[PATCH] crypto: skcipher - add might_sleep() to skcipher_walk_virt()

[PATCH] crypto: skcipher - add might_sleep() to skcipher_walk_virt()

[Eric Biggers]

From: Eric Biggers <ebiggers@google.com>

skcipher_walk_virt() can still sleep even with atomic=true, since that
only affects the later calls to skcipher_walk_done().  But,
skcipher_walk_virt() only has to allocate memory for some input data
layouts, so incorrectly calling it with preemption disabled can go
undetected.  Use might_sleep() so that it's detected reliably.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 crypto/skcipher.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 17be8d9c714eb..41b4f7f27f454 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -474,6 +474,8 @@ int skcipher_walk_virt(struct skcipher_walk *walk,
 {
 	int err;
 
+	might_sleep_if(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+
 	walk->flags &= ~SKCIPHER_WALK_PHYS;
 
 	err = skcipher_walk_skcipher(walk, req);
-- 
2.19.2

Re: [PATCH] crypto: skcipher - add might_sleep() to skcipher_walk_virt()

[Herbert Xu]

On Sat, Dec 15, 2018 at 12:41:53PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> skcipher_walk_virt() can still sleep even with atomic=true, since that
> only affects the later calls to skcipher_walk_done().  But,
> skcipher_walk_virt() only has to allocate memory for some input data
> layouts, so incorrectly calling it with preemption disabled can go
> undetected.  Use might_sleep() so that it's detected reliably.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  crypto/skcipher.c | 2 ++
>  1 file changed, 2 insertions(+)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt