[PATCH] cifs: return correct error in ->calc_signature()

[Enzo Matsumiya <ematsumiya@suse.de>]

If an error happens while getting the key or session in the
->calc_signature implementations, 0 (success) is returned. Fix it by
returning a proper error code.

Since it seems to be highly unlikely to happen wrap the rc check in
unlikely() too.

Fixes: 32811d242ff6 ("cifs: Start using per session key for smb2/3 for signature generation")
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/smb2transport.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 1a5fc3314dbf..4640fc4a8b13 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -225,9 +225,9 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
 	struct smb_rqst drqst;
 
 	ses = smb2_find_smb_ses(server, le64_to_cpu(shdr->SessionId));
-	if (!ses) {
+	if (unlikely(!ses)) {
 		cifs_server_dbg(VFS, "%s: Could not find session\n", __func__);
-		return 0;
+		return -ENOENT;
 	}
 
 	memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
@@ -557,8 +557,10 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
 	u8 key[SMB3_SIGN_KEY_SIZE];
 
 	rc = smb2_get_sign_key(le64_to_cpu(shdr->SessionId), server, key);
-	if (rc)
-		return 0;
+	if (unlikely(rc)) {
+		cifs_server_dbg(VFS, "%s: Could not get signing key\n", __func__);
+		return rc;
+	}
 
 	if (allocate_crypto) {
 		rc = cifs_alloc_hash("cmac(aes)", &hash, &sdesc);
-- 
2.35.3