Messages in this thread Patch in this message | | | Date | Fri, 22 Oct 2010 11:50:48 -0700 | From | Greg KH <> | Subject | [014/103] lib/list_sort: do not pass bad pointers to cmp callback |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Don Mullis <don.mullis@gmail.com>
commit f015ac3edd84ad72f88e08a4d83c56c360aae404 upstream.
If the original list is a POT in length, the first callback from line 73 will pass a==b both pointing to the original list_head. This is dangerous because the 'list_sort()' user can use 'container_of()' and accesses the "containing" object, which does not necessary exist for the list head. So the user can access RAM which does not belong to him. If this is a write access, we can end up with memory corruption.
Signed-off-by: Don Mullis <don.mullis@gmail.com> Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- lib/list_sort.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/list_sort.c +++ b/lib/list_sort.c @@ -70,7 +70,7 @@ static void merge_and_restore_back_links * element comparison is needed, so the client's cmp() * routine can invoke cond_resched() periodically. */ - (*cmp)(priv, tail, tail); + (*cmp)(priv, tail->next, tail->next); tail->next->prev = tail; tail = tail->next;
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