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From d0a2b8832732d297321fddcad56872511ff212f2 Mon Sep 17 00:00:00 2001
From: Michael Scherer <misc@zarb.org>
Date: Thu, 6 Feb 2014 10:05:16 +0100
Subject: [PATCH] exec: Add SELinuxContext configuration item
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This permit to let system administrators decide of the domain of a service.
This can be used with templated units to have each service in a différent
domain ( for example, a per customer database, using MLS or anything ),
or can be used to force a non selinux enabled system (jvm, erlang, etc)
to start in a different domain for each service.

Conflicts:
        src/core/dbus-execute.c
        src/core/execute.c
        src/core/execute.h
        src/shared/exit-status.c
        src/shared/exit-status.h

(cherry picked from commit 7b52a628f8b43ba521c302a7f32bccf9d0dc8bfd)

Related: #1113790
---
 man/systemd.exec.xml                  | 11 +++++++++++
 src/core/dbus-execute.c               |  1 +
 src/core/execute.c                    | 27 +++++++++++++++++++++++++++
 src/core/execute.h                    |  2 ++
 src/core/load-fragment-gperf.gperf.m4 |  3 ++-
 src/shared/exit-status.c              |  3 +++
 src/shared/exit-status.h              |  1 +
 7 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 612b4d2..a68cfa7 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -919,6 +919,17 @@
                         </varlistentry>
 
                         <varlistentry>
+                                <term><varname>SELinuxContext=</varname></term>
+
+                                <listitem><para>Set the SELinux context of the
+                                executed process. If set, this will override the
+                                automated domain transition. However, the policy
+                                still need to autorize the transition. See
+                                <citerefentry><refentrytitle>setexeccon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                                for details.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
                                 <term><varname>IgnoreSIGPIPE=</varname></term>
 
                                 <listitem><para>Takes a boolean
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index 2402e8c..97d75fa 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -429,6 +429,7 @@ const BusProperty bus_exec_context_properties[] = {
         { "PrivateNetwork",           bus_property_append_bool,              "b", offsetof(ExecContext, private_network)              },
         { "SameProcessGroup",         bus_property_append_bool,              "b", offsetof(ExecContext, same_pgrp)                    },
         { "UtmpIdentifier",           bus_property_append_string,            "s", offsetof(ExecContext, utmp_id),                true },
+        { "SELinuxContext",           bus_property_append_string,            "s", offsetof(ExecContext, selinux_context),        true },
         { "IgnoreSIGPIPE",            bus_property_append_bool,              "b", offsetof(ExecContext, ignore_sigpipe)               },
         { "NoNewPrivileges",          bus_property_append_bool,              "b", offsetof(ExecContext, no_new_privileges)            },
         { "SystemCallFilter",         bus_execute_append_syscall_filter,    "au", 0                                                   },
diff --git a/src/core/execute.c b/src/core/execute.c
index 981b9e4..cf9d24e 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -46,6 +46,10 @@
 #include <security/pam_appl.h>
 #endif
 
+#ifdef HAVE_SELINUX
+#include <selinux/selinux.h>
+#endif
+
 #include "execute.h"
 #include "strv.h"
 #include "macro.h"
@@ -1467,6 +1471,20 @@ int exec_spawn(ExecCommand *command,
                                         goto fail_child;
                                 }
                         }
+#ifdef HAVE_SELINUX
+                        if (context->selinux_context) {
+                                err = security_check_context(context->selinux_context);
+                                if (err < 0) {
+                                        r = EXIT_SELINUX_CONTEXT;
+                                        goto fail_child;
+                                }
+                                err = setexeccon(context->selinux_context);
+                                if (err < 0) {
+                                        r = EXIT_SELINUX_CONTEXT;
+                                        goto fail_child;
+                                }
+                        }
+#endif
                 }
 
                 our_env = new0(char*, 7);
@@ -1696,6 +1714,9 @@ void exec_context_done(ExecContext *c, bool reloading_or_reexecuting) {
         free(c->utmp_id);
         c->utmp_id = NULL;
 
+        free(c->selinux_context);
+        c->selinux_context = NULL;
+
         free(c->syscall_filter);
         c->syscall_filter = NULL;
 
@@ -2067,6 +2088,12 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                 fprintf(f,
                         "%sUtmpIdentifier: %s\n",
                         prefix, c->utmp_id);
+
+        if (c->selinux_context)
+                fprintf(f,
+                        "%sSELinuxContext: %s\n",
+                        prefix, c->selinux_context);
+
 }
 
 void exec_status_start(ExecStatus *s, pid_t pid) {
diff --git a/src/core/execute.h b/src/core/execute.h
index c1e9717..92ac8dd 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -124,6 +124,8 @@ struct ExecContext {
 
         char *utmp_id;
 
+        char *selinux_context;
+
         char **read_write_dirs, **read_only_dirs, **inaccessible_dirs;
         unsigned long mount_flags;
 
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 0991cb9..935f04e 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -75,7 +75,8 @@ $1.MountFlags,                   config_parse_exec_mount_flags,      0,
 $1.TCPWrapName,                  config_parse_unit_string_printf,    0,                             offsetof($1, exec_context.tcpwrap_name)
 $1.PAMName,                      config_parse_unit_string_printf,    0,                             offsetof($1, exec_context.pam_name)
 $1.IgnoreSIGPIPE,                config_parse_bool,                  0,                             offsetof($1, exec_context.ignore_sigpipe)
-$1.UtmpIdentifier,               config_parse_unit_string_printf,    0,                             offsetof($1, exec_context.utmp_id)'
+$1.UtmpIdentifier,               config_parse_unit_string_printf,    0,                             offsetof($1, exec_context.utmp_id)
+$1.SELinuxContext,               config_parse_unit_string_printf,    0,                             offsetof($1, exec_context.selinux_context)'
 )m4_dnl
 m4_define(`KILL_CONTEXT_CONFIG_ITEMS',
 `$1.SendSIGKILL,                 config_parse_bool,                  0,                             offsetof($1, kill_context.send_sigkill)
diff --git a/src/shared/exit-status.c b/src/shared/exit-status.c
index f15fdba..676291b 100644
--- a/src/shared/exit-status.c
+++ b/src/shared/exit-status.c
@@ -131,6 +131,9 @@ const char* exit_status_to_string(ExitStatus status, ExitStatusLevel level) {
                 case EXIT_SECCOMP:
                         return "SECCOMP";
 
+                case EXIT_SELINUX_CONTEXT:
+                        return "SELINUX_CONTEXT";
+
                 case EXIT_CHOWN:
                         return "CHOWN";
 
diff --git a/src/shared/exit-status.h b/src/shared/exit-status.h
index 52dd3d0..798f1e1 100644
--- a/src/shared/exit-status.h
+++ b/src/shared/exit-status.h
@@ -68,6 +68,7 @@ typedef enum ExitStatus {
         EXIT_NAMESPACE,
         EXIT_NO_NEW_PRIVILEGES,
         EXIT_SECCOMP,
+        EXIT_SELINUX_CONTEXT,
         EXIT_CHOWN
 } ExitStatus;