[PATCH 5.14 167/172] crypto: aesni - xts_crypt() return if walk.nbytes is 0

[Greg Kroah-Hartman]

From: Shreyansh Chouhan <chouhan.shreyansh630@xxxxxxxxx>

commit 72ff2bf04db2a48840df93a461b7115900f46c05 upstream.

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>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/x86/crypto/aesni-intel_glue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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_req
 		return -EINVAL;
 
 	err = skcipher_walk_virt(&walk, req, false);
-	if (err)
+	if (!walk.nbytes)
 		return err;
 
 	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {