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![Darrick J. Wong](/assets/img/avatar_default.png)
Check extended attribute entry names for invalid characters. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
469 lines
12 KiB
C
469 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2017 Oracle. All Rights Reserved.
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_defer.h"
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#include "xfs_btree.h"
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#include "xfs_bit.h"
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#include "xfs_log_format.h"
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#include "xfs_trans.h"
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#include "xfs_sb.h"
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#include "xfs_inode.h"
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#include "xfs_da_format.h"
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#include "xfs_da_btree.h"
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#include "xfs_dir2.h"
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#include "xfs_attr.h"
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#include "xfs_attr_leaf.h"
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#include "scrub/xfs_scrub.h"
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#include "scrub/scrub.h"
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#include "scrub/common.h"
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#include "scrub/dabtree.h"
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#include "scrub/trace.h"
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#include <linux/posix_acl_xattr.h>
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#include <linux/xattr.h>
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/* Set us up to scrub an inode's extended attributes. */
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int
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xchk_setup_xattr(
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struct xfs_scrub *sc,
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struct xfs_inode *ip)
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{
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size_t sz;
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/*
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* Allocate the buffer without the inode lock held. We need enough
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* space to read every xattr value in the file or enough space to
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* hold three copies of the xattr free space bitmap. (Not both at
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* the same time.)
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*/
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sz = max_t(size_t, XATTR_SIZE_MAX, 3 * sizeof(long) *
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BITS_TO_LONGS(sc->mp->m_attr_geo->blksize));
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sc->buf = kmem_zalloc_large(sz, KM_SLEEP);
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if (!sc->buf)
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return -ENOMEM;
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return xchk_setup_inode_contents(sc, ip, 0);
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}
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/* Extended Attributes */
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struct xchk_xattr {
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struct xfs_attr_list_context context;
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struct xfs_scrub *sc;
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};
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/*
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* Check that an extended attribute key can be looked up by hash.
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*
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* We use the XFS attribute list iterator (i.e. xfs_attr_list_int_ilocked)
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* to call this function for every attribute key in an inode. Once
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* we're here, we load the attribute value to see if any errors happen,
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* or if we get more or less data than we expected.
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*/
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static void
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xchk_xattr_listent(
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struct xfs_attr_list_context *context,
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int flags,
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unsigned char *name,
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int namelen,
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int valuelen)
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{
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struct xchk_xattr *sx;
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struct xfs_da_args args = { NULL };
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int error = 0;
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sx = container_of(context, struct xchk_xattr, context);
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if (xchk_should_terminate(sx->sc, &error)) {
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context->seen_enough = 1;
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return;
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}
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if (flags & XFS_ATTR_INCOMPLETE) {
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/* Incomplete attr key, just mark the inode for preening. */
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xchk_ino_set_preen(sx->sc, context->dp->i_ino);
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return;
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}
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/* Does this name make sense? */
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if (!xfs_attr_namecheck(name, namelen)) {
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xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno);
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return;
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}
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args.flags = ATTR_KERNOTIME;
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if (flags & XFS_ATTR_ROOT)
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args.flags |= ATTR_ROOT;
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else if (flags & XFS_ATTR_SECURE)
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args.flags |= ATTR_SECURE;
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args.geo = context->dp->i_mount->m_attr_geo;
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args.whichfork = XFS_ATTR_FORK;
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args.dp = context->dp;
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args.name = name;
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args.namelen = namelen;
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args.hashval = xfs_da_hashname(args.name, args.namelen);
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args.trans = context->tp;
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args.value = sx->sc->buf;
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args.valuelen = XATTR_SIZE_MAX;
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error = xfs_attr_get_ilocked(context->dp, &args);
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if (error == -EEXIST)
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error = 0;
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if (!xchk_fblock_process_error(sx->sc, XFS_ATTR_FORK, args.blkno,
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&error))
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goto fail_xref;
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if (args.valuelen != valuelen)
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xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK,
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args.blkno);
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fail_xref:
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if (sx->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
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context->seen_enough = 1;
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return;
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}
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/*
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* Mark a range [start, start+len) in this map. Returns true if the
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* region was free, and false if there's a conflict or a problem.
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*
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* Within a char, the lowest bit of the char represents the byte with
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* the smallest address
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*/
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STATIC bool
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xchk_xattr_set_map(
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struct xfs_scrub *sc,
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unsigned long *map,
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unsigned int start,
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unsigned int len)
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{
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unsigned int mapsize = sc->mp->m_attr_geo->blksize;
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bool ret = true;
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if (start >= mapsize)
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return false;
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if (start + len > mapsize) {
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len = mapsize - start;
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ret = false;
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}
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if (find_next_bit(map, mapsize, start) < start + len)
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ret = false;
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bitmap_set(map, start, len);
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return ret;
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}
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/*
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* Check the leaf freemap from the usage bitmap. Returns false if the
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* attr freemap has problems or points to used space.
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*/
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STATIC bool
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xchk_xattr_check_freemap(
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struct xfs_scrub *sc,
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unsigned long *map,
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struct xfs_attr3_icleaf_hdr *leafhdr)
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{
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unsigned long *freemap;
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unsigned long *dstmap;
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unsigned int mapsize = sc->mp->m_attr_geo->blksize;
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int i;
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/* Construct bitmap of freemap contents. */
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freemap = (unsigned long *)sc->buf + BITS_TO_LONGS(mapsize);
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bitmap_zero(freemap, mapsize);
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for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
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if (!xchk_xattr_set_map(sc, freemap,
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leafhdr->freemap[i].base,
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leafhdr->freemap[i].size))
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return false;
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}
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/* Look for bits that are set in freemap and are marked in use. */
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dstmap = freemap + BITS_TO_LONGS(mapsize);
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return bitmap_and(dstmap, freemap, map, mapsize) == 0;
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}
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/*
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* Check this leaf entry's relations to everything else.
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* Returns the number of bytes used for the name/value data.
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*/
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STATIC void
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xchk_xattr_entry(
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struct xchk_da_btree *ds,
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int level,
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char *buf_end,
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struct xfs_attr_leafblock *leaf,
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struct xfs_attr3_icleaf_hdr *leafhdr,
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unsigned long *usedmap,
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struct xfs_attr_leaf_entry *ent,
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int idx,
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unsigned int *usedbytes,
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__u32 *last_hashval)
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{
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struct xfs_mount *mp = ds->state->mp;
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char *name_end;
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struct xfs_attr_leaf_name_local *lentry;
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struct xfs_attr_leaf_name_remote *rentry;
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unsigned int nameidx;
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unsigned int namesize;
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if (ent->pad2 != 0)
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xchk_da_set_corrupt(ds, level);
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/* Hash values in order? */
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if (be32_to_cpu(ent->hashval) < *last_hashval)
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xchk_da_set_corrupt(ds, level);
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*last_hashval = be32_to_cpu(ent->hashval);
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nameidx = be16_to_cpu(ent->nameidx);
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if (nameidx < leafhdr->firstused ||
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nameidx >= mp->m_attr_geo->blksize) {
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xchk_da_set_corrupt(ds, level);
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return;
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}
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/* Check the name information. */
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if (ent->flags & XFS_ATTR_LOCAL) {
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lentry = xfs_attr3_leaf_name_local(leaf, idx);
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namesize = xfs_attr_leaf_entsize_local(lentry->namelen,
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be16_to_cpu(lentry->valuelen));
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name_end = (char *)lentry + namesize;
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if (lentry->namelen == 0)
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xchk_da_set_corrupt(ds, level);
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} else {
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rentry = xfs_attr3_leaf_name_remote(leaf, idx);
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namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
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name_end = (char *)rentry + namesize;
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if (rentry->namelen == 0 || rentry->valueblk == 0)
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xchk_da_set_corrupt(ds, level);
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}
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if (name_end > buf_end)
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xchk_da_set_corrupt(ds, level);
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if (!xchk_xattr_set_map(ds->sc, usedmap, nameidx, namesize))
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xchk_da_set_corrupt(ds, level);
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if (!(ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
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*usedbytes += namesize;
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}
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/* Scrub an attribute leaf. */
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STATIC int
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xchk_xattr_block(
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struct xchk_da_btree *ds,
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int level)
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{
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struct xfs_attr3_icleaf_hdr leafhdr;
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struct xfs_mount *mp = ds->state->mp;
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struct xfs_da_state_blk *blk = &ds->state->path.blk[level];
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struct xfs_buf *bp = blk->bp;
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xfs_dablk_t *last_checked = ds->private;
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struct xfs_attr_leafblock *leaf = bp->b_addr;
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struct xfs_attr_leaf_entry *ent;
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struct xfs_attr_leaf_entry *entries;
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unsigned long *usedmap = ds->sc->buf;
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char *buf_end;
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size_t off;
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__u32 last_hashval = 0;
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unsigned int usedbytes = 0;
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unsigned int hdrsize;
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int i;
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if (*last_checked == blk->blkno)
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return 0;
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*last_checked = blk->blkno;
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bitmap_zero(usedmap, mp->m_attr_geo->blksize);
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/* Check all the padding. */
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if (xfs_sb_version_hascrc(&ds->sc->mp->m_sb)) {
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struct xfs_attr3_leafblock *leaf = bp->b_addr;
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if (leaf->hdr.pad1 != 0 || leaf->hdr.pad2 != 0 ||
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leaf->hdr.info.hdr.pad != 0)
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xchk_da_set_corrupt(ds, level);
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} else {
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if (leaf->hdr.pad1 != 0 || leaf->hdr.info.pad != 0)
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xchk_da_set_corrupt(ds, level);
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}
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/* Check the leaf header */
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xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
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hdrsize = xfs_attr3_leaf_hdr_size(leaf);
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if (leafhdr.usedbytes > mp->m_attr_geo->blksize)
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xchk_da_set_corrupt(ds, level);
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if (leafhdr.firstused > mp->m_attr_geo->blksize)
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xchk_da_set_corrupt(ds, level);
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if (leafhdr.firstused < hdrsize)
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xchk_da_set_corrupt(ds, level);
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if (!xchk_xattr_set_map(ds->sc, usedmap, 0, hdrsize))
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xchk_da_set_corrupt(ds, level);
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if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
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goto out;
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entries = xfs_attr3_leaf_entryp(leaf);
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if ((char *)&entries[leafhdr.count] > (char *)leaf + leafhdr.firstused)
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xchk_da_set_corrupt(ds, level);
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buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize;
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for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) {
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/* Mark the leaf entry itself. */
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off = (char *)ent - (char *)leaf;
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if (!xchk_xattr_set_map(ds->sc, usedmap, off,
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sizeof(xfs_attr_leaf_entry_t))) {
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xchk_da_set_corrupt(ds, level);
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goto out;
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}
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/* Check the entry and nameval. */
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xchk_xattr_entry(ds, level, buf_end, leaf, &leafhdr,
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usedmap, ent, i, &usedbytes, &last_hashval);
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if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
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goto out;
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}
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if (!xchk_xattr_check_freemap(ds->sc, usedmap, &leafhdr))
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xchk_da_set_corrupt(ds, level);
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if (leafhdr.usedbytes != usedbytes)
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xchk_da_set_corrupt(ds, level);
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out:
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return 0;
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}
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/* Scrub a attribute btree record. */
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STATIC int
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xchk_xattr_rec(
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struct xchk_da_btree *ds,
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int level,
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void *rec)
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{
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struct xfs_mount *mp = ds->state->mp;
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struct xfs_attr_leaf_entry *ent = rec;
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struct xfs_da_state_blk *blk;
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struct xfs_attr_leaf_name_local *lentry;
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struct xfs_attr_leaf_name_remote *rentry;
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struct xfs_buf *bp;
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xfs_dahash_t calc_hash;
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xfs_dahash_t hash;
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int nameidx;
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int hdrsize;
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unsigned int badflags;
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int error;
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blk = &ds->state->path.blk[level];
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/* Check the whole block, if necessary. */
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error = xchk_xattr_block(ds, level);
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if (error)
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goto out;
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if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
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goto out;
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/* Check the hash of the entry. */
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error = xchk_da_btree_hash(ds, level, &ent->hashval);
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if (error)
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goto out;
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/* Find the attr entry's location. */
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bp = blk->bp;
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hdrsize = xfs_attr3_leaf_hdr_size(bp->b_addr);
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nameidx = be16_to_cpu(ent->nameidx);
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if (nameidx < hdrsize || nameidx >= mp->m_attr_geo->blksize) {
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xchk_da_set_corrupt(ds, level);
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goto out;
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}
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/* Retrieve the entry and check it. */
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hash = be32_to_cpu(ent->hashval);
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badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE |
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XFS_ATTR_INCOMPLETE);
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if ((ent->flags & badflags) != 0)
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xchk_da_set_corrupt(ds, level);
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if (ent->flags & XFS_ATTR_LOCAL) {
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lentry = (struct xfs_attr_leaf_name_local *)
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(((char *)bp->b_addr) + nameidx);
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if (lentry->namelen <= 0) {
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xchk_da_set_corrupt(ds, level);
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goto out;
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}
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calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen);
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} else {
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rentry = (struct xfs_attr_leaf_name_remote *)
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(((char *)bp->b_addr) + nameidx);
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if (rentry->namelen <= 0) {
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xchk_da_set_corrupt(ds, level);
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goto out;
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}
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calc_hash = xfs_da_hashname(rentry->name, rentry->namelen);
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}
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if (calc_hash != hash)
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xchk_da_set_corrupt(ds, level);
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out:
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return error;
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}
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/* Scrub the extended attribute metadata. */
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int
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xchk_xattr(
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struct xfs_scrub *sc)
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{
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struct xchk_xattr sx;
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struct attrlist_cursor_kern cursor = { 0 };
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xfs_dablk_t last_checked = -1U;
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int error = 0;
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if (!xfs_inode_hasattr(sc->ip))
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return -ENOENT;
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memset(&sx, 0, sizeof(sx));
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/* Check attribute tree structure */
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error = xchk_da_btree(sc, XFS_ATTR_FORK, xchk_xattr_rec,
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&last_checked);
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if (error)
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goto out;
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if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
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goto out;
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/* Check that every attr key can also be looked up by hash. */
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sx.context.dp = sc->ip;
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sx.context.cursor = &cursor;
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sx.context.resynch = 1;
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sx.context.put_listent = xchk_xattr_listent;
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sx.context.tp = sc->tp;
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sx.context.flags = ATTR_INCOMPLETE;
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sx.sc = sc;
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/*
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* Look up every xattr in this file by name.
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*
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* Use the backend implementation of xfs_attr_list to call
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* xchk_xattr_listent on every attribute key in this inode.
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* In other words, we use the same iterator/callback mechanism
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* that listattr uses to scrub extended attributes, though in our
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* _listent function, we check the value of the attribute.
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*
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* The VFS only locks i_rwsem when modifying attrs, so keep all
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* three locks held because that's the only way to ensure we're
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* the only thread poking into the da btree. We traverse the da
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* btree while holding a leaf buffer locked for the xattr name
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* iteration, which doesn't really follow the usual buffer
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* locking order.
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*/
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error = xfs_attr_list_int_ilocked(&sx.context);
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if (!xchk_fblock_process_error(sc, XFS_ATTR_FORK, 0, &error))
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goto out;
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out:
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return error;
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}
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