Zhang Qilong e97c089d7a rose: Fix NULL pointer dereference in rose_send_frame() ... The syzkaller reported an issue: KASAN: null-ptr-deref in range [0x0000000000000380-0x0000000000000387] CPU: 0 PID: 4069 Comm: kworker/0:15 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: rcu_gp srcu_invoke_callbacks RIP: 0010:rose_send_frame+0x1dd/0x2f0 net/rose/rose_link.c:101 Call Trace: <IRQ> rose_transmit_clear_request+0x1d5/0x290 net/rose/rose_link.c:255 rose_rx_call_request+0x4c0/0x1bc0 net/rose/af_rose.c:1009 rose_loopback_timer+0x19e/0x590 net/rose/rose_loopback.c:111 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 [...] </IRQ> It triggers NULL pointer dereference when 'neigh->dev->dev_addr' is called in the rose_send_frame(). It's the first occurrence of the `neigh` is in rose_loopback_timer() as `rose_loopback_neigh', and the 'dev' in 'rose_loopback_neigh' is initialized sa nullptr. It had been fixed by commit 3b3fd068c5 ("rose: Fix Null pointer dereference in rose_send_frame()") ever. But it's introduced by commit 3c53cd65de ("rose: check NULL rose_loopback_neigh->loopback") again. We fix it by add NULL check in rose_transmit_clear_request(). When the 'dev' in 'neigh' is NULL, we don't reply the request and just clear it. syzkaller don't provide repro, and I provide a syz repro like: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) ioctl$sock_inet_SIOCSIFFLAGS(r0, 0x8914, &(0x7f0000000180)={'rose0\x00', 0x201}) r1 = syz_init_net_socket$rose(0xb, 0x5, 0x0) bind$rose(r1, &(0x7f00000000c0)=@full={0xb, @dev, @null, 0x0, [@null, @null, @netrom, @netrom, @default, @null]}, 0x40) connect$rose(r1, &(0x7f0000000240)=@short={0xb, @dev={0xbb, 0xbb, 0xbb, 0x1, 0x0}, @remote={0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0x1}, 0x1, @netrom={0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0x0, 0x0}}, 0x1c) Fixes: 3c53cd65de ("rose: check NULL rose_loopback_neigh->loopback") Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2022-11-02 11:57:30 +00:00
..
af_rose.c	net: rose: add netdev ref tracker to 'struct rose_sock'	2022-08-01 11:59:23 -07:00
Makefile
rose_dev.c	rose: constify dev_addr passing	2021-10-13 09:40:45 -07:00
rose_in.c	net: Don't include filter.h from net/sock.h	2021-12-29 08:48:14 -08:00
rose_link.c	rose: Fix NULL pointer dereference in rose_send_frame()	2022-11-02 11:57:30 +00:00
rose_loopback.c	rose: check NULL rose_loopback_neigh->loopback	2022-08-22 14:24:54 +01:00
rose_out.c
rose_route.c	net: rose: fix netdev reference changes	2022-08-01 11:59:23 -07:00
rose_subr.c
rose_timer.c	net: rose: fix UAF bugs caused by timer handler	2022-06-30 11:07:30 +02:00
sysctl_net_rose.c