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ext4: Fix wrong comparisons in mext_check_arguments() 

The mext_check_arguments() function in move_extents.c has wrong
comparisons.  orig_start which is passed from user-space is block
unit, but i_size of inode is byte unit, therefore the checks do not
work fine.  This mis-check leads to the overflow of 'len' and then
hits BUG_ON() in ext4_move_extents().  The patch fixes this issue.

Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Reviewed-by: Greg Freemyer <greg.freemyer@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Akira Fujita 2009-09-16 14:28:22 -04:00 committed by Theodore Ts'o
parent 5f3481e9a8
commit 70d5d3dcea
1 changed files with 27 additions and 19 deletions
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46
fs/ext4/move_extent.c
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@ -898,6 +898,10 @@ mext_check_arguments(struct inode *orig_inode,
struct inode *donor_inode, __u64 orig_start,
__u64 donor_start, __u64 *len, __u64 moved_len)
{
ext4_lblk_t orig_blocks, donor_blocks;
unsigned int blkbits = orig_inode->i_blkbits;
unsigned int blocksize = 1 << blkbits;
/* Regular file check */
if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
ext4_debug("ext4 move extent: The argument files should be "
@ -972,43 +976,47 @@ mext_check_arguments(struct inode *orig_inode,
}
if (orig_inode->i_size > donor_inode->i_size) {
if (orig_start >= donor_inode->i_size) {
donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits;
/* TODO: eliminate this artificial restriction */
if (orig_start >= donor_blocks) {
ext4_debug("ext4 move extent: orig start offset "
"[%llu] should be less than donor file size "
"[%lld] [ino:orig %lu, donor_inode %lu]\n",
orig_start, donor_inode->i_size,
"[%llu] should be less than donor file blocks "
"[%u] [ino:orig %lu, donor %lu]\n",
orig_start, donor_blocks,
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
if (orig_start + *len > donor_inode->i_size) {
/* TODO: eliminate this artificial restriction */
if (orig_start + *len > donor_blocks) {
ext4_debug("ext4 move extent: End offset [%llu] should "
"be less than donor file size [%lld]."
"So adjust length from %llu to %lld "
"be less than donor file blocks [%u]."
"So adjust length from %llu to %llu "
"[ino:orig %lu, donor %lu]\n",
orig_start + *len, donor_inode->i_size,
*len, donor_inode->i_size - orig_start,
orig_start + *len, donor_blocks,
*len, donor_blocks - orig_start,
orig_inode->i_ino, donor_inode->i_ino);
*len = donor_inode->i_size - orig_start;
*len = donor_blocks - orig_start;
}
} else {
if (orig_start >= orig_inode->i_size) {
orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits;
if (orig_start >= orig_blocks) {
ext4_debug("ext4 move extent: start offset [%llu] "
"should be less than original file size "
"[%lld] [inode:orig %lu, donor %lu]\n",
orig_start, orig_inode->i_size,
"should be less than original file blocks "
"[%u] [ino:orig %lu, donor %lu]\n",
orig_start, orig_blocks,
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
if (orig_start + *len > orig_inode->i_size) {
if (orig_start + *len > orig_blocks) {
ext4_debug("ext4 move extent: Adjust length "
"from %llu to %lld. Because it should be "
"less than original file size "
"from %llu to %llu. Because it should be "
"less than original file blocks "
"[ino:orig %lu, donor %lu]\n",
*len, orig_inode->i_size - orig_start,
*len, orig_blocks - orig_start,
orig_inode->i_ino, donor_inode->i_ino);
*len = orig_inode->i_size - orig_start;
*len = orig_blocks - orig_start;
}
}