The patch titled
Subject: mm: fix use-after-free bug when mm->mmap is reused after being freed
has been added to the -mm tree. Its filename is
mm-fix-use-after-free-bug-when-mm-mmap-is-reused-after-being-freed.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-fix-use-after-free-bug-when-mm-mmap-is-reused-after-being-freed.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-use-after-free-bug-when-mm-mmap-is-reused-after-being-freed.patch
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: mm: fix use-after-free bug when mm->mmap is reused after being freed
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.
Link: https://lore.kernel.org/all/00000000000072ef2c05d7f81950@xxxxxxxxxx/
Link: https://lkml.kernel.org/r/20220215201922.1908156-1-surenb@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Reported-by: syzbot+2ccf63a4bd07cf39cab0@xxxxxxxxxxxxxxxxxxxxxxxxx
Suggested-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Christian Brauner <christian.brauner@xxxxxxxxxx>
Cc: Florian Weimer <fweimer@xxxxxxxxxx>
Cc: Jan Engelhardt <jengelh@xxxxxxx>
Cc: Tim Murray <timmurray@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 1 +
1 file changed, 1 insertion(+)
--- a/mm/mmap.c~mm-fix-use-after-free-bug-when-mm-mmap-is-reused-after-being-freed
+++ a/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);
}
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
mm-fix-use-after-free-when-anon-vma-name-is-used-after-vma-is-freed.patch
mm-fix-use-after-free-bug-when-mm-mmap-is-reused-after-being-freed.patch
