Make net_ns_get_ownership() reusable by networking code outside of core.
This is useful, for example, to allow bridge related sysfs files to be
owned by container root.
Add a function comment since this is a potentially dangerous function to
use given the way that kobject_get_ownership() works by initializing uid
and gid before calling .get_ownership().
Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
---
include/net/net_namespace.h | 7 +++++++
net/core/net-sysfs.c | 15 ---------------
net/core/net_namespace.c | 25 +++++++++++++++++++++++++
3 files changed, 32 insertions(+), 15 deletions(-)
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index a71264d75d7f..a257710527ce 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -170,6 +170,8 @@ extern struct net init_net;
struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
struct net *old_net);
+void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
+
void net_ns_barrier(void);
#else /* CONFIG_NET_NS */
#include <linux/sched.h>
@@ -182,6 +184,11 @@ static inline struct net *copy_net_ns(unsigned long flags,
return old_net;
}
+static inline void net_ns_get_ownership(const struct net *net,
+ kuid_t *uid, kgid_t *gid)
+{
+}
+
static inline void net_ns_barrier(void) {}
#endif /* CONFIG_NET_NS */
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 41d84c40fe51..a3ad8108d296 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -656,21 +656,6 @@ static const struct attribute_group wireless_group = {
#define net_class_groups NULL
#endif /* CONFIG_SYSFS */
-static void net_ns_get_ownership(const struct net *net,
- kuid_t *uid, kgid_t *gid)
-{
- if (net) {
- kuid_t ns_root_uid = make_kuid(net->user_ns, 0);
- kgid_t ns_root_gid = make_kgid(net->user_ns, 0);
-
- if (uid_valid(ns_root_uid))
- *uid = ns_root_uid;
-
- if (gid_valid(ns_root_gid))
- *gid = ns_root_gid;
- }
-}
-
#ifdef CONFIG_SYSFS
#define to_rx_queue_attr(_attr) \
container_of(_attr, struct rx_queue_attribute, attr)
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index a11e03f920d3..5257875fa84d 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -448,6 +448,31 @@ struct net *copy_net_ns(unsigned long flags,
return net;
}
+/**
+ * net_ns_get_ownership - get sysfs ownership data for @net
+ * @net: network namespace in question (can be NULL)
+ * @uid: kernel user ID for sysfs objects (must be GLOBAL_ROOT_UID)
+ * @gid: kernel group ID for sysfs objects (must be GLOBAL_ROOT_GID)
+ *
+ * Returns the uid/gid pair of root in the user namespace associated with the
+ * given network namespace. The caller must initialize @uid and @gid to
+ * GLOBAL_ROOT_UID/GLOBAL_ROOT_GID before calling this function.
+ */
+void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid)
+{
+ if (net) {
+ kuid_t ns_root_uid = make_kuid(net->user_ns, 0);
+ kgid_t ns_root_gid = make_kgid(net->user_ns, 0);
+
+ if (uid_valid(ns_root_uid))
+ *uid = ns_root_uid;
+
+ if (gid_valid(ns_root_gid))
+ *gid = ns_root_gid;
+ }
+}
+EXPORT_SYMBOL_GPL(net_ns_get_ownership);
+
static void unhash_nsid(struct net *net, struct net *last)
{
struct net *tmp;
--
2.7.4
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