rdo/rdo.c
sw1tchbl4d3 cfa1b3b10f Make the hashing failure error message more descriptive
This error occurs when the user we try to hash the password for doesn't
have a password, as seen in #8.

We now mention this, to avoid future confusion.
2022-02-12 08:07:48 +01:00

123 lines
2.8 KiB
C

#include <pwd.h>
#include <err.h>
#include <shadow.h>
#include <crypt.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <bsd/readpassphrase.h>
#include "sessions.h"
#define VERSION "1.3"
void getconf(FILE* fp, const char* entry, char* result, size_t len_result) {
char* line = NULL;
size_t len = 0;
fseek(fp, 0, SEEK_SET);
while (getline(&line, &len, fp) != -1) {
if (strncmp(entry, line, strlen(entry)) == 0) {
strtok(line, "=");
char* token = strtok(NULL, "=");
if (token) {
strncpy(result, token, len_result);
result[strcspn(result, "\n")] = 0;
free(line);
return;
}
}
}
errx(1, "Could not get '%s' entry in config", entry);
}
int runprog(int argc, char** argv) {
for(int i=0; i<argc; i++)
argv[i] = argv[i + 1];
if (setuid(0) < 0)
err(1, "Could not setuid");
if (setgid(0) < 0)
err(1, "Could not setgid");
if (execvp(argv[0], argv) != 0)
perror(argv[0]);
return 0;
}
int main(int argc, char** argv) {
char username[64], wrong_pw_sleep[64], session_ttl[64], password[128];
unsigned int sleep_ms, tries, ts_ttl;
if (argc == 1) {
printf("RootDO version: %s\n\n", VERSION);
printf("Usage: %s [command]\n", argv[0]);
return 0;
}
if (geteuid() != 0)
errx(1, "The rdo binary needs to be installed as SUID.");
int ruid = getuid();
if (ruid == 0)
return runprog(argc, argv);
FILE* fp = fopen("/etc/rdo.conf", "r");
if (!fp)
err(1, "Could not open /etc/rdo.conf");
getconf(fp, "username", username, sizeof(username));
getconf(fp, "wrong_pw_sleep", wrong_pw_sleep, sizeof(wrong_pw_sleep));
getconf(fp, "session_ttl", session_ttl, sizeof(session_ttl));
sleep_ms = atoi(wrong_pw_sleep) * 1000;
ts_ttl = atoi(session_ttl) * 60;
fclose(fp);
if (getsession(getppid(), ts_ttl) == 0)
return runprog(argc, argv);
struct passwd* p = getpwnam(username);
if (!p) {
if (errno == 0)
errx(1, "The user specified in the config file does not exist.");
else
err(1, "Could not get user info");
}
int uid = p->pw_uid;
if (uid != ruid && ruid != 0)
errx(1, "You are not allowed to execute rdo.");
struct spwd* shadowEntry = getspnam(p->pw_name);
if (!shadowEntry || !shadowEntry->sp_pwdp)
err(1, "Could not get shadow entry");
tries = 0;
while (tries < 3) {
if (!readpassphrase("(rdo) Password: ", password, sizeof(password), RPP_REQUIRE_TTY))
err(1, "Could not get passphrase");
char* hashed_pw = crypt(password, shadowEntry->sp_pwdp);
memset(password, 0, sizeof(password));
if (!hashed_pw)
errx(1, "Could not hash password, does your user have a password?");
if (strcmp(shadowEntry->sp_pwdp, hashed_pw) == 0) {
setsession(getppid(), ts_ttl);
return runprog(argc, argv);
}
usleep(sleep_ms);
fprintf(stderr, "Wrong password.\n");
tries++;
}
errx(1, "Too many wrong password attempts.");
return 1;
}