From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + lib-list_sort-do-not-pass-bad-pointers-to-cmp-callback.patch added to -mm tree Date: Mon, 27 Sep 2010 12:05:14 -0700 Message-ID: <201009271905.o8RJ5Edl010702@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:47488 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757120Ab0I0TFV (ORCPT ); Mon, 27 Sep 2010 15:05:21 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: don.mullis@gmail.com, Artem.Bityutskiy@nokia.com, stable@kernel.org The patch titled lib/list_sort: do not pass bad pointers to cmp callback has been added to the -mm tree. Its filename is lib-list_sort-do-not-pass-bad-pointers-to-cmp-callback.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: lib/list_sort: do not pass bad pointers to cmp callback From: Don Mullis 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. This patch fixes the issue. Signed-off-by: Don Mullis Tested-by: Artem Bityutskiy Signed-off-by: Artem Bityutskiy Cc: Signed-off-by: Andrew Morton --- lib/list_sort.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN lib/list_sort.c~lib-list_sort-do-not-pass-bad-pointers-to-cmp-callback lib/list_sort.c --- a/lib/list_sort.c~lib-list_sort-do-not-pass-bad-pointers-to-cmp-callback +++ a/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; _ Patches currently in -mm which might be from don.mullis@gmail.com are linux-next.patch lib-list_sort-do-not-pass-bad-pointers-to-cmp-callback.patch lib-kconfigdebug-add-list_sort-debugging-switch.patch lib-list_sort-test-use-more-reasonable-printk-levels.patch lib-list_sort-test-use-generic-random32.patch lib-list_sort-test-improve-errors-handling.patch lib-list_sort-test-unify-test-messages.patch lib-list_sort-test-check-element-addresses.patch