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Date:   Wed, 9 Mar 2022 08:32:14 -0800
From:   Kees Cook <keescook@chromium.org>
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Denys Vlasenko <vda.linux@googlemail.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Liam R . Howlett" <liam.howlett@oracle.com>,
        Jann Horn <jannh@google.com>, linux-mm@kvack.org
Subject: Re: [GIT PULL] Fix fill_files_note
Message-ID: <202203090830.7E971BD6C@keescook>
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On Wed, Mar 09, 2022 at 10:29:10AM -0600, Eric W. Biederman wrote:
> Kees Cook <keescook@chromium.org> writes:
> 
> > On Tue, Mar 08, 2022 at 01:35:03PM -0600, Eric W. Biederman wrote:
> >> 
> >> Kees,
> >> 
> >> Please pull the coredump-vma-snapshot-fix branch from the git tree:
> >> 
> >>   git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git coredump-vma-snapshot-fix
> >> 
> >>   HEAD: 390031c942116d4733310f0684beb8db19885fe6 coredump: Use the vma snapshot in fill_files_note
> >> 
> >> Matthew Wilcox has reported that a missing mmap_lock in file_files_note,
> >> which could cause trouble.
> >> 
> >> Refactor the code and clean it up so that the vma snapshot makes
> >> it to fill_files_note, and then use the vma snapshot in fill_files_note.
> >> 
> >> Eric W. Biederman (5):
> >>       coredump: Move definition of struct coredump_params into coredump.h
> >>       coredump: Snapshot the vmas in do_coredump
> >>       coredump: Remove the WARN_ON in dump_vma_snapshot
> >>       coredump/elf: Pass coredump_params into fill_note_info
> >>       coredump: Use the vma snapshot in fill_files_note
> >> 
> >>  fs/binfmt_elf.c          | 66 ++++++++++++++++++++++--------------------------
> >>  fs/binfmt_elf_fdpic.c    | 18 +++++--------
> >>  fs/binfmt_flat.c         |  1 +
> >>  fs/coredump.c            | 59 ++++++++++++++++++++++++++++---------------
> >>  include/linux/binfmts.h  | 13 +---------
> >>  include/linux/coredump.h | 20 ++++++++++++---
> >>  6 files changed, 93 insertions(+), 84 deletions(-)
> >> 
> >> ---
> >> 
> >> Kees I realized I needed to rebase this on Jann Horn's commit
> >> 84158b7f6a06 ("coredump: Also dump first pages of non-executable ELF
> >> libraries").  Unfortunately before I got that done I got distracted and
> >> these changes have been sitting in limbo for most of the development
> >> cycle.  Since you are running a tree that is including changes like this
> >> including Jann's can you please pull these changes into your tree.
> >
> > Sure! Can you make a signed tag for this pull?
> 
> Not yet.
> 
> Hopefully I will get the time to set that up soon, but I am not at all
> setup to do signed tags at this point.

Okay, cool. Since I'd already review these before, I've pulled and it
should be in -next now.

> [...]
> Thanks.  That looks like a good place to start.

I will try to clean up that work-flow and stuff it into my kernel-tools
repo.

-- 
Kees Cook