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ext4: Fix softlockup caused by illegal i_file_acl value in on-disk inode

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If the block containing external extended attributes (which is stored
in i_file_acl and i_file_acl_high) is larger than the on-disk
filesystem, the process which tried to access the extended attributes
will endlessly issue kernel printks complaining that
"__find_get_block_slow() failed", locking up that CPU until the system
is forcibly rebooted.

So when we read in the inode, make sure the i_file_acl value is legal,
and if not, flag the filesystem as being corrupted.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2009-04-24 13:43:20 -04:00
parent 0c8454f566
commit 485c26ec70
1 changed files with 11 additions and 1 deletions
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12
fs/ext4/inode.c
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@ -4409,7 +4409,17 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
}
if (ei->i_flags & EXT4_EXTENTS_FL) {
if (ei->i_file_acl &&
((ei->i_file_acl <
(le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
EXT4_SB(sb)->s_gdb_count)) ||
(ei->i_file_acl >= ext4_blocks_count(EXT4_SB(sb)->s_es)))) {
ext4_error(sb, __func__,
"bad extended attribute block %llu in inode #%lu",
ei->i_file_acl, inode->i_ino);
ret = -EIO;
goto bad_inode;
} else 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) ||