Re: [PATCH v2] ext4: fix use-after-free in ext4_ext_shift_extents

[Baokun Li]

On 2022/9/30 11:19, Theodore Ts'o wrote:
> On Thu, 22 Sep 2022 20:04:34 +0800, Baokun Li wrote:
> > If the starting position of our insert range happens to be in the hole
> > between the two ext4_extent_idx, because the lblk of the ext4_extent in
> > the previous ext4_extent_idx is always less than the start, which leads
> > to the "extent" variable access across the boundary, the following UAF is
> > triggered:
> > ==================================================================
> > BUG: KASAN: use-after-free in ext4_ext_shift_extents+0x257/0x790
> > Read of size 4 at addr ffff88819807a008 by task fallocate/8010
> > CPU: 3 PID: 8010 Comm: fallocate Tainted: G            E     5.10.0+ #492
> > Call Trace:
> >   dump_stack+0x7d/0xa3
> >   print_address_description.constprop.0+0x1e/0x220
> >   kasan_report.cold+0x67/0x7f
> >   ext4_ext_shift_extents+0x257/0x790
> >   ext4_insert_range+0x5b6/0x700
> >   ext4_fallocate+0x39e/0x3d0
> >   vfs_fallocate+0x26f/0x470
> >   ksys_fallocate+0x3a/0x70
> >   __x64_sys_fallocate+0x4f/0x60
> >   do_syscall_64+0x33/0x40
> >   entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > ==================================================================
> >
> > [...]
> Applied, thanks!
>
> [1/1] ext4: fix use-after-free in ext4_ext_shift_extents
>        (no commit info)
>
> Best regards,

Hi Theodore,

Could you tell me why this patch has been applied, but there is no cmmit 
info,

and the patch cannot be found on any branch?

--
With Best Regards,
Baokun Li