Re: [PATCH] proc: Track /proc/$pid/attr/ opener mm_struct
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: 2021-06-14 18:04:07
Also in:
lkml, regressions, selinux, stable
Possibly related (same subject, not in this thread)
- 2021-06-16 · Re: [PATCH] proc: Track /proc/$pid/attr/ opener mm_struct · Greg KH <gregkh@linuxfoundation.org>
- 2021-06-16 · Re: [PATCH] proc: Track /proc/$pid/attr/ opener mm_struct · youling 257 <hidden>
- 2021-06-15 · Re: [PATCH] proc: Track /proc/$pid/attr/ opener mm_struct · Kees Cook <hidden>
- 2021-06-15 · Re: [PATCH] proc: Track /proc/$pid/attr/ opener mm_struct · Linus Torvalds <torvalds@linux-foundation.org>
- 2021-06-15 · Re: [PATCH] proc: Track /proc/$pid/attr/ opener mm_struct · youling 257 <hidden>
On Mon, Jun 14, 2021 at 9:45 AM Kees Cook [off-list ref] wrote:
/* A task may only write when it was the opener. */
- if (file->private_data != current->mm)
+ if (!file->private_data || file->private_data != current->mm)
I don't think this is necessary.
If file->private_data is NULL, then the old test for private_data !=
current->mm will still work just fine.
Because if you can fool kernel threads to do the write for you, you
have bigger security issues than that test.
Linus