[PATCH] namespaces: utsname: implement CLONE_NEWUTS flag

Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare. [clg@fr.ibm.com: IPC unshare fix] [bunk@stusta.de: cleanup] Signed-off-by: Serge Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Andrey Savochkin <saw@sw.ru> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] namespaces: utsname: implement CLONE_NEWUTS flag
Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare. [clg@fr.ibm.com: IPC unshare fix] [bunk@stusta.de: cleanup] Signed-off-by: Serge Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Andrey Savochkin <saw@sw.ru> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Serge E. Hallyn · Linus Torvalds
1 parent bf47fdcda6
Showing 5 changed files with 83 additions and 4 deletions Side-by-side Diff
include/linux/sched.h
include/linux/utsname.h
kernel/fork.c
kernel/nsproxy.c
kernel/utsname.c
@@ -24,6 +24,7 @@
 #define CLONE_UNTRACED		0x00800000	/* set if the tracing process can't force CLONE_PTRACE on this clone */
 #define CLONE_CHILD_SETTID	0x01000000	/* set the TID in the child */
 #define CLONE_STOPPED		0x02000000	/* Start in stopped state */
+#define CLONE_NEWUTS		0x04000000	/* New utsname group? */
  
 /*
  * Scheduling policies
@@ -47,6 +47,8 @@
 }
  
 #ifdef CONFIG_UTS_NS
+extern int unshare_utsname(unsigned long unshare_flags,
+				struct uts_namespace **new_uts);
 extern int copy_utsname(int flags, struct task_struct *tsk);
 extern void free_uts_ns(struct kref *kref);
  
@@ -55,6 +57,15 @@
 	kref_put(&ns->kref, free_uts_ns);
 }
 #else
+static inline int unshare_utsname(unsigned long unshare_flags,
+			struct uts_namespace **new_uts)
+{
+	if (unshare_flags & CLONE_NEWUTS)
+		return -EINVAL;
+
+	return 0;
+}
+
 static inline int copy_utsname(int flags, struct task_struct *tsk)
 {
 	return 0;
@@ -1607,13 +1607,14 @@
 	struct files_struct *fd, *new_fd = NULL;
 	struct sem_undo_list *new_ulist = NULL;
 	struct nsproxy *new_nsproxy, *old_nsproxy;
+	struct uts_namespace *uts, *new_uts = NULL;
  
 	check_unshare_flags(&unshare_flags);
  
 	/* Return -EINVAL for all unsupported flags */
 	err = -EINVAL;
 	if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
-				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM))
+				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|CLONE_NEWUTS))
 		goto bad_unshare_out;
  
 	if ((err = unshare_thread(unshare_flags)))
  
  
@@ -1630,14 +1631,17 @@
 		goto bad_unshare_cleanup_vm;
 	if ((err = unshare_semundo(unshare_flags, &new_ulist)))
 		goto bad_unshare_cleanup_fd;
+	if ((err = unshare_utsname(unshare_flags, &new_uts)))
+		goto bad_unshare_cleanup_semundo;
  
-	if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) {
+	if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist ||
+				new_uts) {
  
 		old_nsproxy = current->nsproxy;
 		new_nsproxy = dup_namespaces(old_nsproxy);
 		if (!new_nsproxy) {
 			err = -ENOMEM;
-			goto bad_unshare_cleanup_semundo;
+			goto bad_unshare_cleanup_uts;
 		}
  
 		task_lock(current);
  
@@ -1676,9 +1680,19 @@
 			new_fd = fd;
 		}
  
+		if (new_uts) {
+			uts = current->nsproxy->uts_ns;
+			current->nsproxy->uts_ns = new_uts;
+			new_uts = uts;
+		}
+
 		task_unlock(current);
 		put_nsproxy(old_nsproxy);
 	}
+
+bad_unshare_cleanup_uts:
+	if (new_uts)
+		put_uts_ns(new_uts);
  
 bad_unshare_cleanup_semundo:
 bad_unshare_cleanup_fd:
@@ -82,7 +82,7 @@
  
 	get_nsproxy(old_ns);
  
-	if (!(flags & CLONE_NEWNS))
+	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS)))
 		return 0;
  
 	new_ns = clone_namespaces(old_ns);
@@ -15,6 +15,41 @@
 #include <linux/version.h>
  
 /*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+{
+	struct uts_namespace *ns;
+
+	ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
+	if (ns) {
+		memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+		kref_init(&ns->kref);
+	}
+	return ns;
+}
+
+/*
+ * unshare the current process' utsname namespace.
+ * called only in sys_unshare()
+ */
+int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
+{
+	if (unshare_flags & CLONE_NEWUTS) {
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		*new_uts = clone_uts_ns(current->nsproxy->uts_ns);
+		if (!*new_uts)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/*
  * Copy task tsk's utsname namespace, or clone it if flags
  * specifies CLONE_NEWUTS.  In latter case, changes to the
  * utsname of this process won't be seen by parent, and vice
@@ -23,6 +58,7 @@
 int copy_utsname(int flags, struct task_struct *tsk)
 {
 	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
+	struct uts_namespace *new_ns;
 	int err = 0;
  
 	if (!old_ns)
@@ -30,6 +66,23 @@
  
 	get_uts_ns(old_ns);
  
+	if (!(flags & CLONE_NEWUTS))
+		return 0;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		err = -EPERM;
+		goto out;
+	}
+
+	new_ns = clone_uts_ns(old_ns);
+	if (!new_ns) {
+		err = -ENOMEM;
+		goto out;
+	}
+	tsk->nsproxy->uts_ns = new_ns;
+
+out:
+	put_uts_ns(old_ns);
 	return err;
 }
...	...	@@ -24,6 +24,7 @@
24	24	#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
25	25	#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */
26	26	#define CLONE_STOPPED 0x02000000 /* Start in stopped state */
	27	+#define CLONE_NEWUTS 0x04000000 /* New utsname group? */
27	28
28	29	/*
29	30	* Scheduling policies
...	...	@@ -47,6 +47,8 @@
47	47	}
48	48
49	49	#ifdef CONFIG_UTS_NS
	50	+extern int unshare_utsname(unsigned long unshare_flags,
	51	+ struct uts_namespace **new_uts);
50	52	extern int copy_utsname(int flags, struct task_struct *tsk);
51	53	extern void free_uts_ns(struct kref *kref);
52	54
...	...	@@ -55,6 +57,15 @@
55	57	kref_put(&ns->kref, free_uts_ns);
56	58	}
57	59	#else
	60	+static inline int unshare_utsname(unsigned long unshare_flags,
	61	+ struct uts_namespace **new_uts)
	62	+{
	63	+ if (unshare_flags & CLONE_NEWUTS)
	64	+ return -EINVAL;
	65	+
	66	+ return 0;
	67	+}
	68	+
58	69	static inline int copy_utsname(int flags, struct task_struct *tsk)
59	70	{
60	71	return 0;
...	...	@@ -1607,13 +1607,14 @@
1607	1607	struct files_struct fd, new_fd = NULL;
1608	1608	struct sem_undo_list *new_ulist = NULL;
1609	1609	struct nsproxy new_nsproxy, old_nsproxy;
	1610	+ struct uts_namespace uts, new_uts = NULL;
1610	1611
1611	1612	check_unshare_flags(&unshare_flags);
1612	1613
1613	1614	/* Return -EINVAL for all unsupported flags */
1614	1615	err = -EINVAL;
1615	1616	if (unshare_flags & ~(CLONE_THREAD\|CLONE_FS\|CLONE_NEWNS\|CLONE_SIGHAND\|
1616		- CLONE_VM\|CLONE_FILES\|CLONE_SYSVSEM))
	1617	+ CLONE_VM\|CLONE_FILES\|CLONE_SYSVSEM\|CLONE_NEWUTS))
1617	1618	goto bad_unshare_out;
1618	1619
1619	1620	if ((err = unshare_thread(unshare_flags)))
1620	1621
1621	1622
...	...	@@ -1630,14 +1631,17 @@
1630	1631	goto bad_unshare_cleanup_vm;
1631	1632	if ((err = unshare_semundo(unshare_flags, &new_ulist)))
1632	1633	goto bad_unshare_cleanup_fd;
	1634	+ if ((err = unshare_utsname(unshare_flags, &new_uts)))
	1635	+ goto bad_unshare_cleanup_semundo;
1633	1636
1634		- if (new_fs \|\| new_ns \|\| new_sigh \|\| new_mm \|\| new_fd \|\| new_ulist) {
	1637	+ if (new_fs \|\| new_ns \|\| new_sigh \|\| new_mm \|\| new_fd \|\| new_ulist \|\|
	1638	+ new_uts) {
1635	1639
1636	1640	old_nsproxy = current->nsproxy;
1637	1641	new_nsproxy = dup_namespaces(old_nsproxy);
1638	1642	if (!new_nsproxy) {
1639	1643	err = -ENOMEM;
1640		- goto bad_unshare_cleanup_semundo;
	1644	+ goto bad_unshare_cleanup_uts;
1641	1645	}
1642	1646
1643	1647	task_lock(current);
1644	1648
...	...	@@ -1676,9 +1680,19 @@
1676	1680	new_fd = fd;
1677	1681	}
1678	1682
	1683	+ if (new_uts) {
	1684	+ uts = current->nsproxy->uts_ns;
	1685	+ current->nsproxy->uts_ns = new_uts;
	1686	+ new_uts = uts;
	1687	+ }
	1688	+
1679	1689	task_unlock(current);
1680	1690	put_nsproxy(old_nsproxy);
1681	1691	}
	1692	+
	1693	+bad_unshare_cleanup_uts:
	1694	+ if (new_uts)
	1695	+ put_uts_ns(new_uts);
1682	1696
1683	1697	bad_unshare_cleanup_semundo:
1684	1698	bad_unshare_cleanup_fd:
...	...	@@ -82,7 +82,7 @@
82	82
83	83	get_nsproxy(old_ns);
84	84
85		- if (!(flags & CLONE_NEWNS))
	85	+ if (!(flags & (CLONE_NEWNS \| CLONE_NEWUTS)))
86	86	return 0;
87	87
88	88	new_ns = clone_namespaces(old_ns);
...	...	@@ -15,6 +15,41 @@
15	15	#include <linux/version.h>
16	16
17	17	/*
	18	+ * Clone a new ns copying an original utsname, setting refcount to 1
	19	+ * @old_ns: namespace to clone
	20	+ * Return NULL on error (failure to kmalloc), new ns otherwise
	21	+ */
	22	+static struct uts_namespace clone_uts_ns(struct uts_namespace old_ns)
	23	+{
	24	+ struct uts_namespace *ns;
	25	+
	26	+ ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
	27	+ if (ns) {
	28	+ memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
	29	+ kref_init(&ns->kref);
	30	+ }
	31	+ return ns;
	32	+}
	33	+
	34	+/*
	35	+ * unshare the current process' utsname namespace.
	36	+ * called only in sys_unshare()
	37	+ */
	38	+int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
	39	+{
	40	+ if (unshare_flags & CLONE_NEWUTS) {
	41	+ if (!capable(CAP_SYS_ADMIN))
	42	+ return -EPERM;
	43	+
	44	+ *new_uts = clone_uts_ns(current->nsproxy->uts_ns);
	45	+ if (!*new_uts)
	46	+ return -ENOMEM;
	47	+ }
	48	+
	49	+ return 0;
	50	+}
	51	+
	52	+/*
18	53	* Copy task tsk's utsname namespace, or clone it if flags
19	54	* specifies CLONE_NEWUTS. In latter case, changes to the
20	55	* utsname of this process won't be seen by parent, and vice
...	...	@@ -23,6 +58,7 @@
23	58	int copy_utsname(int flags, struct task_struct *tsk)
24	59	{
25	60	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
	61	+ struct uts_namespace *new_ns;
26	62	int err = 0;
27	63
28	64	if (!old_ns)
...	...	@@ -30,6 +66,23 @@
30	66
31	67	get_uts_ns(old_ns);
32	68
	69	+ if (!(flags & CLONE_NEWUTS))
	70	+ return 0;
	71	+
	72	+ if (!capable(CAP_SYS_ADMIN)) {
	73	+ err = -EPERM;
	74	+ goto out;
	75	+ }
	76	+
	77	+ new_ns = clone_uts_ns(old_ns);
	78	+ if (!new_ns) {
	79	+ err = -ENOMEM;
	80	+ goto out;
	81	+ }
	82	+ tsk->nsproxy->uts_ns = new_ns;
	83	+
	84	+out:
	85	+ put_uts_ns(old_ns);
33	86	return err;
34	87	}
35	88