The patch titled
/8] user ns: implement user ns unshare
has been added to the -mm tree. Its filename is
user-ns-implement-user-ns-unshare.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: /8] user ns: implement user ns unshare
From: "Serge E. Hallyn" <serue@xxxxxxxxxx>
Quoting Frederik Deweerdt (deweerdt@xxxxxxx):
> On Thu, Jan 04, 2007 at 12:13:10PM -0600, Serge E. Hallyn wrote:
> > From: Serge E. Hallyn <serue@xxxxxxxxxx>
> > Subject: [PATCH -mm 8/8] user ns: implement user ns unshare
> >
> > Implement CLONE_NEWUSER flag useable at clone/unshare.
> >
> > Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
> > ---
>
> > int copy_user_ns(int flags, struct task_struct *tsk)
> > {
> > - struct user_namespace *old_ns = tsk->nsproxy->user_ns;
> > + struct user_namespace *new_ns, *old_ns = tsk->nsproxy->user_ns;
> > int err = 0;
> ^^^^^^^^^^^^
> The "= 0" is superfluous here.
Ah, since I set it anyway, good point.
> >
> > if (!old_ns)
> > return 0;
> >
> > get_user_ns(old_ns);
> > - return err;
> > + if (!(flags & CLONE_NEWUSER))
> > + return 0;
> > + err = -EPERM;
> > + if (!capable(CAP_SYS_ADMIN))
> > + goto out;
> > + err = -ENOMEM;
> > + new_ns = clone_user_ns(old_ns);
> > + if (!new_ns)
> > + goto out;
> > +
> > + tsk->nsproxy->user_ns = new_ns;
> > + err = 0;
> > +out:
> > + put_user_ns(old_ns);
> > + return 0;
> ^^^^^^^^^
> Should be "return err;"
Yes it should.
New patch attached.
(I suppose the testcase should check for the CAP_SYS_ADMIN
error case...)
Thanks for the close review!
-serge
Subject: [PATCH 8/8] user ns: implement user ns unshare
Implement CLONE_NEWUSER flag useable at clone/unshare.
Changes:
Jan 4: return the actual error value in copy_user_ns().
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
Cc: Herbert Poetzl <herbert@xxxxxxxxxxxx>
Cc: Kirill Korotaev <dev@xxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/sched.h | 1
include/linux/user_namespace.h | 10 ++++
kernel/fork.c | 22 +++++++--
kernel/nsproxy.c | 2
kernel/user_namespace.c | 74 ++++++++++++++++++++++++++++++-
5 files changed, 102 insertions(+), 7 deletions(-)
diff -puN include/linux/sched.h~user-ns-implement-user-ns-unshare include/linux/sched.h
--- a/include/linux/sched.h~user-ns-implement-user-ns-unshare
+++ a/include/linux/sched.h
@@ -26,6 +26,7 @@
#define CLONE_STOPPED 0x02000000 /* Start in stopped state */
#define CLONE_NEWUTS 0x04000000 /* New utsname group? */
#define CLONE_NEWIPC 0x08000000 /* New ipcs */
+#define CLONE_NEWUSER 0x10000000 /* New user namespace */
/*
* Scheduling policies
diff -puN include/linux/user_namespace.h~user-ns-implement-user-ns-unshare include/linux/user_namespace.h
--- a/include/linux/user_namespace.h~user-ns-implement-user-ns-unshare
+++ a/include/linux/user_namespace.h
@@ -26,6 +26,7 @@ static inline struct user_namespace *get
}
extern int copy_user_ns(int flags, struct task_struct *tsk);
+extern int unshare_user_ns(unsigned long flags, struct user_namespace **new_user);
extern void free_user_ns(struct kref *kref);
static inline void put_user_ns(struct user_namespace *ns)
@@ -51,6 +52,15 @@ static inline struct user_namespace *get
return &init_user_ns;
}
+static inline int unshare_user_ns(unsigned long flags,
+ struct user_namespace **new_user)
+{
+ if (flags & CLONE_NEWUSER)
+ return -EINVAL;
+
+ return 0;
+}
+
static inline int copy_user_ns(int flags, struct task_struct *tsk)
{
return 0;
diff -puN kernel/fork.c~user-ns-implement-user-ns-unshare kernel/fork.c
--- a/kernel/fork.c~user-ns-implement-user-ns-unshare
+++ a/kernel/fork.c
@@ -49,6 +49,7 @@
#include <linux/delayacct.h>
#include <linux/taskstats_kern.h>
#include <linux/random.h>
+#include <linux/user_namespace.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -1624,6 +1625,7 @@ asmlinkage long sys_unshare(unsigned lon
struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL;
struct uts_namespace *uts, *new_uts = NULL;
struct ipc_namespace *ipc, *new_ipc = NULL;
+ struct user_namespace *user, *new_user = NULL;
check_unshare_flags(&unshare_flags);
@@ -1631,7 +1633,7 @@ asmlinkage long sys_unshare(unsigned lon
err = -EINVAL;
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
- CLONE_NEWUTS|CLONE_NEWIPC))
+ CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER))
goto bad_unshare_out;
if ((err = unshare_thread(unshare_flags)))
@@ -1652,18 +1654,20 @@ asmlinkage long sys_unshare(unsigned lon
goto bad_unshare_cleanup_semundo;
if ((err = unshare_ipcs(unshare_flags, &new_ipc)))
goto bad_unshare_cleanup_uts;
+ if ((err = unshare_user_ns(unshare_flags, &new_user)))
+ goto bad_unshare_cleanup_ipc;
- if (new_ns || new_uts || new_ipc) {
+ if (new_ns || new_uts || new_ipc || new_user) {
old_nsproxy = current->nsproxy;
new_nsproxy = dup_namespaces(old_nsproxy);
if (!new_nsproxy) {
err = -ENOMEM;
- goto bad_unshare_cleanup_ipc;
+ goto bad_unshare_cleanup_user;
}
}
if (new_fs || new_ns || new_mm || new_fd || new_ulist ||
- new_uts || new_ipc) {
+ new_uts || new_ipc || new_user) {
task_lock(current);
@@ -1711,12 +1715,22 @@ asmlinkage long sys_unshare(unsigned lon
new_ipc = ipc;
}
+ if (new_user) {
+ user = current->nsproxy->user_ns;
+ current->nsproxy->user_ns = new_user;
+ new_user = user;
+ }
+
task_unlock(current);
}
if (new_nsproxy)
put_and_finalize_nsproxy(new_nsproxy);
+bad_unshare_cleanup_user:
+ if (new_user)
+ put_user_ns(new_user);
+
bad_unshare_cleanup_ipc:
if (new_ipc)
put_ipc_ns(new_ipc);
diff -puN kernel/nsproxy.c~user-ns-implement-user-ns-unshare kernel/nsproxy.c
--- a/kernel/nsproxy.c~user-ns-implement-user-ns-unshare
+++ a/kernel/nsproxy.c
@@ -99,7 +99,7 @@ int copy_namespaces(int flags, struct ta
get_nsproxy(old_ns);
- if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
+ if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER)))
return 0;
new_ns = clone_namespaces(old_ns);
diff -puN kernel/user_namespace.c~user-ns-implement-user-ns-unshare kernel/user_namespace.c
--- a/kernel/user_namespace.c~user-ns-implement-user-ns-unshare
+++ a/kernel/user_namespace.c
@@ -20,16 +20,86 @@ struct user_namespace init_user_ns = {
EXPORT_SYMBOL_GPL(init_user_ns);
#ifdef CONFIG_USER_NS
+/*
+ * Clone a new ns copying an original user ns, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
+{
+ struct user_namespace *ns;
+ struct user_struct *new_user;
+ int n;
+
+ ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
+ if (!ns)
+ return NULL;
+
+ kref_init(&ns->kref);
+
+ for(n = 0; n < UIDHASH_SZ; ++n)
+ INIT_LIST_HEAD(ns->uidhash_table + n);
+
+ /* Insert new root user. */
+ ns->root_user = alloc_uid(ns, 0);
+ if (!ns->root_user) {
+ kfree(ns);
+ return NULL;
+ }
+
+ /* Reset current->user with a new one */
+ new_user = alloc_uid(ns, current->uid);
+ if (!new_user) {
+ free_uid(ns->root_user);
+ kfree(ns);
+ return NULL;
+ }
+
+ switch_uid(new_user);
+ return ns;
+}
+
+/*
+ * unshare the current process' user namespace.
+ */
+int unshare_user_ns(unsigned long flags,
+ struct user_namespace **new_user)
+{
+ if (flags & CLONE_NEWUSER) {
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ *new_user = clone_user_ns(current->nsproxy->user_ns);
+ if (!*new_user)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
int copy_user_ns(int flags, struct task_struct *tsk)
{
- struct user_namespace *old_ns = tsk->nsproxy->user_ns;
- int err = 0;
+ struct user_namespace *new_ns, *old_ns = tsk->nsproxy->user_ns;
+ int err;
if (!old_ns)
return 0;
get_user_ns(old_ns);
+ if (!(flags & CLONE_NEWUSER))
+ return 0;
+ err = -EPERM;
+ if (!capable(CAP_SYS_ADMIN))
+ goto out;
+ err = -ENOMEM;
+ new_ns = clone_user_ns(old_ns);
+ if (!new_ns)
+ goto out;
+
+ tsk->nsproxy->user_ns = new_ns;
+ err = 0;
+out:
+ put_user_ns(old_ns);
return err;
}
_
Patches currently in -mm which might be from serue@xxxxxxxxxx are
fix-null-nsproxy-dereference-in-proc-mounts.patch
namespaces-fix-exit-race-by-splitting-exit.patch
implement-file-posix-capabilities.patch
file-capabilities-dont-do-file-caps-if-mnt_nosuid.patch
file-capabilities-honor-secure_noroot.patch
introduce-and-use-get_task_mnt_ns.patch
introduce-and-use-get_task_mnt_ns-tweaks.patch
nsproxy-externalizes-exit_task_namespaces.patch
user-namespace-add-the-framework.patch
user-namespace-add-the-framework-fix.patch
user-namespace-add-the-framework-fixes.patch
user-ns-add-user_namespace-ptr-to-vfsmount.patch
user-ns-add-user_namespace-ptr-to-vfsmount-fixes.patch
user-ns-hook-permission.patch
user-ns-prepare-copy_tree-copy_mnt-and-their-callers-to-handle-errs.patch
user-ns-prepare-copy_tree-copy_mnt-and-their-callers-to-handle-errs-fix.patch
user-ns-implement-shared-mounts.patch
user-ns-implement-shared-mounts-fixes.patch
user_ns-handle-file-sigio.patch
user_ns-handle-file-sigio-fix.patch
user_ns-handle-file-sigio-fix-2.patch
user-ns-implement-user-ns-unshare.patch
user-ns-implement-user-ns-unshare-tidy.patch
rename-attach_pid-to-find_attach_pid.patch
attach_pid-with-struct-pid-parameter.patch
remove-find_attach_pid.patch
statically-initialize-struct-pid-for-swapper.patch
explicitly-set-pgid-sid-of-init.patch
uts-namespace-remove-config_uts_ns.patch
ipc-namespace-remove-config_ipc_ns.patch
integrity-service-api-and-dummy-provider-fix.patch
sysctl-move-utsname-sysctls-to-their-own-file.patch
sysctl-move-sysv-ipc-sysctls-to-their-own-file.patch
-
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