From: Andrew Morton <akpm@linux-foundation.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: mhocko@kernel.org, mhocko@suse.com, shy828301@gmail.com,
rientjes@google.com, willy@infradead.org, hannes@cmpxchg.org,
guro@fb.com, riel@surriel.com, minchan@kernel.org,
kirill@shutemov.name, aarcange@redhat.com, brauner@kernel.org,
christian@brauner.io, hch@infradead.org, oleg@redhat.com,
david@redhat.com, jannh@google.com, shakeelb@google.com,
luto@kernel.org, christian.brauner@ubuntu.com,
fweimer@redhat.com, jengelh@inai.de, timmurray@google.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@android.com,
syzbot+2ccf63a4bd07cf39cab0@syzkaller.appspotmail.com,
Liam Howlett <liam.howlett@oracle.com>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH 1/1] mm: fix use-after-free bug when mm->mmap is reused after being freed
Date: Thu, 24 Feb 2022 20:18:59 -0800 [thread overview]
Message-ID: <20220224201859.a38299b6c9d52cb51e6738ea@linux-foundation.org> (raw)
In-Reply-To: <20220215201922.1908156-1-surenb@google.com>
On Tue, 15 Feb 2022 12:19:22 -0800 Suren Baghdasaryan <surenb@google.com> wrote:
> After exit_mmap frees all vmas in the mm, mm->mmap needs to be reset,
> otherwise it points to a vma that was freed and when reused leads to
> a use-after-free bug.
>
> ...
>
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3186,6 +3186,7 @@ void exit_mmap(struct mm_struct *mm)
> vma = remove_vma(vma);
> cond_resched();
> }
> + mm->mmap = NULL;
> mmap_write_unlock(mm);
> vm_unacct_memory(nr_accounted);
> }
After the Maple tree patches, mm_struct.mmap doesn't exist. So I'll
revert this fix as part of merging the maple-tree parts of linux-next.
I'll be sending this fix to Linus this week.
All of which means that the thusly-resolved Maple tree patches might
reintroduce this use-after-free bug.
next prev parent reply other threads:[~2022-02-25 4:19 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-15 20:19 [PATCH 1/1] mm: fix use-after-free bug when mm->mmap is reused after being freed Suren Baghdasaryan
2022-02-15 20:26 ` Rik van Riel
2022-02-15 20:37 ` Andrew Morton
2022-02-15 20:45 ` Suren Baghdasaryan
2022-02-15 20:46 ` Suren Baghdasaryan
2022-02-15 20:51 ` Andrew Morton
2022-02-15 20:42 ` Yang Shi
2022-02-16 7:54 ` Michal Hocko
2022-02-17 19:51 ` Suren Baghdasaryan
2022-02-17 20:50 ` Andrew Morton
2022-02-18 8:11 ` Michal Hocko
2022-02-18 8:10 ` Michal Hocko
2022-02-25 4:18 ` Andrew Morton [this message]
2022-02-25 4:23 ` Matthew Wilcox
2022-02-25 5:50 ` Suren Baghdasaryan
2022-03-10 15:55 ` Liam Howlett
2022-03-10 16:28 ` Suren Baghdasaryan
2022-03-10 22:22 ` Liam Howlett
2022-03-10 23:31 ` Suren Baghdasaryan
2022-03-11 1:34 ` Liam Howlett
2022-02-25 10:17 ` Michal Hocko
2022-02-26 1:04 ` Andrew Morton
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