Merge tag 'v3.9-rc3' into v4l_for_linus

Linux 3.9-rc3

* tag 'v3.9-rc3': (11231 commits)
  Linux 3.9-rc3
  perf,x86: fix link failure for non-Intel configs
  perf,x86: fix wrmsr_on_cpu() warning on suspend/resume
  Btrfs: fix warning of free_extent_map
  perf,x86: fix kernel crash with PEBS/BTS after suspend/resume
  ALSA: hda - Fix missing EAPD/GPIO setup for Cirrus codecs
  sound: sequencer: cap array index in seq_chn_common_event()
  mfd: twl4030-madc: Remove __exit_p annotation
  ALSA: hda/ca0132 - Remove extra setting of dsp_state.
  ALSA: hda/ca0132 - Check download state of DSP.
  ALSA: hda/ca0132 - Check if dspload_image succeeded.
  mm/fremap.c: fix possible oops on error path
  list: Fix double fetch of pointer in hlist_entry_safe()
  Btrfs: fix warning when creating snapshots
  Btrfs: return as soon as possible when edquot happens
  Btrfs: return EIO if we have extent tree corruption
  btrfs: use rcu_barrier() to wait for bdev puts at unmount
  Btrfs: remove btrfs_try_spin_lock
  Btrfs: get better concurrency for snapshot-aware defrag work
  hwmon: (pmbus/ltc2978) Fix temperature reporting
  ...

1 files changed, 52 insertions, 14 deletions

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 2b042c42fbc4..b14f4d342043 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -21,6 +21,7 @@
 #include <linux/uaccess.h>
 #include <linux/ctype.h>
 #include <linux/projid.h>
+#include <linux/fs_struct.h>
 
 static struct kmem_cache *user_ns_cachep __read_mostly;
 
@@ -78,7 +79,7 @@ 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 +105,16 @@ 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 +521,42 @@ 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 +569,7 @@ 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 +672,11 @@ 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) &&
@@ -803,6 +838,9 @@ static int userns_install(struct nsproxy *nsproxy, void *ns)
 	if (atomic_read(&current->mm->mm_users) > 1)
 		return -EINVAL;
 
+	if (current->fs->users != 1)
+		return -EINVAL;
+
 	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
 		return -EPERM;