Re: [PATCH v2 0/3] namei: fix use-after-free and adjust calling conventions

From: Stephen Brennan
Date: Tue Sep 07 2021 - 17:45:05 EST


Stephen Brennan <stephen.s.brennan@xxxxxxxxxx> writes:
> Drawing from the comments on the last two patches from me and Dmitry,
> the concensus is that __filename_parentat() is inherently buggy, and
> should be removed. But there's some nice consistency to the way that
> the other functions (filename_create, filename_lookup) are named which
> would get broken.
>
> I looked at the callers of filename_create and filename_lookup. All are
> small functions which are trivial to modify to include a putname(). It
> seems to me that adding a few more lines to these functions is a good
> traedoff for better clarity on lifetimes (as it's uncommon for functions
> to drop references to their parameters) and better consistency.
>
> This small series combines the UAF fix from me, and the removal of
> __filename_parentat() from Dmitry as patch 1. Then I standardize
> filename_create() and filename_lookup() and their callers.
>
> v2: Fix double getname in user_path_create()
>
> Stephen Brennan (3):
> namei: Fix use after free in kern_path_locked
> namei: Standardize callers of filename_lookup()
> namei: Standardize callers of filename_create()

Please ignore this! I missed some feedback from Al and will send a v3.

>
> fs/fs_parser.c | 1 -
> fs/namei.c | 126 ++++++++++++++++++++++++++-----------------------
> 2 files changed, 66 insertions(+), 61 deletions(-)
>
> --
> 2.30.2