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authorHerbert Xu <herbert@gondor.apana.org.au>2025-09-16 17:20:59 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-10-02 13:39:13 +0200
commite4c1ec11132ec466f7362a95f36a506ce4dc08c9 (patch)
tree4e3b7bd33eea4c48c989a3950f48385861cfd27f /crypto/af_alg.c
parente15de80737d444ed743b1c60ced4a3a97913169b (diff)
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crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg
[ Upstream commit 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ] Issuing two writes to the same af_alg socket is bogus as the data will be interleaved in an unpredictable fashion. Furthermore, concurrent writes may create inconsistencies in the internal socket state. Disallow this by adding a new ctx->write field that indiciates exclusive ownership for writing. Fixes: 8ff590903d5 ("crypto: algif_skcipher - User-space interface for skcipher operations") Reported-by: Muhammad Alifa Ramdhan <ramdhan@starlabs.sg> Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'crypto/af_alg.c')
-rw-r--r--crypto/af_alg.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index aa93501e27b9..24c273f53e90 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -862,6 +862,12 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
}
lock_sock(sk);
+ if (ctx->write) {
+ release_sock(sk);
+ return -EBUSY;
+ }
+ ctx->write = true;
+
if (ctx->init && !ctx->more) {
if (ctx->used) {
err = -EINVAL;
@@ -969,6 +975,7 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
unlock:
af_alg_data_wakeup(sk);
+ ctx->write = false;
release_sock(sk);
return copied ?: err;