From 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Fri, 11 Apr 2025 15:19:46 +0900 Subject: [PATCH] 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 @@ -93,17 +93,21 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk) return t; } -static void free_transport(struct tcp_transport *t) +void ksmbd_free_transport(struct ksmbd_transport *kt) { - kernel_sock_shutdown(t->sock, SHUT_RDWR); - sock_release(t->sock); - t->sock = NULL; + struct tcp_transport *t = TCP_TRANS(kt); - ksmbd_conn_free(KSMBD_TRANS(t)->conn); + sock_release(t->sock); kfree(t->iov); kfree(t); } +static void free_transport(struct tcp_transport *t) +{ + kernel_sock_shutdown(t->sock, SHUT_RDWR); + ksmbd_conn_free(KSMBD_TRANS(t)->conn); +} + /** * kvec_array_init() - initialize a IO vector segment * @new: IO vector to be initialized 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);