[PATCH 6.12 094/567] ksmbd: Fix refcount leak when invalid session is found on session lookup

Greg Kroah-Hartman
2026-01-06T17:19:28Z

From: Namjae Jeon <linkinjeon@kernel.org>

commit cafb57f7bdd57abba87725eb4e82bbdca4959644 upstream.

When a session is found but its state is not SMB2_SESSION_VALID, It
indicates that no valid session was found, but it is missing to decrement
the reference count acquired by the session lookup, which results in
a reference count leak. This patch fixes the issue by explicitly calling
ksmbd_user_session_put to release the reference to the session.

Cc: stable@vger.kernel.org
Reported-by: Alexandre <roger.andersen@protonmail.com>
Reported-by: Stanislas Polu <spolu@dust.tt>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/smb/server/mgmt/user_session.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/smb/server/mgmt/user_session.c
+++ b/fs/smb/server/mgmt/user_session.c
@@ -325,8 +325,10 @@ struct ksmbd_session *ksmbd_session_look
sess = ksmbd_session_lookup(conn, id);
if (!sess && conn->binding)
sess = ksmbd_session_lookup_slowpath(id);
- if (sess && sess->state != SMB2_SESSION_VALID)
+ if (sess && sess->state != SMB2_SESSION_VALID) {
+ ksmbd_user_session_put(sess);
sess = NULL;
+ }
return sess;
}