From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 22 Jun 2021 10:59:55 +0000 (+0300)
Subject: cifs: fix NULL dereference in smb2_check_message()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1689b0b554defd5a7863bbd434ae911b8869504a;p=linux.git

cifs: fix NULL dereference in smb2_check_message()

This code sets "ses" to NULL which will lead to a NULL dereference on
the second iteration through the loop.

Fixes: 85346c17e425 ("cifs: convert list_for_each to entry variant in smb2misc.c")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index c6bb2ea1983ba..668f771088318 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -158,11 +158,10 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *srvr)
 		list_for_each_entry(ses, &srvr->smb_ses_list, smb_ses_list) {
 			if (ses->Suid == thdr->SessionId)
 				break;
-
-			ses = NULL;
 		}
 		spin_unlock(&cifs_tcp_ses_lock);
-		if (ses == NULL) {
+		if (list_entry_is_head(ses, &srvr->smb_ses_list,
+				       smb_ses_list)) {
 			cifs_dbg(VFS, "no decryption - session id not found\n");
 			return 1;
 		}