crypto: lrw - Fix atomic sleep when walking skcipher

crypto: lrw - Fix atomic sleep when walking skcipher

[Herbert Xu]

When we perform a walk in the completion function, we need to ensure
that it is atomic.

Fixes: ac3c8f36c31d ("crypto: lrw - Do not use auxiliary buffer")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/lrw.c b/crypto/lrw.c
index 0430ccd08728..aef3588e1550 100644
--- a/crypto/lrw.c
+++ b/crypto/lrw.c
@@ -143,7 +143,8 @@ static int next_index(u32 *counter)
  * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
  * just doing the next_index() calls again.
  */
-static int xor_tweak(struct skcipher_request *req, bool second_pass)
+static int xor_tweak(struct skcipher_request *req, bool second_pass,
+		     bool atomic)
 {
 	const int bs = LRW_BLOCK_SIZE;
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -161,7 +162,7 @@ static int xor_tweak(struct skcipher_request *req, bool second_pass)
 		skcipher_request_set_tfm(req, tfm);
 	}
 
-	err = skcipher_walk_virt(&w, req, false);
+	err = skcipher_walk_virt(&w, req, atomic);
 	iv = (__be32 *)w.iv;
 
 	counter[0] = be32_to_cpu(iv[3]);
@@ -200,12 +201,12 @@ static int xor_tweak(struct skcipher_request *req, bool second_pass)
 
 static int xor_tweak_pre(struct skcipher_request *req)
 {
-	return xor_tweak(req, false);
+	return xor_tweak(req, false, false);
 }
 
-static int xor_tweak_post(struct skcipher_request *req)
+static int xor_tweak_post(struct skcipher_request *req, bool atomic)
 {
-	return xor_tweak(req, true);
+	return xor_tweak(req, true, atomic);
 }
 
 static void crypt_done(struct crypto_async_request *areq, int err)
@@ -213,7 +214,7 @@ static void crypt_done(struct crypto_async_request *areq, int err)
 	struct skcipher_request *req = areq->data;
 
 	if (!err)
-		err = xor_tweak_post(req);
+		err = xor_tweak_post(req, true);
 
 	skcipher_request_complete(req, err);
 }
@@ -245,7 +246,7 @@ static int encrypt(struct skcipher_request *req)
 	init_crypt(req);
 	return xor_tweak_pre(req) ?:
 		crypto_skcipher_encrypt(subreq) ?:
-		xor_tweak_post(req);
+		xor_tweak_post(req, false);
 }
 
 static int decrypt(struct skcipher_request *req)
@@ -256,7 +257,7 @@ static int decrypt(struct skcipher_request *req)
 	init_crypt(req);
 	return xor_tweak_pre(req) ?:
 		crypto_skcipher_decrypt(subreq) ?:
-		xor_tweak_post(req);
+		xor_tweak_post(req, false);
 }
 
 static int init_tfm(struct crypto_skcipher *tfm)
-- 
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

[v2 PATCH] crypto: lrw - Fix atomic sleep when walking skcipher

[Herbert Xu]

When we perform a walk in the completion function, we need to ensure
that it is atomic.

Fixes: ac3c8f36c31d ("crypto: lrw - Do not use auxiliary buffer")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/lrw.c b/crypto/lrw.c
index 0430ccd08728..08a0e458bc3e 100644
--- a/crypto/lrw.c
+++ b/crypto/lrw.c
@@ -212,8 +212,12 @@ static void crypt_done(struct crypto_async_request *areq, int err)
 {
 	struct skcipher_request *req = areq->data;
 
-	if (!err)
+	if (!err) {
+		struct rctx *rctx = skcipher_request_ctx(req);
+
+		rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 		err = xor_tweak_post(req);
+	}
 
 	skcipher_request_complete(req, err);
 }
-- 
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

Re: [v2 PATCH] crypto: lrw - Fix atomic sleep when walking skcipher

[Ondrej Mosnacek]

On Mon, Apr 15, 2019 at 8:37 AM Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> When we perform a walk in the completion function, we need to ensure
> that it is atomic.
>
> Fixes: ac3c8f36c31d ("crypto: lrw - Do not use auxiliary buffer")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Acked-by: Ondrej Mosnacek <omosnace@redhat.com>

>
> diff --git a/crypto/lrw.c b/crypto/lrw.c
> index 0430ccd08728..08a0e458bc3e 100644
> --- a/crypto/lrw.c
> +++ b/crypto/lrw.c
> @@ -212,8 +212,12 @@ static void crypt_done(struct crypto_async_request *areq, int err)
>  {
>         struct skcipher_request *req = areq->data;
>
> -       if (!err)
> +       if (!err) {
> +               struct rctx *rctx = skcipher_request_ctx(req);
> +
> +               rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
>                 err = xor_tweak_post(req);
> +       }
>
>         skcipher_request_complete(req, err);
>  }
> --
> 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

-- 
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.