implement naive privilege drop

1 files changed, 40 insertions, 18 deletions

diff --git a/src/main.c b/src/main.c
index 1c242cf..ee5a912 100644
--- a/src/main.c
+++ b/src/main.c
@@ -9,7 +9,9 @@
 #include <netinet/in.h>
 #include <netdb.h>
 #include <pthread.h>
+#include <sys/types.h>
 #include <pwd.h>
+#include <grp.h>
 #include <errno.h>
 #include <signal.h>
 
@@ -20,6 +22,7 @@ static int stop = 0;
 
 void stop_handler() {
 	stop = 1;
+	return;
 }
 
 void usage(char* name) {
@@ -29,7 +32,6 @@ void usage(char* name) {
 	printf("\tg: group to run as (default: nobody)\n");
 	printf("\ta: address to bind to (default: 127.0.0.1)\n");
 	printf("\tp: port to bind to (default: 69)\n");
-	printf("\tt: number of worker threads to spawn (default 128)\n");
 }
 
 int main(int argc, char** argv) {
@@ -42,10 +44,9 @@ int main(int argc, char** argv) {
 	strcpy(user, "nobody");
 	strcpy(group, "nobody");
 	int port = 69;
-	int threadcount = 128;
 	
 	int ch = 0;
-	while ((ch = getopt(argc, argv, "da:p:u:g:t:h")) != -1) {
+	while ((ch = getopt(argc, argv, "da:p:u:g:h")) != -1) {
 		switch (ch) {
 			case 'a':
 				//TODO: this is unsafe
@@ -58,13 +59,6 @@ int main(int argc, char** argv) {
 					return -1;
 				}
 				break;
-			case 't':
-				threadcount = atoi(optarg);
-				if ((threadcount <= 0) || (threadcount > 51200)) {
-					fprintf(stderr, "threadcount must be between 1 and 51200\n");
-					return -1;
-				}
-				break;
 			case 'd':
 				daemonize = 1;
 				break;
@@ -133,21 +127,49 @@ int main(int argc, char** argv) {
 	}
 	syslog(LOG_INFO, "socket bind success");
 
-	//TODO: drop privs!
+	//TODO: use getpwnam_r() and getgrnam_r()
+	struct passwd u = getpwnam(&user);
+	struct group g = getgrnam(&group);
+	if (setuid(u.pw_uid) == -1) {
+		syslog(LOG_ERR, "failed to drop privileges");
+		return -1;
+	}
+	if (setgit(g.gr_gid) == -1) {
+		syslog(LOG_ERR, "failed to drop privileges");
+		return -1;
+	}
 
-	pthread_t threads[128];
-	memset(threads, '\0', sizeof(threads));
-	//TODO: spawn threadpool
+	// create persistent buffer
+	char* buf;
+	buf = malloc(1024);
+	if (buf == NULL) {
+		syslog(LOG_PANIC, "unable to allocate memory!");
+		close(s);
+		return -1;
+	}
 	while (!stop) {
 		struct sockaddr_in caddr;
 		unsigned int clen = sizeof(caddr);
-		char buf[1024];
-		if (recvfrom(s, buf, sizeof(buf), 0,
-				(struct sockaddr*)&caddr, &clen) < 0) {
+		memset(buf, '\0', 1024);
+		if (recvfrom(s, buf, 1024, 0, (struct sockaddr*)&caddr, &clen) < 0) {
 			syslog(LOG_ERR,
 					"got a client connection, but unable to receive data!");
+			free(buf);
+			continue;
 		}
-		//TODO: handle threadpool
+		//TODO: process packet
+
+		// we will never actually join on this thread, and don't care to keep it around.
+		pthread_t* _thread;
+
 	}
+
+	// free our persistent buffer
+	free(buf);
+	// close socket
+	close(s);
+	// wait for threads to exit
+	pthread_exit(NULL);
+	// exit program
 	return 0;
 }