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authorJonathan Cameron <Jonathan.Cameron@huawei.com>2017-12-19 10:27:24 +0000
committerHerbert Xu <herbert@gondor.apana.org.au>2017-12-22 19:02:40 +1100
commitaf955bf15d2c27496b0269b1f05c26f758c68314 (patch)
tree93a46f7d3a6038882d956007e9b8a927df37b36c /include/crypto
parente57121d08c38dabec15cf3e1e2ad46721af30cae (diff)
downloadlinux-af955bf15d2c27496b0269b1f05c26f758c68314.tar.gz
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>
Diffstat (limited to 'include/crypto')
-rw-r--r--include/crypto/if_alg.h5
1 files changed, 3 insertions, 2 deletions
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);
 }
 
 /**