From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 141EB41A86; Wed, 20 Dec 2023 16:14:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="oAI2Em4C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DB50C433C8; Wed, 20 Dec 2023 16:14:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1703088869; bh=HTi9zvIoQ3ovi+wjOo27c2gbmoCU3uZCD57CV/WTDJo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oAI2Em4CV2HX6hsl34i0dluvw76N2SnSNJtHGZfr6lWBblEO4bIF9g38sLi55lR0B EGrc1M/9nFGqJa9ssDYxFd+sKjCjJWaX+1bcAwnSFPu+NyOt22i6Cfnu/8ma2nR48v Xy5VoH8OJwEqyZ7UmMaJXLf0JpfPlYq35gUyV+R8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Namjae Jeon , Steve French , zdi-disclosures@trendmicro.com Subject: [PATCH 5.15 088/159] ksmbd: fix racy issue from session setup and logoff Date: Wed, 20 Dec 2023 17:09:13 +0100 Message-ID: <20231220160935.480188228@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231220160931.251686445@linuxfoundation.org> References: <20231220160931.251686445@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Namjae Jeon [ Upstream commit f5c779b7ddbda30866cf2a27c63e34158f858c73 ] This racy issue is triggered by sending concurrent session setup and logoff requests. This patch does not set connection status as KSMBD_SESS_GOOD if state is KSMBD_SESS_NEED_RECONNECT in session setup. And relookup session to validate if session is deleted in logoff. Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-20481, ZDI-CAN-20590, ZDI-CAN-20596 Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/ksmbd/connection.c | 14 ++++---- fs/ksmbd/connection.h | 39 ++++++++++++++----------- fs/ksmbd/mgmt/user_session.c | 1 fs/ksmbd/server.c | 3 + fs/ksmbd/smb2pdu.c | 67 +++++++++++++++++++++++++++---------------- fs/ksmbd/transport_tcp.c | 2 - 6 files changed, 77 insertions(+), 49 deletions(-) --- a/fs/ksmbd/connection.c +++ b/fs/ksmbd/connection.c @@ -56,7 +56,7 @@ struct ksmbd_conn *ksmbd_conn_alloc(void return NULL; conn->need_neg = true; - conn->status = KSMBD_SESS_NEW; + ksmbd_conn_set_new(conn); conn->local_nls = load_nls("utf8"); if (!conn->local_nls) conn->local_nls = load_nls_default(); @@ -147,12 +147,12 @@ int ksmbd_conn_try_dequeue_request(struc return ret; } -static void ksmbd_conn_lock(struct ksmbd_conn *conn) +void ksmbd_conn_lock(struct ksmbd_conn *conn) { mutex_lock(&conn->srv_mutex); } -static void ksmbd_conn_unlock(struct ksmbd_conn *conn) +void ksmbd_conn_unlock(struct ksmbd_conn *conn) { mutex_unlock(&conn->srv_mutex); } @@ -243,7 +243,7 @@ bool ksmbd_conn_alive(struct ksmbd_conn if (!ksmbd_server_running()) return false; - if (conn->status == KSMBD_SESS_EXITING) + if (ksmbd_conn_exiting(conn)) return false; if (kthread_should_stop()) @@ -303,7 +303,7 @@ int ksmbd_conn_handler_loop(void *p) pdu_size = get_rfc1002_len(hdr_buf); ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size); - if (conn->status == KSMBD_SESS_GOOD) + if (ksmbd_conn_good(conn)) max_allowed_pdu_size = SMB3_MAX_MSGSIZE + conn->vals->max_write_size; else @@ -312,7 +312,7 @@ int ksmbd_conn_handler_loop(void *p) if (pdu_size > max_allowed_pdu_size) { pr_err_ratelimited("PDU length(%u) exceeded maximum allowed pdu size(%u) on connection(%d)\n", pdu_size, max_allowed_pdu_size, - conn->status); + READ_ONCE(conn->status)); break; } @@ -417,7 +417,7 @@ again: if (task) ksmbd_debug(CONN, "Stop session handler %s/%d\n", task->comm, task_pid_nr(task)); - conn->status = KSMBD_SESS_EXITING; + ksmbd_conn_set_exiting(conn); if (t->ops->shutdown) { read_unlock(&conn_list_lock); t->ops->shutdown(t); --- a/fs/ksmbd/connection.h +++ b/fs/ksmbd/connection.h @@ -162,6 +162,8 @@ void ksmbd_conn_init_server_callbacks(st int ksmbd_conn_handler_loop(void *p); int ksmbd_conn_transport_init(void); void ksmbd_conn_transport_destroy(void); +void ksmbd_conn_lock(struct ksmbd_conn *conn); +void ksmbd_conn_unlock(struct ksmbd_conn *conn); /* * WARNING @@ -169,43 +171,48 @@ void ksmbd_conn_transport_destroy(void); * This is a hack. We will move status to a proper place once we land * a multi-sessions support. */ -static inline bool ksmbd_conn_good(struct ksmbd_work *work) +static inline bool ksmbd_conn_good(struct ksmbd_conn *conn) { - return work->conn->status == KSMBD_SESS_GOOD; + return READ_ONCE(conn->status) == KSMBD_SESS_GOOD; } -static inline bool ksmbd_conn_need_negotiate(struct ksmbd_work *work) +static inline bool ksmbd_conn_need_negotiate(struct ksmbd_conn *conn) { - return work->conn->status == KSMBD_SESS_NEED_NEGOTIATE; + return READ_ONCE(conn->status) == KSMBD_SESS_NEED_NEGOTIATE; } -static inline bool ksmbd_conn_need_reconnect(struct ksmbd_work *work) +static inline bool ksmbd_conn_need_reconnect(struct ksmbd_conn *conn) { - return work->conn->status == KSMBD_SESS_NEED_RECONNECT; + return READ_ONCE(conn->status) == KSMBD_SESS_NEED_RECONNECT; } -static inline bool ksmbd_conn_exiting(struct ksmbd_work *work) +static inline bool ksmbd_conn_exiting(struct ksmbd_conn *conn) { - return work->conn->status == KSMBD_SESS_EXITING; + return READ_ONCE(conn->status) == KSMBD_SESS_EXITING; } -static inline void ksmbd_conn_set_good(struct ksmbd_work *work) +static inline void ksmbd_conn_set_new(struct ksmbd_conn *conn) { - work->conn->status = KSMBD_SESS_GOOD; + WRITE_ONCE(conn->status, KSMBD_SESS_NEW); } -static inline void ksmbd_conn_set_need_negotiate(struct ksmbd_work *work) +static inline void ksmbd_conn_set_good(struct ksmbd_conn *conn) { - work->conn->status = KSMBD_SESS_NEED_NEGOTIATE; + WRITE_ONCE(conn->status, KSMBD_SESS_GOOD); } -static inline void ksmbd_conn_set_need_reconnect(struct ksmbd_work *work) +static inline void ksmbd_conn_set_need_negotiate(struct ksmbd_conn *conn) { - work->conn->status = KSMBD_SESS_NEED_RECONNECT; + WRITE_ONCE(conn->status, KSMBD_SESS_NEED_NEGOTIATE); } -static inline void ksmbd_conn_set_exiting(struct ksmbd_work *work) +static inline void ksmbd_conn_set_need_reconnect(struct ksmbd_conn *conn) { - work->conn->status = KSMBD_SESS_EXITING; + WRITE_ONCE(conn->status, KSMBD_SESS_NEED_RECONNECT); +} + +static inline void ksmbd_conn_set_exiting(struct ksmbd_conn *conn) +{ + WRITE_ONCE(conn->status, KSMBD_SESS_EXITING); } #endif /* __CONNECTION_H__ */ --- a/fs/ksmbd/mgmt/user_session.c +++ b/fs/ksmbd/mgmt/user_session.c @@ -315,6 +315,7 @@ static struct ksmbd_session *__session_c if (ksmbd_init_file_table(&sess->file_table)) goto error; + sess->state = SMB2_SESSION_IN_PROGRESS; set_session_flag(sess, protocol); xa_init(&sess->tree_conns); xa_init(&sess->ksmbd_chann_list); --- a/fs/ksmbd/server.c +++ b/fs/ksmbd/server.c @@ -93,7 +93,8 @@ static inline int check_conn_state(struc { struct smb_hdr *rsp_hdr; - if (ksmbd_conn_exiting(work) || ksmbd_conn_need_reconnect(work)) { + if (ksmbd_conn_exiting(work->conn) || + ksmbd_conn_need_reconnect(work->conn)) { rsp_hdr = work->response_buf; rsp_hdr->Status.CifsError = STATUS_CONNECTION_DISCONNECTED; return 1; --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -265,7 +265,7 @@ int init_smb2_neg_rsp(struct ksmbd_work rsp = smb2_get_msg(work->response_buf); - WARN_ON(ksmbd_conn_good(work)); + WARN_ON(ksmbd_conn_good(conn)); rsp->StructureSize = cpu_to_le16(65); ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect); @@ -295,7 +295,7 @@ int init_smb2_neg_rsp(struct ksmbd_work rsp->SecurityMode |= SMB2_NEGOTIATE_SIGNING_REQUIRED_LE; conn->use_spnego = true; - ksmbd_conn_set_need_negotiate(work); + ksmbd_conn_set_need_negotiate(conn); return 0; } @@ -574,7 +574,7 @@ int smb2_check_user_session(struct ksmbd cmd == SMB2_SESSION_SETUP_HE) return 0; - if (!ksmbd_conn_good(work)) + if (!ksmbd_conn_good(conn)) return -EIO; sess_id = le64_to_cpu(req_hdr->SessionId); @@ -625,7 +625,7 @@ static void destroy_previous_session(str prev_sess->state = SMB2_SESSION_EXPIRED; xa_for_each(&prev_sess->ksmbd_chann_list, index, chann) - chann->conn->status = KSMBD_SESS_EXITING; + ksmbd_conn_set_exiting(chann->conn); } /** @@ -1081,7 +1081,7 @@ int smb2_handle_negotiate(struct ksmbd_w ksmbd_debug(SMB, "Received negotiate request\n"); conn->need_neg = false; - if (ksmbd_conn_good(work)) { + if (ksmbd_conn_good(conn)) { pr_err("conn->tcp_status is already in CifsGood State\n"); work->send_no_response = 1; return rc; @@ -1236,7 +1236,7 @@ int smb2_handle_negotiate(struct ksmbd_w } conn->srv_sec_mode = le16_to_cpu(rsp->SecurityMode); - ksmbd_conn_set_need_negotiate(work); + ksmbd_conn_set_need_negotiate(conn); err_out: if (rc < 0) @@ -1658,6 +1658,7 @@ int smb2_sess_setup(struct ksmbd_work *w rsp->SecurityBufferLength = 0; inc_rfc1001_len(work->response_buf, 9); + ksmbd_conn_lock(conn); if (!req->hdr.SessionId) { sess = ksmbd_smb2_session_create(); if (!sess) { @@ -1705,6 +1706,12 @@ int smb2_sess_setup(struct ksmbd_work *w goto out_err; } + if (ksmbd_conn_need_reconnect(conn)) { + rc = -EFAULT; + sess = NULL; + goto out_err; + } + if (ksmbd_session_lookup(conn, sess_id)) { rc = -EACCES; goto out_err; @@ -1729,12 +1736,20 @@ int smb2_sess_setup(struct ksmbd_work *w rc = -ENOENT; goto out_err; } + + if (sess->state == SMB2_SESSION_EXPIRED) { + rc = -EFAULT; + goto out_err; + } + + if (ksmbd_conn_need_reconnect(conn)) { + rc = -EFAULT; + sess = NULL; + goto out_err; + } } work->sess = sess; - if (sess->state == SMB2_SESSION_EXPIRED) - sess->state = SMB2_SESSION_IN_PROGRESS; - negblob_off = le16_to_cpu(req->SecurityBufferOffset); negblob_len = le16_to_cpu(req->SecurityBufferLength); if (negblob_off < offsetof(struct smb2_sess_setup_req, Buffer) || @@ -1764,8 +1779,10 @@ int smb2_sess_setup(struct ksmbd_work *w goto out_err; } - ksmbd_conn_set_good(work); - sess->state = SMB2_SESSION_VALID; + if (!ksmbd_conn_need_reconnect(conn)) { + ksmbd_conn_set_good(conn); + sess->state = SMB2_SESSION_VALID; + } kfree(sess->Preauth_HashValue); sess->Preauth_HashValue = NULL; } else if (conn->preferred_auth_mech == KSMBD_AUTH_NTLMSSP) { @@ -1787,8 +1804,10 @@ int smb2_sess_setup(struct ksmbd_work *w if (rc) goto out_err; - ksmbd_conn_set_good(work); - sess->state = SMB2_SESSION_VALID; + if (!ksmbd_conn_need_reconnect(conn)) { + ksmbd_conn_set_good(conn); + sess->state = SMB2_SESSION_VALID; + } if (conn->binding) { struct preauth_session *preauth_sess; @@ -1856,14 +1875,13 @@ out_err: if (sess->user && sess->user->flags & KSMBD_USER_FLAG_DELAY_SESSION) try_delay = true; - xa_erase(&conn->sessions, sess->id); - ksmbd_session_destroy(sess); - work->sess = NULL; + sess->state = SMB2_SESSION_EXPIRED; if (try_delay) ssleep(5); } } + ksmbd_conn_unlock(conn); return rc; } @@ -2087,21 +2105,24 @@ int smb2_session_logoff(struct ksmbd_wor { struct ksmbd_conn *conn = work->conn; struct smb2_logoff_rsp *rsp = smb2_get_msg(work->response_buf); - struct ksmbd_session *sess = work->sess; + struct ksmbd_session *sess; + struct smb2_logoff_req *req = smb2_get_msg(work->request_buf); rsp->StructureSize = cpu_to_le16(4); inc_rfc1001_len(work->response_buf, 4); ksmbd_debug(SMB, "request\n"); - /* setting CifsExiting here may race with start_tcp_sess */ - ksmbd_conn_set_need_reconnect(work); + ksmbd_conn_set_need_reconnect(conn); ksmbd_close_session_fds(work); ksmbd_conn_wait_idle(conn); + /* + * Re-lookup session to validate if session is deleted + * while waiting request complete + */ + sess = ksmbd_session_lookup(conn, le64_to_cpu(req->hdr.SessionId)); if (ksmbd_tree_conn_session_logoff(sess)) { - struct smb2_logoff_req *req = smb2_get_msg(work->request_buf); - ksmbd_debug(SMB, "Invalid tid %d\n", req->hdr.Id.SyncId.TreeId); rsp->hdr.Status = STATUS_NETWORK_NAME_DELETED; smb2_set_err_rsp(work); @@ -2113,9 +2134,7 @@ int smb2_session_logoff(struct ksmbd_wor ksmbd_free_user(sess->user); sess->user = NULL; - - /* let start_tcp_sess free connection info now */ - ksmbd_conn_set_need_negotiate(work); + ksmbd_conn_set_need_negotiate(conn); return 0; } --- a/fs/ksmbd/transport_tcp.c +++ b/fs/ksmbd/transport_tcp.c @@ -333,7 +333,7 @@ static int ksmbd_tcp_readv(struct tcp_tr if (length == -EINTR) { total_read = -ESHUTDOWN; break; - } else if (conn->status == KSMBD_SESS_NEED_RECONNECT) { + } else if (ksmbd_conn_need_reconnect(conn)) { total_read = -EAGAIN; break; } else if (length == -ERESTARTSYS || length == -EAGAIN) {