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ext4: add checks of block references for non-extent inodes

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Check block references in the inode and indorect blocks for non-extent
inodes to make sure they are valid, and flag an error if they are
invalid.

Signed-off-by: Thiemo Nagel <thiemo.nagel@ph.tum.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Thiemo Nagel 2009-03-31 08:36:10 -04:00 • committed by Theodore Ts'o
commit fe2c8191fa
1 changed files with 52 additions and 7 deletions
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53
fs/ext4/inode.c
View file

@ -371,6 +371,34 @@ static int ext4_block_to_path(struct inode *inode,
return n;
}
static int __ext4_check_blockref(const char *function, struct inode *inode,
unsigned int *p, unsigned int max) {
unsigned int maxblocks = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es);
unsigned int *bref = p;
while (bref < p+max) {
if (unlikely(*bref >= maxblocks)) {
ext4_error(inode->i_sb, function,
"block reference %u >= max (%u) "
"in inode #%lu, offset=%d",
*bref, maxblocks,
inode->i_ino, (int)(bref-p));
return -EIO;
}
bref++;
}
return 0;
}
#define ext4_check_indirect_blockref(inode, bh) \
__ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data, \
EXT4_ADDR_PER_BLOCK((inode)->i_sb))
#define ext4_check_inode_blockref(inode) \
__ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data, \
EXT4_NDIR_BLOCKS)
/**
* ext4_get_branch - read the chain of indirect blocks leading to data
* @inode: inode in question
@ -415,9 +443,22 @@ static Indirect *ext4_get_branch(struct inode *inode, int depth,
if (!p->key)
goto no_block;
while (--depth) {
bh = sb_bread(sb, le32_to_cpu(p->key));
if (!bh)
bh = sb_getblk(sb, le32_to_cpu(p->key));
if (unlikely(!bh))
goto failure;
if (!bh_uptodate_or_lock(bh)) {
if (bh_submit_read(bh) < 0) {
put_bh(bh);
goto failure;
}
/* validate block references */
if (ext4_check_indirect_blockref(inode, bh)) {
put_bh(bh);
goto failure;
}
}
add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
/* Reader: end */
if (!p->key)
@ -4371,13 +4412,17 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
if (ei->i_flags & EXT4_EXTENTS_FL) {
/* Validate extent which is part of inode */
ret = ext4_ext_check_inode(inode);
} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
(S_ISLNK(inode->i_mode) &&
!ext4_inode_is_fast_symlink(inode))) {
/* Validate block references which are part of inode */
ret = ext4_check_inode_blockref(inode);
}
if (ret) {
brelse(bh);
goto bad_inode;
}
}
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext4_file_inode_operations;
inode->i_fop = &ext4_file_operations;