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-rw-r--r--0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch102
1 files changed, 102 insertions, 0 deletions
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 00000000000..0249a08eb72
--- /dev/null
+++ b/0001-add-sysctl-to-disallow-unprivileged-CLONE_NEWUSER-by.patch
@@ -0,0 +1,102 @@
+From 66a37293bf1ec5bf9d22ede72818099f2c72fbc1 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 1/5] 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 5ad558e6f8fe..767485c6f7cc 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -103,6 +103,11 @@
+
+ #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
+@@ -1600,6 +1605,10 @@ 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.
+@@ -2394,6 +2403,12 @@ 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 6a78cf70761d..35a1d24282f4 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;
+@@ -519,6 +522,15 @@ 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);
+
+--
+2.18.0
+