userns: Convert devpts to use kuid/kgid where appropriate

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

2 files changed, 16 insertions, 9 deletions

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 10f5e0b484d..979c1e309c7 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -98,8 +98,8 @@ static struct vfsmount *devpts_mnt;
 struct pts_mount_opts {
         int setuid;
         int setgid;
-        uid_t   uid;
-        gid_t   gid;
+        kuid_t   uid;
+        kgid_t   gid;
         umode_t mode;
         umode_t ptmxmode;
         int newinstance;
@@ -158,11 +158,13 @@ static inline struct super_block *pts_sb_from_inode(struct inode *inode)
 static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
 {
         char *p;
+        kuid_t uid;
+        kgid_t gid;
 
         opts->setuid  = 0;
         opts->setgid  = 0;
-        opts->uid     = 0;
-        opts->gid     = 0;
+        opts->uid     = GLOBAL_ROOT_UID;
+        opts->gid     = GLOBAL_ROOT_GID;
         opts->mode    = DEVPTS_DEFAULT_MODE;
         opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
         opts->max     = NR_UNIX98_PTY_MAX;
@@ -184,13 +186,19 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
                 case Opt_uid:
                         if (match_int(&args[0], &option))
                                 return -EINVAL;
-                        opts->uid = option;
+                        uid = make_kuid(current_user_ns(), option);
+                        if (!uid_valid(uid))
+                                return -EINVAL;
+                        opts->uid = uid;
                         opts->setuid = 1;
                         break;
                 case Opt_gid:
                         if (match_int(&args[0], &option))
                                 return -EINVAL;
-                        opts->gid = option;
+                        gid = make_kgid(current_user_ns(), option);
+                        if (!gid_valid(gid))
+                                return -EINVAL;
+                        opts->gid = gid;
                         opts->setgid = 1;
                         break;
                 case Opt_mode:
@@ -315,9 +323,9 @@ static int devpts_show_options(struct seq_file *seq, struct dentry *root)
         struct pts_mount_opts *opts = &fsi->mount_opts;
 
         if (opts->setuid)
-                seq_printf(seq, ",uid=%u", opts->uid);
+                seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, opts->uid));
         if (opts->setgid)
-                seq_printf(seq, ",gid=%u", opts->gid);
+                seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, opts->gid));
         seq_printf(seq, ",mode=%03o", opts->mode);
 #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
         seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode);
diff --git a/init/Kconfig b/init/Kconfig
index 994a53ec1d8..2738a7c4793 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -865,7 +865,6 @@ config UIDGID_CONVERTED
 
         # List of kernel pieces that need user namespace work
         # Features
-        depends on UNIX98_PTYS = n
         depends on CGROUPS = n
         depends on MIGRATION = n
         depends on NUMA = n