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linux-stable/fs/xfs/scrub/attr.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017-2023 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#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_log_format.h"
#include "xfs_inode.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_attr_sf.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/dabtree.h"
#include "scrub/attr.h"
/* Free the buffers linked from the xattr buffer. */
static void
xchk_xattr_buf_cleanup(
void *priv)
{
struct xchk_xattr_buf *ab = priv;
kvfree(ab->freemap);
ab->freemap = NULL;
kvfree(ab->usedmap);
ab->usedmap = NULL;
kvfree(ab->value);
ab->value = NULL;
ab->value_sz = 0;
}
/*
* Allocate the free space bitmap if we're trying harder; there are leaf blocks
* in the attr fork; or we can't tell if there are leaf blocks.
*/
static inline bool
xchk_xattr_want_freemap(
struct xfs_scrub *sc)
{
struct xfs_ifork *ifp;
if (sc->flags & XCHK_TRY_HARDER)
return true;
if (!sc->ip)
return true;
ifp = xfs_ifork_ptr(sc->ip, XFS_ATTR_FORK);
if (!ifp)
return false;
return xfs_ifork_has_extents(ifp);
}
/*
* Allocate enough memory to hold an attr value and attr block bitmaps,
* reallocating the buffer if necessary. Buffer contents are not preserved
* across a reallocation.
*/
static int
xchk_setup_xattr_buf(
struct xfs_scrub *sc,
size_t value_size)
{
size_t bmp_sz;
struct xchk_xattr_buf *ab = sc->buf;
void *new_val;
bmp_sz = sizeof(long) * BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
if (ab)
goto resize_value;
ab = kvzalloc(sizeof(struct xchk_xattr_buf), XCHK_GFP_FLAGS);
if (!ab)
return -ENOMEM;
sc->buf = ab;
sc->buf_cleanup = xchk_xattr_buf_cleanup;
ab->usedmap = kvmalloc(bmp_sz, XCHK_GFP_FLAGS);
if (!ab->usedmap)
return -ENOMEM;
if (xchk_xattr_want_freemap(sc)) {
ab->freemap = kvmalloc(bmp_sz, XCHK_GFP_FLAGS);
if (!ab->freemap)
return -ENOMEM;
}
resize_value:
if (ab->value_sz >= value_size)
return 0;
if (ab->value) {
kvfree(ab->value);
ab->value = NULL;
ab->value_sz = 0;
}
new_val = kvmalloc(value_size, XCHK_GFP_FLAGS);
if (!new_val)
return -ENOMEM;
ab->value = new_val;
ab->value_sz = value_size;
return 0;
}
/* Set us up to scrub an inode's extended attributes. */
int
xchk_setup_xattr(
struct xfs_scrub *sc)
{
int error;
/*
* We failed to get memory while checking attrs, so this time try to
* get all the memory we're ever going to need. Allocate the buffer
* without the inode lock held, which means we can sleep.
*/
if (sc->flags & XCHK_TRY_HARDER) {
error = xchk_setup_xattr_buf(sc, XATTR_SIZE_MAX);
if (error)
return error;
}
return xchk_setup_inode_contents(sc, 0);
}
/* Extended Attributes */
struct xchk_xattr {
struct xfs_attr_list_context context;
struct xfs_scrub *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_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
xchk_xattr_listent(
struct xfs_attr_list_context *context,
int flags,
unsigned char *name,
int namelen,
int valuelen)
{
struct xfs_da_args args = {
.op_flags = XFS_DA_OP_NOTIME,
.attr_filter = flags & XFS_ATTR_NSP_ONDISK_MASK,
.geo = context->dp->i_mount->m_attr_geo,
.whichfork = XFS_ATTR_FORK,
.dp = context->dp,
.name = name,
.namelen = namelen,
.hashval = xfs_da_hashname(name, namelen),
.trans = context->tp,
.valuelen = valuelen,
};
struct xchk_xattr_buf *ab;
struct xchk_xattr *sx;
int error = 0;
sx = container_of(context, struct xchk_xattr, context);
ab = sx->sc->buf;
if (xchk_should_terminate(sx->sc, &error)) {
context->seen_enough = error;
return;
}
if (flags & XFS_ATTR_INCOMPLETE) {
/* Incomplete attr key, just mark the inode for preening. */
xchk_ino_set_preen(sx->sc, context->dp->i_ino);
return;
}
/* Only one namespace bit allowed. */
if (hweight32(flags & XFS_ATTR_NSP_ONDISK_MASK) > 1) {
xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno);
goto fail_xref;
}
/* Does this name make sense? */
if (!xfs_attr_namecheck(name, namelen)) {
xchk_fblock_set_corrupt(sx->sc, XFS_ATTR_FORK, args.blkno);
goto fail_xref;
}
/*
* Local xattr values are stored in the attr leaf block, so we don't
* need to retrieve the value from a remote block to detect corruption
* problems.
*/
if (flags & XFS_ATTR_LOCAL)
goto fail_xref;
/*
* Try to allocate enough memory to extrat the attr value. If that
* doesn't work, we overload the seen_enough variable to convey
* the error message back to the main scrub function.
*/
error = xchk_setup_xattr_buf(sx->sc, valuelen);
if (error == -ENOMEM)
error = -EDEADLOCK;
if (error) {
context->seen_enough = error;
return;
}
args.value = ab->value;
error = xfs_attr_get_ilocked(&args);
/* ENODATA means the hash lookup failed and the attr is bad */
if (error == -ENODATA)
error = -EFSCORRUPTED;
if (!xchk_fblock_process_error(sx->sc, XFS_ATTR_FORK, args.blkno,
&error))
goto fail_xref;
if (args.valuelen != valuelen)
xchk_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
xchk_xattr_set_map(
struct xfs_scrub *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
xchk_xattr_check_freemap(
struct xfs_scrub *sc,
struct xfs_attr3_icleaf_hdr *leafhdr)
{
struct xchk_xattr_buf *ab = sc->buf;
unsigned int mapsize = sc->mp->m_attr_geo->blksize;
int i;
/* Construct bitmap of freemap contents. */
bitmap_zero(ab->freemap, mapsize);
for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
if (!xchk_xattr_set_map(sc, ab->freemap,
leafhdr->freemap[i].base,
leafhdr->freemap[i].size))
return false;
}
/* Look for bits that are set in freemap and are marked in use. */
return !bitmap_intersects(ab->freemap, ab->usedmap, mapsize);
}
/*
* Check this leaf entry's relations to everything else.
* Returns the number of bytes used for the name/value data.
*/
STATIC void
xchk_xattr_entry(
struct xchk_da_btree *ds,
int level,
char *buf_end,
struct xfs_attr_leafblock *leaf,
struct xfs_attr3_icleaf_hdr *leafhdr,
struct xfs_attr_leaf_entry *ent,
int idx,
unsigned int *usedbytes,
__u32 *last_hashval)
{
struct xfs_mount *mp = ds->state->mp;
struct xchk_xattr_buf *ab = ds->sc->buf;
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)
xchk_da_set_corrupt(ds, level);
/* Hash values in order? */
if (be32_to_cpu(ent->hashval) < *last_hashval)
xchk_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) {
xchk_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)
xchk_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)
xchk_da_set_corrupt(ds, level);
}
if (name_end > buf_end)
xchk_da_set_corrupt(ds, level);
if (!xchk_xattr_set_map(ds->sc, ab->usedmap, nameidx, namesize))
xchk_da_set_corrupt(ds, level);
if (!(ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
*usedbytes += namesize;
}
/* Scrub an attribute leaf. */
STATIC int
xchk_xattr_block(
struct xchk_da_btree *ds,
int level)
{
struct xfs_attr3_icleaf_hdr leafhdr;
struct xfs_mount *mp = ds->state->mp;
struct xfs_da_state_blk *blk = &ds->state->path.blk[level];
struct xfs_buf *bp = blk->bp;
xfs_dablk_t *last_checked = ds->private;
struct xfs_attr_leafblock *leaf = bp->b_addr;
struct xfs_attr_leaf_entry *ent;
struct xfs_attr_leaf_entry *entries;
struct xchk_xattr_buf *ab = ds->sc->buf;
char *buf_end;
size_t off;
__u32 last_hashval = 0;
unsigned int usedbytes = 0;
unsigned int hdrsize;
int i;
if (*last_checked == blk->blkno)
return 0;
*last_checked = blk->blkno;
bitmap_zero(ab->usedmap, mp->m_attr_geo->blksize);
/* Check all the padding. */
if (xfs_has_crc(ds->sc->mp)) {
struct xfs_attr3_leafblock *leaf3 = bp->b_addr;
if (leaf3->hdr.pad1 != 0 || leaf3->hdr.pad2 != 0 ||
leaf3->hdr.info.hdr.pad != 0)
xchk_da_set_corrupt(ds, level);
} else {
if (leaf->hdr.pad1 != 0 || leaf->hdr.info.pad != 0)
xchk_da_set_corrupt(ds, level);
}
/* Check the leaf header */
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);
if (leafhdr.firstused > mp->m_attr_geo->blksize)
xchk_da_set_corrupt(ds, level);
if (leafhdr.firstused < hdrsize)
xchk_da_set_corrupt(ds, level);
if (!xchk_xattr_set_map(ds->sc, ab->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, ab->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, &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;
}
/* Check space usage of shortform attrs. */
STATIC int
xchk_xattr_check_sf(
struct xfs_scrub *sc)
{
struct xchk_xattr_buf *ab = sc->buf;
struct xfs_ifork *ifp = &sc->ip->i_af;
struct xfs_attr_sf_hdr *sf = ifp->if_data;
struct xfs_attr_sf_entry *sfe = xfs_attr_sf_firstentry(sf);
struct xfs_attr_sf_entry *next;
unsigned char *end = ifp->if_data + ifp->if_bytes;
int i;
int error = 0;
bitmap_zero(ab->usedmap, ifp->if_bytes);
xchk_xattr_set_map(sc, ab->usedmap, 0, sizeof(*sf));
if ((unsigned char *)sfe > end) {
xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
return 0;
}
for (i = 0; i < sf->count; i++) {
unsigned char *name = sfe->nameval;
unsigned char *value = &sfe->nameval[sfe->namelen];
if (xchk_should_terminate(sc, &error))
return error;
next = xfs_attr_sf_nextentry(sfe);
if ((unsigned char *)next > end) {
xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
break;
}
if (!xchk_xattr_set_map(sc, ab->usedmap,
(char *)sfe - (char *)sf,
sizeof(struct xfs_attr_sf_entry))) {
xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
break;
}
if (!xchk_xattr_set_map(sc, ab->usedmap,
(char *)name - (char *)sf,
sfe->namelen)) {
xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
break;
}
if (!xchk_xattr_set_map(sc, ab->usedmap,
(char *)value - (char *)sf,
sfe->valuelen)) {
xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
break;
}
sfe = next;
}
return 0;
}
/* Scrub the extended attribute metadata. */
int
xchk_xattr(
struct xfs_scrub *sc)
{
struct xchk_xattr sx = {
.sc = sc,
.context = {
.dp = sc->ip,
.tp = sc->tp,
.resynch = 1,
.put_listent = xchk_xattr_listent,
.allow_incomplete = true,
},
};
xfs_dablk_t last_checked = -1U;
int error = 0;
if (!xfs_inode_hasattr(sc->ip))
return -ENOENT;
/* Allocate memory for xattr checking. */
error = xchk_setup_xattr_buf(sc, 0);
if (error == -ENOMEM)
return -EDEADLOCK;
if (error)
return error;
/* Check the physical structure of the xattr. */
if (sc->ip->i_af.if_format == XFS_DINODE_FMT_LOCAL)
error = xchk_xattr_check_sf(sc);
else
error = xchk_da_btree(sc, XFS_ATTR_FORK, xchk_xattr_rec,
&last_checked);
if (error)
return error;
if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
return 0;
/*
* Look up every xattr in this file by name and hash.
*
* 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))
return error;
/* Did our listent function try to return any errors? */
if (sx.context.seen_enough < 0)
return sx.context.seen_enough;
return 0;
}
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