Merge tag 'v3.7-rc3' into for-linus to sync up with recent USB changes

1 files changed, 31 insertions, 8 deletions

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index b3c7fd554250..7b07cc0dfb75 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/proc_fs.h>
 #include <linux/reboot.h>
+#include <linux/export.h>
 
 #define BITS_PER_PAGE           (PAGE_SIZE*8)
 
@@ -70,12 +71,22 @@ err_alloc:
         return NULL;
 }
 
+/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
+#define MAX_PID_NS_LEVEL 32
+
 static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
 {
         struct pid_namespace *ns;
         unsigned int level = parent_pid_ns->level + 1;
-        int i, err = -ENOMEM;
+        int i;
+        int err;
+
+        if (level > MAX_PID_NS_LEVEL) {
+                err = -EINVAL;
+                goto out;
+        }
 
+        err = -ENOMEM;
         ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
         if (ns == NULL)
                 goto out;
@@ -132,18 +143,26 @@ struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old
         return create_pid_namespace(old_ns);
 }
 
-void free_pid_ns(struct kref *kref)
+static void free_pid_ns(struct kref *kref)
 {
-        struct pid_namespace *ns, *parent;
+        struct pid_namespace *ns;
 
         ns = container_of(kref, struct pid_namespace, kref);
-
-        parent = ns->parent;
         destroy_pid_namespace(ns);
+}
+
+void put_pid_ns(struct pid_namespace *ns)
+{
+        struct pid_namespace *parent;
 
-        if (parent != NULL)
-                put_pid_ns(parent);
+        while (ns != &init_pid_ns) {
+                parent = ns->parent;
+                if (!kref_put(&ns->kref, free_pid_ns))
+                        break;
+                ns = parent;
+        }
 }
+EXPORT_SYMBOL_GPL(put_pid_ns);
 
 void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {
@@ -232,15 +251,19 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
          */
 
         tmp.data = &current->nsproxy->pid_ns->last_pid;
-        return proc_dointvec(&tmp, write, buffer, lenp, ppos);
+        return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 }
 
+extern int pid_max;
+static int zero = 0;
 static struct ctl_table pid_ns_ctl_table[] = {
         {
                 .procname = "ns_last_pid",
                 .maxlen = sizeof(int),
                 .mode = 0666, /* permissions are checked in the handler */
                 .proc_handler = pid_ns_ctl_handler,
+                .extra1 = &zero,
+                .extra2 = &pid_max,
         },
         { }
 };