Re: [syzbot] [bpf?] KASAN: slab-out-of-bounds Write in copy_array (2)

[Lorenz Bauer]

On Wed, May 10, 2023 at 5:14 PM syzbot
<syzbot+d742fd7d34097f949179@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    950b879b7f02 riscv: Fixup race condition on PG_dcache_clea..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
> console output: https://syzkaller.appspot.com/x/log.txt?x=17eaa0c6280000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ecebece1b90c0342
> dashboard link: https://syzkaller.appspot.com/bug?extid=d742fd7d34097f949179
> compiler:       riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: riscv64
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/5ab53d394dbf/non_bootable_disk-950b879b.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/938475579d6c/vmlinux-950b879b.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/bcf263d8c574/Image-950b879b.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d742fd7d34097f949179@xxxxxxxxxxxxxxxxxxxxxxxxx

That tree doesn't have the fix yet:
https://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git/tree/kernel/bpf/verifier.c?h=fixes&id=950b879b7f02#n1065

#syz fix: bpf: Always use maximal size for copy_array()