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7c759040c1
When receiving a CAN frame the current code logic does not consider
concurrently receiving processes which do not show up in real world
usage.
Ziyang Xuan writes:
The following syz problem is one of the scenarios. so->rx.len is
changed by isotp_rcv_ff() during isotp_rcv_cf(), so->rx.len equals
0 before alloc_skb() and equals 4096 after alloc_skb(). That will
trigger skb_over_panic() in skb_put().
=======================================================
CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 5.16.0-rc8-syzkaller #0
RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:113
Call Trace:
<TASK>
skb_over_panic net/core/skbuff.c:118 [inline]
skb_put.cold+0x24/0x24 net/core/skbuff.c:1990
isotp_rcv_cf net/can/isotp.c:570 [inline]
isotp_rcv+0xa38/0x1e30 net/can/isotp.c:668
deliver net/can/af_can.c:574 [inline]
can_rcv_filter+0x445/0x8d0 net/can/af_can.c:635
can_receive+0x31d/0x580 net/can/af_can.c:665
can_rcv+0x120/0x1c0 net/can/af_can.c:696
__netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5465
__netif_receive_skb+0x24/0x1b0 net/core/dev.c:5579
Therefore we make sure the state changes and data structures stay
consistent at CAN frame reception time by adding a spin_lock in
isotp_rcv(). This fixes the issue reported by syzkaller but does not
affect real world operation.
Fixes:
|
||
|---|---|---|
| .. | ||
| j1939 | ||
| af_can.c | ||
| af_can.h | ||
| bcm.c | ||
| gw.c | ||
| isotp.c | ||
| Kconfig | ||
| Makefile | ||
| proc.c | ||
| raw.c | ||