linux-ext4 - [PATCH] ext4: kill i_version support for Hurd-castrated file systems

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 20 Mar 2014 00:34:11 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:	1o5g4r8o@...il.com, 738758@...s.debian.org,
	Theodore Ts'o <tytso@....edu>
Subject: [PATCH] ext4: kill i_version support for Hurd-castrated file systems

The Hurd file system uses uses the inode field which is now used for
i_version for its translator block.  This means that ext2 file systems
that are formatted for GNU Hurd can't be used to support NFSv4.  Given
that Hurd file systems don't support extents, and a huge number of
modern file system features, this is no great loss.

If we don't do this, the attempt to update the i_version field will
stomp over the translator block field, which will cause file system
corruption for Hurd file systems.  This can be replicated via:

mke2fs -t ext2 -o hurd /dev/vdc
mount -t ext4 /dev/vdc /vdc
touch /vdc/bug0000
umount /dev/vdc
e2fsck -f /dev/vdc

Addresses-Debian-Bug: #738758

Reported-By: Gabriele Giacone <1o5g4r8o@...il.com>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
 fs/ext4/inode.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7cc2455..ed2c13a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4168,11 +4168,14 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
 	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
 
-	inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
-	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
-		if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
-			inode->i_version |=
-			(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
+	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+	    cpu_to_le32(EXT4_OS_HURD)) {
+		inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
+		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+				inode->i_version |=
+		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
+		}
 	}
 
 	ret = 0;
@@ -4388,12 +4391,16 @@ static int ext4_do_update_inode(handle_t *handle,
 			raw_inode->i_block[block] = ei->i_data[block];
 	}
 
-	raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
-	if (ei->i_extra_isize) {
-		if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
-			raw_inode->i_version_hi =
-			cpu_to_le32(inode->i_version >> 32);
-		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
+	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+	    cpu_to_le32(EXT4_OS_HURD)) {
+		raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
+		if (ei->i_extra_isize) {
+			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+				raw_inode->i_version_hi =
+					cpu_to_le32(inode->i_version >> 32);
+			raw_inode->i_extra_isize =
+				cpu_to_le16(ei->i_extra_isize);
+		}
 	}
 
 	ext4_inode_csum_set(inode, raw_inode, ei);
-- 
1.9.0

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html