m68knommu: make ColdFire M532x platform support more v3 generic

[karo-tx-linux.git] / kernel / user_namespace.c

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index b14f4d3420439ca629be08494ef417e734513499..e134d8f365ddea425ac6a8df541875038928298d 100644 (file)
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -25,7 +25,8 @@
 
 static struct kmem_cache *user_ns_cachep __read_mostly;
 
-static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
+static bool new_idmap_permitted(const struct file *file,
+                               struct user_namespace *ns, int cap_setid,
                                struct uid_gid_map *map);
 
 static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
@@ -61,6 +62,15 @@ int create_user_ns(struct cred *new)
        kgid_t group = new->egid;
        int ret;
 
+       /*
+        * Verify that we can not violate the policy of which files
+        * may be accessed that is specified by the root directory,
+        * by verifing that the root directory is at the root of the
+        * mount namespace which allows all files to be accessed.
+        */
+       if (current_chrooted())
+               return -EPERM;
+
        /* The creator needs a mapping in the parent user namespace
         * or else we won't be able to reasonably tell userspace who
         * created a user_namespace.
@@ -87,6 +97,8 @@ int create_user_ns(struct cred *new)
 
        set_cred_user_ns(new, ns);
 
+       update_mnt_policy(ns);
+
        return 0;
 }
 
@@ -601,10 +613,10 @@ static ssize_t map_write(struct file *file, const char __user *buf,
        if (map->nr_extents != 0)
                goto out;
 
-       /* Require the appropriate privilege CAP_SETUID or CAP_SETGID
-        * over the user namespace in order to set the id mapping.
+       /*
+        * Adjusting namespace settings requires capabilities on the target.
         */
-       if (cap_valid(cap_setid) && !ns_capable(ns, cap_setid))
+       if (cap_valid(cap_setid) && !file_ns_capable(file, ns, CAP_SYS_ADMIN))
                goto out;
 
        /* Get a buffer */
@@ -689,7 +701,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
 
        ret = -EPERM;
        /* Validate the user is allowed to use user id's mapped to. */
-       if (!new_idmap_permitted(ns, cap_setid, &new_map))
+       if (!new_idmap_permitted(file, ns, cap_setid, &new_map))
                goto out;
 
        /* Map the lower ids from the parent user namespace to the
@@ -776,7 +788,8 @@ ssize_t proc_projid_map_write(struct file *file, const char __user *buf, size_t
                         &ns->projid_map, &ns->parent->projid_map);
 }
 
-static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
+static bool new_idmap_permitted(const struct file *file, 
+                               struct user_namespace *ns, int cap_setid,
                                struct uid_gid_map *new_map)
 {
        /* Allow mapping to your own filesystem ids */
@@ -784,12 +797,12 @@ static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
                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()))
+                       if (uid_eq(uid, file->f_cred->fsuid))
                                return true;
                }
                else if (cap_setid == CAP_SETGID) {
                        kgid_t gid = make_kgid(ns->parent, id);
-                       if (gid_eq(gid, current_fsgid()))
+                       if (gid_eq(gid, file->f_cred->fsgid))
                                return true;
                }
        }
@@ -800,8 +813,10 @@ static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
 
        /* Allow the specified ids if we have the appropriate capability
         * (CAP_SETUID or CAP_SETGID) over the parent user namespace.
+        * And the opener of the id file also had the approprpiate capability.
         */
-       if (ns_capable(ns->parent, cap_setid))
+       if (ns_capable(ns->parent, cap_setid) &&
+           file_ns_capable(file, ns->parent, cap_setid))
                return true;
 
        return false;