From: Herbert Xu herbert@gondor.apana.org.au
commit 7db3b61b6bba4310f454588c2ca6faf2958ad79f upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- crypto/algapi.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- 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);