userns: add a user namespace owner of ipc ns

Changelog: Feb 15: Don't set new ipc->user_ns if we didn't create a new ipc_ns. Feb 23: Move extern declaration to ipc_namespace.h, and group fwd declarations at top. Signed-off-by: Serge E. Hallyn <[email protected]> Acked-by: "Eric W. Biederman" <[email protected]> Acked-by: Daniel Lezcano <[email protected]> Acked-by: David Howells <[email protected]> Cc: James Morris <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
CamonZ · Mar 24, 2011 · b515498 · b515498
1 parent fc832ad
commit b515498
Show file tree

Hide file tree

Showing 4 changed files with 16 additions and 2 deletions.
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
@@ -15,6 +15,7 @@
 
 #define IPCNS_CALLBACK_PRI 0
 
+struct user_namespace;
 
 struct ipc_ids {
 	int in_use;
@@ -56,6 +57,8 @@ struct ipc_namespace {
 	unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
 	unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
 
+	/* user_ns which owns the ipc ns */
+	struct user_namespace *user_ns;
 };
 
 extern struct ipc_namespace init_ipc_ns;

diff --git a/ipc/msgutil.c b/ipc/msgutil.c
@@ -32,6 +32,7 @@ struct ipc_namespace init_ipc_ns = {
 	.mq_msg_max      = DFLT_MSGMAX,
 	.mq_msgsize_max  = DFLT_MSGSIZEMAX,
 #endif
+	.user_ns = &init_user_ns,
 };
 
 atomic_t nr_ipc_ns = ATOMIC_INIT(1);

diff --git a/ipc/namespace.c b/ipc/namespace.c
@@ -11,10 +11,11 @@
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/mount.h>
+#include <linux/user_namespace.h>
 
 #include "util.h"
 
-static struct ipc_namespace *create_ipc_ns(void)
+static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
 {
 	struct ipc_namespace *ns;
 	int err;
@@ -43,14 +44,17 @@ static struct ipc_namespace *create_ipc_ns(void)
 	ipcns_notify(IPCNS_CREATED);
 	register_ipcns_notifier(ns);
 
+	ns->user_ns = old_ns->user_ns;
+	get_user_ns(ns->user_ns);
+
 	return ns;
 }
 
 struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
 {
 	if (!(flags & CLONE_NEWIPC))
 		return get_ipc_ns(ns);
-	return create_ipc_ns();
+	return create_ipc_ns(ns);
 }
 
 /*
@@ -105,6 +109,7 @@ static void free_ipc_ns(struct ipc_namespace *ns)
 	 * order to have a correct value when recomputing msgmni.
 	 */
 	ipcns_notify(IPCNS_REMOVED);
+	put_user_ns(ns->user_ns);
 }
 
 /*

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
@@ -80,6 +80,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		err = PTR_ERR(new_nsp->ipc_ns);
 		goto out_ipc;
 	}
+	if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
+		put_user_ns(new_nsp->ipc_ns->user_ns);
+		new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
+		get_user_ns(new_nsp->ipc_ns->user_ns);
+	}
 
 	new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
 	if (IS_ERR(new_nsp->pid_ns)) {