POSIX ACLs on XFS are exposed as system.posix_acl_* as well as
trusted.SGI_ACL_*. Setting the system attributes updates inode->i_mode,
inode->i_acl, and inode->i_default_acl as it should, but setting the trusted
attributes does not do that. Fix that by adding xattr handlers for the two
trusted.SGI_ACL_* attributes.
The handlers must be installed before the trusted.* xattr handler in
xfs_xattr_handlers to take effect.
Other than before, trusted.SGI_ACL_* attribute values are now verified and
cannot be set to invalid values anymore. Access to those attributes is still
limited to users capable of CAP_SYS_ADMIN, while the system.posix_acl_*
attributes can be read by anyone and set by the file owner.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
fs/xfs/xfs_acl.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_acl.h | 3 +++
fs/xfs/xfs_xattr.c | 4 ++-
3 files changed, 82 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 763e365..0eea7ee 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -305,3 +305,79 @@ xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
set_acl:
return __xfs_set_acl(inode, type, acl);
}
+
+static int
+xfs_xattr_acl_get(struct dentry *dentry, const char *name,
+ void *value, size_t size, int type)
+{
+ struct inode *inode = d_inode(dentry);
+ struct posix_acl *acl;
+ int error;
+
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+
+ acl = get_acl(inode, type);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl == NULL)
+ return -ENODATA;
+
+ error = XFS_ACL_SIZE(acl->a_count);
+ if (value) {
+ if (error > size)
+ error = -ERANGE;
+ else
+ xfs_acl_to_disk(value, acl);
+ }
+
+ posix_acl_release(acl);
+ return error;
+}
+
+static int
+xfs_xattr_acl_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags, int type)
+{
+ struct inode *inode = d_inode(dentry);
+ struct xfs_inode *ip = XFS_I(inode);
+ struct posix_acl *acl = NULL;
+ int error;
+
+ if (!inode->i_op->set_acl)
+ return -EOPNOTSUPP;
+
+ if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
+ return value ? -EACCES : 0;
+
+ if (value) {
+ acl = xfs_acl_from_disk(value, size, XFS_ACL_MAX_ENTRIES(ip->i_mount));
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+
+ if (acl) {
+ error = posix_acl_valid(acl);
+ if (error)
+ goto out;
+ }
+ }
+
+ error = inode->i_op->set_acl(inode, acl, type);
+out:
+ posix_acl_release(acl);
+ return error;
+}
+
+const struct xattr_handler xfs_xattr_sgi_acl_file = {
+ .prefix = XATTR_TRUSTED_PREFIX SGI_ACL_FILE,
+ .flags = ACL_TYPE_ACCESS,
+ .get = xfs_xattr_acl_get,
+ .set = xfs_xattr_acl_set,
+};
+
+const struct xattr_handler xfs_xattr_sgi_acl_default = {
+ .prefix = XATTR_TRUSTED_PREFIX SGI_ACL_DEFAULT,
+ .flags = ACL_TYPE_DEFAULT,
+ .get = xfs_xattr_acl_get,
+ .set = xfs_xattr_acl_set,
+};
diff --git a/fs/xfs/xfs_acl.h b/fs/xfs/xfs_acl.h
index 3841b07..461dea6 100644
--- a/fs/xfs/xfs_acl.h
+++ b/fs/xfs/xfs_acl.h
@@ -27,6 +27,9 @@ extern struct posix_acl *xfs_get_acl(struct inode *inode, int type);
extern int xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
extern int posix_acl_access_exists(struct inode *inode);
extern int posix_acl_default_exists(struct inode *inode);
+
+extern const struct xattr_handler xfs_xattr_sgi_acl_file;
+extern const struct xattr_handler xfs_xattr_sgi_acl_default;
#else
static inline struct posix_acl *xfs_get_acl(struct inode *inode, int type)
{
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index c0368151..7534cb5 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -97,12 +97,14 @@ static const struct xattr_handler xfs_xattr_security_handler = {
const struct xattr_handler *xfs_xattr_handlers[] = {
&xfs_xattr_user_handler,
- &xfs_xattr_trusted_handler,
&xfs_xattr_security_handler,
#ifdef CONFIG_XFS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
+ &xfs_xattr_sgi_acl_file,
+ &xfs_xattr_sgi_acl_default,
#endif
+ &xfs_xattr_trusted_handler,
NULL
};
--
2.5.0
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