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authorJonathan Cameron <Jonathan.Cameron@huawei.com>2017-12-19 13:27:24 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2017-12-22 11:02:40 +0300
commitaf955bf15d2c27496b0269b1f05c26f758c68314 (patch)
tree93a46f7d3a6038882d956007e9b8a927df37b36c
parente57121d08c38dabec15cf3e1e2ad46721af30cae (diff)
downloadlinux-af955bf15d2c27496b0269b1f05c26f758c68314.tar.xz
crypto: af_alg - Fix race around ctx->rcvused by making it atomic_t
This variable was increased and decreased without any protection. Result was an occasional misscount and negative wrap around resulting in false resource allocation failures. Fixes: 7d2c3f54e6f6 ("crypto: af_alg - remove locking in async callback") Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/af_alg.c4
-rw-r--r--crypto/algif_aead.c2
-rw-r--r--crypto/algif_skcipher.c2
-rw-r--r--include/crypto/if_alg.h5
4 files changed, 7 insertions, 6 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index f1a2caf1b59b..d3f1c431724b 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)
@@ -1162,7 +1162,7 @@ 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 b73db2b27656..20df8c1b6851 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -571,7 +571,7 @@ 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 baef9bfccdda..c5c47b680152 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -390,7 +390,7 @@ 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 <linux/if_alg.h>
#include <linux/scatterlist.h>
#include <linux/types.h>
+#include <linux/atomic.h>
#include <net/sock.h>
#include <crypto/aead.h>
@@ -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);
}
/**