[PATCH v5 13/24] xfs: add attribute type for fs-verity

Andrey Albershteyn
2024-03-04T19:12:26Z

The Merkle tree blocks and descriptor are stored in the extended
attributes of the inode. Add new attribute type for fs-verity
metadata. Add XFS_ATTR_INTERNAL_MASK to skip parent pointer and
fs-verity attributes as those are only for internal use. While we're
at it add a few comments in relevant places that internally visible
attributes are not suppose to be handled via interface defined in
xfs_xattr.c.

Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_da_format.h | 10 +++++++++-
fs/xfs/libxfs/xfs_log_format.h | 1 +
fs/xfs/xfs_ioctl.c | 5 +++++
fs/xfs/xfs_trace.h | 3 ++-
fs/xfs/xfs_xattr.c | 10 ++++++++++
5 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_da_format.h b/fs/xfs/libxfs/xfs_da_format.h
index 839df0e5401b..28d4ac6fa156 100644
--- a/fs/xfs/libxfs/xfs_da_format.h
+++ b/fs/xfs/libxfs/xfs_da_format.h
@@ -715,14 +715,22 @@ struct xfs_attr3_leafblock {
#define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
#define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
#define XFS_ATTR_PARENT_BIT 3 /* parent pointer attrs */
+#define XFS_ATTR_VERITY_BIT 4 /* verity merkle tree and descriptor */
#define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
#define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT)
#define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT)
#define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT)
#define XFS_ATTR_PARENT (1u << XFS_ATTR_PARENT_BIT)
+#define XFS_ATTR_VERITY (1u << XFS_ATTR_VERITY_BIT)
#define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT)
#define XFS_ATTR_NSP_ONDISK_MASK \
- (XFS_ATTR_ROOT | XFS_ATTR_SECURE | XFS_ATTR_PARENT)
+ (XFS_ATTR_ROOT | XFS_ATTR_SECURE | XFS_ATTR_PARENT | \
+ XFS_ATTR_VERITY)
+
+/*
+ * Internal attributes not exposed to the user
+ */
+#define XFS_ATTR_INTERNAL_MASK (XFS_ATTR_PARENT | XFS_ATTR_VERITY)

/*
* Alignment for namelist and valuelist entries (since they are mixed
diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index 9cbcba4bd363..407fadfb5c06 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -975,6 +975,7 @@ struct xfs_icreate_log {
#define XFS_ATTRI_FILTER_MASK (XFS_ATTR_ROOT | \
XFS_ATTR_SECURE | \
XFS_ATTR_PARENT | \
+ XFS_ATTR_VERITY | \
XFS_ATTR_INCOMPLETE)

/*
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index d0e2cec6210d..ab61d7d552fb 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -352,6 +352,11 @@ static unsigned int
xfs_attr_filter(
u32 ioc_flags)
{
+ /*
+ * Only externally visible attributes should be specified here.
+ * Internally used attributes (such as parent pointers or fs-verity)
+ * should not be exposed to userspace.
+ */
if (ioc_flags & XFS_IOC_ATTR_ROOT)
return XFS_ATTR_ROOT;
if (ioc_flags & XFS_IOC_ATTR_SECURE)
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index d4f1b2da21e7..9d4ae05abfc8 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -87,7 +87,8 @@ struct xfs_bmap_intent;
{ XFS_ATTR_ROOT, "ROOT" }, \
{ XFS_ATTR_SECURE, "SECURE" }, \
{ XFS_ATTR_INCOMPLETE, "INCOMPLETE" }, \
- { XFS_ATTR_PARENT, "PARENT" }
+ { XFS_ATTR_PARENT, "PARENT" }, \
+ { XFS_ATTR_VERITY, "VERITY" }

DECLARE_EVENT_CLASS(xfs_attr_list_class,
TP_PROTO(struct xfs_attr_list_context *ctx),
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index 364104e1b38a..e4c88dde4e44 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -20,6 +20,13 @@

#include <linux/posix_acl_xattr.h>

+/*
+ * This file defines interface to work with externally visible extended
+ * attributes, such as those in user, system or security namespaces. This
+ * interface should not be used for internally used attributes (consider
+ * xfs_attr.c).
+ */
+
/*
* Get permission to use log-assisted atomic exchange of file extents.
*
@@ -244,6 +251,9 @@ xfs_xattr_put_listent(

ASSERT(context->count >= 0);

+ if (flags & XFS_ATTR_INTERNAL_MASK)
+ return;
+
if (flags & XFS_ATTR_ROOT) {
#ifdef CONFIG_XFS_POSIX_ACL
if (namelen == SGI_ACL_FILE_SIZE &&
--
2.42.0