From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
As we walk the attribute btree, explicitly check the structure of the
attribute leaves to make sure the pointers make sense and the freemap is
sensible.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/scrub/attr.c | 233 ++++++++++++++++++++++++++++++++++++++++++++----
fs/xfs/scrub/dabtree.c | 4 +
fs/xfs/scrub/dabtree.h | 3 -
fs/xfs/scrub/dir.c | 2
4 files changed, 218 insertions(+), 24 deletions(-)
diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
index a70cd9b..5d624ca 100644
--- a/fs/xfs/scrub/attr.c
+++ b/fs/xfs/scrub/attr.c
@@ -50,8 +50,17 @@ xfs_scrub_setup_xattr(
struct xfs_scrub_context *sc,
struct xfs_inode *ip)
{
- /* Allocate the buffer without the inode lock held. */
- sc->buf = kmem_zalloc_large(XATTR_SIZE_MAX, KM_SLEEP);
+ size_t sz;
+
+ /*
+ * Allocate the buffer without the inode lock held. We need enough
+ * space to read every xattr value in the file and 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;
@@ -122,6 +131,197 @@ xfs_scrub_xattr_listent(
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;
+ }
+
+ ret &= find_next_bit(map, mapsize, start) >= (start + len);
+ 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;
+}
+
+/* Scrub an attribute leaf. */
+STATIC int
+xfs_scrub_xattr_block(
+ struct xfs_scrub_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 xfs_attr_leaf_name_local *lentry;
+ struct xfs_attr_leaf_name_remote *rentry;
+ unsigned long *usedmap = ds->sc->buf;
+ char *name_end;
+ char *buf_end;
+ __u32 last_hashval = 0;
+ unsigned int usedbytes = 0;
+ unsigned int nameidx;
+ unsigned int hdrsize;
+ unsigned int namesize;
+ int i;
+
+ if (*last_checked == blk->blkno)
+ return 0;
+ *last_checked = blk->blkno;
+ bitmap_zero(usedmap, mp->m_attr_geo->blksize);
+
+ /* Check all the padding. */
+ if (xfs_sb_version_hascrc(&ds->sc->mp->m_sb)) {
+ struct xfs_attr3_leafblock *leaf = bp->b_addr;
+
+ if (leaf->hdr.pad1 != 0 ||
+ leaf->hdr.pad2 != cpu_to_be32(0) ||
+ leaf->hdr.info.hdr.pad != cpu_to_be16(0))
+ xfs_scrub_da_set_corrupt(ds, level);
+ } else {
+ if (leaf->hdr.pad1 != 0 ||
+ leaf->hdr.info.pad != cpu_to_be16(0))
+ xfs_scrub_da_set_corrupt(ds, level);
+ }
+
+ /* Check the leaf header */
+ xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
+
+ if (leafhdr.usedbytes > mp->m_attr_geo->blksize)
+ xfs_scrub_da_set_corrupt(ds, level);
+ if (leafhdr.firstused > mp->m_attr_geo->blksize)
+ xfs_scrub_da_set_corrupt(ds, level);
+ hdrsize = xfs_attr3_leaf_hdr_size(leaf);
+ if (leafhdr.firstused < hdrsize)
+ xfs_scrub_da_set_corrupt(ds, level);
+
+ if (!xfs_scrub_xattr_set_map(ds->sc, usedmap, 0, hdrsize)) {
+ xfs_scrub_da_set_corrupt(ds, level);
+ goto out;
+ }
+
+ entries = xfs_attr3_leaf_entryp(leaf);
+ if ((char *)&entries[leafhdr.count] > (char *)leaf + leafhdr.firstused)
+ xfs_scrub_da_set_corrupt(ds, level);
+
+ /* Check the entries' relations to each other */
+ buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize;
+ for (i = 0, ent = entries; i < leafhdr.count; ent++, i++) {
+ if (!xfs_scrub_xattr_set_map(ds->sc, usedmap,
+ (char *)ent - (char *)leaf,
+ sizeof(xfs_attr_leaf_entry_t))) {
+ xfs_scrub_da_set_corrupt(ds, level);
+ goto out;
+ }
+
+ if (ent->pad2 != cpu_to_be32(0))
+ xfs_scrub_da_set_corrupt(ds, level);
+
+ 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 < hdrsize ||
+ nameidx < leafhdr.firstused ||
+ nameidx >= mp->m_attr_geo->blksize) {
+ xfs_scrub_da_set_corrupt(ds, level);
+ goto out;
+ }
+
+ if (ent->flags & XFS_ATTR_LOCAL) {
+ lentry = xfs_attr3_leaf_name_local(leaf, i);
+ if (lentry->namelen <= 0)
+ xfs_scrub_da_set_corrupt(ds, level);
+ name_end = (char *)lentry->nameval + lentry->namelen +
+ be16_to_cpu(lentry->valuelen);
+ if (name_end > buf_end)
+ xfs_scrub_da_set_corrupt(ds, level);
+ namesize = xfs_attr_leaf_entsize_local(
+ lentry->namelen,
+ be16_to_cpu(lentry->valuelen));
+ } else {
+ rentry = xfs_attr3_leaf_name_remote(leaf, i);
+ if (rentry->namelen <= 0)
+ xfs_scrub_da_set_corrupt(ds, level);
+ name_end = (char *)rentry->name + rentry->namelen;
+ if (name_end > buf_end)
+ xfs_scrub_da_set_corrupt(ds, level);
+ namesize = xfs_attr_leaf_entsize_remote(
+ rentry->namelen);
+ if (rentry->valueblk == cpu_to_be32(0))
+ xfs_scrub_da_set_corrupt(ds, level);
+ }
+ usedbytes += namesize;
+ if (!xfs_scrub_xattr_set_map(ds->sc, usedmap, nameidx,
+ namesize)) {
+ xfs_scrub_da_set_corrupt(ds, level);
+ goto out;
+ }
+ }
+
+ if (!xfs_scrub_xattr_check_freemap(ds->sc, usedmap, &leafhdr))
+ xfs_scrub_da_set_corrupt(ds, level);
+
+ if (leafhdr.usedbytes != usedbytes)
+ xfs_scrub_da_set_corrupt(ds, level);
+
+out:
+ return 0;
+}
+
/* Scrub a attribute btree record. */
STATIC int
xfs_scrub_xattr_rec(
@@ -144,6 +344,13 @@ xfs_scrub_xattr_rec(
blk = &ds->state->path.blk[level];
+ /* Check the whole block, if necessary. */
+ error = xfs_scrub_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 = xfs_scrub_da_btree_hash(ds, level, &ent->hashval);
if (error)
@@ -158,24 +365,6 @@ xfs_scrub_xattr_rec(
goto out;
}
- /* Check all the padding. */
- if (xfs_sb_version_hascrc(&ds->sc->mp->m_sb)) {
- struct xfs_attr3_leafblock *leaf = bp->b_addr;
-
- if (leaf->hdr.pad1 != 0 ||
- leaf->hdr.pad2 != cpu_to_be32(0) ||
- leaf->hdr.info.hdr.pad != cpu_to_be16(0))
- xfs_scrub_da_set_corrupt(ds, level);
- } else {
- struct xfs_attr_leafblock *leaf = bp->b_addr;
-
- if (leaf->hdr.pad1 != 0 ||
- leaf->hdr.info.pad != cpu_to_be16(0))
- xfs_scrub_da_set_corrupt(ds, level);
- }
- if (ent->pad2 != 0)
- xfs_scrub_da_set_corrupt(ds, level);
-
/* Retrieve the entry and check it. */
hash = be32_to_cpu(ent->hashval);
badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE |
@@ -213,6 +402,7 @@ xfs_scrub_xattr(
{
struct xfs_scrub_xattr sx = { 0 };
struct attrlist_cursor_kern cursor = { 0 };
+ xfs_dablk_t last_checked = -1U;
int error = 0;
if (!xfs_inode_hasattr(sc->ip))
@@ -220,7 +410,8 @@ xfs_scrub_xattr(
memset(&sx, 0, sizeof(sx));
/* Check attribute tree structure */
- error = xfs_scrub_da_btree(sc, XFS_ATTR_FORK, xfs_scrub_xattr_rec);
+ error = xfs_scrub_da_btree(sc, XFS_ATTR_FORK, xfs_scrub_xattr_rec,
+ &last_checked);
if (error)
goto out;
diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c
index 4a93cf1..c21c528 100644
--- a/fs/xfs/scrub/dabtree.c
+++ b/fs/xfs/scrub/dabtree.c
@@ -467,7 +467,8 @@ int
xfs_scrub_da_btree(
struct xfs_scrub_context *sc,
int whichfork,
- xfs_scrub_da_btree_rec_fn scrub_fn)
+ xfs_scrub_da_btree_rec_fn scrub_fn,
+ void *private)
{
struct xfs_scrub_da_btree ds = {};
struct xfs_mount *mp = sc->mp;
@@ -492,6 +493,7 @@ xfs_scrub_da_btree(
ds.state->args = &ds.dargs;
ds.state->mp = mp;
ds.sc = sc;
+ ds.private = private;
if (whichfork == XFS_ATTR_FORK) {
ds.dargs.geo = mp->m_attr_geo;
ds.lowest = 0;
diff --git a/fs/xfs/scrub/dabtree.h b/fs/xfs/scrub/dabtree.h
index 2a766de1f..d31468d 100644
--- a/fs/xfs/scrub/dabtree.h
+++ b/fs/xfs/scrub/dabtree.h
@@ -28,6 +28,7 @@ struct xfs_scrub_da_btree {
int maxrecs[XFS_DA_NODE_MAXDEPTH];
struct xfs_da_state *state;
struct xfs_scrub_context *sc;
+ void *private;
/*
* Lowest and highest directory block address in which we expect
@@ -53,6 +54,6 @@ void xfs_scrub_da_set_corrupt(struct xfs_scrub_da_btree *ds, int level);
int xfs_scrub_da_btree_hash(struct xfs_scrub_da_btree *ds, int level,
__be32 *hashp);
int xfs_scrub_da_btree(struct xfs_scrub_context *sc, int whichfork,
- xfs_scrub_da_btree_rec_fn scrub_fn);
+ xfs_scrub_da_btree_rec_fn scrub_fn, void *private);
#endif /* __XFS_SCRUB_DABTREE_H__ */
diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
index 169fb10..c61362f 100644
--- a/fs/xfs/scrub/dir.c
+++ b/fs/xfs/scrub/dir.c
@@ -770,7 +770,7 @@ xfs_scrub_directory(
}
/* Check directory tree structure */
- error = xfs_scrub_da_btree(sc, XFS_DATA_FORK, xfs_scrub_dir_rec);
+ error = xfs_scrub_da_btree(sc, XFS_DATA_FORK, xfs_scrub_dir_rec, NULL);
if (error)
return error;
--
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