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crypto: api - Check spawn->alg under lock in crypto_drop_spawn
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: 7ede5a5ba5
("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>
This commit is contained in:
parent
0ed43162f5
commit
d2b1dcd543
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@ -669,11 +669,9 @@ EXPORT_SYMBOL_GPL(crypto_grab_spawn);
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void crypto_drop_spawn(struct crypto_spawn *spawn)
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void crypto_drop_spawn(struct crypto_spawn *spawn)
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{
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{
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if (!spawn->alg)
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return;
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down_write(&crypto_alg_sem);
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down_write(&crypto_alg_sem);
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list_del(&spawn->list);
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if (spawn->alg)
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list_del(&spawn->list);
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up_write(&crypto_alg_sem);
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up_write(&crypto_alg_sem);
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}
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}
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EXPORT_SYMBOL_GPL(crypto_drop_spawn);
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EXPORT_SYMBOL_GPL(crypto_drop_spawn);
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