This is a note to let you know that I've just added the patch titled
hfsplus: fix B-tree corruption after insertion at position 0
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hfsplus-fix-b-tree-corruption-after-insertion-at-position-0.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 98cf21c61a7f5419d82f847c4d77bf6e96a76f5f Mon Sep 17 00:00:00 2001
From: Sergei Antonov <saproj@xxxxxxxxx>
Date: Wed, 25 Mar 2015 15:55:34 -0700
Subject: hfsplus: fix B-tree corruption after insertion at position 0
From: Sergei Antonov <saproj@xxxxxxxxx>
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 <saproj@xxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Reviewed-by: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
Acked-by: Hin-Tak Leung <htl10@xxxxxxxxxxxxxxxxxxxxx>
Cc: Anton Altaparmakov <aia21@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/hfsplus/brec.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
--- a/fs/hfsplus/brec.c
+++ b/fs/hfsplus/brec.c
@@ -131,13 +131,16 @@ 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);
@@ -168,9 +171,6 @@ skip:
goto again;
}
- if (!rec)
- hfs_brec_update_parent(fd);
-
return 0;
}
@@ -370,6 +370,8 @@ again:
if (IS_ERR(parent))
return PTR_ERR(parent);
__hfs_brec_find(parent, fd, hfs_find_rec_by_key);
+ if (fd->record < 0)
+ return -ENOENT;
hfs_bnode_dump(parent);
rec = fd->record;
Patches currently in stable-queue which might be from saproj@xxxxxxxxx are
queue-3.19/hfsplus-fix-b-tree-corruption-after-insertion-at-position-0.patch
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