hfs: handle more on-disk corruptions without oopsing
hfs seems prone to bad things when it encounters on disk corruption. Many
values are read from disk, and used as lengths to memcpy, as an example.
This patch fixes up several of these problematic cases.
o sanity check the on-disk maximum key lengths on mount
(these are set to a defined value at mkfs time and shouldn't differ)
o check on-disk node keylens against the maximum key length for each tree
o fix hfs_btree_open so that going out via free_tree: doesn't wind
up in hfs_releasepage, which wants to follow the very pointer
we were trying to set up:
HFS_SB(sb)->cat_tree = hfs_btree_open()
...
failure gets to hfs_releasepage and tries
to follow HFS_SB(sb)->cat_tree
Tested with the fsfuzzer; it survives more than it used to.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index 5c87cf4..8626ee3 100644
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -44,10 +44,21 @@
recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
if (!recoff)
return 0;
- if (node->tree->attributes & HFS_TREE_BIGKEYS)
+ if (node->tree->attributes & HFS_TREE_BIGKEYS) {
retval = hfs_bnode_read_u16(node, recoff) + 2;
- else
+ if (retval > node->tree->max_key_len + 2) {
+ printk(KERN_ERR "hfs: keylen %d too large\n",
+ retval);
+ retval = HFS_BAD_KEYLEN;
+ }
+ } else {
retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
+ if (retval > node->tree->max_key_len + 1) {
+ printk(KERN_ERR "hfs: keylen %d too large\n",
+ retval);
+ retval = HFS_BAD_KEYLEN;
+ }
+ }
}
return retval;
}