From 48ce6ddfde98185060510a021cde369933246191 Mon Sep 17 00:00:00 2001
From: Jakob Kaivo <jkk@ung.org>
Date: Thu, 18 Feb 2021 11:18:49 -0500
Subject: add logging of user and command when executed

---
 exec/exec.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/exec/exec.c b/exec/exec.c
index 4a8b22f..f00f768 100644
--- a/exec/exec.c
+++ b/exec/exec.c
@@ -1,12 +1,34 @@
-#define _POSIX_C_SOURCE 200809L
+#define _XOPEN_SOURCE 700
 #include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
 #include <stdio.h>
 #include <string.h>
+#include <syslog.h>
 #include <unistd.h>
 
+#define PRIVEXEC_LOG_ID	"privexec"
 #define NOT_RUN		(126)
 #define NOT_FOUND	(127)
 
+#ifndef ARG_MAX
+#define ARG_MAX _POSIX_ARG_MAX
+#endif
+
+void log_execution(int argc, char *argv[])
+{
+	char cmd[ARG_MAX] = "";
+	strncat(cmd, argv[1], sizeof(cmd) - 1);
+	for (int i = 2; i < argc; i++) {
+		strncat(cmd, " ", sizeof(cmd) - 1);
+		strncat(cmd, argv[i], sizeof(cmd) - 1);
+	}
+
+	openlog(PRIVEXEC_LOG_ID, LOG_PID, LOG_AUTH);
+	syslog(LOG_INFO, "UID %jd running \"%s\"", (intmax_t)getuid(), cmd);
+	closelog();
+}
+
 int main(int argc, char *argv[])
 {
 	if (argc < 2 || argv == NULL) {
@@ -14,6 +36,8 @@ int main(int argc, char *argv[])
 		return NOT_RUN;
 	}
 
+	log_execution(argc, argv);
+
 	setuid(geteuid());
 	execvp(argv[1], argv + 1);
 	fprintf(stderr, "%s: %s: %s\n", argv[0], argv[1], strerror(errno));
-- 
cgit v1.2.1