You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
114 lines
4.6 KiB
114 lines
4.6 KiB
1 year ago
|
From c971d99ffc43df89ca4e15cd81f9e44f4139ba91 Mon Sep 17 00:00:00 2001
|
||
|
1 year ago
|
From: Lennart Poettering <lennart@poettering.net>
|
||
|
|
Date: Mon, 31 Aug 2020 19:37:13 +0200
|
||
|
|
Subject: [PATCH] pager: set $LESSSECURE whenver we invoke a pager
|
||
|
|
|
||
|
|
Some extra safety when invoked via "sudo". With this we address a
|
||
|
|
genuine design flaw of sudo, and we shouldn't need to deal with this.
|
||
|
|
But it's still a good idea to disable this surface given how exotic it
|
||
|
|
is.
|
||
|
|
|
||
|
|
Prompted by #5666
|
||
|
|
|
||
|
|
(cherry picked from commit 612ebf6c913dd0e4197c44909cb3157f5c51a2f0)
|
||
|
|
|
||
|
1 year ago
|
Related: #2175624
|
||
|
1 year ago
|
---
|
||
|
|
man/less-variables.xml | 8 ++++++++
|
||
|
|
man/systemctl.xml | 1 +
|
||
|
|
man/systemd.xml | 2 ++
|
||
|
|
src/basic/pager.c | 23 +++++++++++++++++++++--
|
||
|
|
4 files changed, 32 insertions(+), 2 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/man/less-variables.xml b/man/less-variables.xml
|
||
|
|
index a3faa38997..9dad4247da 100644
|
||
|
|
--- a/man/less-variables.xml
|
||
|
|
+++ b/man/less-variables.xml
|
||
|
|
@@ -36,5 +36,13 @@
|
||
|
|
the invoking terminal is determined to be UTF-8 compatible).</para></listitem>
|
||
|
|
</varlistentry>
|
||
|
|
|
||
|
|
+ <varlistentry id='lesssecure'>
|
||
|
|
+ <term><varname>$SYSTEMD_LESSSECURE</varname></term>
|
||
|
|
+
|
||
|
|
+ <listitem><para>Takes a boolean argument. Overrides the <varname>$LESSSECURE</varname> environment
|
||
|
|
+ variable when invoking the pager, which controls the "secure" mode of less (which disables commands
|
||
|
|
+ such as <literal>|</literal> which allow to easily shell out to external command lines). By default
|
||
|
|
+ less secure mode is enabled, with this setting it may be disabled.</para></listitem>
|
||
|
|
+ </varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</refsect1>
|
||
|
|
diff --git a/man/systemctl.xml b/man/systemctl.xml
|
||
|
|
index a71e6c7c4f..abc386e6fb 100644
|
||
|
|
--- a/man/systemctl.xml
|
||
|
|
+++ b/man/systemctl.xml
|
||
|
|
@@ -2010,6 +2010,7 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
|
||
|
|
<xi:include href="less-variables.xml" xpointer="pager"/>
|
||
|
|
<xi:include href="less-variables.xml" xpointer="less"/>
|
||
|
|
<xi:include href="less-variables.xml" xpointer="lesscharset"/>
|
||
|
|
+ <xi:include href="less-variables.xml" xpointer="lesssecure"/>
|
||
|
|
</refsect1>
|
||
|
|
|
||
|
|
<refsect1>
|
||
|
|
diff --git a/man/systemd.xml b/man/systemd.xml
|
||
|
|
index 17ab59beb5..66ae4d841d 100644
|
||
|
|
--- a/man/systemd.xml
|
||
|
|
+++ b/man/systemd.xml
|
||
|
|
@@ -862,6 +862,8 @@
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
|
||
|
|
+ <xi:include href="less-variables.xml" xpointer="lesssecure"/>
|
||
|
|
+
|
||
|
|
<varlistentry>
|
||
|
|
<term><varname>$LISTEN_PID</varname></term>
|
||
|
|
<term><varname>$LISTEN_FDS</varname></term>
|
||
|
|
diff --git a/src/basic/pager.c b/src/basic/pager.c
|
||
|
|
index f241261119..4efb01c483 100644
|
||
|
|
--- a/src/basic/pager.c
|
||
|
|
+++ b/src/basic/pager.c
|
||
|
|
@@ -11,6 +11,7 @@
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
#include "copy.h"
|
||
|
|
+#include "env-util.h"
|
||
|
|
#include "fd-util.h"
|
||
|
|
#include "locale-util.h"
|
||
|
|
#include "log.h"
|
||
|
|
@@ -94,8 +95,7 @@ int pager_open(bool no_pager, bool jump_to_end) {
|
||
|
|
if (setenv("LESS", less_opts, 1) < 0)
|
||
|
|
_exit(EXIT_FAILURE);
|
||
|
|
|
||
|
|
- /* Initialize a good charset for less. This is
|
||
|
|
- * particularly important if we output UTF-8
|
||
|
|
+ /* Initialize a good charset for less. This is particularly important if we output UTF-8
|
||
|
|
* characters. */
|
||
|
|
less_charset = getenv("SYSTEMD_LESSCHARSET");
|
||
|
|
if (!less_charset && is_locale_utf8())
|
||
|
|
@@ -104,6 +104,25 @@ int pager_open(bool no_pager, bool jump_to_end) {
|
||
|
|
setenv("LESSCHARSET", less_charset, 1) < 0)
|
||
|
|
_exit(EXIT_FAILURE);
|
||
|
|
|
||
|
|
+ /* People might invoke us from sudo, don't needlessly allow less to be a way to shell out
|
||
|
|
+ * privileged stuff. */
|
||
|
|
+ r = getenv_bool("SYSTEMD_LESSSECURE");
|
||
|
|
+ if (r == 0) { /* Remove env var if off */
|
||
|
|
+ if (unsetenv("LESSSECURE") < 0) {
|
||
|
|
+ log_error_errno(errno, "Failed to uset environment variable LESSSECURE: %m");
|
||
|
|
+ _exit(EXIT_FAILURE);
|
||
|
|
+ }
|
||
|
|
+ } else {
|
||
|
|
+ /* Set env var otherwise */
|
||
|
|
+ if (r < 0)
|
||
|
|
+ log_warning_errno(r, "Unable to parse $SYSTEMD_LESSSECURE, ignoring: %m");
|
||
|
|
+
|
||
|
|
+ if (setenv("LESSSECURE", "1", 1) < 0) {
|
||
|
|
+ log_error_errno(errno, "Failed to set environment variable LESSSECURE: %m");
|
||
|
|
+ _exit(EXIT_FAILURE);
|
||
|
|
+ }
|
||
|
|
+ }
|
||
|
|
+
|
||
|
|
if (pager) {
|
||
|
|
execlp(pager, pager, NULL);
|
||
|
|
execl("/bin/sh", "sh", "-c", pager, NULL);
|