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/bfind.c b/fs/hfs/bfind.c
index f13f149..f8452a0 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -52,6 +52,10 @@
rec = (e + b) / 2;
len = hfs_brec_lenoff(bnode, rec, &off);
keylen = hfs_brec_keylen(bnode, rec);
+ if (keylen == HFS_BAD_KEYLEN) {
+ res = -EINVAL;
+ goto done;
+ }
hfs_bnode_read(bnode, fd->key, off, keylen);
cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
if (!cmpval) {
@@ -67,6 +71,10 @@
if (rec != e && e >= 0) {
len = hfs_brec_lenoff(bnode, e, &off);
keylen = hfs_brec_keylen(bnode, e);
+ if (keylen == HFS_BAD_KEYLEN) {
+ res = -EINVAL;
+ goto done;
+ }
hfs_bnode_read(bnode, fd->key, off, keylen);
}
done:
@@ -198,6 +206,10 @@
len = hfs_brec_lenoff(bnode, fd->record, &off);
keylen = hfs_brec_keylen(bnode, fd->record);
+ if (keylen == HFS_BAD_KEYLEN) {
+ res = -EINVAL;
+ goto out;
+ }
fd->keyoffset = off;
fd->keylength = keylen;
fd->entryoffset = off + keylen;
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;
}
diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 8a3a650..31284c7 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -81,6 +81,17 @@
goto fail_page;
if (!tree->node_count)
goto fail_page;
+ if ((id == HFS_EXT_CNID) && (tree->max_key_len != HFS_MAX_EXT_KEYLEN)) {
+ printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
+ tree->max_key_len);
+ goto fail_page;
+ }
+ if ((id == HFS_CAT_CNID) && (tree->max_key_len != HFS_MAX_CAT_KEYLEN)) {
+ printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
+ tree->max_key_len);
+ goto fail_page;
+ }
+
tree->node_size_shift = ffs(size) - 1;
tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
@@ -89,9 +100,9 @@
return tree;
fail_page:
- tree->inode->i_mapping->a_ops = &hfs_aops;
page_cache_release(page);
free_tree:
+ tree->inode->i_mapping->a_ops = &hfs_aops;
iput(tree->inode);
kfree(tree);
return NULL;
diff --git a/fs/hfs/hfs.h b/fs/hfs/hfs.h
index 1445e3a..c6aae61 100644
--- a/fs/hfs/hfs.h
+++ b/fs/hfs/hfs.h
@@ -28,6 +28,8 @@
#define HFS_MAX_NAMELEN 128
#define HFS_MAX_VALENCE 32767U
+#define HFS_BAD_KEYLEN 0xFF
+
/* Meanings of the drAtrb field of the MDB,
* Reference: _Inside Macintosh: Files_ p. 2-61
*/
@@ -167,6 +169,9 @@
struct hfs_ext_key ext;
} hfs_btree_key;
+#define HFS_MAX_CAT_KEYLEN (sizeof(struct hfs_cat_key) - sizeof(u8))
+#define HFS_MAX_EXT_KEYLEN (sizeof(struct hfs_ext_key) - sizeof(u8))
+
typedef union hfs_btree_key btree_key;
struct hfs_extent {