ext4: Fix softlockup caused by illegal i_file_acl value in on-disk inode (485c26ec) · Commits · 戴 / test

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>

fs/ext4/inode.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -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) \|\|

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