CIFS: Fix NULL ptr deref
cifs->master_tlink is NULL against Win Server 2016 (which is
strange.. not sure why) and is dereferenced in cifs_sb_master_tcon().
move master_tlink getter to cifsglob.h so it can be used from
smb2misc.c
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index cb5728e..e2bec47 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -453,8 +453,10 @@ cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
start_of_path = from + 1;
#ifdef CONFIG_CIFS_SMB311
/* SMB311 POSIX extensions paths do not include leading slash */
- else if (cifs_sb_master_tcon(cifs_sb)->posix_extensions)
+ else if (cifs_sb_master_tlink(cifs_sb) &&
+ cifs_sb_master_tcon(cifs_sb)->posix_extensions) {
start_of_path = from + 1;
+ }
#endif /* 311 */
else
start_of_path = from;