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Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup/namespace.c5
-rw-r--r--kernel/nsproxy.c305
-rw-r--r--kernel/pid_namespace.c5
-rw-r--r--kernel/time/namespace.c5
-rw-r--r--kernel/user_namespace.c8
-rw-r--r--kernel/utsname.c5
6 files changed, 299 insertions, 34 deletions
diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c
index b05f1dd58a62..812a61afd538 100644
--- a/kernel/cgroup/namespace.c
+++ b/kernel/cgroup/namespace.c
@@ -95,11 +95,12 @@ static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
return container_of(ns, struct cgroup_namespace, ns);
}
-static int cgroupns_install(struct nsproxy *nsproxy, struct ns_common *ns)
+static int cgroupns_install(struct nsset *nsset, struct ns_common *ns)
{
+ struct nsproxy *nsproxy = nsset->nsproxy;
struct cgroup_namespace *cgroup_ns = to_cg_ns(ns);
- if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN) ||
+ if (!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ed9882108cd2..b03df67621d0 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -19,6 +19,8 @@
#include <net/net_namespace.h>
#include <linux/ipc_namespace.h>
#include <linux/time_namespace.h>
+#include <linux/fs_struct.h>
+#include <linux/proc_fs.h>
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
@@ -257,37 +259,296 @@ void exit_task_namespaces(struct task_struct *p)
switch_task_namespaces(p, NULL);
}
-SYSCALL_DEFINE2(setns, int, fd, int, nstype)
+static int check_setns_flags(unsigned long flags)
{
- struct task_struct *tsk = current;
- struct nsproxy *new_nsproxy;
- struct file *file;
- struct ns_common *ns;
- int err;
+ if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+ CLONE_NEWNET | CLONE_NEWUSER | CLONE_NEWPID |
+ CLONE_NEWCGROUP)))
+ return -EINVAL;
- file = proc_ns_fget(fd);
- if (IS_ERR(file))
- return PTR_ERR(file);
+#ifndef CONFIG_USER_NS
+ if (flags & CLONE_NEWUSER)
+ return -EINVAL;
+#endif
+#ifndef CONFIG_PID_NS
+ if (flags & CLONE_NEWPID)
+ return -EINVAL;
+#endif
+#ifndef CONFIG_UTS_NS
+ if (flags & CLONE_NEWUTS)
+ return -EINVAL;
+#endif
+#ifndef CONFIG_IPC_NS
+ if (flags & CLONE_NEWIPC)
+ return -EINVAL;
+#endif
+#ifndef CONFIG_CGROUPS
+ if (flags & CLONE_NEWCGROUP)
+ return -EINVAL;
+#endif
+#ifndef CONFIG_NET_NS
+ if (flags & CLONE_NEWNET)
+ return -EINVAL;
+#endif
- err = -EINVAL;
- ns = get_proc_ns(file_inode(file));
- if (nstype && (ns->ops->type != nstype))
- goto out;
+ return 0;
+}
+
+static void put_nsset(struct nsset *nsset)
+{
+ unsigned flags = nsset->flags;
+
+ if (flags & CLONE_NEWUSER)
+ put_cred(nsset_cred(nsset));
+ /*
+ * We only created a temporary copy if we attached to more than just
+ * the mount namespace.
+ */
+ if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
+ free_fs_struct(nsset->fs);
+ if (nsset->nsproxy)
+ free_nsproxy(nsset->nsproxy);
+}
+
+static int prepare_nsset(unsigned flags, struct nsset *nsset)
+{
+ struct task_struct *me = current;
+
+ nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
+ if (IS_ERR(nsset->nsproxy))
+ return PTR_ERR(nsset->nsproxy);
- new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
- if (IS_ERR(new_nsproxy)) {
- err = PTR_ERR(new_nsproxy);
+ if (flags & CLONE_NEWUSER)
+ nsset->cred = prepare_creds();
+ else
+ nsset->cred = current_cred();
+ if (!nsset->cred)
goto out;
+
+ /* Only create a temporary copy of fs_struct if we really need to. */
+ if (flags == CLONE_NEWNS) {
+ nsset->fs = me->fs;
+ } else if (flags & CLONE_NEWNS) {
+ nsset->fs = copy_fs_struct(me->fs);
+ if (!nsset->fs)
+ goto out;
}
- err = ns->ops->install(new_nsproxy, ns);
- if (err) {
- free_nsproxy(new_nsproxy);
- goto out;
+ nsset->flags = flags;
+ return 0;
+
+out:
+ put_nsset(nsset);
+ return -ENOMEM;
+}
+
+static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
+{
+ return ns->ops->install(nsset, ns);
+}
+
+/*
+ * This is the inverse operation to unshare().
+ * Ordering is equivalent to the standard ordering used everywhere else
+ * during unshare and process creation. The switch to the new set of
+ * namespaces occurs at the point of no return after installation of
+ * all requested namespaces was successful in commit_nsset().
+ */
+static int validate_nsset(struct nsset *nsset, struct pid *pid)
+{
+ int ret = 0;
+ unsigned flags = nsset->flags;
+ struct user_namespace *user_ns = NULL;
+ struct pid_namespace *pid_ns = NULL;
+ struct nsproxy *nsp;
+ struct task_struct *tsk;
+
+ /* Take a "snapshot" of the target task's namespaces. */
+ rcu_read_lock();
+ tsk = pid_task(pid, PIDTYPE_PID);
+ if (!tsk) {
+ rcu_read_unlock();
+ return -ESRCH;
+ }
+
+ if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
+ rcu_read_unlock();
+ return -EPERM;
+ }
+
+ task_lock(tsk);
+ nsp = tsk->nsproxy;
+ if (nsp)
+ get_nsproxy(nsp);
+ task_unlock(tsk);
+ if (!nsp) {
+ rcu_read_unlock();
+ return -ESRCH;
+ }
+
+#ifdef CONFIG_PID_NS
+ if (flags & CLONE_NEWPID) {
+ pid_ns = task_active_pid_ns(tsk);
+ if (unlikely(!pid_ns)) {
+ rcu_read_unlock();
+ ret = -ESRCH;
+ goto out;
+ }
+ get_pid_ns(pid_ns);
+ }
+#endif
+
+#ifdef CONFIG_USER_NS
+ if (flags & CLONE_NEWUSER)
+ user_ns = get_user_ns(__task_cred(tsk)->user_ns);
+#endif
+ rcu_read_unlock();
+
+ /*
+ * Install requested namespaces. The caller will have
+ * verified earlier that the requested namespaces are
+ * supported on this kernel. We don't report errors here
+ * if a namespace is requested that isn't supported.
+ */
+#ifdef CONFIG_USER_NS
+ if (flags & CLONE_NEWUSER) {
+ ret = validate_ns(nsset, &user_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
+ if (flags & CLONE_NEWNS) {
+ ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
+ if (ret)
+ goto out;
+ }
+
+#ifdef CONFIG_UTS_NS
+ if (flags & CLONE_NEWUTS) {
+ ret = validate_ns(nsset, &nsp->uts_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
+#ifdef CONFIG_IPC_NS
+ if (flags & CLONE_NEWIPC) {
+ ret = validate_ns(nsset, &nsp->ipc_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
+#ifdef CONFIG_PID_NS
+ if (flags & CLONE_NEWPID) {
+ ret = validate_ns(nsset, &pid_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
+#ifdef CONFIG_CGROUPS
+ if (flags & CLONE_NEWCGROUP) {
+ ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
+#ifdef CONFIG_NET_NS
+ if (flags & CLONE_NEWNET) {
+ ret = validate_ns(nsset, &nsp->net_ns->ns);
+ if (ret)
+ goto out;
+ }
+#endif
+
+out:
+ if (pid_ns)
+ put_pid_ns(pid_ns);
+ if (nsp)
+ put_nsproxy(nsp);
+ put_user_ns(user_ns);
+
+ return ret;
+}
+
+/*
+ * This is the point of no return. There are just a few namespaces
+ * that do some actual work here and it's sufficiently minimal that
+ * a separate ns_common operation seems unnecessary for now.
+ * Unshare is doing the same thing. If we'll end up needing to do
+ * more in a given namespace or a helper here is ultimately not
+ * exported anymore a simple commit handler for each namespace
+ * should be added to ns_common.
+ */
+static void commit_nsset(struct nsset *nsset)
+{
+ unsigned flags = nsset->flags;
+ struct task_struct *me = current;
+
+#ifdef CONFIG_USER_NS
+ if (flags & CLONE_NEWUSER) {
+ /* transfer ownership */
+ commit_creds(nsset_cred(nsset));
+ nsset->cred = NULL;
+ }
+#endif
+
+ /* We only need to commit if we have used a temporary fs_struct. */
+ if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
+ set_fs_root(me->fs, &nsset->fs->root);
+ set_fs_pwd(me->fs, &nsset->fs->pwd);
}
- switch_task_namespaces(tsk, new_nsproxy);
- perf_event_namespaces(tsk);
+#ifdef CONFIG_IPC_NS
+ if (flags & CLONE_NEWIPC)
+ exit_sem(me);
+#endif
+
+ /* transfer ownership */
+ switch_task_namespaces(me, nsset->nsproxy);
+ nsset->nsproxy = NULL;
+}
+
+SYSCALL_DEFINE2(setns, int, fd, int, flags)
+{
+ struct file *file;
+ struct ns_common *ns = NULL;
+ struct nsset nsset = {};
+ int err = 0;
+
+ file = fget(fd);
+ if (!file)
+ return -EBADF;
+
+ if (proc_ns_file(file)) {
+ ns = get_proc_ns(file_inode(file));
+ if (flags && (ns->ops->type != flags))
+ err = -EINVAL;
+ flags = ns->ops->type;
+ } else if (!IS_ERR(pidfd_pid(file))) {
+ err = check_setns_flags(flags);
+ } else {
+ err = -EBADF;
+ }
+ if (err)
+ goto out;
+
+ err = prepare_nsset(flags, &nsset);
+ if (err)
+ goto out;
+
+ if (proc_ns_file(file))
+ err = validate_ns(&nsset, ns);
+ else
+ err = validate_nsset(&nsset, file->private_data);
+ if (!err) {
+ commit_nsset(&nsset);
+ perf_event_namespaces(current);
+ }
+ put_nsset(&nsset);
out:
fput(file);
return err;
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 01f8ba32cc0c..11db2bdbb41e 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -378,13 +378,14 @@ static void pidns_put(struct ns_common *ns)
put_pid_ns(to_pid_ns(ns));
}
-static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns)
+static int pidns_install(struct nsset *nsset, struct ns_common *ns)
{
+ struct nsproxy *nsproxy = nsset->nsproxy;
struct pid_namespace *active = task_active_pid_ns(current);
struct pid_namespace *ancestor, *new = to_pid_ns(ns);
if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
- !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+ !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
/*
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index 53bce347cd50..5d9fc22d836a 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -280,8 +280,9 @@ static void timens_put(struct ns_common *ns)
put_time_ns(to_time_ns(ns));
}
-static int timens_install(struct nsproxy *nsproxy, struct ns_common *new)
+static int timens_install(struct nsset *nsset, struct ns_common *new)
{
+ struct nsproxy *nsproxy = nsset->nsproxy;
struct time_namespace *ns = to_time_ns(new);
int err;
@@ -289,7 +290,7 @@ static int timens_install(struct nsproxy *nsproxy, struct ns_common *new)
return -EUSERS;
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
- !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+ !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
timens_set_vvar_page(current, ns);
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 8eadadc478f9..87804e0371fe 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1253,7 +1253,7 @@ static void userns_put(struct ns_common *ns)
put_user_ns(to_user_ns(ns));
}
-static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
+static int userns_install(struct nsset *nsset, struct ns_common *ns)
{
struct user_namespace *user_ns = to_user_ns(ns);
struct cred *cred;
@@ -1274,14 +1274,14 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
- cred = prepare_creds();
+ cred = nsset_cred(nsset);
if (!cred)
- return -ENOMEM;
+ return -EINVAL;
put_user_ns(cred->user_ns);
set_cred_user_ns(cred, get_user_ns(user_ns));
- return commit_creds(cred);
+ return 0;
}
struct ns_common *ns_get_owner(struct ns_common *ns)
diff --git a/kernel/utsname.c b/kernel/utsname.c
index f0e491193009..e488d0e2ab45 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -140,12 +140,13 @@ static void utsns_put(struct ns_common *ns)
put_uts_ns(to_uts_ns(ns));
}
-static int utsns_install(struct nsproxy *nsproxy, struct ns_common *new)
+static int utsns_install(struct nsset *nsset, struct ns_common *new)
{
+ struct nsproxy *nsproxy = nsset->nsproxy;
struct uts_namespace *ns = to_uts_ns(new);
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
- !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+ !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
get_uts_ns(ns);
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-24 08:30:25 +0000