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[7/7] crypto: ccree: don't copy zero size ciphertext

Message ID 20190115134318.28712-8-gilad@benyossef.com
State Accepted
Commit 2b5ac17463dcb2411fed506edcf259a89bb538ba
Headers show
Series bug fixes and cleanups | expand

Commit Message

Gilad Ben-Yossef Jan. 15, 2019, 1:43 p.m. UTC
For decryption in CBC mode we need to save the last ciphertext block
for use as the next IV. However, we were trying to do this also with
zero sized ciphertext resulting in a panic.

Fix this by only doing the copy if the ciphertext length is at least
of IV size.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>

Cc: stable@vger.kernel.org
---
 drivers/crypto/ccree/cc_cipher.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

-- 
2.20.1
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Patch

diff --git a/drivers/crypto/ccree/cc_cipher.c b/drivers/crypto/ccree/cc_cipher.c
index 98ea53524250..e202d7c7ea00 100644
--- a/drivers/crypto/ccree/cc_cipher.c
+++ b/drivers/crypto/ccree/cc_cipher.c
@@ -800,7 +800,8 @@  static int cc_cipher_decrypt(struct skcipher_request *req)
 
 	memset(req_ctx, 0, sizeof(*req_ctx));
 
-	if (ctx_p->cipher_mode == DRV_CIPHER_CBC) {
+	if ((ctx_p->cipher_mode == DRV_CIPHER_CBC) &&
+	    (req->cryptlen >= ivsize)) {
 
 		/* Allocate and save the last IV sized bytes of the source,
 		 * which will be lost in case of in-place decryption.