Add groups support

rdo now supports taking a group name instead of only allowing a single
user.
This also completely removes the user option, as it isn't necessary
anymore with groups support.

README.md

@@ -35,12 +35,12 @@ rdo [command]
 
 The configuration file has the following variables:
 ```
-username=sw1tchbl4d3
+group=wheel
 wrong_pw_sleep=1000
 session_ttl=5
 ```
 
-- `username`: The username of the user that is allowed to execute rdo (no multi user or group support (yet)).
+- `group`: The group of users that is allowed to execute rdo.
 - `wrong_pw_sleep`: The amount of milliseconds to sleep at a wrong password attempt. Must be a positive integer. Set to 0 to disable.
 - `session_ttl`: The amount of minutes a session lasts. Must be a positive integer. Set to 0 to disable.
 

rdo.c

@@ -1,4 +1,5 @@
 #include <pwd.h>
+#include <grp.h>
 #include <err.h>
 #include <shadow.h>
 #include <crypt.h>
@@ -46,7 +47,7 @@ void runprog(char** program_argv) {
 }
 
 int main(int argc, char** argv) {
-	char username[64], wrong_pw_sleep[64], session_ttl[64], password[128];
+	char groupname[64], wrong_pw_sleep[64], session_ttl[64], password[128];
 	unsigned int sleep_us, tries, ts_ttl;
 
 	if (argc == 1) {
@@ -67,7 +68,7 @@ int main(int argc, char** argv) {
 	if (!fp)
 		err(1, "Could not open /etc/rdo.conf");
 
-	getconf(fp, "username", username, sizeof(username));
+	getconf(fp, "group", groupname, sizeof(groupname));
 	getconf(fp, "wrong_pw_sleep", wrong_pw_sleep, sizeof(wrong_pw_sleep));
 	getconf(fp, "session_ttl", session_ttl, sizeof(session_ttl));
 	sleep_us = atoi(wrong_pw_sleep) * 1000;
@@ -75,22 +76,38 @@ int main(int argc, char** argv) {
 
 	fclose(fp);
 
-	if (getsession(getppid(), ts_ttl) == 0)
+	if (getsession(getppid(), ts_ttl, ruid) == 0)
 		runprog(&argv[1]);
 
-	struct passwd* p = getpwnam(username);
-	if (!p) {
+	struct passwd* pw = getpwuid(ruid);
+	if (!pw) {
 		if (errno == 0)
-			errx(1, "The user specified in the config file does not exist.");
+			errx(1, "No user with UID %d", ruid);
 		else
 			err(1, "Could not get user info");
 	}
 
-	int uid = p->pw_uid;
-	if (uid != ruid)
+	struct group* current_group_entry = getgrent();
+	while (current_group_entry) {
+		if (strcmp(current_group_entry->gr_name, groupname) == 0)
+			break;
+		current_group_entry = getgrent();
+	}
+
+	if (!current_group_entry)
+		errx(1, "The group '%s' does not exist.", groupname);
+	
+	char* current_member = current_group_entry->gr_mem[0];
+	for (int i = 1; current_member; i++) {
+		if (strcmp(current_member, pw->pw_name) == 0)
+			break;
+		current_member = current_group_entry->gr_mem[i];
+	}
+
+	if (!current_member)
 		errx(1, "You are not allowed to execute rdo.");
 
-	struct spwd* shadowEntry = getspnam(p->pw_name);
+	struct spwd* shadowEntry = getspnam(pw->pw_name);
 
 	if (!shadowEntry || !shadowEntry->sp_pwdp)
 		err(1, "Could not get shadow entry");
@@ -107,7 +124,7 @@ int main(int argc, char** argv) {
 			errx(1, "Could not hash password, does your user have a password?");
 
 		if (strcmp(shadowEntry->sp_pwdp, hashed_pw) == 0) {
-			setsession(getppid(), ts_ttl);
+			setsession(getppid(), ts_ttl, ruid);
 			runprog(&argv[1]);
 		}
 

rdo_sample.conf

@@ -1,3 +1,3 @@
-username=sw1tchbl4d3
+group=wheel
 wrong_pw_sleep=1000
 session_ttl=5

sessions.h

@@ -77,7 +77,7 @@ int ensuredir() {
 	return 0;
 }
 
-void setsession(int pid, unsigned int ts_ttl) {
+void setsession(int pid, unsigned int ts_ttl, int ruid) {
 	unsigned long long startts;
 	char path[1024], ts_str[32];
 
@@ -87,7 +87,7 @@ void setsession(int pid, unsigned int ts_ttl) {
 	if (ensuredir() < 0 || getpstartts(pid, &startts) < 0)
 		return;
 
-	snprintf(path, sizeof(path), "/run/rdo/%d-%llu", pid, startts);
+	snprintf(path, sizeof(path), "/run/rdo/%d-%d-%llu", ruid, pid, startts);
 
 	int fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0700);
 	if (fd < 0) {
@@ -108,7 +108,7 @@ void setsession(int pid, unsigned int ts_ttl) {
 	return;
 }
 
-int getsession(int pid, unsigned int ts_ttl) {
+int getsession(int pid, unsigned int ts_ttl, int ruid) {
 	unsigned long long startts, current;
 	char path[1024], ts_str[32];
 
@@ -118,7 +118,7 @@ int getsession(int pid, unsigned int ts_ttl) {
 	if (ensuredir() < 0 || getpstartts(pid, &startts) < 0)
 		return -1;
 
-	snprintf(path, sizeof(path), "/run/rdo/%d-%llu", pid, startts);
+	snprintf(path, sizeof(path), "/run/rdo/%d-%d-%llu", ruid, pid, startts);
 
 	int fd = open(path, O_RDONLY);
 	if (fd < 0) {