linux 6.1.y: Update our unprivileged CLONE_NEWUSER patch to current

This commit is contained in:
Tk-Glitch
2022-12-22 00:07:43 +01:00
parent f4324da8a1
commit 73e9a2eb3c

View File

@@ -1,121 +1,45 @@
From 5ec2dd3a095442ec1a21d86042a4994f2ba24e63 Mon Sep 17 00:00:00 2001
Message-Id: <5ec2dd3a095442ec1a21d86042a4994f2ba24e63.1512651251.git.jan.steffens@gmail.com>
From: Serge Hallyn <serge.hallyn@canonical.com>
Date: Fri, 31 May 2013 19:12:12 +0100
Subject: [PATCH] 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 07cc743698d3668e..4011d68a8ff9305c 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
@@ -1555,6 +1560,10 @@ 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.
@@ -2348,6 +2357,12 @@ 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 b86520ed3fb60fbf..f7dab3760839f1a1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -105,6 +105,9 @@ extern int core_uses_pid;
#if defined(CONFIG_SYSCTL)
+#ifdef CONFIG_USER_NS
+extern int unprivileged_userns_clone;
+#endif
/* Constants used for minimum and maximum */
#ifdef CONFIG_PERF_EVENTS
@@ -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 c490f1e4313b998a..dd03bd39d7bf194d 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -24,6 +24,9 @@
#include <linux/projid.h>
#include <linux/fs_struct.h>
+/* sysctl */
+int unprivileged_userns_clone;
+
static struct kmem_cache *user_ns_cachep __read_mostly;
static DEFINE_MUTEX(userns_state_mutex);
--
2.15.1
From b5202296055dd333db4425120d3f93ef4e6a0573 Mon Sep 17 00:00:00 2001
From d50977b164e708bf523a35ef53315355528c3ca6 Mon Sep 17 00:00:00 2001
From: "Jan Alexander Steffens (heftig)" <jan.steffens@gmail.com>
Date: Thu, 7 Dec 2017 13:50:48 +0100
Subject: ZEN: Add CONFIG for unprivileged_userns_clone
Date: Mon, 16 Sep 2019 04:53:20 +0200
Subject: [PATCH] ZEN: Add sysctl and CONFIG to disallow unprivileged
CLONE_NEWUSER
This way our default behavior continues to match the vanilla kernel.
Our default behavior continues to match the vanilla kernel.
---
init/Kconfig | 16 ++++++++++++++++
kernel/user_namespace.c | 4 ++++
2 files changed, 20 insertions(+)
include/linux/user_namespace.h | 4 ++++
init/Kconfig | 16 ++++++++++++++++
kernel/fork.c | 14 ++++++++++++++
kernel/sysctl.c | 12 ++++++++++++
kernel/user_namespace.c | 7 +++++++
5 files changed, 53 insertions(+)
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 45f09bec02c485..87b20e2ee27445 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -148,6 +148,8 @@ static inline void set_userns_rlimit_max(struct user_namespace *ns,
#ifdef CONFIG_USER_NS
+extern int unprivileged_userns_clone;
+
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
{
if (ns)
@@ -181,6 +183,8 @@ extern bool current_in_userns(const struct user_namespace *target_ns);
struct ns_common *ns_get_owner(struct ns_common *ns);
#else
+#define unprivileged_userns_clone 0
+
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
{
return &init_user_ns;
diff --git a/init/Kconfig b/init/Kconfig
index 4592bf7997c0..f3df02990aff 100644
index 94125d3b6893c7..9f7139b536f638 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1004,6 +1004,22 @@ config USER_NS
@@ -1247,6 +1247,22 @@ config USER_NS
If unsure, say N.
@@ -138,19 +62,90 @@ index 4592bf7997c0..f3df02990aff 100644
config PID_NS
bool "PID Namespaces"
default y
diff --git a/kernel/fork.c b/kernel/fork.c
index 08969f5aa38d59..ff601cb7a1fae0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -98,6 +98,10 @@
#include <linux/io_uring.h>
#include <linux/bpf.h>
+#ifdef CONFIG_USER_NS
+#include <linux/user_namespace.h>
+#endif
+
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
@@ -2008,6 +2012,10 @@ 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.
@@ -3166,6 +3174,12 @@ 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 c6d9dec11b749d..9a4514ad481b21 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -81,6 +81,9 @@
#ifdef CONFIG_RT_MUTEXES
#include <linux/rtmutex.h>
#endif
+#ifdef CONFIG_USER_NS
+#include <linux/user_namespace.h>
+#endif
/* shared constants to be used in various sysctls */
const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
@@ -1659,6 +1662,15 @@ 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",
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 6b9dbc257e34..107b17f0d528 100644
index 54211dbd516c57..16ca0c1516298d 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -27,7 +27,11 @@
@@ -22,6 +22,13 @@
#include <linux/bsearch.h>
#include <linux/sort.h>
/* sysctl */
+/* sysctl */
+#ifdef CONFIG_USER_NS_UNPRIVILEGED
+int unprivileged_userns_clone = 1;
+#else
int unprivileged_userns_clone;
+int unprivileged_userns_clone;
+#endif
+
static struct kmem_cache *user_ns_cachep __read_mostly;
static DEFINE_MUTEX(userns_state_mutex);