userns: Convert hugetlbfs to use kuid/kgid where appropriate

Note sysctl_hugetlb_shm_group can only be written in the root user
in the initial user namespace, so we can assume sysctl_hugetlb_shm_group
is in the initial user namespace.

Cc: William Irwin <wli@holomorphy.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 11 insertions, 5 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 8349a899912e..6e572c4fbf68 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -42,8 +42,8 @@ static const struct inode_operations hugetlbfs_dir_inode_operations;
 static const struct inode_operations hugetlbfs_inode_operations;
 
 struct hugetlbfs_config {
-        uid_t   uid;
-        gid_t   gid;
+        kuid_t   uid;
+        kgid_t   gid;
         umode_t mode;
         long    nr_blocks;
         long    nr_inodes;
@@ -785,13 +785,17 @@ hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
                 case Opt_uid:
                         if (match_int(&args[0], &option))
                                 goto bad_val;
-                        pconfig->uid = option;
+                        pconfig->uid = make_kuid(current_user_ns(), option);
+                        if (!uid_valid(pconfig->uid))
+                                goto bad_val;
                         break;
 
                 case Opt_gid:
                         if (match_int(&args[0], &option))
                                 goto bad_val;
-                        pconfig->gid = option;
+                        pconfig->gid = make_kgid(current_user_ns(), option);
+                        if (!gid_valid(pconfig->gid))
+                                goto bad_val;
                         break;
 
                 case Opt_mode:
@@ -924,7 +928,9 @@ static struct vfsmount *hugetlbfs_vfsmount;
 
 static int can_do_hugetlb_shm(void)
 {
-        return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
+        kgid_t shm_group;
+        shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
+        return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 }
 
 struct file *hugetlb_file_setup(const char *name, unsigned long addr,