Commit 7db3b61b authored Dec 06, 2019 by Herbert Xu

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: 7ede5a5b ("crypto: api - Fix crypto_drop_spawn crash...")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 579d705c

crypto/algapi.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -669,10 +669,8 @@ EXPORT_SYMBOL_GPL(crypto_grab_spawn);

		void crypto_drop_spawn(struct crypto_spawn *spawn)
		{
		if (!spawn->alg)
		return;

		down_write(&crypto_alg_sem);
		if (spawn->alg)
		list_del(&spawn->list);
		up_write(&crypto_alg_sem);
		}

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