From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: [Plinth PATCH]{topost} crypto: Fix race around ctx->rcvused by making it atomic_t Date: Tue, 19 Dec 2017 10:27:24 +0000 Message-ID: <20171218161045.0000161c@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit To: , , Stephan Mueller , , Return-path: Received: from szxga07-in.huawei.com ([45.249.212.35]:49247 "EHLO huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S933241AbdLSK1q (ORCPT ); Tue, 19 Dec 2017 05:27:46 -0500 Sender: linux-crypto-owner@vger.kernel.org List-ID: This variable was increased and decreased without any protection. Result was an occasional misscount and negative wrap around resulting in false resource allocation failures. Signed-off-by: Jonathan Cameron Fixes: 2d97591ef43d ("crypto: af_alg - consolidation of duplicate code") --- The fixes tag is probably not ideal as I'm not 100% sure when this actually became a bug. The code in question was introduced in Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management") and related. rcvused moved in Fixes: 2d97591ef43d ("crypto: af_alg - consolidation of duplicate code") So I have gone with the latter option as that is where it will cleanly apply. However, it probably doesn't matter as both are present only in the 4.14 final kernel. crypto/af_alg.c | 4 ++-- crypto/algif_aead.c | 2 +- crypto/algif_skcipher.c | 2 +- include/crypto/if_alg.h | 5 +++-- 4 files changed, 7 insertions(+), 6 deletions(-) diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 8612aa36a3ef..759cfa678c04 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -664,7 +664,7 @@ void af_alg_free_areq_sgls(struct af_alg_async_req *areq) unsigned int i; list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) { - ctx->rcvused -= rsgl->sg_num_bytes; + atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused); af_alg_free_sg(&rsgl->sgl); list_del(&rsgl->list); if (rsgl != &areq->first_rsgl) @@ -1173,7 +1173,7 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, areq->last_rsgl = rsgl; len += err; - ctx->rcvused += err; + atomic_add(err, &ctx->rcvused); rsgl->sg_num_bytes = err; iov_iter_advance(&msg->msg_iter, err); } diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c index db9378a45296..d3da3b0869f5 100644 --- a/crypto/algif_aead.c +++ b/crypto/algif_aead.c @@ -550,7 +550,7 @@ static int aead_accept_parent_nokey(void *private, struct sock *sk) INIT_LIST_HEAD(&ctx->tsgl_list); ctx->len = len; ctx->used = 0; - ctx->rcvused = 0; + atomic_set(&ctx->rcvused, 0); ctx->more = 0; ctx->merge = 0; ctx->enc = 0; diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c index c7c75ef41952..a5b4898f625a 100644 --- a/crypto/algif_skcipher.c +++ b/crypto/algif_skcipher.c @@ -388,7 +388,7 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk) INIT_LIST_HEAD(&ctx->tsgl_list); ctx->len = len; ctx->used = 0; - ctx->rcvused = 0; + atomic_set(&ctx->rcvused, 0); ctx->more = 0; ctx->merge = 0; ctx->enc = 0; diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index 38d9c5861ed8..f38227a78eae 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -150,7 +151,7 @@ struct af_alg_ctx { struct crypto_wait wait; size_t used; - size_t rcvused; + atomic_t rcvused; bool more; bool merge; @@ -215,7 +216,7 @@ static inline int af_alg_rcvbuf(struct sock *sk) struct af_alg_ctx *ctx = ask->private; return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) - - ctx->rcvused, 0); + atomic_read(&ctx->rcvused), 0); } /** -- 2.11.0