From 1e440d5b25b7efccb3defe542a73c51005799a5f Mon Sep 17 00:00:00 2001 From: Sean Heelan Date: Mon, 7 Apr 2025 11:26:50 +0000 Subject: [PATCH 1/6] ksmbd: Fix dangling pointer in krb_authenticate krb_authenticate frees sess->user and does not set the pointer to NULL. It calls ksmbd_krb5_authenticate to reinitialise sess->user but that function may return without doing so. If that happens then smb2_sess_setup, which calls krb_authenticate, will be accessing free'd memory when it later uses sess->user. Cc: stable@vger.kernel.org Signed-off-by: Sean Heelan Acked-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/smb2pdu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index d24d95d15d87..57839f9708bb 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -1602,8 +1602,10 @@ static int krb5_authenticate(struct ksmbd_work *work, if (prev_sess_id && prev_sess_id != sess->id) destroy_previous_session(conn, sess->user, prev_sess_id); - if (sess->state == SMB2_SESSION_VALID) + if (sess->state == SMB2_SESSION_VALID) { ksmbd_free_user(sess->user); + sess->user = NULL; + } retval = ksmbd_krb5_authenticate(sess, in_blob, in_len, out_blob, &out_len); From 1df0d4c616138784e033ad337961b6e1a6bcd999 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 15 Apr 2025 09:26:10 +0900 Subject: [PATCH 2/6] ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING" wait_event_timeout() will set the state of the current task to TASK_UNINTERRUPTIBLE, before doing the condition check. This means that ksmbd_durable_scavenger_alive() will try to acquire the mutex while already in a sleeping state. The scheduler warns us by giving the following warning: do not call blocking ops when !TASK_RUNNING; state=2 set at [<0000000061515a6f>] prepare_to_wait_event+0x9f/0x6c0 WARNING: CPU: 2 PID: 4147 at kernel/sched/core.c:10099 __might_sleep+0x12f/0x160 mutex lock is not needed in ksmbd_durable_scavenger_alive(). Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/vfs_cache.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index 8d1f30dcba7e..1f8fa3468173 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -713,12 +713,8 @@ static bool tree_conn_fd_check(struct ksmbd_tree_connect *tcon, static bool ksmbd_durable_scavenger_alive(void) { - mutex_lock(&durable_scavenger_lock); - if (!durable_scavenger_running) { - mutex_unlock(&durable_scavenger_lock); + if (!durable_scavenger_running) return false; - } - mutex_unlock(&durable_scavenger_lock); if (kthread_should_stop()) return false; @@ -799,9 +795,7 @@ static int ksmbd_durable_scavenger(void *dummy) break; } - mutex_lock(&durable_scavenger_lock); durable_scavenger_running = false; - mutex_unlock(&durable_scavenger_lock); module_put(THIS_MODULE); From 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Fri, 11 Apr 2025 15:19:46 +0900 Subject: [PATCH 3/6] ksmbd: fix use-after-free in __smb2_lease_break_noti() Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei Tested-by: Norbert Szetei Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/connection.c | 4 +++- fs/smb/server/transport_tcp.c | 14 +++++++++----- fs/smb/server/transport_tcp.h | 1 + 3 files changed, 13 insertions(+), 6 deletions(-) diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index c1f22c129111..83764c230e9d 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -39,8 +39,10 @@ void ksmbd_conn_free(struct ksmbd_conn *conn) xa_destroy(&conn->sessions); kvfree(conn->request_buf); kfree(conn->preauth_info); - if (atomic_dec_and_test(&conn->refcnt)) + if (atomic_dec_and_test(&conn->refcnt)) { + ksmbd_free_transport(conn->transport); kfree(conn); + } } /** diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c index 7f38a3c3f5bd..abedf510899a 100644 --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -93,15 +93,19 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk) return t; } +void ksmbd_free_transport(struct ksmbd_transport *kt) +{ + struct tcp_transport *t = TCP_TRANS(kt); + + sock_release(t->sock); + kfree(t->iov); + kfree(t); +} + static void free_transport(struct tcp_transport *t) { kernel_sock_shutdown(t->sock, SHUT_RDWR); - sock_release(t->sock); - t->sock = NULL; - ksmbd_conn_free(KSMBD_TRANS(t)->conn); - kfree(t->iov); - kfree(t); } /** diff --git a/fs/smb/server/transport_tcp.h b/fs/smb/server/transport_tcp.h index 8c9aa624cfe3..1e51675ee1b2 100644 --- a/fs/smb/server/transport_tcp.h +++ b/fs/smb/server/transport_tcp.h @@ -8,6 +8,7 @@ int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz); struct interface *ksmbd_find_netdev_name_iface_list(char *netdev_name); +void ksmbd_free_transport(struct ksmbd_transport *kt); int ksmbd_tcp_init(void); void ksmbd_tcp_destroy(void); From 18b4fac5ef17f77fed9417d22210ceafd6525fc7 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 15 Apr 2025 09:30:21 +0900 Subject: [PATCH 4/6] ksmbd: fix use-after-free in smb_break_all_levII_oplock() There is a room in smb_break_all_levII_oplock that can cause racy issues when unlocking in the middle of the loop. This patch use read lock to protect whole loop. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei Tested-by: Norbert Szetei Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/oplock.c | 29 +++++++++-------------------- fs/smb/server/oplock.h | 1 - 2 files changed, 9 insertions(+), 21 deletions(-) diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c index f103b1bd0400..81a29857b1e3 100644 --- a/fs/smb/server/oplock.c +++ b/fs/smb/server/oplock.c @@ -129,14 +129,6 @@ static void free_opinfo(struct oplock_info *opinfo) kfree(opinfo); } -static inline void opinfo_free_rcu(struct rcu_head *rcu_head) -{ - struct oplock_info *opinfo; - - opinfo = container_of(rcu_head, struct oplock_info, rcu_head); - free_opinfo(opinfo); -} - struct oplock_info *opinfo_get(struct ksmbd_file *fp) { struct oplock_info *opinfo; @@ -157,8 +149,8 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci) if (list_empty(&ci->m_op_list)) return NULL; - rcu_read_lock(); - opinfo = list_first_or_null_rcu(&ci->m_op_list, struct oplock_info, + down_read(&ci->m_lock); + opinfo = list_first_entry(&ci->m_op_list, struct oplock_info, op_entry); if (opinfo) { if (opinfo->conn == NULL || @@ -171,8 +163,7 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci) } } } - - rcu_read_unlock(); + up_read(&ci->m_lock); return opinfo; } @@ -185,7 +176,7 @@ void opinfo_put(struct oplock_info *opinfo) if (!atomic_dec_and_test(&opinfo->refcount)) return; - call_rcu(&opinfo->rcu_head, opinfo_free_rcu); + free_opinfo(opinfo); } static void opinfo_add(struct oplock_info *opinfo) @@ -193,7 +184,7 @@ static void opinfo_add(struct oplock_info *opinfo) struct ksmbd_inode *ci = opinfo->o_fp->f_ci; down_write(&ci->m_lock); - list_add_rcu(&opinfo->op_entry, &ci->m_op_list); + list_add(&opinfo->op_entry, &ci->m_op_list); up_write(&ci->m_lock); } @@ -207,7 +198,7 @@ static void opinfo_del(struct oplock_info *opinfo) write_unlock(&lease_list_lock); } down_write(&ci->m_lock); - list_del_rcu(&opinfo->op_entry); + list_del(&opinfo->op_entry); up_write(&ci->m_lock); } @@ -1347,8 +1338,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp, ci = fp->f_ci; op = opinfo_get(fp); - rcu_read_lock(); - list_for_each_entry_rcu(brk_op, &ci->m_op_list, op_entry) { + down_read(&ci->m_lock); + list_for_each_entry(brk_op, &ci->m_op_list, op_entry) { if (brk_op->conn == NULL) continue; @@ -1358,7 +1349,6 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp, if (ksmbd_conn_releasing(brk_op->conn)) continue; - rcu_read_unlock(); if (brk_op->is_lease && (brk_op->o_lease->state & (~(SMB2_LEASE_READ_CACHING_LE | SMB2_LEASE_HANDLE_CACHING_LE)))) { @@ -1388,9 +1378,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp, oplock_break(brk_op, SMB2_OPLOCK_LEVEL_NONE, NULL); next: opinfo_put(brk_op); - rcu_read_lock(); } - rcu_read_unlock(); + up_read(&ci->m_lock); if (op) opinfo_put(op); diff --git a/fs/smb/server/oplock.h b/fs/smb/server/oplock.h index 3f64f0787263..9a56eaadd0dd 100644 --- a/fs/smb/server/oplock.h +++ b/fs/smb/server/oplock.h @@ -71,7 +71,6 @@ struct oplock_info { struct list_head lease_entry; wait_queue_head_t oplock_q; /* Other server threads */ wait_queue_head_t oplock_brk; /* oplock breaking wait */ - struct rcu_head rcu_head; }; struct lease_break_info { From b37f2f332b40ad1c27f18682a495850f2f04db0a Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Tue, 15 Apr 2025 09:31:08 +0900 Subject: [PATCH 5/6] ksmbd: fix the warning from __kernel_write_iter [ 2110.972290] ------------[ cut here ]------------ [ 2110.972301] WARNING: CPU: 3 PID: 735 at fs/read_write.c:599 __kernel_write_iter+0x21b/0x280 This patch doesn't allow writing to directory. Cc: stable@vger.kernel.org Reported-by: Norbert Szetei Tested-by: Norbert Szetei Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/vfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index 8554aa5a1059..391d07da586c 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -479,7 +479,8 @@ int ksmbd_vfs_write(struct ksmbd_work *work, struct ksmbd_file *fp, int err = 0; if (work->conn->connection_type) { - if (!(fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE))) { + if (!(fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) || + S_ISDIR(file_inode(fp->filp)->i_mode)) { pr_err("no right to write(%pD)\n", fp->filp); err = -EACCES; goto out; From a93ff742820f75bf8bb3fcf21d9f25ca6eb3d4c6 Mon Sep 17 00:00:00 2001 From: Denis Arefev Date: Wed, 9 Apr 2025 12:04:49 +0300 Subject: [PATCH 6/6] ksmbd: Prevent integer overflow in calculation of deadtime The user can set any value for 'deadtime'. This affects the arithmetic expression 'req->deadtime * SMB_ECHO_INTERVAL', which is subject to overflow. The added check makes the server behavior more predictable. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable@vger.kernel.org Signed-off-by: Denis Arefev Acked-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/transport_ipc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 3f185ae60dc5..2a3e2b0ce557 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -310,7 +310,11 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) server_conf.signing = req->signing; server_conf.tcp_port = req->tcp_port; server_conf.ipc_timeout = req->ipc_timeout * HZ; - server_conf.deadtime = req->deadtime * SMB_ECHO_INTERVAL; + if (check_mul_overflow(req->deadtime, SMB_ECHO_INTERVAL, + &server_conf.deadtime)) { + ret = -EINVAL; + goto out; + } server_conf.share_fake_fscaps = req->share_fake_fscaps; ksmbd_init_domain(req->sub_auth); @@ -337,6 +341,7 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) server_conf.bind_interfaces_only = req->bind_interfaces_only; ret |= ksmbd_tcp_set_interfaces(KSMBD_STARTUP_CONFIG_INTERFACES(req), req->ifc_list_sz); +out: if (ret) { pr_err("Server configuration error: %s %s %s\n", req->netbios_name, req->server_string,