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authorStephan Mueller <smueller@chronox.de>2017-11-29 12:02:23 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2017-12-11 22:29:54 +1100
commit11edb555966ed2c66c533d17c604f9d7e580a829 (patch)
treedae6e140f8c759c9d966e7cb0e25b5c69f0dae7b /crypto/af_alg.c
parent2b4f27c36bcd46e820ddb9a8e6fe6a63fa4250b8 (diff)
downloadlwn-11edb555966ed2c66c533d17c604f9d7e580a829.tar.gz
lwn-11edb555966ed2c66c533d17c604f9d7e580a829.zip
crypto: af_alg - wait for data at beginning of recvmsg
The wait for data is a non-atomic operation that can sleep and therefore potentially release the socket lock. The release of the socket lock allows another thread to modify the context data structure. The waiting operation for new data therefore must be called at the beginning of recvmsg. This prevents a race condition where checks of the members of the context data structure are performed by recvmsg while there is a potential for modification of these values. Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management") Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management") Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> # v4.14+ Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/af_alg.c')
-rw-r--r--crypto/af_alg.c6
1 files changed, 0 insertions, 6 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 358749c38894..f1a2caf1b59b 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1137,12 +1137,6 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
if (!af_alg_readable(sk))
break;
- if (!ctx->used) {
- err = af_alg_wait_for_data(sk, flags);
- if (err)
- return err;
- }
-
seglen = min_t(size_t, (maxsize - len),
msg_data_left(msg));