From f0804759cf168b201347ce8aa2faefa17376191c Mon Sep 17 00:00:00 2001
From: =?utf8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Wed, 28 Jul 2021 16:59:51 +0200
Subject: [PATCH] selinux: add function name to audit data

Include the systemd C function name in the audit message to improve the
debug ability on denials.
Similar like kernel denial messages include the syscall name.
---
 src/core/selinux-access.c | 14 ++++++++++----
 src/core/selinux-access.h | 10 +++++++---
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/core/selinux-access.c b/src/core/selinux-access.c
index 513a4fb00e7..f6d4e7cc508 100644
--- a/src/core/selinux-access.c
+++ b/src/core/selinux-access.c
@@ -31,6 +31,7 @@ struct audit_info {
         sd_bus_creds *creds;
         const char *path;
         const char *cmdline;
+        const char *function;
 };
 
 /*
@@ -58,10 +59,11 @@ static int audit_callback(
                 xsprintf(gid_buf, GID_FMT, gid);
 
         (void) snprintf(msgbuf, msgbufsize,
-                        "auid=%s uid=%s gid=%s%s%s%s%s%s%s",
+                        "auid=%s uid=%s gid=%s%s%s%s%s%s%s%s%s%s",
                         login_uid_buf, uid_buf, gid_buf,
                         audit->path ? " path=\"" : "", strempty(audit->path), audit->path ? "\"" : "",
-                        audit->cmdline ? " cmdline=\"" : "", strempty(audit->cmdline), audit->cmdline ? "\"" : "");
+                        audit->cmdline ? " cmdline=\"" : "", strempty(audit->cmdline), audit->cmdline ? "\"" : "",
+                        audit->function ? " function=\"" : "", strempty(audit->function), audit->function ? "\"" : "");
 
         return 0;
 }
@@ -179,6 +181,7 @@ int mac_selinux_generic_access_check(
                 sd_bus_message *message,
                 const char *path,
                 const char *permission,
+                const char *function,
                 sd_bus_error *error) {
 
         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
@@ -191,6 +194,7 @@ int mac_selinux_generic_access_check(
 
         assert(message);
         assert(permission);
+        assert(function);
         assert(error);
 
         r = access_init(error);
@@ -263,6 +267,7 @@ int mac_selinux_generic_access_check(
                 .creds = creds,
                 .path = path,
                 .cmdline = cl,
+                .function = function,
         };
 
         r = selinux_check_access(scon, fcon, tclass, permission, &audit_info);
@@ -274,8 +279,8 @@ int mac_selinux_generic_access_check(
         }
 
         log_full_errno_zerook(LOG_DEBUG, r,
-                              "SELinux access check scon=%s tcon=%s tclass=%s perm=%s state=%s path=%s cmdline=%s: %m",
-                              scon, fcon, tclass, permission, enforce ? "enforcing" : "permissive", path, cl);
+                              "SELinux access check scon=%s tcon=%s tclass=%s perm=%s state=%s function=%s path=%s cmdline=%s: %m",
+                              scon, fcon, tclass, permission, enforce ? "enforcing" : "permissive", function, path, cl);
         return enforce ? r : 0;
 }
 
@@ -285,6 +290,7 @@ int mac_selinux_generic_access_check(
                 sd_bus_message *message,
                 const char *path,
                 const char *permission,
+                const char *function,
                 sd_bus_error *error) {
 
         return 0;
diff --git a/src/core/selinux-access.h b/src/core/selinux-access.h
index c6bfb325443..93aedc2347e 100644
--- a/src/core/selinux-access.h
+++ b/src/core/selinux-access.h
@@ -5,10 +5,14 @@
 
 #include "manager.h"
 
-int mac_selinux_generic_access_check(sd_bus_message *message, const char *path, const char *permission, sd_bus_error *error);
+int mac_selinux_generic_access_check(sd_bus_message *message,
+                                     const char *path,
+                                     const char *permission,
+                                     const char *function,
+                                     sd_bus_error *error);
 
 #define mac_selinux_access_check(message, permission, error) \
-        mac_selinux_generic_access_check((message), NULL, (permission), (error))
+        mac_selinux_generic_access_check((message), NULL, (permission), __func__, (error))
 
 #define mac_selinux_unit_access_check(unit, message, permission, error) \
-        mac_selinux_generic_access_check((message), unit_label_path(unit), (permission), (error))
+        mac_selinux_generic_access_check((message), unit_label_path(unit), (permission), __func__, (error))
-- 
2.47.3