[v4 PATCH 2/3] crypto: algif_skcipher - Do not dereference ctx without socket lock
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2016-02-03 13:39:28
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
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 <herbert@gondor.apana.org.au> --- 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;