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linux-sg2042
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ext4: Add checks to validate extent entries. 

This patch adds checks to validate the extent entries along with extent
headers, to avoid crashes caused by corrupt filesystems.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Aneesh Kumar K.V 2009-03-12 09:51:20 -04:00 committed by Theodore Ts'o
parent e6f009b0b4
commit 56b19868ac
1 changed files with 71 additions and 10 deletions
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81
fs/ext4/extents.c
View File

@ -324,7 +324,64 @@ ext4_ext_max_entries(struct inode *inode, int depth)
return max;
}
static int __ext4_ext_check_header(const char *function, struct inode *inode,
static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
{
ext4_fsblk_t block = ext_pblock(ext);
int len = ext4_ext_get_actual_len(ext);
struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
((block + len) > ext4_blocks_count(es))))
return 0;
else
return 1;
}
static int ext4_valid_extent_idx(struct inode *inode,
struct ext4_extent_idx *ext_idx)
{
ext4_fsblk_t block = idx_pblock(ext_idx);
struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
(block > ext4_blocks_count(es))))
return 0;
else
return 1;
}
static int ext4_valid_extent_entries(struct inode *inode,
struct ext4_extent_header *eh,
int depth)
{
struct ext4_extent *ext;
struct ext4_extent_idx *ext_idx;
unsigned short entries;
if (eh->eh_entries == 0)
return 1;
entries = le16_to_cpu(eh->eh_entries);
if (depth == 0) {
/* leaf entries */
ext = EXT_FIRST_EXTENT(eh);
while (entries) {
if (!ext4_valid_extent(inode, ext))
return 0;
ext++;
entries--;
}
} else {
ext_idx = EXT_FIRST_INDEX(eh);
while (entries) {
if (!ext4_valid_extent_idx(inode, ext_idx))
return 0;
ext_idx++;
entries--;
}
}
return 1;
}
static int __ext4_ext_check(const char *function, struct inode *inode,
struct ext4_extent_header *eh,
int depth)
{
@ -352,11 +409,15 @@ static int __ext4_ext_check_header(const char *function, struct inode *inode,
error_msg = "invalid eh_entries";
goto corrupted;
}
if (!ext4_valid_extent_entries(inode, eh, depth)) {
error_msg = "invalid extent entries";
goto corrupted;
}
return 0;
corrupted:
ext4_error(inode->i_sb, function,
"bad header in inode #%lu: %s - magic %x, "
"bad header/extent 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),
@ -365,8 +426,8 @@ corrupted:
return -EIO;
}
#define ext4_ext_check_header(inode, eh, depth) \
__ext4_ext_check_header(__func__, inode, eh, depth)
#define ext4_ext_check(inode, eh, depth) \
__ext4_ext_check(__func__, inode, eh, depth)
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
@ -570,7 +631,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
eh = ext_inode_hdr(inode);
depth = ext_depth(inode);
if (ext4_ext_check_header(inode, eh, depth))
if (ext4_ext_check(inode, eh, depth))
return ERR_PTR(-EIO);
@ -607,7 +668,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
path[ppos].p_hdr = eh;
i--;
if (ext4_ext_check_header(inode, eh, i))
if (ext4_ext_check(inode, eh, i))
goto err;
}
@ -1204,7 +1265,7 @@ got_index:
return -EIO;
eh = ext_block_hdr(bh);
/* subtract from p_depth to get proper eh_depth */
if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) {
if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
put_bh(bh);
return -EIO;
}
@ -1217,7 +1278,7 @@ got_index:
if (bh == NULL)
return -EIO;
eh = ext_block_hdr(bh);
if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) {
if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
put_bh(bh);
return -EIO;
}
@ -2160,7 +2221,7 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
return -ENOMEM;
}
path[0].p_hdr = ext_inode_hdr(inode);
if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) {
if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
err = -EIO;
goto out;
}
@ -2214,7 +2275,7 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
err = -EIO;
break;
}
if (ext4_ext_check_header(inode, ext_block_hdr(bh),
if (ext4_ext_check(inode, ext_block_hdr(bh),
depth - i - 1)) {
err = -EIO;
break;