Re: [PATCH v2] ext4: check if offset+length is valid in fallocate

[Tadeusz Struk]

On 3/15/22 14:54, Tadeusz Struk wrote:
> Syzbot found an issue [1] in ext4_fallocate().
> The C reproducer [2] calls fallocate(), passing size 0xffeffeff000ul,
> and offset 0x1000000ul, which, when added together exceed the disk size,
> and trigger a BUG in ext4_ind_remove_space() [3].
> According to the comment doc in ext4_ind_remove_space() the 'end' block
> parameter needs to be one block after the last block to remove.
> In the case when the BUG is triggered it points to the last block on
> a 4GB virtual disk image. This is calculated in
> ext4_ind_remove_space() in [4].
> This patch adds a check that ensure the length + offest to be
> within the valid range and returns -ENOSPC error code in case
> it is invalid.

Hi,
Any feedback on this?

--
Thanks,
Tadeusz