[PATCH 04/31] xfs: create a separate hashname function for extended attributes

Darrick J. Wong
2024-04-16T01:27:05Z

Create a separate function to compute name hashvalues for extended
attributes. When we get to parent pointers we'll be altering the rules
so that metadump obfuscation doesn't turn heinous.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/libxfs/xfs_attr.c | 28 ++++++++++++++++++++++++++--
fs/xfs/libxfs/xfs_attr.h | 14 ++++++++++++++
fs/xfs/libxfs/xfs_attr_leaf.c | 3 +--
fs/xfs/scrub/attr.c | 11 ++++++++---
fs/xfs/xfs_attr_item.c | 2 +-
fs/xfs/xfs_attr_list.c | 5 ++++-
6 files changed, 54 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 50eab63ff3be1..8262c263be9d1 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -280,7 +280,7 @@ xfs_attr_get(
args->owner = args->dp->i_ino;
args->geo = args->dp->i_mount->m_attr_geo;
args->whichfork = XFS_ATTR_FORK;
- args->hashval = xfs_da_hashname(args->name, args->namelen);
+ xfs_attr_sethash(args);

/* Entirely possible to look up a name which doesn't exist */
args->op_flags = XFS_DA_OP_OKNOENT;
@@ -415,6 +415,30 @@ xfs_attr_sf_addname(
return error;
}

+/* Compute the hash value for a user/root/secure extended attribute */
+xfs_dahash_t
+xfs_attr_hashname(
+ const uint8_t *name,
+ int namelen)
+{
+ return xfs_da_hashname(name, namelen);
+}
+
+/* Compute the hash value for any extended attribute from any namespace. */
+xfs_dahash_t
+xfs_attr_hashval(
+ struct xfs_mount *mp,
+ unsigned int attr_flags,
+ const uint8_t *name,
+ int namelen,
+ const void *value,
+ int valuelen)
+{
+ ASSERT(xfs_attr_check_namespace(attr_flags));
+
+ return xfs_attr_hashname(name, namelen);
+}
+
/*
* Handle the state change on completion of a multi-state attr operation.
*
@@ -925,7 +949,7 @@ xfs_attr_set(
args->owner = args->dp->i_ino;
args->geo = mp->m_attr_geo;
args->whichfork = XFS_ATTR_FORK;
- args->hashval = xfs_da_hashname(args->name, args->namelen);
+ xfs_attr_sethash(args);

/*
* We have no control over the attribute names that userspace passes us
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index cd106b0a424fa..c63b1d610e53b 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -628,6 +628,20 @@ xfs_attr_init_replace_state(struct xfs_da_args *args)
return xfs_attr_init_add_state(args);
}

+xfs_dahash_t xfs_attr_hashname(const uint8_t *name, int namelen);
+
+xfs_dahash_t xfs_attr_hashval(struct xfs_mount *mp, unsigned int attr_flags,
+ const uint8_t *name, int namelen, const void *value,
+ int valuelen);
+
+/* Set the hash value for any extended attribute from any namespace. */
+static inline void xfs_attr_sethash(struct xfs_da_args *args)
+{
+ args->hashval = xfs_attr_hashval(args->dp->i_mount, args->attr_filter,
+ args->name, args->namelen,
+ args->value, args->valuelen);
+}
+
extern struct kmem_cache *xfs_attr_intent_cache;
int __init xfs_attr_intent_init_cache(void);
void xfs_attr_intent_destroy_cache(void);
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index c47fad39744ee..e54a8372a30a4 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -948,14 +948,13 @@ xfs_attr_shortform_to_leaf(
nargs.namelen = sfe->namelen;
nargs.value = &sfe->nameval[nargs.namelen];
nargs.valuelen = sfe->valuelen;
- nargs.hashval = xfs_da_hashname(sfe->nameval,
- sfe->namelen);
nargs.attr_filter = sfe->flags & XFS_ATTR_NSP_ONDISK_MASK;
if (!xfs_attr_check_namespace(sfe->flags)) {
xfs_da_mark_sick(args);
error = -EFSCORRUPTED;
goto out;
}
+ xfs_attr_sethash(&nargs);
error = xfs_attr3_leaf_lookup_int(bp, &nargs); /* set a->index */
ASSERT(error == -ENOATTR);
error = xfs_attr3_leaf_add(bp, &nargs);
diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
index 7789bd2f09507..22d7ef4df1699 100644
--- a/fs/xfs/scrub/attr.c
+++ b/fs/xfs/scrub/attr.c
@@ -179,7 +179,6 @@ xchk_xattr_actor(
.dp = ip,
.name = name,
.namelen = namelen,
- .hashval = xfs_da_hashname(name, namelen),
.trans = sc->tp,
.valuelen = valuelen,
.owner = ip->i_ino,
@@ -230,6 +229,7 @@ xchk_xattr_actor(

args.value = ab->value;

+ xfs_attr_sethash(&args);
error = xfs_attr_get_ilocked(&args);
/* ENODATA means the hash lookup failed and the attr is bad */
if (error == -ENODATA)
@@ -525,7 +525,10 @@ xchk_xattr_rec(
xchk_da_set_corrupt(ds, level);
goto out;
}
- calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen);
+ calc_hash = xfs_attr_hashval(mp, ent->flags, lentry->nameval,
+ lentry->namelen,
+ lentry->nameval + lentry->namelen,
+ be16_to_cpu(lentry->valuelen));
} else {
rentry = (struct xfs_attr_leaf_name_remote *)
(((char *)bp->b_addr) + nameidx);
@@ -533,7 +536,9 @@ xchk_xattr_rec(
xchk_da_set_corrupt(ds, level);
goto out;
}
- calc_hash = xfs_da_hashname(rentry->name, rentry->namelen);
+ calc_hash = xfs_attr_hashval(mp, ent->flags, rentry->name,
+ rentry->namelen, NULL,
+ be32_to_cpu(rentry->valuelen));
}
if (calc_hash != hash)
xchk_da_set_corrupt(ds, level);
diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index a7d6c9af47e88..4a57bcff49ebd 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -582,13 +582,13 @@ xfs_attri_recover_work(
args->whichfork = XFS_ATTR_FORK;
args->name = nv->name.i_addr;
args->namelen = nv->name.i_len;
- args->hashval = xfs_da_hashname(args->name, args->namelen);
args->value = nv->value.i_addr;
args->valuelen = nv->value.i_len;
args->attr_filter = attrp->alfi_attr_filter & XFS_ATTRI_FILTER_MASK;
args->op_flags = XFS_DA_OP_RECOVERY | XFS_DA_OP_OKNOENT |
XFS_DA_OP_LOGGED;
args->owner = args->dp->i_ino;
+ xfs_attr_sethash(args);

switch (xfs_attr_intent_op(attr)) {
case XFS_ATTRI_OP_FLAGS_SET:
diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
index 903ed46c68872..9bc4b5322539a 100644
--- a/fs/xfs/xfs_attr_list.c
+++ b/fs/xfs/xfs_attr_list.c
@@ -135,12 +135,15 @@ xfs_attr_shortform_list(
}

sbp->entno = i;
- sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
sbp->name = sfe->nameval;
sbp->namelen = sfe->namelen;
/* These are bytes, and both on-disk, don't endian-flip */
sbp->valuelen = sfe->valuelen;
sbp->flags = sfe->flags;
+ sbp->hash = xfs_attr_hashval(dp->i_mount, sfe->flags,
+ sfe->nameval, sfe->namelen,
+ sfe->nameval + sfe->namelen,
+ sfe->valuelen);
sfe = xfs_attr_sf_nextentry(sfe);
sbp++;
nsbuf++;