Re: [syzbot] KASAN: vmalloc-out-of-bounds Read in __bpf_prog_put

syzbot
2021-12-07T17:36:33Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 1c5526968e27 net/smc: Clear memory when release and reuse ..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13a9eabdb00000
kernel config: https://syzkaller.appspot.com/x/.config?x=2b8e24e3a80e3875
dashboard link: https://syzkaller.appspot.com/bug?extid=5027de09e0964fd78ce1
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12b749a9b00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=170d7519b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5027de09e0964fd78ce1@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in __bpf_prog_put.constprop.0+0x1dd/0x220 kernel/bpf/syscall.c:1812
Read of size 8 at addr ffffc90001a16038 by task kworker/0:3/2934

CPU: 0 PID: 2934 Comm: kworker/0:3 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events sk_psock_destroy
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0xf/0x320 mm/kasan/report.c:247
__kasan_report mm/kasan/report.c:433 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
__bpf_prog_put.constprop.0+0x1dd/0x220 kernel/bpf/syscall.c:1812
psock_set_prog include/linux/skmsg.h:477 [inline]
psock_progs_drop include/linux/skmsg.h:495 [inline]
sk_psock_destroy+0xad/0x620 net/core/skmsg.c:804
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

Memory state around the buggy address:
ffffc90001a15f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90001a15f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90001a16000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
ffffc90001a16080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90001a16100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================