104 lines
3.0 KiB
Diff
104 lines
3.0 KiB
Diff
From 4aefcc4253233dce6ac5938e01371074958b8f1c Mon Sep 17 00:00:00 2001
|
|
Message-Id: <4aefcc4253233dce6ac5938e01371074958b8f1c.1517188106.git.jan.steffens@gmail.com>
|
|
From: Serge Hallyn <serge.hallyn@canonical.com>
|
|
Date: Fri, 31 May 2013 19:12:12 +0100
|
|
Subject: [PATCH 1/2] add sysctl to disallow unprivileged CLONE_NEWUSER by
|
|
default
|
|
|
|
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
|
|
[bwh: Remove unneeded binary sysctl bits]
|
|
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
|
|
---
|
|
kernel/fork.c | 15 +++++++++++++++
|
|
kernel/sysctl.c | 12 ++++++++++++
|
|
kernel/user_namespace.c | 3 +++
|
|
3 files changed, 30 insertions(+)
|
|
|
|
diff --git a/kernel/fork.c b/kernel/fork.c
|
|
index 2295fc69717f..6f320a216e7d 100644
|
|
--- a/kernel/fork.c
|
|
+++ b/kernel/fork.c
|
|
@@ -102,6 +102,11 @@
|
|
|
|
#define CREATE_TRACE_POINTS
|
|
#include <trace/events/task.h>
|
|
+#ifdef CONFIG_USER_NS
|
|
+extern int unprivileged_userns_clone;
|
|
+#else
|
|
+#define unprivileged_userns_clone 0
|
|
+#endif
|
|
|
|
/*
|
|
* Minimum number of threads to boot the kernel
|
|
@@ -1550,6 +1555,10 @@ static __latent_entropy struct task_struct *copy_process(
|
|
if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
+ if ((clone_flags & CLONE_NEWUSER) && !unprivileged_userns_clone)
|
|
+ if (!capable(CAP_SYS_ADMIN))
|
|
+ return ERR_PTR(-EPERM);
|
|
+
|
|
/*
|
|
* Thread groups must share signals as well, and detached threads
|
|
* can only be started up within the thread group.
|
|
@@ -2343,6 +2352,12 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
|
|
if (unshare_flags & CLONE_NEWNS)
|
|
unshare_flags |= CLONE_FS;
|
|
|
|
+ if ((unshare_flags & CLONE_NEWUSER) && !unprivileged_userns_clone) {
|
|
+ err = -EPERM;
|
|
+ if (!capable(CAP_SYS_ADMIN))
|
|
+ goto bad_unshare_out;
|
|
+ }
|
|
+
|
|
err = check_unshare_flags(unshare_flags);
|
|
if (err)
|
|
goto bad_unshare_out;
|
|
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
|
|
index 557d46728577..c19d7a828913 100644
|
|
--- a/kernel/sysctl.c
|
|
+++ b/kernel/sysctl.c
|
|
@@ -105,6 +105,9 @@ extern int core_uses_pid;
|
|
extern char core_pattern[];
|
|
extern unsigned int core_pipe_limit;
|
|
#endif
|
|
+#ifdef CONFIG_USER_NS
|
|
+extern int unprivileged_userns_clone;
|
|
+#endif
|
|
extern int pid_max;
|
|
extern int pid_max_min, pid_max_max;
|
|
extern int percpu_pagelist_fraction;
|
|
@@ -513,6 +516,15 @@ static struct ctl_table kern_table[] = {
|
|
.proc_handler = proc_dointvec,
|
|
},
|
|
#endif
|
|
+#ifdef CONFIG_USER_NS
|
|
+ {
|
|
+ .procname = "unprivileged_userns_clone",
|
|
+ .data = &unprivileged_userns_clone,
|
|
+ .maxlen = sizeof(int),
|
|
+ .mode = 0644,
|
|
+ .proc_handler = proc_dointvec,
|
|
+ },
|
|
+#endif
|
|
#ifdef CONFIG_PROC_SYSCTL
|
|
{
|
|
.procname = "tainted",
|
|
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
|
|
index 246d4d4ce5c7..f64432b45cec 100644
|
|
--- a/kernel/user_namespace.c
|
|
+++ b/kernel/user_namespace.c
|
|
@@ -26,6 +26,9 @@
|
|
#include <linux/bsearch.h>
|
|
#include <linux/sort.h>
|
|
|
|
+/* sysctl */
|
|
+int unprivileged_userns_clone;
|
|
+
|
|
static struct kmem_cache *user_ns_cachep __read_mostly;
|
|
static DEFINE_MUTEX(userns_state_mutex);
|
|
|
|
--
|
|
2.16.1
|
|
|