nfsd: Convert nfsxdr to use kuids and kgids

[~andy/linux] / kernel / user_namespace.c

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 2b042c42fbc415b24beb45b095fc6059612de0f8..8b650837083e74f7c8bcac7b4f83081c448e36ed 100644 (file)
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -78,7 +78,7 @@ int create_user_ns(struct cred *new)
                return ret;
        }
 
-       kref_init(&ns->kref);
+       atomic_set(&ns->count, 1);
        /* Leave the new->user_ns reference with the new user namespace. */
        ns->parent = parent_ns;
        ns->owner = owner;
@@ -104,15 +104,16 @@ int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
        return create_user_ns(cred);
 }
 
-void free_user_ns(struct kref *kref)
+void free_user_ns(struct user_namespace *ns)
 {
-       struct user_namespace *parent, *ns =
-               container_of(kref, struct user_namespace, kref);
+       struct user_namespace *parent;
 
-       parent = ns->parent;
-       proc_free_inum(ns->proc_inum);
-       kmem_cache_free(user_ns_cachep, ns);
-       put_user_ns(parent);
+       do {
+               parent = ns->parent;
+               proc_free_inum(ns->proc_inum);
+               kmem_cache_free(user_ns_cachep, ns);
+               ns = parent;
+       } while (atomic_dec_and_test(&parent->count));
 }
 EXPORT_SYMBOL(free_user_ns);
 
@@ -519,6 +520,42 @@ struct seq_operations proc_projid_seq_operations = {
        .show = projid_m_show,
 };
 
+static bool mappings_overlap(struct uid_gid_map *new_map, struct uid_gid_extent *extent)
+{
+       u32 upper_first, lower_first, upper_last, lower_last;
+       unsigned idx;
+
+       upper_first = extent->first;
+       lower_first = extent->lower_first;
+       upper_last = upper_first + extent->count - 1;
+       lower_last = lower_first + extent->count - 1;
+
+       for (idx = 0; idx < new_map->nr_extents; idx++) {
+               u32 prev_upper_first, prev_lower_first;
+               u32 prev_upper_last, prev_lower_last;
+               struct uid_gid_extent *prev;
+
+               prev = &new_map->extent[idx];
+
+               prev_upper_first = prev->first;
+               prev_lower_first = prev->lower_first;
+               prev_upper_last = prev_upper_first + prev->count - 1;
+               prev_lower_last = prev_lower_first + prev->count - 1;
+
+               /* Does the upper range intersect a previous extent? */
+               if ((prev_upper_first <= upper_last) &&
+                   (prev_upper_last >= upper_first))
+                       return true;
+
+               /* Does the lower range intersect a previous extent? */
+               if ((prev_lower_first <= lower_last) &&
+                   (prev_lower_last >= lower_first))
+                       return true;
+       }
+       return false;
+}
+
+
 static DEFINE_MUTEX(id_map_mutex);
 
 static ssize_t map_write(struct file *file, const char __user *buf,
@@ -531,7 +568,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
        struct user_namespace *ns = seq->private;
        struct uid_gid_map new_map;
        unsigned idx;
-       struct uid_gid_extent *extent, *last = NULL;
+       struct uid_gid_extent *extent = NULL;
        unsigned long page = 0;
        char *kbuf, *pos, *next_line;
        ssize_t ret = -EINVAL;
@@ -634,14 +671,11 @@ static ssize_t map_write(struct file *file, const char __user *buf,
                if ((extent->lower_first + extent->count) <= extent->lower_first)
                        goto out;
 
-               /* For now only accept extents that are strictly in order */
-               if (last &&
-                   (((last->first + last->count) > extent->first) ||
-                    ((last->lower_first + last->count) > extent->lower_first)))
+               /* Do the ranges in extent overlap any previous extents? */
+               if (mappings_overlap(&new_map, extent))
                        goto out;
 
                new_map.nr_extents++;
-               last = extent;
 
                /* Fail if the file contains too many extents */
                if ((new_map.nr_extents == UID_GID_MAP_MAX_EXTENTS) &&