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Renamed project from checkpw to chkpw. (1.2.0)

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Johannes Findeisen 2025-06-01 19:23:47 +02:00
commit 22e4f0790a
7 changed files with 58 additions and 58 deletions
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184
checkpw.c
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@ -1,184 +0,0 @@
/**
* checkpw is a program that checks the validity of a users password on a
* UNIX/PAM-based system.
*
* Author: Johannes Findeisen <you@hanez.org> - 2024
* License: Apache-2.0 (see LICENSE)
*/
#include "checkpw.h"
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#ifndef MAX_PASSWORD_LEN
#define MAX_PASSWORD_LEN 256
#endif
#ifndef MAX_USERNAME_LEN
#define MAX_USERNAME_LEN 32
#endif
#ifndef MAX_UID
#define MAX_UID 1000
#endif
#ifndef MIN_UID
#define MIN_UID 1000
#endif
// Function to prompt user for input, optionally hiding input
void prompt_for_input(char *buffer, size_t size, const char *prompt,
bool hide_input)
{
printf("%s", prompt);
fflush(stdout);
if (hide_input) {
struct termios oldt, newt;
if (tcgetattr(STDIN_FILENO, &oldt) != 0) {
perror("tcgetattr");
exit(1);
}
newt = oldt;
newt.c_lflag &= ~(ECHO);
if (tcsetattr(STDIN_FILENO, TCSANOW, &newt) != 0) {
perror("tcsetattr");
exit(1);
}
}
if (fgets(buffer, size, stdin) == NULL) {
fprintf(stderr, "\nError reading input.\n");
if (hide_input) {
// Restore terminal settings
struct termios oldt;
tcgetattr(STDIN_FILENO, &oldt);
oldt.c_lflag |= ECHO;
tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
}
exit(1);
}
// Remove trailing newline
buffer[strcspn(buffer, "\n")] = '\0';
if (hide_input) {
// Restore terminal settings
struct termios oldt;
tcgetattr(STDIN_FILENO, &oldt);
oldt.c_lflag |= ECHO;
tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
printf("\n"); // Move to the next line after password input
}
}
void print_usage(const char *prog_name)
{
printf("\n");
printf("Usage: %s [-u <username>] [-p <password>] [-v] [-V] [-h]\n",
prog_name);
printf("\n");
printf("Options:\n");
printf(" -u <username> Set username (if not set, the program asks for it).\n");
printf(" -p <password> Set password (if not set, the program asks for it).\n");
printf(" -v Enable verbose mode.\n");
printf(" -V Print program version.\n");
printf(" -h Show this help.\n");
printf("\n");
}
int main(int argc, char *argv[])
{
bool verbose = false;
bool version = false;
char password[MAX_PASSWORD_LEN] = {0};
char username[MAX_USERNAME_LEN] = {0};
int opt;
// Parse command-line arguments
while ((opt = getopt(argc, argv, "u:p:hvV")) != -1) {
switch (opt) {
case 'u':
if (strlen(optarg) >= MAX_USERNAME_LEN) {
fprintf(stderr, "Error: Username is too long (maximum %d characters).\n",
MAX_USERNAME_LEN);
exit(1);
}
strncpy(username, optarg, MAX_USERNAME_LEN - 1);
break;
case 'p':
if (strlen(optarg) >= MAX_PASSWORD_LEN) {
fprintf(stderr, "Error: Password is too long (maximum %d characters).\n",
MAX_PASSWORD_LEN);
exit(1);
}
strncpy(password, optarg, MAX_PASSWORD_LEN - 1);
break;
case 'h':
print_usage(argv[0]);
exit(0);
case 'v':
verbose = true;
break;
case 'V':
version = true;
break;
default:
break;
}
}
if (version) {
printf("%s\n", VERSION);
exit(0);
}
if (username[0] == '\0') {
prompt_for_input(username, sizeof(username), "Username: ", false);
if (strlen(username) == 0) {
fprintf(stderr, "Error: Username cannot be empty.\n");
exit(1);
}
}
if (password[0] == '\0') {
prompt_for_input(password, sizeof(password), "Password: ", true);
if (strlen(password) == 0) {
fprintf(stderr, "Error: Password cannot be empty.\n");
exit(1);
}
}
// Retrieve user information from the username
struct passwd *pwd = getpwnam(username);
if (pwd == NULL) {
fprintf(stderr, "Error: User '%s' not found.\n", username);
exit(1);
}
// Check if the user's UID is below the minimum allowed UID and not higher
// than maximum allowed UID
if (pwd->pw_uid < MIN_UID || pwd->pw_uid > MAX_UID) {
fprintf(stderr, "Error: User '%s' has a UID higher than %d or lower than %d and is not allowed to authenticate.\n",
username, MAX_UID, MIN_UID);
exit(1);
}
if (verbose)
printf("User '%s' passed UID check (UID: %d).\n", username,
pwd->pw_uid);
if (checkpw_authenticate(username, password, verbose) == true) {
printf("Authenticated successfully.\n");
return 0;
} else {
printf("Authentication failed.\n");
return 1;
}
}