cifs: fix missing null session check in mount

Although it is unlikely to be have ended up with a null
session pointer calling cifs_try_adding_channels in cifs_mount.
Coverity correctly notes that we are already checking for
it earlier (when we return from do_dfs_failover), so at
a minimum to clarify the code we should make sure we also
check for it when we exit the loop so we don't end up calling
cifs_try_adding_channels or mount_setup_tlink with a null
ses pointer.

Addresses-Coverity: 1505608 ("Derefernce after null check")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index d49c9e5..a1e8702 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3508,7 +3508,7 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
                        rc = -ELOOP;
        } while (rc == -EREMOTE);
 
-       if (rc || !tcon)
+       if (rc || !tcon || !ses)
                goto error;
 
        kfree(ref_path);