From 068733044f4941bf862811b0224d64104ee776e6 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Fri, 27 Jul 2012 06:21:27 -0700
Subject: [PATCH] --- yaml --- r: 346324 b: refs/heads/master c:
 37657da3c5d4a3bbbbb9d3b78f53a8134a0abae0 h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/kernel/user_namespace.c | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 339adc7825bc..4d9df272e3e0 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7fa294c8991ce0ed4e713f08209eb2ce3e1044ac
+refs/heads/master: 37657da3c5d4a3bbbbb9d3b78f53a8134a0abae0
diff --git a/trunk/kernel/user_namespace.c b/trunk/kernel/user_namespace.c
index 456a6b9fba34..49096d559e08 100644
--- a/trunk/kernel/user_namespace.c
+++ b/trunk/kernel/user_namespace.c
@@ -709,6 +709,21 @@ ssize_t proc_projid_map_write(struct file *file, const char __user *buf, size_t
 static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
 				struct uid_gid_map *new_map)
 {
+	/* Allow mapping to your own filesystem ids */
+	if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1)) {
+		u32 id = new_map->extent[0].lower_first;
+		if (cap_setid == CAP_SETUID) {
+			kuid_t uid = make_kuid(ns->parent, id);
+			if (uid_eq(uid, current_fsuid()))
+				return true;
+		}
+		else if (cap_setid == CAP_SETGID) {
+			kgid_t gid = make_kgid(ns->parent, id);
+			if (gid_eq(gid, current_fsgid()))
+				return true;
+		}
+	}
+
 	/* Allow anyone to set a mapping that doesn't require privilege */
 	if (!cap_valid(cap_setid))
 		return true;