Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753069AbbEEBeF (ORCPT ); Mon, 4 May 2015 21:34:05 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50964 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752572AbbEEBXH (ORCPT ); Mon, 4 May 2015 21:23:07 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Anton Altaparmakov" , "Sergei Antonov" , "Vyacheslav Dubeyko" , "Hin-Tak Leung" , "Joe Perches" , "Christoph Hellwig" , "Linus Torvalds" , "Al Viro" Date: Tue, 05 May 2015 02:16:39 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 157/221] hfsplus: fix B-tree corruption after insertion at position 0 In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3694 Lines: 110 3.2.69-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sergei Antonov commit 98cf21c61a7f5419d82f847c4d77bf6e96a76f5f upstream. Fix B-tree corruption when a new record is inserted at position 0 in the node in hfs_brec_insert(). In this case a hfs_brec_update_parent() is called to update the parent index node (if exists) and it is passed hfs_find_data with a search_key containing a newly inserted key instead of the key to be updated. This results in an inconsistent index node. The bug reproduces on my machine after an extents overflow record for the catalog file (CNID=4) is inserted into the extents overflow B-tree. Because of a low (reserved) value of CNID=4, it has to become the first record in the first leaf node. The resulting first leaf node is correct: ---------------------------------------------------- | key0.CNID=4 | key1.CNID=123 | key2.CNID=456, ... | ---------------------------------------------------- But the parent index key0 still contains the previous key CNID=123: ----------------------- | key0.CNID=123 | ... | ----------------------- A change in hfs_brec_insert() makes hfs_brec_update_parent() work correctly by preventing it from getting fd->record=-1 value from __hfs_brec_find(). Along the way, I removed duplicate code with unification of the if condition. The resulting code is equivalent to the original code because node is never 0. Also hfs_brec_update_parent() will now return an error after getting a negative fd->record value. However, the return value of hfs_brec_update_parent() is not checked anywhere in the file and I'm leaving it unchanged by this patch. brec.c lacks error checking after some other calls too, but this issue is of less importance than the one being fixed by this patch. Signed-off-by: Sergei Antonov Cc: Joe Perches Reviewed-by: Vyacheslav Dubeyko Acked-by: Hin-Tak Leung Cc: Anton Altaparmakov Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/hfsplus/brec.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) --- a/fs/hfsplus/brec.c +++ b/fs/hfsplus/brec.c @@ -130,13 +130,16 @@ skip: hfs_bnode_write(node, entry, data_off + key_len, entry_len); hfs_bnode_dump(node); - if (new_node) { - /* update parent key if we inserted a key - * at the start of the first node - */ - if (!rec && new_node != node) - hfs_brec_update_parent(fd); + /* + * update parent key if we inserted a key + * at the start of the node and it is not the new node + */ + if (!rec && new_node != node) { + hfs_bnode_read_key(node, fd->search_key, data_off + size); + hfs_brec_update_parent(fd); + } + if (new_node) { hfs_bnode_put(fd->bnode); if (!new_node->parent) { hfs_btree_inc_height(tree); @@ -166,9 +169,6 @@ skip: goto again; } - if (!rec) - hfs_brec_update_parent(fd); - return 0; } @@ -368,6 +368,8 @@ again: if (IS_ERR(parent)) return PTR_ERR(parent); __hfs_brec_find(parent, fd); + if (fd->record < 0) + return -ENOENT; hfs_bnode_dump(parent); rec = fd->record; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/