xfs: convert kuid_t to/from uid_t in ACLs

Change permission check for setting ACL to use inode_owner_or_capable()
which will additionally allow a CAP_FOWNER user in a user namespace to
be able to set an ACL on an inode covered by the user namespace mapping.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 2f77db865ad9..69518960b2ba 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -70,14 +70,15 @@ xfs_acl_from_disk(
 
                 switch (acl_e->e_tag) {
                 case ACL_USER:
+                        acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
+                        break;
                 case ACL_GROUP:
-                        acl_e->e_id = be32_to_cpu(ace->ae_id);
+                        acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
                         break;
                 case ACL_USER_OBJ:
                 case ACL_GROUP_OBJ:
                 case ACL_MASK:
                 case ACL_OTHER:
-                        acl_e->e_id = ACL_UNDEFINED_ID;
                         break;
                 default:
                         goto fail;
@@ -103,7 +104,18 @@ xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
                 acl_e = &acl->a_entries[i];
 
                 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
-                ace->ae_id = cpu_to_be32(acl_e->e_id);
+                switch (acl_e->e_tag) {
+                case ACL_USER:
+                        ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
+                        break;
+                case ACL_GROUP:
+                        ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
+                        break;
+                default:
+                        ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
+                        break;
+                }
+
                 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
         }
 }
@@ -362,7 +374,7 @@ xfs_xattr_acl_set(struct dentry *dentry, const char *name,
                 return -EINVAL;
         if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
                 return value ? -EACCES : 0;
-        if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
+        if (!inode_owner_or_capable(inode))
                 return -EPERM;
 
         if (!value)