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authorHerbert Xu <herbert@gondor.apana.org.au>2019-12-06 13:55:17 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2019-12-11 16:48:38 +0800
commit7db3b61b6bba4310f454588c2ca6faf2958ad79f (patch)
tree531463d296fa92e7a02896dd19aeadb4dc23bcd0
parent579d705cd64e44f3fcda1a6cfd5f37468a5ddf63 (diff)
downloadlinux-7db3b61b6bba4310f454588c2ca6faf2958ad79f.tar.bz2
crypto: api - Check spawn->alg under lock in crypto_drop_spawn
We need to check whether spawn->alg is NULL under lock as otherwise the algorithm could be removed from under us after we have checked it and found it to be non-NULL. This could cause us to remove the spawn from a non-existent list. Fixes: 7ede5a5ba55a ("crypto: api - Fix crypto_drop_spawn crash...") Cc: <stable@vger.kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/algapi.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c
index b052f38edba6..9ecb4a57b342 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -669,11 +669,9 @@ EXPORT_SYMBOL_GPL(crypto_grab_spawn);
void crypto_drop_spawn(struct crypto_spawn *spawn)
{
- if (!spawn->alg)
- return;
-
down_write(&crypto_alg_sem);
- list_del(&spawn->list);
+ if (spawn->alg)
+ list_del(&spawn->list);
up_write(&crypto_alg_sem);
}
EXPORT_SYMBOL_GPL(crypto_drop_spawn);