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Message-ID: <m364a1wys5.fsf@bzzz.home.net>
Date: Sat, 17 Feb 2007 00:57:35 +0300
From: Alex Tomas <alex@...sterfs.com>
To: <linux-ext4@...r.kernel.org>
Subject: [PATCH] sanity checks for on-disk data in extents code
Good day,
with the patch all headers are checked. the code should become
more resistant to on-disk corruptions. needless BUG_ON() have
been removed. please, review for inclusion.
thanks, Alex
Signed-off-by: Alex Tomas <alex@...sterfs.com>
Index: linux-2.6.20/fs/ext4/extents.c
===================================================================
--- linux-2.6.20.orig/fs/ext4/extents.c 2007-02-17 00:34:32.000000000 +0300
+++ linux-2.6.20/fs/ext4/extents.c 2007-02-17 00:50:24.000000000 +0300
@@ -92,36 +92,6 @@
ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
}
-static int ext4_ext_check_header(const char *function, struct inode *inode,
- struct ext4_extent_header *eh)
-{
- const char *error_msg = NULL;
-
- if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
- error_msg = "invalid magic";
- goto corrupted;
- }
- if (unlikely(eh->eh_max == 0)) {
- error_msg = "invalid eh_max";
- goto corrupted;
- }
- if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
- error_msg = "invalid eh_entries";
- goto corrupted;
- }
- return 0;
-
-corrupted:
- ext4_error(inode->i_sb, function,
- "bad header in inode #%lu: %s - magic %x, "
- "entries %u, max %u, depth %u",
- inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
- le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
- le16_to_cpu(eh->eh_depth));
-
- return -EIO;
-}
-
static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
{
int err;
@@ -270,6 +240,70 @@
return size;
}
+static inline int
+ext4_ext_max_entries(struct inode *inode, int depth)
+{
+ int max;
+
+ if (depth == ext_depth(inode)) {
+ if (depth == 0)
+ max = ext4_ext_space_root(inode);
+ else
+ max = ext4_ext_space_root_idx(inode);
+ } else {
+ if (depth == 0)
+ max = ext4_ext_space_block(inode);
+ else
+ max = ext4_ext_space_block_idx(inode);
+ }
+
+ return max;
+}
+
+static int __ext4_ext_check_header(const char *function, struct inode *inode,
+ struct ext4_extent_header *eh,
+ int depth)
+{
+ const char *error_msg = NULL;
+ int max = 0;
+
+ if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
+ error_msg = "invalid magic";
+ goto corrupted;
+ }
+ if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
+ error_msg = "unexpected eh_depth";
+ goto corrupted;
+ }
+ if (unlikely(eh->eh_max == 0)) {
+ error_msg = "invalid eh_max";
+ goto corrupted;
+ }
+ max = ext4_ext_max_entries(inode, depth);
+ if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
+ error_msg = "too large eh_max";
+ goto corrupted;
+ }
+ if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
+ error_msg = "invalid eh_entries";
+ goto corrupted;
+ }
+ return 0;
+
+corrupted:
+ ext4_error(inode->i_sb, function,
+ "bad header in inode #%lu: %s - magic %x, "
+ "entries %u, max %u(%u), depth %u(%u)",
+ inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
+ le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
+ max, le16_to_cpu(eh->eh_depth), depth);
+
+ return -EIO;
+}
+
+#define ext4_ext_check_header(inode,eh,depth) \
+ __ext4_ext_check_header(__FUNCTION__,inode,eh,depth)
+
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
{
@@ -330,6 +364,7 @@
/*
* ext4_ext_binsearch_idx:
* binary search for the closest index of the given block
+ * the header must be checked before calling this
*/
static void
ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
@@ -337,9 +372,6 @@
struct ext4_extent_header *eh = path->p_hdr;
struct ext4_extent_idx *r, *l, *m;
- BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
- BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
- BUG_ON(le16_to_cpu(eh->eh_entries) <= 0);
ext_debug("binsearch for %d(idx): ", block);
@@ -389,6 +421,7 @@
/*
* ext4_ext_binsearch:
* binary search for closest extent of the given block
+ * the header must be checked before calling this
*/
static void
ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
@@ -396,9 +429,6 @@
struct ext4_extent_header *eh = path->p_hdr;
struct ext4_extent *r, *l, *m;
- BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
- BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
-
if (eh->eh_entries == 0) {
/*
* this leaf is empty:
@@ -469,11 +499,10 @@
short int depth, i, ppos = 0, alloc = 0;
eh = ext_inode_hdr(inode);
- BUG_ON(eh == NULL);
- if (ext4_ext_check_header(__FUNCTION__, inode, eh))
+ i = depth = ext_depth(inode);
+ if (ext4_ext_check_header(inode, eh, depth))
return ERR_PTR(-EIO);
- i = depth = ext_depth(inode);
/* account possible depth increase */
if (!path) {
@@ -489,6 +518,7 @@
while (i) {
ext_debug("depth %d: num %d, max %d\n",
ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
+
ext4_ext_binsearch_idx(inode, path + ppos, block);
path[ppos].p_block = idx_pblock(path[ppos].p_idx);
path[ppos].p_depth = i;
@@ -505,7 +535,7 @@
path[ppos].p_hdr = eh;
i--;
- if (ext4_ext_check_header(__FUNCTION__, inode, eh))
+ if (ext4_ext_check_header(inode, eh, i))
goto err;
}
@@ -514,9 +544,6 @@
path[ppos].p_ext = NULL;
path[ppos].p_idx = NULL;
- if (ext4_ext_check_header(__FUNCTION__, inode, eh))
- goto err;
-
/* find extent */
ext4_ext_binsearch(inode, path + ppos, block);
@@ -1625,13 +1652,12 @@
unsigned short ex_ee_len;
struct ext4_extent *ex;
+ /* the header must be checked already in ext4_ext_remove_space() */
ext_debug("truncate since %lu in leaf\n", start);
if (!path[depth].p_hdr)
path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
eh = path[depth].p_hdr;
BUG_ON(eh == NULL);
- BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
- BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
/* find where to start removing */
ex = EXT_LAST_EXTENT(eh);
@@ -1777,7 +1803,7 @@
return -ENOMEM;
}
path[0].p_hdr = ext_inode_hdr(inode);
- if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) {
+ if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) {
err = -EIO;
goto out;
}
@@ -1798,17 +1824,8 @@
if (!path[i].p_hdr) {
ext_debug("initialize header\n");
path[i].p_hdr = ext_block_hdr(path[i].p_bh);
- if (ext4_ext_check_header(__FUNCTION__, inode,
- path[i].p_hdr)) {
- err = -EIO;
- goto out;
- }
}
- BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries)
- > le16_to_cpu(path[i].p_hdr->eh_max));
- BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
-
if (!path[i].p_idx) {
/* this level hasn't been touched yet */
path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
@@ -1825,17 +1842,24 @@
i, EXT_FIRST_INDEX(path[i].p_hdr),
path[i].p_idx);
if (ext4_ext_more_to_rm(path + i)) {
+ struct buffer_head *bh;
/* go to the next level */
ext_debug("move to level %d (block %llu)\n",
i + 1, idx_pblock(path[i].p_idx));
memset(path + i + 1, 0, sizeof(*path));
- path[i+1].p_bh =
- sb_bread(sb, idx_pblock(path[i].p_idx));
- if (!path[i+1].p_bh) {
+ bh = sb_bread(sb, idx_pblock(path[i].p_idx));
+ if (!bh) {
/* should we reset i_size? */
err = -EIO;
break;
}
+ BUG_ON(i + 1 > depth);
+ if (ext4_ext_check_header(inode, ext_block_hdr(bh),
+ depth - i - 1)) {
+ err = -EIO;
+ break;
+ }
+ path[i+1].p_bh = bh;
/* save actual number of indexes since this
* number is changed at the next iteration */
-
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