[PATCH 5.10.y] cifs: Fix connections leak when tlink setup failed

[PATCH 5.10.y] cifs: Fix connections leak when tlink setup failed

[Vasiliy Kovalev]

From: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>

commit 1dcdf5f5b2137185cbdd5385f29949ab3da4f00c upstream.

If the tlink setup failed, lost to put the connections, then
the module refcnt leak since the cifsd kthread not exit.

Also leak the fscache info, and for next mount with fsc, it will
print the follow errors:
  CIFS: Cache volume key already in use (cifs,127.0.0.1:445,TEST)

Let's check the result of tlink setup, and do some cleanup.

Fixes: 56c762eb9bee ("cifs: Refactor out cifs_mount()")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
[ kovalev: bp to fix CVE-2022-49822; adapted to use direct xid/ses/tcon
  variables instead of mnt_ctx struct fields due to the older kernel not
  having the corresponding cifs_mount() refactoring (see upstream commit
  c88f7dcd6d64) ]
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
---
 fs/cifs/connect.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 769c7759601d..3161155fd069 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -4786,9 +4786,13 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
 	vol->prepath = NULL;
 
 out:
-	free_xid(xid);
 	cifs_try_adding_channels(ses);
-	return mount_setup_tlink(cifs_sb, ses, tcon);
+	rc = mount_setup_tlink(cifs_sb, ses, tcon);
+	if (rc)
+		goto error;
+
+	free_xid(xid);
+	return rc;
 
 error:
 	kfree(ref_path);
@@ -4820,9 +4824,12 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
 			goto error;
 	}
 
-	free_xid(xid);
+	rc = mount_setup_tlink(cifs_sb, ses, tcon);
+	if (rc)
+		goto error;
 
-	return mount_setup_tlink(cifs_sb, ses, tcon);
+	free_xid(xid);
+	return rc;
 
 error:
 	mount_put_conns(cifs_sb, xid, server, ses, tcon);
-- 
2.50.1