userns: Convert tmpfs to use kuid and kgid where appropriate

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

1 files changed, 16 insertions, 6 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index f99ff3e50bd6..d7b433a1ef5e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2075,6 +2075,8 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
                                bool remount)
 {
         char *this_char, *value, *rest;
+        uid_t uid;
+        gid_t gid;
 
         while (options != NULL) {
                 this_char = options;
@@ -2134,15 +2136,21 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
                 } else if (!strcmp(this_char,"uid")) {
                         if (remount)
                                 continue;
-                        sbinfo->uid = simple_strtoul(value, &rest, 0);
+                        uid = simple_strtoul(value, &rest, 0);
                         if (*rest)
                                 goto bad_val;
+                        sbinfo->uid = make_kuid(current_user_ns(), uid);
+                        if (!uid_valid(sbinfo->uid))
+                                goto bad_val;
                 } else if (!strcmp(this_char,"gid")) {
                         if (remount)
                                 continue;
-                        sbinfo->gid = simple_strtoul(value, &rest, 0);
+                        gid = simple_strtoul(value, &rest, 0);
                         if (*rest)
                                 goto bad_val;
+                        sbinfo->gid = make_kgid(current_user_ns(), gid);
+                        if (!gid_valid(sbinfo->gid))
+                                goto bad_val;
                 } else if (!strcmp(this_char,"mpol")) {
                         if (mpol_parse_str(value, &sbinfo->mpol, 1))
                                 goto bad_val;
@@ -2210,10 +2218,12 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root)
                 seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
         if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
                 seq_printf(seq, ",mode=%03ho", sbinfo->mode);
-        if (sbinfo->uid != 0)
-                seq_printf(seq, ",uid=%u", sbinfo->uid);
-        if (sbinfo->gid != 0)
-                seq_printf(seq, ",gid=%u", sbinfo->gid);
+        if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
+                seq_printf(seq, ",uid=%u",
+                                from_kuid_munged(&init_user_ns, sbinfo->uid));
+        if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
+                seq_printf(seq, ",gid=%u",
+                                from_kgid_munged(&init_user_ns, sbinfo->gid));
         shmem_show_mpol(seq, sbinfo->mpol);
         return 0;
 }