; - struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(&ctx->req); + struct skcipher_tfm *skc = pask->private; + struct crypto_skcipher *tfm = skc->skcipher; unsigned ivsize = crypto_skcipher_ivsize(tfm); struct skcipher_sg_list *sgl; struct af_alg_control con = {}; @@ -508,7 +511,7 @@ static int skcipher_recvmsg_async(struct socket *sock, struct msghdr *msg, struct skcipher_async_req *sreq; struct skcipher_request *req; struct skcipher_async_rsgl *last_rsgl = NULL; - unsigned int txbufs = 0, len = 0, tx_nents = skcipher_all_sg_nents(ctx); + unsigned int txbufs = 0, len = 0, tx_nents; unsigned int reqsize = crypto_skcipher_reqsize(tfm); unsigned int ivsize = crypto_skcipher_ivsize(tfm); int err = -ENOMEM; @@ -526,6 +529,7 @@ static int skcipher_recvmsg_async(struct socket *sock, struct msghdr *msg, sreq->inflight = &ctx->inflight; lock_sock(sk); + tx_nents = skcipher_all_sg_nents(ctx); sreq->tsg = kcalloc(tx_nents, sizeof(*sg), GFP_KERNEL); if (unlikely(!sreq->tsg)) goto unlock; @@ -633,9 +637,12 @@ static int skcipher_recvmsg_sync(struct socket *sock, struct msghdr *msg, { struct sock *sk = sock->sk; struct alg_sock *ask = alg_sk(sk); + struct sock *psk = ask->parent; + struct alg_sock *pask = alg_sk(psk); struct skcipher_ctx *ctx = ask->private; - unsigned bs = crypto_skcipher_blocksize(crypto_skcipher_reqtfm( - &ctx->req)); + struct skcipher_tfm *skc = pask->private; + struct crypto_skcipher *tfm = skc->skcipher; + unsigned bs = crypto_skcipher_blocksize(tfm); struct skcipher_sg_list *sgl; struct scatterlist *sg; int err = -EAGAIN;