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systemd/0321-socket-introduce-SELinuxContextFromNet-option.patch

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Update to latest git
2014-10-04 02:43:52 +00:00
From 16115b0a7b7cdf08fb38084d857d572d8a9088dc Mon Sep 17 00:00:00 2001
From: Michal Sekletar <msekleta@redhat.com>
Date: Thu, 24 Jul 2014 10:40:28 +0200
Subject: [PATCH] socket: introduce SELinuxContextFromNet option
This makes possible to spawn service instances triggered by socket with
MLS/MCS SELinux labels which are created based on information provided by
connected peer.
Implementation of label_get_child_mls_label derived from xinetd.
Reviewed-by: Paul Moore <pmoore@redhat.com>
---
man/systemd.socket.xml | 26 ++++++++
src/core/execute.c | 29 +++++++--
src/core/execute.h | 1 +
src/core/load-fragment-gperf.gperf.m4 | 3 +
src/core/service.c | 4 +-
src/core/service.h | 3 +-
src/core/socket.c | 16 +++--
src/core/socket.h | 2 +
src/shared/label.c | 113 ++++++++++++++++++++++++++++++++++
src/shared/label.h | 2 +
10 files changed, 187 insertions(+), 12 deletions(-)
diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml
index 7a63348caf..dad0267467 100644
--- a/man/systemd.socket.xml
+++ b/man/systemd.socket.xml
@@ -676,6 +676,32 @@
</varlistentry>
<varlistentry>
+ <term><varname>SELinuxContextFromNet=</varname></term>
+ <listitem><para>Takes a boolean
+ argument. When true systemd will attempt
+ to figure out the SELinux label used
+ for the instantiated service from the
+ information handed by the peer over the
+ network. Note that only the security
+ level is used from the information
+ provided by the peer. Other parts of
+ the resulting SELinux context originate
+ from either the target binary that is
+ effectively triggered by socket unit
+ are taken from the value of the
+ <varname>SELinuxContext=</varname>
+ option.This configuration option only
+ affects sockets with
+ <varname>Accept=</varname> mode set to
+ <literal>true</literal>. Also note that
+ this option is useful only when
+ MLS/MCS SELinux policy is
+ deployed. Defaults to
+ <literal>false</literal>.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><varname>PipeSize=</varname></term>
<listitem><para>Takes a size in
bytes. Controls the pipe buffer size
diff --git a/src/core/execute.c b/src/core/execute.c
index db755777c1..8c9dfde00a 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -84,6 +84,7 @@
#include "mkdir.h"
#include "apparmor-util.h"
#include "bus-kernel.h"
+#include "label.h"
#ifdef HAVE_SECCOMP
#include "seccomp-util.h"
@@ -1665,11 +1666,29 @@ static int exec_child(ExecCommand *command,
#endif
#ifdef HAVE_SELINUX
- if (context->selinux_context && use_selinux()) {
- err = setexeccon(context->selinux_context);
- if (err < 0 && !context->selinux_context_ignore) {
- *error = EXIT_SELINUX_CONTEXT;
- return err;
+ if (use_selinux()) {
+ if (context->selinux_context) {
+ err = setexeccon(context->selinux_context);
+ if (err < 0 && !context->selinux_context_ignore) {
+ *error = EXIT_SELINUX_CONTEXT;
+ return err;
+ }
+ }
+
+ if (params->selinux_context_net && socket_fd >= 0) {
+ _cleanup_free_ char *label = NULL;
+
+ err = label_get_child_mls_label(socket_fd, command->path, &label);
+ if (err < 0) {
+ *error = EXIT_SELINUX_CONTEXT;
+ return err;
+ }
+
+ err = setexeccon(label);
+ if (err < 0) {
+ *error = EXIT_SELINUX_CONTEXT;
+ return err;
+ }
}
}
#endif
diff --git a/src/core/execute.h b/src/core/execute.h
index 9c1f249cd4..6f35736eda 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -204,6 +204,7 @@ struct ExecParameters {
bool apply_chroot;
bool apply_tty_stdin;
bool confirm_spawn;
+ bool selinux_context_net;
CGroupControllerMask cgroup_supported;
const char *cgroup_path;
const char *runtime_prefix;
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index e764d68ce4..050c5d819f 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -265,6 +265,9 @@ Socket.SmackLabelIPOut, config_parse_string, 0,
`Socket.SmackLabel, config_parse_warn_compat, 0, 0
Socket.SmackLabelIPIn, config_parse_warn_compat, 0, 0
Socket.SmackLabelIPOut, config_parse_warn_compat, 0, 0')
+m4_ifdef(`HAVE_SELINUX',
+`Socket.SELinuxContextFromNet, config_parse_bool, 0, offsetof(Socket, selinux_context_from_net)',
+`Socket.SELinuxContextFromNet, config_parse_warn_compat, 0, 0')
EXEC_CONTEXT_CONFIG_ITEMS(Socket)m4_dnl
CGROUP_CONTEXT_CONFIG_ITEMS(Socket)m4_dnl
KILL_CONTEXT_CONFIG_ITEMS(Socket)m4_dnl
diff --git a/src/core/service.c b/src/core/service.c
index 3f6595c5c8..395e0ca8c6 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -901,6 +901,7 @@ static int service_spawn(
.apply_chroot = apply_chroot,
.apply_tty_stdin = apply_tty_stdin,
.bus_endpoint_fd = -1,
+ .selinux_context_net = s->socket_fd_selinux_context_net
};
assert(s);
@@ -2748,7 +2749,7 @@ static void service_bus_name_owner_change(
}
}
-int service_set_socket_fd(Service *s, int fd, Socket *sock) {
+int service_set_socket_fd(Service *s, int fd, Socket *sock, bool selinux_context_net) {
_cleanup_free_ char *peer = NULL;
int r;
@@ -2786,6 +2787,7 @@ int service_set_socket_fd(Service *s, int fd, Socket *sock) {
}
s->socket_fd = fd;
+ s->socket_fd_selinux_context_net = selinux_context_net;
unit_ref_set(&s->accept_socket, UNIT(sock));
diff --git a/src/core/service.h b/src/core/service.h
index ad0b3b381e..0db0c4d64c 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -161,6 +161,7 @@ struct Service {
pid_t main_pid, control_pid;
int socket_fd;
+ bool socket_fd_selinux_context_net;
int bus_endpoint_fd;
@@ -205,7 +206,7 @@ extern const UnitVTable service_vtable;
struct Socket;
-int service_set_socket_fd(Service *s, int fd, struct Socket *socket);
+int service_set_socket_fd(Service *s, int fd, struct Socket *socket, bool selinux_context_net);
const char* service_state_to_string(ServiceState i) _const_;
ServiceState service_state_from_string(const char *s) _pure_;
diff --git a/src/core/socket.c b/src/core/socket.c
index 68e21e60ac..00d5fd1192 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -489,7 +489,8 @@ static void socket_dump(Unit *u, FILE *f, const char *prefix) {
"%sPassCredentials: %s\n"
"%sPassSecurity: %s\n"
"%sTCPCongestion: %s\n"
- "%sRemoveOnStop: %s\n",
+ "%sRemoveOnStop: %s\n"
+ "%sSELinuxContextFromNet: %s\n",
prefix, socket_state_to_string(s->state),
prefix, socket_result_to_string(s->result),
prefix, socket_address_bind_ipv6_only_to_string(s->bind_ipv6_only),
@@ -504,7 +505,8 @@ static void socket_dump(Unit *u, FILE *f, const char *prefix) {
prefix, yes_no(s->pass_cred),
prefix, yes_no(s->pass_sec),
prefix, strna(s->tcp_congestion),
- prefix, yes_no(s->remove_on_stop));
+ prefix, yes_no(s->remove_on_stop),
+ prefix, yes_no(s->selinux_context_from_net));
if (s->control_pid > 0)
fprintf(f,
@@ -1128,8 +1130,12 @@ static int socket_open_fds(Socket *s) {
continue;
if (p->type == SOCKET_SOCKET) {
-
- if (!know_label) {
+ if (!know_label && s->selinux_context_from_net) {
+ r = label_get_our_label(&label);
+ if (r < 0)
+ return r;
+ know_label = true;
+ } else if (!know_label) {
r = socket_instantiate_service(s);
if (r < 0)
@@ -1821,7 +1827,7 @@ static void socket_enter_running(Socket *s, int cfd) {
unit_choose_id(UNIT(service), name);
- r = service_set_socket_fd(service, cfd, s);
+ r = service_set_socket_fd(service, cfd, s, s->selinux_context_from_net);
if (r < 0)
goto fail;
diff --git a/src/core/socket.h b/src/core/socket.h
index eede70564a..a2e08998c0 100644
--- a/src/core/socket.h
+++ b/src/core/socket.h
@@ -165,6 +165,8 @@ struct Socket {
char *smack_ip_in;
char *smack_ip_out;
+ bool selinux_context_from_net;
+
char *user, *group;
};
diff --git a/src/shared/label.c b/src/shared/label.c
index 25a8b361b7..02b41f02d8 100644
--- a/src/shared/label.c
+++ b/src/shared/label.c
@@ -31,6 +31,7 @@
#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#include <selinux/label.h>
+#include <selinux/context.h>
#endif
#include "label.h"
@@ -41,6 +42,12 @@
#include "smack-util.h"
#ifdef HAVE_SELINUX
+DEFINE_TRIVIAL_CLEANUP_FUNC(security_context_t, freecon);
+DEFINE_TRIVIAL_CLEANUP_FUNC(context_t, context_free);
+
+#define _cleanup_security_context_free_ _cleanup_(freeconp)
+#define _cleanup_context_free_ _cleanup_(context_freep)
+
static struct selabel_handle *label_hnd = NULL;
#endif
@@ -243,6 +250,112 @@ fail:
return r;
}
+int label_get_our_label(char **label) {
+ int r = -EOPNOTSUPP;
+ char *l = NULL;
+
+#ifdef HAVE_SELINUX
+ r = getcon(&l);
+ if (r < 0)
+ return r;
+
+ *label = l;
+#endif
+
+ return r;
+}
+
+int label_get_child_mls_label(int socket_fd, const char *exe, char **label) {
+ int r = -EOPNOTSUPP;
+
+#ifdef HAVE_SELINUX
+
+ _cleanup_security_context_free_ security_context_t mycon = NULL, peercon = NULL, fcon = NULL, ret = NULL;
+ _cleanup_context_free_ context_t pcon = NULL, bcon = NULL;
+ security_class_t sclass;
+
+ const char *range = NULL;
+
+ assert(socket_fd >= 0);
+ assert(exe);
+ assert(label);
+
+ r = getcon(&mycon);
+ if (r < 0) {
+ r = -EINVAL;
+ goto out;
+ }
+
+ r = getpeercon(socket_fd, &peercon);
+ if (r < 0) {
+ r = -EINVAL;
+ goto out;
+ }
+
+ r = getexeccon(&fcon);
+ if (r < 0) {
+ r = -EINVAL;
+ goto out;
+ }
+
+ if (!fcon) {
+ /* If there is no context set for next exec let's use context
+ of target executable */
+ r = getfilecon(exe, &fcon);
+ if (r < 0) {
+ r = -errno;
+ goto out;
+ }
+ }
+
+ bcon = context_new(mycon);
+ if (!bcon) {
+ r = -ENOMEM;
+ goto out;
+ }
+
+ pcon = context_new(peercon);
+ if (!pcon) {
+ r = -ENOMEM;
+ goto out;
+ }
+
+ range = context_range_get(pcon);
+ if (!range) {
+ r = -errno;
+ goto out;
+ }
+
+ r = context_range_set(bcon, range);
+ if (r) {
+ r = -errno;
+ goto out;
+ }
+
+ freecon(mycon);
+ mycon = context_str(bcon);
+ if (!mycon) {
+ r = -errno;
+ goto out;
+ }
+
+ sclass = string_to_security_class("process");
+ r = security_compute_create(mycon, fcon, sclass, &ret);
+ if (r < 0) {
+ r = -EINVAL;
+ goto out;
+ }
+
+ *label = ret;
+ r = 0;
+
+out:
+ if (r < 0 && security_getenforce() == 1)
+ return r;
+#endif
+ return r;
+}
+
int label_context_set(const char *path, mode_t mode) {
int r = 0;
diff --git a/src/shared/label.h b/src/shared/label.h
index cb2ec79eea..ce1e5c3f57 100644
--- a/src/shared/label.h
+++ b/src/shared/label.h
@@ -40,6 +40,8 @@ void label_context_clear(void);
void label_free(const char *label);
int label_get_create_label_from_exe(const char *exe, char **label);
+int label_get_our_label(char **label);
+int label_get_child_mls_label(int socket_fd, const char *exec, char **label);
int label_mkdir(const char *path, mode_t mode);
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