ext4: refactor __ext4_check_dir_entry() to accept start and size
The __ext4_check_dir_entry() function() is used to check whether the
de is over the block boundary. Now with inline data, it could be
within the block boundary while exceeds the inode size. So check this
function to check the overflow more precisely.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 8e07d2a..7c9d08b 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -72,7 +72,7 @@
int __ext4_check_dir_entry(const char *function, unsigned int line,
struct inode *dir, struct file *filp,
struct ext4_dir_entry_2 *de,
- struct buffer_head *bh,
+ struct buffer_head *bh, char *buf, int size,
unsigned int offset)
{
const char *error_msg = NULL;
@@ -85,9 +85,8 @@
error_msg = "rec_len % 4 != 0";
else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
error_msg = "rec_len is too small for name_len";
- else if (unlikely(((char *) de - bh->b_data) + rlen >
- dir->i_sb->s_blocksize))
- error_msg = "directory entry across blocks";
+ else if (unlikely(((char *) de - buf) + rlen > size))
+ error_msg = "directory entry across range";
else if (unlikely(le32_to_cpu(de->inode) >
le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
error_msg = "inode out of bounds";
@@ -98,14 +97,14 @@
ext4_error_file(filp, function, line, bh->b_blocknr,
"bad entry in directory: %s - offset=%u(%u), "
"inode=%u, rec_len=%d, name_len=%d",
- error_msg, (unsigned) (offset % bh->b_size),
+ error_msg, (unsigned) (offset % size),
offset, le32_to_cpu(de->inode),
rlen, de->name_len);
else
ext4_error_inode(dir, function, line, bh->b_blocknr,
"bad entry in directory: %s - offset=%u(%u), "
"inode=%u, rec_len=%d, name_len=%d",
- error_msg, (unsigned) (offset % bh->b_size),
+ error_msg, (unsigned) (offset % size),
offset, le32_to_cpu(de->inode),
rlen, de->name_len);
@@ -221,8 +220,9 @@
while (!error && filp->f_pos < inode->i_size
&& offset < sb->s_blocksize) {
de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
- if (ext4_check_dir_entry(inode, filp, de,
- bh, offset)) {
+ if (ext4_check_dir_entry(inode, filp, de, bh,
+ bh->b_data, bh->b_size,
+ offset)) {
/*
* On error, skip the f_pos to the next block
*/