From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756793Ab2FNX7d (ORCPT ); Thu, 14 Jun 2012 19:59:33 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:46571 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756778Ab2FNX72 (ORCPT ); Thu, 14 Jun 2012 19:59:28 -0400 Message-Id: <20120614235624.253607282@linuxfoundation.org> User-Agent: quilt/0.60-20.1 Date: Thu, 14 Jun 2012 16:56:27 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Roland Dreier , Joern Engel Subject: [ 04/42] btree: fix tree corruption in btree_get_prev() In-Reply-To: <20120614235636.GA5275@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roland Dreier commit cbf8ae32f66a9ceb8907ad9e16663c2a29e48990 upstream. The memory the parameter __key points to is used as an iterator in btree_get_prev(), so if we save off a bkey() pointer in retry_key and then assign that to __key, we'll end up corrupting the btree internals when we do eg longcpy(__key, bkey(geo, node, i), geo->keylen); to return the key value. What we should do instead is use longcpy() to copy the key value that retry_key points to __key. This can cause a btree to get corrupted by seemingly read-only operations such as btree_for_each_safe. [akpm@linux-foundation.org: avoid the double longcpy()] Signed-off-by: Roland Dreier Acked-by: Joern Engel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- lib/btree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/lib/btree.c +++ b/lib/btree.c @@ -319,8 +319,8 @@ void *btree_get_prev(struct btree_head * if (head->height == 0) return NULL; -retry: longcpy(key, __key, geo->keylen); +retry: dec_key(geo, key); node = head->node; @@ -351,7 +351,7 @@ retry: } miss: if (retry_key) { - __key = retry_key; + longcpy(key, retry_key, geo->keylen); retry_key = NULL; goto retry; }