Re: [PATCH] procfs: block chmod on /proc/thread-self/comm

[Aleksa Sarai]

On 2023-07-13, Willy Tarreau <w@xxxxxx> wrote:
> +Cc Thomas Weißschuh <thomas@xxxxxxxx> as this seems quite related to
> his finding about /proc/self/net:
> 
>   https://lore.kernel.org/lkml/20230624-proc-net-setattr-v1-0-73176812adee@xxxxxxxxxxxxxx/#b

Yeah I saw this patch and (along with an earlier discussion with
Christian on the topic of chmod on symlinks -- see [1]) lead us to find
that there were three other cases where this happens unintentionally:

 * /proc/self (on the symlink itself)
 * /proc/thread-self (on the symlink itself)
 * /proc/thread-self/comm

The first two will be fixed by [1] so fixing them isn't necessary.

[1]: https://lore.kernel.org/linux-fsdevel/20230712-vfs-chmod-symlinks-v2-1-08cfb92b61dd@xxxxxxxxxx/

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>