This is a note to let you know that I've just added the patch titled
ksmbd: fix racy issue from session setup and logoff
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ksmbd-fix-racy-issue-from-session-setup-and-logoff.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f5c779b7ddbda30866cf2a27c63e34158f858c73 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Date: Wed, 3 May 2023 16:45:00 +0900
Subject: ksmbd: fix racy issue from session setup and logoff
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
commit f5c779b7ddbda30866cf2a27c63e34158f858c73 upstream.
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@xxxxxxxxxxxxxxx
Reported-by: zdi-disclosures@xxxxxxxxxxxxxx # ZDI-CAN-20481, ZDI-CAN-20590, ZDI-CAN-20596
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
@@ -416,7 +416,7 @@ 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
@@ -248,7 +248,7 @@ 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);
@@ -277,7 +277,7 @@ 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;
}
@@ -561,7 +561,7 @@ 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 -EINVAL;
sess_id = le64_to_cpu(req_hdr->SessionId);
@@ -594,7 +594,7 @@ 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);
}
/**
@@ -1079,7 +1079,7 @@ 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;
@@ -1233,7 +1233,7 @@ 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)
@@ -1656,6 +1656,7 @@ 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) {
@@ -1703,6 +1704,12 @@ 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;
@@ -1727,12 +1734,20 @@ 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) ||
@@ -1762,8 +1777,10 @@ 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) {
@@ -1785,8 +1802,10 @@ 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;
@@ -1854,14 +1873,13 @@ 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;
}
@@ -2086,21 +2104,24 @@ 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);
@@ -2112,9 +2133,7 @@ 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) {
Patches currently in stable-queue which might be from linkinjeon@xxxxxxxxxx are
queue-6.3/ksmbd-block-asynchronous-requests-when-making-a-delay-on-session-setup.patch
queue-6.3/ksmbd-not-allow-guest-user-on-multichannel.patch
queue-6.3/ksmbd-fix-racy-issue-from-smb2-close-and-logoff-with-multichannel.patch
queue-6.3/ksmbd-fix-memleak-in-session-setup.patch
queue-6.3/ksmbd-fix-null-pointer-dereference-in-smb2_get_info_filesystem.patch
queue-6.3/ksmbd-fix-racy-issue-from-session-setup-and-logoff.patch
queue-6.3/ksmbd-fix-racy-issue-under-cocurrent-smb2-tree-disconnect.patch
queue-6.3/ksmbd-fix-deadlock-in-ksmbd_find_crypto_ctx.patch
queue-6.3/ksmbd-destroy-expired-sessions.patch
queue-6.3/ksmbd-call-rcu_barrier-in-ksmbd_server_exit.patch
