1 files changed, 656 insertions, 0 deletions

diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
new file mode 100644
index 0000000000..6c16d9530c
--- /dev/null
+++ b/fs/xfs/scrub/attr.c
@@ -0,0 +1,656 @@
+// 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_attr_shortform	*sf;
+	struct xfs_attr_sf_entry	*sfe;
+	struct xfs_attr_sf_entry	*next;
+	struct xfs_ifork		*ifp;
+	unsigned char			*end;
+	int				i;
+	int				error = 0;
+
+	ifp = xfs_ifork_ptr(sc->ip, XFS_ATTR_FORK);
+
+	bitmap_zero(ab->usedmap, ifp->if_bytes);
+	sf = (struct xfs_attr_shortform *)sc->ip->i_af.if_u1.if_data;
+	end = (unsigned char *)ifp->if_u1.if_data + ifp->if_bytes;
+	xchk_xattr_set_map(sc, ab->usedmap, 0, sizeof(sf->hdr));
+
+	sfe = &sf->list[0];
+	if ((unsigned char *)sfe > end) {
+		xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+		return 0;
+	}
+
+	for (i = 0; i < sf->hdr.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;
+}