security: rework selinux, smack, ima, apparmor detection logic

Always cache the results, and bypass low-level security calls when the
respective subsystem is not enabled.

2 files changed, 11 insertions, 24 deletions

diff --git a/src/core/condition.c b/src/core/condition.c
index 6c387450af..c53d406682 100644
--- a/src/core/condition.c
+++ b/src/core/condition.c
@@ -27,10 +27,6 @@
 #include <sys/statvfs.h>
 #include <fnmatch.h>
 
-#ifdef HAVE_SELINUX
-#include <selinux/selinux.h>
-#endif
-
 #include <systemd/sd-id128.h>
 #include "util.h"
 #include "condition.h"
@@ -38,6 +34,10 @@
 #include "path-util.h"
 #include "fileio.h"
 #include "unit.h"
+#include "smack-util.h"
+#include "apparmor-util.h"
+#include "ima-util.h"
+#include "selinux-util.h"
 
 Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {
         Condition *c;
@@ -158,28 +158,15 @@ static bool test_virtualization(const char *parameter) {
         return v > 0 && streq(parameter, id);
 }
 
-static bool test_apparmor_enabled(void) {
-        int r;
-        _cleanup_free_ char *p = NULL;
-
-        r = read_one_line_file("/sys/module/apparmor/parameters/enabled", &p);
-        if (r < 0)
-                return false;
-
-        return parse_boolean(p) > 0;
-}
-
 static bool test_security(const char *parameter) {
-#ifdef HAVE_SELINUX
         if (streq(parameter, "selinux"))
-                return is_selinux_enabled() > 0;
-#endif
+                return use_selinux();
         if (streq(parameter, "apparmor"))
-                return test_apparmor_enabled();
+                return use_apparmor();
         if (streq(parameter, "ima"))
-                return access("/sys/kernel/security/ima/", F_OK) == 0;
+                return use_ima();
         if (streq(parameter, "smack"))
-                return access("/sys/fs/smackfs", F_OK) == 0;
+                return use_smack();
         return false;
 }
 
diff --git a/src/core/socket.c b/src/core/socket.c
index 6c0ac1a898..345601f0ae 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -775,12 +775,12 @@ static void socket_apply_socket_options(Socket *s, int fd) {
         }
 
 #ifdef HAVE_SMACK
-        if (s->smack_ip_in)
+        if (s->smack_ip_in && use_smack())
                 if (fsetxattr(fd, "security.SMACK64IPIN", s->smack_ip_in, strlen(s->smack_ip_in), 0) < 0)
                         log_error_unit(UNIT(s)->id,
                                        "fsetxattr(\"security.SMACK64IPIN\"): %m");
 
-        if (s->smack_ip_out)
+        if (s->smack_ip_out && use_smack())
                 if (fsetxattr(fd, "security.SMACK64IPOUT", s->smack_ip_out, strlen(s->smack_ip_out), 0) < 0)
                         log_error_unit(UNIT(s)->id,
                                        "fsetxattr(\"security.SMACK64IPOUT\"): %m");
@@ -797,7 +797,7 @@ static void socket_apply_fifo_options(Socket *s, int fd) {
                                          "F_SETPIPE_SZ: %m");
 
 #ifdef HAVE_SMACK
-        if (s->smack)
+        if (s->smack && use_smack())
                 if (fsetxattr(fd, "security.SMACK64", s->smack, strlen(s->smack), 0) < 0)
                         log_error_unit(UNIT(s)->id,
                                        "fsetxattr(\"security.SMACK64\"): %m");