path: root/fs/xfs/scrub/attr.c

/*
 * Copyright (C) 2017 Oracle.  All Rights Reserved.
 *
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_btree.h"
#include "xfs_bit.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_inode.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_dir2.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/dabtree.h"
#include "scrub/trace.h"

#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>

/* Set us up to scrub an inode's extended attributes. */
int
xfs_scrub_setup_xattr(
	struct xfs_scrub_context	*sc,
	struct xfs_inode		*ip)
{
	size_t				sz;

	/*
	 * Allocate the buffer without the inode lock held.  We need enough
	 * space to read every xattr value in the file or enough space to
	 * hold three copies of the xattr free space bitmap.  (Not both at
	 * the same time.)
	 */
	sz = max_t(size_t, XATTR_SIZE_MAX, 3 * sizeof(long) *
			BITS_TO_LONGS(sc->mp->m_attr_geo->blksize));
	sc->buf = kmem_zalloc_large(sz, KM_SLEEP);
	if (!sc->buf)
		return -ENOMEM;

	return xfs_scrub_setup_inode_contents(sc, ip, 0);
}

/* Extended Attributes */

struct xfs_scrub_xattr {
	struct xfs_attr_list_context	context;
	struct xfs_scrub_context	*sc;
};

/*
 * Check that an extended attribute key can be looked up by hash.
 *
 * We use the XFS attribute list iterator (i.e. xfs_attr_list_int_ilocked)
 * to call this function for every attribute key in an inode.  Once
 * we're here, we load the attribute value to see if any errors happen,
 * or if we get more or less data than we expected.
 */
static void
xfs_scrub_xattr_listent(
	struct xfs_attr_list_context	*context,
	int				flags,
	unsigned char			*name,
	int				namelen,
	int				valuelen)
{
	struct xfs_scrub_xattr		*sx;
	struct xfs_da_args		args = { NULL };
	int				error = 0;

	sx = container_of(context, struct xfs_scrub_xattr, context);

	if (flags & XFS_ATTR_INCOMPLETE) {
		/* Incomplete attr key, just mark the inode for preening. */
		xfs_scrub_ino_set_preen(sx->sc, context->dp->i_ino);
		return;
	}

	args.flags = ATTR_KERNOTIME;
	if (flags & XFS_ATTR_ROOT)
		args.flags |= ATTR_ROOT;
	else if (flags & XFS_ATTR_SECURE)
		args.flags |= ATTR_SECURE;
	args.geo = context->dp->i_mount->m_attr_geo;
	args.whichfork = XFS_ATTR_FORK;
	args.dp = context->dp;
	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(args.name, args.namelen);
	args.trans = context->tp;
	args.value = sx->sc->buf;
	args.valuelen = XATTR_SIZE_MAX;

	error = xfs_attr_get_ilocked(context->dp, &args);
	if (error == -EEXIST)
		error = 0;
	if (!xfs_scrub_fblock_process_error(sx->sc, XFS_ATTR_FORK, args.blkno,
			&error))
		goto fail_xref;
	if (args.valuelen != valuelen)
		xfs_scrub_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK,
					     args.blkno);
fail_xref:
	if (sx->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		context->seen_enough = 1;
	return;
}

/*
 * Mark a range [start, start+len) in this map.  Returns true if the
 * region was free, and false if there's a conflict or a problem.
 *
 * Within a char, the lowest bit of the char represents the byte with
 * the smallest address
 */
STATIC bool
xfs_scrub_xattr_set_map(
	struct xfs_scrub_context	*sc,
	unsigned long			*map,
	unsigned int			start,
	unsigned int			len)
{
	unsigned int			mapsize = sc->mp->m_attr_geo->blksize;
	bool				ret = true;

	if (start >= mapsize)
		return false;
	if (start + len > mapsize) {
		len = mapsize - start;
		ret = false;
	}

	if (find_next_bit(map, mapsize, start) < start + len)
		ret = false;
	bitmap_set(map, start, len);

	return ret;
}

/*
 * Check the leaf freemap from the usage bitmap.  Returns false if the
 * attr freemap has problems or points to used space.
 */
STATIC bool
xfs_scrub_xattr_check_freemap(
	struct xfs_scrub_context	*sc,
	unsigned long			*map,
	struct xfs_attr3_icleaf_hdr	*leafhdr)
{
	unsigned long			*freemap;
	unsigned long			*dstmap;
	unsigned int			mapsize = sc->mp->m_attr_geo->blksize;
	int				i;

	/* Construct bitmap of freemap contents. */
	freemap = (unsigned long *)sc->buf + BITS_TO_LONGS(mapsize);
	bitmap_zero(freemap, mapsize);
	for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
		if (!xfs_scrub_xattr_set_map(sc, freemap,
				leafhdr->freemap[i].base,
				leafhdr->freemap[i].size))
			return false;
	}

	/* Look for bits that are set in freemap and are marked in use. */
	dstmap = freemap + BITS_TO_LONGS(mapsize);
	return bitmap_and(dstmap, freemap, map, mapsize) == 0;
}

/*
 * Check this leaf entry's relations to everything else.
 * Returns the number of bytes used for the name/value data.
 */
STATIC void
xfs_scrub_xattr_entry(
	struct xfs_scrub_da_btree	*ds,
	int				level,
	char				*buf_end,
	struct xfs_attr_leafblock	*leaf,
	struct xfs_attr3_icleaf_hdr	*leafhdr,
	unsigned long			*usedmap,
	struct xfs_attr_leaf_entry	*ent,
	int				idx,
	unsigned int			*usedbytes,
	__u32				*last_hashval)
{
	struct xfs_mount		*mp = ds->state->mp;
	char				*name_end;
	struct xfs_attr_leaf_name_local	*lentry;
	struct xfs_attr_leaf_name_remote *rentry;
	unsigned int			nameidx;
	unsigned int			namesize;

	if (ent->pad2 != 0)
		xfs_scrub_da_set_corrupt(ds, level);

	/* Hash values in order? */
	if (be32_to_cpu(ent->hashval) < *last_hashval)
		xfs_scrub_da_set_corrupt(ds, level);
	*last_hashval = be32_to_cpu(ent->hashval);

	nameidx = be16_to_cpu(ent->nameidx);
	if (nameidx < leafhdr->firstused ||
	    nameidx >= mp->m_attr_geo->blksize) {
		xfs_scrub_da_set_corrupt(ds, level);
		return;
	}

	/* Check the name information. */
	if (ent->flags & XFS_ATTR_LOCAL) {
		lentry = xfs_attr3_leaf_name_local(leaf, idx);
		namesize = xfs_attr_leaf_entsize_local(lentry->namelen,
				be16_to_cpu(lentry->valuelen));
		name_end = (char *)lentry + namesize;
		if (lentry->namelen == 0)
			xfs_scrub_da_set_corrupt(ds, level);
	} else {
		rentry = xfs_attr3_leaf_name_remote(leaf, idx);
		namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
		name_end = (char *)rentry + namesize;
		if (rentry->namelen == 0 || rentry->valueblk == 0)
			xfs_scrub_da_set_corrupt(ds, level);
	}
	if (name_end > buf_end)
		xfs_scrub_da_set_corrupt(ds, level);

	if (!xfs_scrub_xattr_set_map(ds->sc, usedmap, nameidx, namesize))
		xfs_scrub_da_set_corrupt(ds, level);
	if (