From: Gil Portnoy Date: Mon, 13 Jul 2026 00:20:09 +0000 (+0900) Subject: ksmbd: lock the binding preauth session in smb3_preauth_hash_rsp X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=35754558f6c21d0fa0985dceb3387071a3348aff;p=thirdparty%2Fkernel%2Flinux.git ksmbd: lock the binding preauth session in smb3_preauth_hash_rsp smb3_preauth_hash_rsp() computes the SMB3.1.1 preauth integrity hash on the response path. For a binding SESSION_SETUP it looks up the per-connection preauth_session and reads its Preauth_HashValue. smb2_sess_setup() frees that preauth_session under ksmbd_conn_lock(). Two SMB2 requests on one connection can run concurrently, so an unlocked lookup and hash can use a preauth_session after another worker frees it. Take ksmbd_conn_lock() before selecting conn->binding and hold it across the selected preauth hash lookup and update. This preserves the existing hash selection while preventing the lookup-to-use lifetime race. Fixes: 1c5daa2ea924 ("ksmbd: handle channel binding with a different user") Signed-off-by: Gil Portnoy Acked-by: Namjae Jeon Signed-off-by: Steve French --- diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 8686b9a4a696..bec692bca1ca 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -9808,22 +9808,21 @@ void smb3_preauth_hash_rsp(struct ksmbd_work *work) } if (le16_to_cpu(rsp->Command) == SMB2_SESSION_SETUP_HE && sess) { - __u8 *hash_value; + ksmbd_conn_lock(conn); if (conn->binding) { struct preauth_session *preauth_sess; preauth_sess = ksmbd_preauth_session_lookup(conn, sess->id); - if (!preauth_sess) - return; - hash_value = preauth_sess->Preauth_HashValue; - } else { - hash_value = sess->Preauth_HashValue; - if (!hash_value) - return; + if (preauth_sess) + ksmbd_gen_preauth_integrity_hash(conn, + work->response_buf, + preauth_sess->Preauth_HashValue); + } else if (sess->Preauth_HashValue) { + ksmbd_gen_preauth_integrity_hash(conn, work->response_buf, + sess->Preauth_HashValue); } - ksmbd_gen_preauth_integrity_hash(conn, work->response_buf, - hash_value); + ksmbd_conn_unlock(conn); } }