smb2_tree_disconnect() freed the struct ksmbd_tree_connect, but it left the dangling pointer. It can be accessed again under compound requests.
This bug can lead an oops looking something link:
[ 1685.468014 ] BUG: KASAN: use-after-free in ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd] [ 1685.468068 ] Read of size 4 at addr ffff888102172180 by task kworker/1:2/4807 ... [ 1685.468130 ] Call Trace: [ 1685.468132 ] <TASK> [ 1685.468135 ] dump_stack_lvl+0x49/0x5f [ 1685.468141 ] print_report.cold+0x5e/0x5cf [ 1685.468145 ] ? ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd] [ 1685.468157 ] kasan_report+0xaa/0x120 [ 1685.468194 ] ? ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd] [ 1685.468206 ] __asan_report_load4_noabort+0x14/0x20 [ 1685.468210 ] ksmbd_tree_conn_disconnect+0x131/0x160 [ksmbd] [ 1685.468222 ] smb2_tree_disconnect+0x175/0x250 [ksmbd] [ 1685.468235 ] handle_ksmbd_work+0x30e/0x1020 [ksmbd] [ 1685.468247 ] process_one_work+0x778/0x11c0 [ 1685.468251 ] ? _raw_spin_lock_irq+0x8e/0xe0 [ 1685.468289 ] worker_thread+0x544/0x1180 [ 1685.468293 ] ? __cpuidle_text_end+0x4/0x4 [ 1685.468297 ] kthread+0x282/0x320 [ 1685.468301 ] ? process_one_work+0x11c0/0x11c0 [ 1685.468305 ] ? kthread_complete_and_exit+0x30/0x30 [ 1685.468309 ] ret_from_fork+0x1f/0x30
Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-17816 Signed-off-by: Namjae Jeon linkinjeon@kernel.org Reviewed-by: Hyunchul Lee hyc.lee@gmail.com --- v2: - add missing fixes and stable tags.
fs/ksmbd/smb2pdu.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index 41ef076af072..7ecb6d87ae3e 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -2057,6 +2057,7 @@ int smb2_tree_disconnect(struct ksmbd_work *work)
ksmbd_close_tree_conn_fds(work); ksmbd_tree_conn_disconnect(sess, tcon); + work->tcon = NULL; return 0; }