1 files changed, 101 insertions, 0 deletions
diff --git a/debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch b/debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch
new file mode 100644
index 000000000..205510d6b
--- /dev/null
+++ b/debian/patches/debian/add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by-default.patch
@@ -0,0 +1,101 @@
+From: Serge Hallyn <serge.hallyn@canonical.com>
+Date: Fri, 31 May 2013 19:12:12 +0000 (+0100)
+Subject: add sysctl to disallow unprivileged CLONE_NEWUSER by default
+Origin: http://kernel.ubuntu.com/git?p=serge%2Fubuntu-saucy.git;a=commit;h=5c847404dcb2e3195ad0057877e1422ae90892b8
+
+add sysctl to disallow unprivileged CLONE_NEWUSER by default
+
+This is a short-term patch.  Unprivileged use of CLONE_NEWUSER
+is certainly an intended feature of user namespaces.  However
+for at least saucy we want to make sure that, if any security
+issues are found, we have a fail-safe.
+
+Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
+[bwh: Remove unneeded binary sysctl bits]
+[bwh: Keep this sysctl, but change the default to enabled]
+---
+Index: linux/kernel/fork.c
+===================================================================
+--- linux.orig/kernel/fork.c
++++ linux/kernel/fork.c
+@@ -108,6 +108,11 @@
+ 
+ #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
+@@ -2008,6 +2013,10 @@ static __latent_entropy struct task_stru
+ 	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.
+@@ -3166,6 +3175,12 @@ int ksys_unshare(unsigned long unshare_f
+ 	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;
+Index: linux/kernel/sysctl.c
+===================================================================
+--- linux.orig/kernel/sysctl.c
++++ linux/kernel/sysctl.c
+@@ -136,6 +136,10 @@ static enum sysctl_writes_mode sysctl_wr
+ int sysctl_legacy_va_layout;
+ #endif
+ 
++#ifdef CONFIG_USER_NS
++extern int unprivileged_userns_clone;
++#endif
++
+ #endif /* CONFIG_SYSCTL */
+ 
+ /*
+@@ -1659,6 +1663,15 @@ static struct ctl_table kern_table[] = {
+ 		.mode		= 0644,
+ 		.proc_handler	= proc_dointvec,
+ 	},
++#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",
+Index: linux/kernel/user_namespace.c
+===================================================================
+--- linux.orig/kernel/user_namespace.c
++++ linux/kernel/user_namespace.c
+@@ -22,6 +22,9 @@
+ #include <linux/bsearch.h>
+ #include <linux/sort.h>
+ 
++/* sysctl */
++int unprivileged_userns_clone = 1;
++
+ static struct kmem_cache *user_ns_cachep __read_mostly;
+ static DEFINE_MUTEX(userns_state_mutex);
+