From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit f0d62aec931e4ae3333c797d346dc4f188f454ba upstream.
Generalize id_map_mutex so it can be used for more state of a user namespace.
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
kernel/user_namespace.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index c2ca6c01e575..a607b24bec0b 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -24,6 +24,7 @@
#include <linux/fs_struct.h>
static struct kmem_cache *user_ns_cachep __read_mostly;
+static DEFINE_MUTEX(userns_state_mutex);
static bool new_idmap_permitted(const struct file *file,
struct user_namespace *ns, int cap_setid,
@@ -575,9 +576,6 @@ static bool mappings_overlap(struct uid_gid_map *new_map, struct uid_gid_extent
return false;
}
-
-static DEFINE_MUTEX(id_map_mutex);
-
static ssize_t map_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos,
int cap_setid,
@@ -594,7 +592,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
ssize_t ret = -EINVAL;
/*
- * The id_map_mutex serializes all writes to any given map.
+ * The userns_state_mutex serializes all writes to any given map.
*
* Any map is only ever written once.
*
@@ -612,7 +610,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
* order and smp_rmb() is guaranteed that we don't have crazy
* architectures returning stale data.
*/
- mutex_lock(&id_map_mutex);
+ mutex_lock(&userns_state_mutex);
ret = -EPERM;
/* Only allow one successful write to the map */
@@ -739,7 +737,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
*ppos = count;
ret = count;
out:
- mutex_unlock(&id_map_mutex);
+ mutex_unlock(&userns_state_mutex);
if (page)
free_page(page);
return ret;
@@ -831,12 +829,12 @@ bool userns_may_setgroups(const struct user_namespace *ns)
{
bool allowed;
- mutex_lock(&id_map_mutex);
+ mutex_lock(&userns_state_mutex);
/* It is not safe to use setgroups until a gid mapping in
* the user namespace has been established.
*/
allowed = ns->gid_map.nr_extents != 0;
- mutex_unlock(&id_map_mutex);
+ mutex_unlock(&userns_state_mutex);
return allowed;
}
--
2.2.1
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