Re: [PATCH v4] jfs: validate max amount of blocks before allocation.

Greg KH
2023-07-23T14:11:43Z

On Sun, Jul 23, 2023 at 04:58:22PM +0300, Aleksei Filippov wrote:
> From: Alexei Filippov <halip0503@gmail.com>
>
> The lack of checking bmp->db_max_freebud in extBalloc() can lead to
> shift out of bounds, so this patch prevents undefined behavior, because
> bmp->db_max_freebud == -1 only if there is no free space.
>
> Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
> ---
> Changes:
> Fix commit message.
> fs/jfs/jfs_extent.c | 5 +++++
> 1 file changed, 5 insertions(+)

{sigh}

Please, take some time, read the documentation for how to do this
correctly. Wait a day, and then submit it again, properly.

Also, do you have a jfs system? Isn't this filesystem obsolete?

thanks,

greg k-h