Initial import

1 files changed, 122 insertions, 0 deletions

diff --git a/0001-ZEN-Add-sysctl-and-CONFIG-to-disallow-unprivileged-CLONE_NEWUSER.patch b/0001-ZEN-Add-sysctl-and-CONFIG-to-disallow-unprivileged-CLONE_NEWUSER.patch
new file mode 100644
index 000000000000..5301464f63c0
--- /dev/null
+++ b/0001-ZEN-Add-sysctl-and-CONFIG-to-disallow-unprivileged-CLONE_NEWUSER.patch
@@ -0,0 +1,122 @@
+--- a/include/linux/sysctl.h	2020-06-12 19:27:22.382363840 +0200
++++ b/include/linux/sysctl.h	2020-06-12 19:27:04.715697333 +0200
+@@ -204,6 +204,10 @@ extern int unaligned_enabled;
+ extern int unaligned_dump_stack;
+ extern int no_unaligned_warning;
+ 
++#ifdef CONFIG_USER_NS
++extern int unprivileged_userns_clone;
++#endif
++
+ extern struct ctl_table sysctl_mount_point[];
+ extern struct ctl_table random_table[];
+ extern struct ctl_table firmware_config_table[];
+
+diff --git a/init/Kconfig b/init/Kconfig
+index bd7d650d4a99..658f9c052151 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -1091,6 +1091,22 @@ config USER_NS
+ 
+ 	  If unsure, say N.
+ 
++config USER_NS_UNPRIVILEGED
++	bool "Allow unprivileged users to create namespaces"
++	default y
++	depends on USER_NS
++	help
++	  When disabled, unprivileged users will not be able to create
++	  new namespaces. Allowing users to create their own namespaces
++	  has been part of several recent local privilege escalation
++	  exploits, so if you need user namespaces but are
++	  paranoid^Wsecurity-conscious you want to disable this.
++
++	  This setting can be overridden at runtime via the
++	  kernel.unprivileged_userns_clone sysctl.
++
++	  If unsure, say Y.
++
+ config PID_NS
+ 	bool "PID Namespaces"
+ 	default y
+diff --git a/kernel/fork.c b/kernel/fork.c
+index 541fd805fb88..ffd57c812153 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -106,6 +106,11 @@
+ 
+ #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
+@@ -1788,6 +1793,10 @@ 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.
+@@ -2819,6 +2828,12 @@ 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 078950d9605b..baead3605bbe 100644
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -545,6 +548,15 @@ 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 8eadadc478f9..c36ecd19562c 100644
+--- a/kernel/user_namespace.c
++++ b/kernel/user_namespace.c
+@@ -21,6 +21,13 @@
+ #include <linux/bsearch.h>
+ #include <linux/sort.h>
+ 
++/* sysctl */
++#ifdef CONFIG_USER_NS_UNPRIVILEGED
++int unprivileged_userns_clone = 1;
++#else
++int unprivileged_userns_clone;
++#endif
++
+ static struct kmem_cache *user_ns_cachep __read_mostly;
+ static DEFINE_MUTEX(userns_state_mutex);
+ 
+-- 
+cgit v1.2.1-1-g437b
+