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

Message ID 20210907205043.16768-1-stephen.s.brennan@oracle.com (mailing list archive)
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Series namei: fix use-after-free and adjust calling conventions | expand

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Stephen Brennan Sept. 7, 2021, 8:50 p.m. UTC 
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()

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

Comments

Stephen Brennan Sept. 7, 2021, 9:44 p.m. UTC | #1 
Stephen Brennan <stephen.s.brennan@oracle.com> 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