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Commit 485c26ec authored by Theodore Ts'o's avatar Theodore Ts'o
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ext4: Fix softlockup caused by illegal i_file_acl value in on-disk inode 



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: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 0c8454f5

fs/ext4/inode.c

+11 −1
Original line number Original line 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;

			(__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 */

		/* Validate extent which is part of inode */

		ret = ext4_ext_check_inode(inode);

		ret = ext4_ext_check_inode(inode);

 	} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||

 	} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||