From a6d4bdbc3f0bd181f1bbd1a343afa37bb2c74e07 Mon Sep 17 00:00:00 2001
From: jc_gargma <jc_gargma@iserlohn-fortress.net>
Date: Sat, 23 Mar 2019 21:10:23 -0700
Subject: Initial commit

---
 ...to-disallow-unprivileged-CLONE_NEWUSER-by.patch | 102 +++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch

(limited to '0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch')

diff --git a/0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch b/0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch
new file mode 100644
index 0000000..e7432e3
--- /dev/null
+++ b/0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch
@@ -0,0 +1,102 @@
+From e71668257d1353a7bd428ec90f0871b038db813b Mon Sep 17 00:00:00 2001
+From: Serge Hallyn <serge.hallyn@canonical.com>
+Date: Fri, 31 May 2013 19:12:12 +0100
+Subject: [PATCH 1/3] 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 b69248e6f0e0..3b1cd11dc6dc 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -104,6 +104,11 @@
+ 
+ #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
+@@ -1695,6 +1700,10 @@ 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.
+@@ -2528,6 +2537,12 @@ int ksys_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 ba4d9e85feb8..e88b93a850df 100644
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -106,6 +106,9 @@ 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;
+@@ -515,6 +518,15 @@ 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 923414a246e9..6b9dbc257e34 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);
+ 
+-- 
+2.21.0
+
-- 
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