linux/fs/hfs/brec.c
Eric Sandeen cf05946250 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>
2008-01-08 16:10:36 -08:00

508 lines
13 KiB
C

/*
* linux/fs/hfs/brec.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handle individual btree records
*/
#include "btree.h"
static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
static int hfs_brec_update_parent(struct hfs_find_data *fd);
static int hfs_btree_inc_height(struct hfs_btree *tree);
/* Get the length and offset of the given record in the given node */
u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
{
__be16 retval[2];
u16 dataoff;
dataoff = node->tree->node_size - (rec + 2) * 2;
hfs_bnode_read(node, retval, dataoff, 4);
*off = be16_to_cpu(retval[1]);
return be16_to_cpu(retval[0]) - *off;
}
/* Get the length of the key from a keyed record */
u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
{
u16 retval, recoff;
if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
return 0;
if ((node->type == HFS_NODE_INDEX) &&
!(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
if (node->tree->attributes & HFS_TREE_BIGKEYS)
retval = node->tree->max_key_len + 2;
else
retval = node->tree->max_key_len + 1;
} else {
recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
if (!recoff)
return 0;
if (node->tree->attributes & HFS_TREE_BIGKEYS) {
retval = hfs_bnode_read_u16(node, recoff) + 2;
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;
}
int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *new_node;
int size, key_len, rec;
int data_off, end_off;
int idx_rec_off, data_rec_off, end_rec_off;
__be32 cnid;
tree = fd->tree;
if (!fd->bnode) {
if (!tree->root)
hfs_btree_inc_height(tree);
fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
if (IS_ERR(fd->bnode))
return PTR_ERR(fd->bnode);
fd->record = -1;
}
new_node = NULL;
key_len = (fd->search_key->key_len | 1) + 1;
again:
/* new record idx and complete record size */
rec = fd->record + 1;
size = key_len + entry_len;
node = fd->bnode;
hfs_bnode_dump(node);
/* get last offset */
end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
end_off = hfs_bnode_read_u16(node, end_rec_off);
end_rec_off -= 2;
dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
if (size > end_rec_off - end_off) {
if (new_node)
panic("not enough room!\n");
new_node = hfs_bnode_split(fd);
if (IS_ERR(new_node))
return PTR_ERR(new_node);
goto again;
}
if (node->type == HFS_NODE_LEAF) {
tree->leaf_count++;
mark_inode_dirty(tree->inode);
}
node->num_recs++;
/* write new last offset */
hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
hfs_bnode_write_u16(node, end_rec_off, end_off + size);
data_off = end_off;
data_rec_off = end_rec_off + 2;
idx_rec_off = tree->node_size - (rec + 1) * 2;
if (idx_rec_off == data_rec_off)
goto skip;
/* move all following entries */
do {
data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
hfs_bnode_write_u16(node, data_rec_off, data_off + size);
data_rec_off += 2;
} while (data_rec_off < idx_rec_off);
/* move data away */
hfs_bnode_move(node, data_off + size, data_off,
end_off - data_off);
skip:
hfs_bnode_write(node, fd->search_key, data_off, key_len);
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);
hfs_bnode_put(fd->bnode);
if (!new_node->parent) {
hfs_btree_inc_height(tree);
new_node->parent = tree->root;
}
fd->bnode = hfs_bnode_find(tree, new_node->parent);
/* create index data entry */
cnid = cpu_to_be32(new_node->this);
entry = &cnid;
entry_len = sizeof(cnid);
/* get index key */
hfs_bnode_read_key(new_node, fd->search_key, 14);
__hfs_brec_find(fd->bnode, fd);
hfs_bnode_put(new_node);
new_node = NULL;
if (tree->attributes & HFS_TREE_VARIDXKEYS)
key_len = fd->search_key->key_len + 1;
else {
fd->search_key->key_len = tree->max_key_len;
key_len = tree->max_key_len + 1;
}
goto again;
}
if (!rec)
hfs_brec_update_parent(fd);
return 0;
}
int hfs_brec_remove(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *parent;
int end_off, rec_off, data_off, size;
tree = fd->tree;
node = fd->bnode;
again:
rec_off = tree->node_size - (fd->record + 2) * 2;
end_off = tree->node_size - (node->num_recs + 1) * 2;
if (node->type == HFS_NODE_LEAF) {
tree->leaf_count--;
mark_inode_dirty(tree->inode);
}
hfs_bnode_dump(node);
dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
if (!--node->num_recs) {
hfs_bnode_unlink(node);
if (!node->parent)
return 0;
parent = hfs_bnode_find(tree, node->parent);
if (IS_ERR(parent))
return PTR_ERR(parent);
hfs_bnode_put(node);
node = fd->bnode = parent;
__hfs_brec_find(node, fd);
goto again;
}
hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
if (rec_off == end_off)
goto skip;
size = fd->keylength + fd->entrylength;
do {
data_off = hfs_bnode_read_u16(node, rec_off);
hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
rec_off -= 2;
} while (rec_off >= end_off);
/* fill hole */
hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
data_off - fd->keyoffset - size);
skip:
hfs_bnode_dump(node);
if (!fd->record)
hfs_brec_update_parent(fd);
return 0;
}
static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *new_node;
struct hfs_bnode_desc node_desc;
int num_recs, new_rec_off, new_off, old_rec_off;
int data_start, data_end, size;
tree = fd->tree;
node = fd->bnode;
new_node = hfs_bmap_alloc(tree);
if (IS_ERR(new_node))
return new_node;
hfs_bnode_get(node);
dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
node->this, new_node->this, node->next);
new_node->next = node->next;
new_node->prev = node->this;
new_node->parent = node->parent;
new_node->type = node->type;
new_node->height = node->height;
size = tree->node_size / 2 - node->num_recs * 2 - 14;
old_rec_off = tree->node_size - 4;
num_recs = 1;
for (;;) {
data_start = hfs_bnode_read_u16(node, old_rec_off);
if (data_start > size)
break;
old_rec_off -= 2;
if (++num_recs < node->num_recs)
continue;
/* panic? */
hfs_bnode_put(node);
hfs_bnode_put(new_node);
return ERR_PTR(-ENOSPC);
}
if (fd->record + 1 < num_recs) {
/* new record is in the lower half,
* so leave some more space there
*/
old_rec_off += 2;
num_recs--;
data_start = hfs_bnode_read_u16(node, old_rec_off);
} else {
hfs_bnode_put(node);
hfs_bnode_get(new_node);
fd->bnode = new_node;
fd->record -= num_recs;
fd->keyoffset -= data_start - 14;
fd->entryoffset -= data_start - 14;
}
new_node->num_recs = node->num_recs - num_recs;
node->num_recs = num_recs;
new_rec_off = tree->node_size - 2;
new_off = 14;
size = data_start - new_off;
num_recs = new_node->num_recs;
data_end = data_start;
while (num_recs) {
hfs_bnode_write_u16(new_node, new_rec_off, new_off);
old_rec_off -= 2;
new_rec_off -= 2;
data_end = hfs_bnode_read_u16(node, old_rec_off);
new_off = data_end - size;
num_recs--;
}
hfs_bnode_write_u16(new_node, new_rec_off, new_off);
hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
/* update new bnode header */
node_desc.next = cpu_to_be32(new_node->next);
node_desc.prev = cpu_to_be32(new_node->prev);
node_desc.type = new_node->type;
node_desc.height = new_node->height;
node_desc.num_recs = cpu_to_be16(new_node->num_recs);
node_desc.reserved = 0;
hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
/* update previous bnode header */
node->next = new_node->this;
hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
node_desc.next = cpu_to_be32(node->next);
node_desc.num_recs = cpu_to_be16(node->num_recs);
hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
/* update next bnode header */
if (new_node->next) {
struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
next_node->prev = new_node->this;
hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
node_desc.prev = cpu_to_be32(next_node->prev);
hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
hfs_bnode_put(next_node);
} else if (node->this == tree->leaf_tail) {
/* if there is no next node, this might be the new tail */
tree->leaf_tail = new_node->this;
mark_inode_dirty(tree->inode);
}
hfs_bnode_dump(node);
hfs_bnode_dump(new_node);
hfs_bnode_put(node);
return new_node;
}
static int hfs_brec_update_parent(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *new_node, *parent;
int newkeylen, diff;
int rec, rec_off, end_rec_off;
int start_off, end_off;
tree = fd->tree;
node = fd->bnode;
new_node = NULL;
if (!node->parent)
return 0;
again:
parent = hfs_bnode_find(tree, node->parent);
if (IS_ERR(parent))
return PTR_ERR(parent);
__hfs_brec_find(parent, fd);
hfs_bnode_dump(parent);
rec = fd->record;
/* size difference between old and new key */
if (tree->attributes & HFS_TREE_VARIDXKEYS)
newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
else
fd->keylength = newkeylen = tree->max_key_len + 1;
dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
rec_off = tree->node_size - (rec + 2) * 2;
end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
diff = newkeylen - fd->keylength;
if (!diff)
goto skip;
if (diff > 0) {
end_off = hfs_bnode_read_u16(parent, end_rec_off);
if (end_rec_off - end_off < diff) {
printk(KERN_DEBUG "hfs: splitting index node...\n");
fd->bnode = parent;
new_node = hfs_bnode_split(fd);
if (IS_ERR(new_node))
return PTR_ERR(new_node);
parent = fd->bnode;
rec = fd->record;
rec_off = tree->node_size - (rec + 2) * 2;
end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
}
}
end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
hfs_bnode_write_u16(parent, rec_off, start_off + diff);
start_off -= 4; /* move previous cnid too */
while (rec_off > end_rec_off) {
rec_off -= 2;
end_off = hfs_bnode_read_u16(parent, rec_off);
hfs_bnode_write_u16(parent, rec_off, end_off + diff);
}
hfs_bnode_move(parent, start_off + diff, start_off,
end_off - start_off);
skip:
hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
hfs_bnode_dump(parent);
hfs_bnode_put(node);
node = parent;
if (new_node) {
__be32 cnid;
fd->bnode = hfs_bnode_find(tree, new_node->parent);
/* create index key and entry */
hfs_bnode_read_key(new_node, fd->search_key, 14);
cnid = cpu_to_be32(new_node->this);
__hfs_brec_find(fd->bnode, fd);
hfs_brec_insert(fd, &cnid, sizeof(cnid));
hfs_bnode_put(fd->bnode);
hfs_bnode_put(new_node);
if (!rec) {
if (new_node == node)
goto out;
/* restore search_key */
hfs_bnode_read_key(node, fd->search_key, 14);
}
}
if (!rec && node->parent)
goto again;
out:
fd->bnode = node;
return 0;
}
static int hfs_btree_inc_height(struct hfs_btree *tree)
{
struct hfs_bnode *node, *new_node;
struct hfs_bnode_desc node_desc;
int key_size, rec;
__be32 cnid;
node = NULL;
if (tree->root) {
node = hfs_bnode_find(tree, tree->root);
if (IS_ERR(node))
return PTR_ERR(node);
}
new_node = hfs_bmap_alloc(tree);
if (IS_ERR(new_node)) {
hfs_bnode_put(node);
return PTR_ERR(new_node);
}
tree->root = new_node->this;
if (!tree->depth) {
tree->leaf_head = tree->leaf_tail = new_node->this;
new_node->type = HFS_NODE_LEAF;
new_node->num_recs = 0;
} else {
new_node->type = HFS_NODE_INDEX;
new_node->num_recs = 1;
}
new_node->parent = 0;
new_node->next = 0;
new_node->prev = 0;
new_node->height = ++tree->depth;
node_desc.next = cpu_to_be32(new_node->next);
node_desc.prev = cpu_to_be32(new_node->prev);
node_desc.type = new_node->type;
node_desc.height = new_node->height;
node_desc.num_recs = cpu_to_be16(new_node->num_recs);
node_desc.reserved = 0;
hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
rec = tree->node_size - 2;
hfs_bnode_write_u16(new_node, rec, 14);
if (node) {
/* insert old root idx into new root */
node->parent = tree->root;
if (node->type == HFS_NODE_LEAF ||
tree->attributes & HFS_TREE_VARIDXKEYS)
key_size = hfs_bnode_read_u8(node, 14) + 1;
else
key_size = tree->max_key_len + 1;
hfs_bnode_copy(new_node, 14, node, 14, key_size);
if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
key_size = tree->max_key_len + 1;
hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
}
key_size = (key_size + 1) & -2;
cnid = cpu_to_be32(node->this);
hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
rec -= 2;
hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
hfs_bnode_put(node);
}
hfs_bnode_put(new_node);
mark_inode_dirty(tree->inode);
return 0;
}