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[PATCH] xfs_metadump: obfuscate attrs on CRC fs

To: xfs-oss <xfs@xxxxxxxxxxx>
Subject: [PATCH] xfs_metadump: obfuscate attrs on CRC fs
From: Eric Sandeen <sandeen@xxxxxxxxxx>
Date: Fri, 12 Jun 2015 17:50:10 -0500
Delivered-to: xfs@xxxxxxxxxxx
Lots of issues in xfs_metadump obfuscation of extended
attributes with CRC filesystems; this fixes it up.

The main issues are that the headers differ, and the
space in the remote blocks differ.

Tested with a script I'm using to do other metadump
work; I still owe an xfstest for this and other bits.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

Brief/hacky testcase; populate w/ many attr types with:

        MNTPT=/mount/test

        # FMT_LOCAL
        touch $MNTPT/S_IFREG.ATTR.FMT_LOCAL
        setfattr -n user.localattrname -v localattrvalue 
$MNTPT/S_IFREG.ATTR.FMT_LOCAL

        # FMT_EXTENTS
        touch $MNTPT/S_IFREG.ATTR.FMT_EXTENTS
        for I in `seq 1 50`; do
                setfattr -n user.extentattrname$I -v extentattrvalue 
$MNTPT/S_IFREG.ATTR.FMT_EXTENTS
        done

        # FMT_EXTENTS with a single remote 3k value, fill with "C"
        touch $MNTPT/S_IFREG.ATTR.FMT_EXTENTS_REMOTE3K
        xfs_io -f -c "pwrite -S 0x43 0 3k" attrvalfile &>/dev/null
        attr -q -s user.remotebtreeattrname 
$MNTPT/S_IFREG.ATTR.FMT_EXTENTS_REMOTE3K < attrvalfile

        # FMT_EXTENTS with a single remote 4k value, fill with "D"
        touch $MNTPT/S_IFREG.ATTR.FMT_EXTENTS_REMOTE4K
        xfs_io -f -c "pwrite -S 0x44 0 4k" attrvalfile &>/dev/null
        attr -q -s user.remotebtreeattrname 
$MNTPT/S_IFREG.ATTR.FMT_EXTENTS_REMOTE4K < attrvalfile

        # FMT_BTREE
        touch $MNTPT/S_IFREG.ATTR.FMT_BTREE
        for I in `seq 1 1000`; do
                setfattr -n user.btreeattrname$I -v btreelongerattrvalue 
$MNTPT/S_IFREG.ATTR.FMT_BTREE
        done

on a crc filesystem, an obfuscated metadump will show all these attrs in the 
clear
with getfattr -dR $MNTPT

diff --git a/db/metadump.c b/db/metadump.c
index 94f92bc..793f39e 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -1268,39 +1268,54 @@ add_remote_vals(
        }
 }
 
+/* Handle remote and leaf attributes */
 static void
 obfuscate_attr_block(
-       char                    *block,
-       xfs_fileoff_t           offset)
+       char                            *block,
+       xfs_fileoff_t                   offset)
 {
-       xfs_attr_leafblock_t    *leaf;
-       int                     i;
-       int                     nentries;
-       xfs_attr_leaf_entry_t   *entry;
-       xfs_attr_leaf_name_local_t *local;
-       xfs_attr_leaf_name_remote_t *remote;
+       struct xfs_attr_leafblock       *leaf;
+       struct xfs_attr3_icleaf_hdr     hdr;
+       int                             i;
+       int                             nentries;
+       xfs_attr_leaf_entry_t           *entry;
+       xfs_attr_leaf_name_local_t      *local;
+       xfs_attr_leaf_name_remote_t     *remote;
+       __uint32_t                      bs = mp->m_sb.sb_blocksize;
+
 
        leaf = (xfs_attr_leafblock_t *)block;
 
-       if (be16_to_cpu(leaf->hdr.info.magic) != XFS_ATTR_LEAF_MAGIC) {
+       /* Get header; accounts for crc & non-crc */
+       xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &hdr, leaf);
+
+       /* Remote attributes */
+       if ((hdr.magic != XFS_ATTR_LEAF_MAGIC) &&
+           (hdr.magic != XFS_ATTR3_LEAF_MAGIC)) {
                for (i = 0; i < attr_data.remote_val_count; i++) {
-                       /* XXX: need to handle CRC headers */
                        if (attr_data.remote_vals[i] == offset)
-                               memset(block, 0, mp->m_sb.sb_blocksize);
+                               /* magic to handle attr and attr3 */
+                               memset(block +
+                                       (bs - XFS_ATTR3_RMT_BUF_SPACE(mp, bs)),
+                                     0, XFS_ATTR3_RMT_BUF_SPACE(mp, bs));
                }
                return;
        }
 
-       nentries = be16_to_cpu(leaf->hdr.count);
+       nentries = hdr.count;
+
        if (nentries * sizeof(xfs_attr_leaf_entry_t) +
-                       sizeof(xfs_attr_leaf_hdr_t) > mp->m_sb.sb_blocksize) {
+                       xfs_attr3_leaf_hdr_size(leaf) >
+                               XFS_ATTR3_RMT_BUF_SPACE(mp, bs)) {
                if (show_warnings)
                        print_warning("invalid attr count in inode %llu",
                                        (long long)cur_ino);
                return;
        }
 
-       for (i = 0, entry = &leaf->entries[0]; i < nentries; i++, entry++) {
+       entry = xfs_attr3_leaf_entryp(leaf);
+
+       for (i = 0; i < nentries; i++, entry++) {
                if (be16_to_cpu(entry->nameidx) > mp->m_sb.sb_blocksize) {
                        if (show_warnings)
                                print_warning(

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