[PATCH] crypto: xts_crypt() return if walk.nbytes is 0

[Shreyansh Chouhan]

xts_crypt() code doesn't call kernel_fpu_end() after calling
kernel_fpu_begin() if walk.nbytes is 0. The correct behavior should be
not calling kernel_fpu_begin() if walk.nbytes is 0.

Reported-by: syzbot+20191dc583eff8602d2d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@xxxxxxxxx>
---
 arch/x86/crypto/aesni-intel_glue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 388643ca2177..ec6eac57c493 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -849,7 +849,7 @@ static int xts_crypt(struct skcipher_request *req, bool encrypt)
 		return -EINVAL;
 
 	err = skcipher_walk_virt(&walk, req, false);
-	if (err)
+	if (err || !walk.nbytes)
 		return err;
 
 	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
-- 
2.31.1