On 1/7/21 9:25 PM, KP Singh wrote:
On Thu, Jan 7, 2021 at 8:15 PM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
On Thu, Jan 7, 2021 at 11:07 AM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
On Thu, Jan 7, 2021 at 9:37 AM KP Singh <kpsingh@xxxxxxxxxx> wrote:
The verifier allows ARG_PTR_TO_BTF_ID helper arguments to be NULL, so
helper implementations need to check this before dereferencing them.
This was already fixed for the socket storage helpers but not for task
and inode.
The issue can be reproduced by attaching an LSM program to
inode_rename hook (called when moving files) which tries to get the
inode of the new file without checking for its nullness and then trying
to move an existing file to a new path:
mv existing_file new_file_does_not_exist
Seems like it's simple to write a selftest for this then?
Sure, I will send in a separate patch for selftest and also for the typo.
If it's small or trivial to add a selftest for the fix, I'd suggest to add it
as part of this series for 'ease of logistics' as it would otherwise be a bit
odd to i) either have a stand-alone patch against bpf tree with just a selftest
or ii) having to wait until bpf syncs into bpf-next and then send one against
bpf-next where for the latter there's risk that it gets forgotten in meantime
as it might take a while.
Thanks,
Daniel
