// 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_log_format.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_attr.h"
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#include "xfs_attr_leaf.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/attr.h"
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/*
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* Allocate enough memory to hold an attr value and attr block bitmaps,
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* reallocating the buffer if necessary. Buffer contents are not preserved
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* across a reallocation.
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*/
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int
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xchk_setup_xattr_buf(
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struct xfs_scrub *sc,
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size_t value_size,
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xfs_km_flags_t flags)
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{
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size_t sz;
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struct xchk_xattr_buf *ab = sc->buf;
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/*
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* We need enough space to read an xattr value from the file or enough
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* space to hold three copies of the xattr free space bitmap. We don't
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* need the buffer space for both purposes at the same time.
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*/
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sz = 3 * sizeof(long) * BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
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sz = max_t(size_t, sz, value_size);
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/*
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* If there's already a buffer, figure out if we need to reallocate it
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* to accommodate a larger size.
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*/
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if (ab) {
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if (sz <= ab->sz)
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return 0;
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kmem_free(ab);
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sc->buf = NULL;
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}
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/*
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* Don't zero the buffer upon allocation to avoid runtime overhead.
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* All users must be careful never to read uninitialized contents.
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*/
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ab = kmem_alloc_large(sizeof(*ab) + sz, flags);
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if (!ab)
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return -ENOMEM;
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ab->sz = sz;
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sc->buf = ab;
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return 0;
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}
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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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int error;
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/*
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* We failed to get memory while checking attrs, so this time try to
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* get all the memory we're ever going to need. Allocate the buffer
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* without the inode lock held, which means we can sleep.
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*/
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if (sc->flags & XCHK_TRY_HARDER) {
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error = xchk_setup_xattr_buf(sc, XATTR_SIZE_MAX, 0);
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if (error)
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return error;
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}
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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_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 = error;
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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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/*
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* Try to allocate enough memory to extrat the attr value. If that
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* doesn't work, we overload the seen_enough variable to convey
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* the error message back to the main scrub function.
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*/
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error = xchk_setup_xattr_buf(sx->sc, valuelen, KM_MAYFAIL);
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if (error == -ENOMEM)
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error = -EDEADLOCK;
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if (error) {
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context->seen_enough = error;
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return;
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}
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args.op_flags = XFS_DA_OP_NOTIME;
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args.attr_filter = flags & XFS_ATTR_NSP_ONDISK_MASK;
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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 = xchk_xattr_valuebuf(sx->sc);
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args.valuelen = valuelen;
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error = xfs_attr_get_ilocked(&args);
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/* ENODATA means the hash lookup failed and the attr is bad */
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if (error == -ENODATA)
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error = -EFSCORRUPTED;
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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 = xchk_xattr_freemap(sc);
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unsigned long *dstmap = xchk_xattr_dstmap(sc);
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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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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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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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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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unsigned long *usedmap = xchk_xattr_usedmap(ds->sc);
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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;
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char *buf_end;
|
size_t off;
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__u32 last_hashval = 0;
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unsigned int usedbytes = 0;
|
unsigned int hdrsize;
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int i;
|
int error;
|
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if (*last_checked == blk->blkno)
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return 0;
|
|
/* Allocate memory for block usage checking. */
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error = xchk_setup_xattr_buf(ds->sc, 0, KM_MAYFAIL);
|
if (error == -ENOMEM)
|
return -EDEADLOCK;
|
if (error)
|
return error;
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usedmap = xchk_xattr_usedmap(ds->sc);
|
|
*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;
|
|
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)
|
xchk_da_set_corrupt(ds, level);
|
}
|
|
/* Check the leaf header */
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xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
|
hdrsize = xfs_attr3_leaf_hdr_size(leaf);
|
|
if (leafhdr.usedbytes > mp->m_attr_geo->blksize)
|
xchk_da_set_corrupt(ds, level);
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if (leafhdr.firstused > mp->m_attr_geo->blksize)
|
xchk_da_set_corrupt(ds, level);
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if (leafhdr.firstused < hdrsize)
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xchk_da_set_corrupt(ds, level);
|
if (!xchk_xattr_set_map(ds->sc, usedmap, 0, hdrsize))
|
xchk_da_set_corrupt(ds, level);
|
|
if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
|
goto out;
|
|
entries = xfs_attr3_leaf_entryp(leaf);
|
if ((char *)&entries[leafhdr.count] > (char *)leaf + leafhdr.firstused)
|
xchk_da_set_corrupt(ds, level);
|
|
buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize;
|
for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) {
|
/* Mark the leaf entry itself. */
|
off = (char *)ent - (char *)leaf;
|
if (!xchk_xattr_set_map(ds->sc, usedmap, off,
|
sizeof(xfs_attr_leaf_entry_t))) {
|
xchk_da_set_corrupt(ds, level);
|
goto out;
|
}
|
|
/* Check the entry and nameval. */
|
xchk_xattr_entry(ds, level, buf_end, leaf, &leafhdr,
|
ent, i, &usedbytes, &last_hashval);
|
|
if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
|
goto out;
|
}
|
|
if (!xchk_xattr_check_freemap(ds->sc, usedmap, &leafhdr))
|
xchk_da_set_corrupt(ds, level);
|
|
if (leafhdr.usedbytes != usedbytes)
|
xchk_da_set_corrupt(ds, level);
|
|
out:
|
return 0;
|
}
|
|
/* Scrub a attribute btree record. */
|
STATIC int
|
xchk_xattr_rec(
|
struct xchk_da_btree *ds,
|
int level)
|
{
|
struct xfs_mount *mp = ds->state->mp;
|
struct xfs_da_state_blk *blk = &ds->state->path.blk[level];
|
struct xfs_attr_leaf_name_local *lentry;
|
struct xfs_attr_leaf_name_remote *rentry;
|
struct xfs_buf *bp;
|
struct xfs_attr_leaf_entry *ent;
|
xfs_dahash_t calc_hash;
|
xfs_dahash_t hash;
|
int nameidx;
|
int hdrsize;
|
unsigned int badflags;
|
int error;
|
|
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
|
|
ent = xfs_attr3_leaf_entryp(blk->bp->b_addr) + blk->index;
|
|
/* Check the whole block, if necessary. */
|
error = xchk_xattr_block(ds, level);
|
if (error)
|
goto out;
|
if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
|
goto out;
|
|
/* Check the hash of the entry. */
|
error = xchk_da_btree_hash(ds, level, &ent->hashval);
|
if (error)
|
goto out;
|
|
/* Find the attr entry's location. */
|
bp = blk->bp;
|
hdrsize = xfs_attr3_leaf_hdr_size(bp->b_addr);
|
nameidx = be16_to_cpu(ent->nameidx);
|
if (nameidx < hdrsize || nameidx >= mp->m_attr_geo->blksize) {
|
xchk_da_set_corrupt(ds, level);
|
goto out;
|
}
|
|
/* Retrieve the entry and check it. */
|
hash = be32_to_cpu(ent->hashval);
|
badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE |
|
XFS_ATTR_INCOMPLETE);
|
if ((ent->flags & badflags) != 0)
|
xchk_da_set_corrupt(ds, level);
|
if (ent->flags & XFS_ATTR_LOCAL) {
|
lentry = (struct xfs_attr_leaf_name_local *)
|
(((char *)bp->b_addr) + nameidx);
|
if (lentry->namelen <= 0) {
|
xchk_da_set_corrupt(ds, level);
|
goto out;
|
}
|
calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen);
|
} else {
|
rentry = (struct xfs_attr_leaf_name_remote *)
|
(((char *)bp->b_addr) + nameidx);
|
if (rentry->namelen <= 0) {
|
xchk_da_set_corrupt(ds, level);
|
goto out;
|
}
|
calc_hash = xfs_da_hashname(rentry->name, rentry->namelen);
|
}
|
if (calc_hash != hash)
|
xchk_da_set_corrupt(ds, level);
|
|
out:
|
return error;
|
}
|
|
/* Scrub the extended attribute metadata. */
|
int
|
xchk_xattr(
|
struct xfs_scrub *sc)
|
{
|
struct xchk_xattr sx;
|
xfs_dablk_t last_checked = -1U;
|
int error = 0;
|
|
if (!xfs_inode_hasattr(sc->ip))
|
return -ENOENT;
|
|
memset(&sx, 0, sizeof(sx));
|
/* Check attribute tree structure */
|
error = xchk_da_btree(sc, XFS_ATTR_FORK, xchk_xattr_rec,
|
&last_checked);
|
if (error)
|
goto out;
|
|
if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
|
goto out;
|
|
/* Check that every attr key can also be looked up by hash. */
|
sx.context.dp = sc->ip;
|
sx.context.resynch = 1;
|
sx.context.put_listent = xchk_xattr_listent;
|
sx.context.tp = sc->tp;
|
sx.context.allow_incomplete = true;
|
sx.sc = sc;
|
|
/*
|
* Look up every xattr in this file by name.
|
*
|
* Use the backend implementation of xfs_attr_list to call
|
* xchk_xattr_listent on every attribute key in this inode.
|
* In other words, we use the same iterator/callback mechanism
|
* that listattr uses to scrub extended attributes, though in our
|
* _listent function, we check the value of the attribute.
|
*
|
* The VFS only locks i_rwsem when modifying attrs, so keep all
|
* three locks held because that's the only way to ensure we're
|
* the only thread poking into the da btree. We traverse the da
|
* btree while holding a leaf buffer locked for the xattr name
|
* iteration, which doesn't really follow the usual buffer
|
* locking order.
|
*/
|
error = xfs_attr_list_ilocked(&sx.context);
|
if (!xchk_fblock_process_error(sc, XFS_ATTR_FORK, 0, &error))
|
goto out;
|
|
/* Did our listent function try to return any errors? */
|
if (sx.context.seen_enough < 0)
|
error = sx.context.seen_enough;
|
out:
|
return error;
|
}
|
