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

John Fastabend
2021-12-06T19:02:54Z

syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: ce83278f313c Merge branch 'qed-enhancements'
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=11c8ce3ab00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=b5949d4891208a1b
> 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
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> 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 ffffc90000cf2038 by task kworker/0:24/16179
>
> CPU: 0 PID: 16179 Comm: kworker/0:24 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:
> ffffc90000cf1f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ffffc90000cf1f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> >ffffc90000cf2000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ^
> ffffc90000cf2080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ffffc90000cf2100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ==================================================================
>
>
> ---
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> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
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I'll take look some psock issue here.