2 files changed, 47 insertions, 7 deletions

diff --git a/include/linux/uidgid.h b/include/linux/uidgid.h
index 5398568..8e522cbc 100644
--- a/include/linux/uidgid.h
+++ b/include/linux/uidgid.h
@@ -127,6 +127,28 @@ static inline bool gid_valid(kgid_t gid)
 	return !gid_eq(gid, INVALID_GID);
 }
 
+#ifdef CONFIG_USER_NS
+
+extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
+extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
+
+extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
+extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
+extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
+extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
+
+static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
+{
+	return from_kuid(ns, uid) != (uid_t) -1;
+}
+
+static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
+{
+	return from_kgid(ns, gid) != (gid_t) -1;
+}
+
+#else
+
 static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
 {
 	return KUIDT_INIT(uid);
@@ -173,4 +195,6 @@ static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 	return true;
 }
 
+#endif /* CONFIG_USER_NS */
+
 #endif /* _LINUX_UIDGID_H */
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 8a391bd..4c9846d 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -6,7 +6,20 @@
 #include <linux/sched.h>
 #include <linux/err.h>
 
+#define UID_GID_MAP_MAX_EXTENTS 5
+
+struct uid_gid_map {	/* 64 bytes -- 1 cache line */
+	u32 nr_extents;
+	struct uid_gid_extent {
+		u32 first;
+		u32 lower_first;
+		u32 count;
+	} extent[UID_GID_MAP_MAX_EXTENTS];
+};
+
 struct user_namespace {
+	struct uid_gid_map	uid_map;
+	struct uid_gid_map	gid_map;
 	struct kref		kref;
 	struct user_namespace	*parent;
 	kuid_t			owner;
@@ -33,9 +46,11 @@ static inline void put_user_ns(struct user_namespace *ns)
 		kref_put(&ns->kref, free_user_ns);
 }
 
-uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t uid);
-gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t gid);
-
+struct seq_operations;
+extern struct seq_operations proc_uid_seq_operations;
+extern struct seq_operations proc_gid_seq_operations;
+extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
+extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 #else
 
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
@@ -52,17 +67,18 @@ static inline void put_user_ns(struct user_namespace *ns)
 {
 }
 
+#endif
+
 static inline uid_t user_ns_map_uid(struct user_namespace *to,
 	const struct cred *cred, uid_t uid)
 {
-	return uid;
+	return from_kuid_munged(to, make_kuid(cred->user_ns, uid));
 }
+
 static inline gid_t user_ns_map_gid(struct user_namespace *to,
 	const struct cred *cred, gid_t gid)
 {
-	return gid;
+	return from_kgid_munged(to, make_kgid(cred->user_ns, gid));
 }
 
-#endif
-
 #endif /* _LINUX_USER_H */