hanez/chkusr
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Added an interactive mode (-i) to ask for a missing username or password.

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This commit is contained in:
Johannes Findeisen 2024-08-10 15:03:57 +02:00
commit 739c0f2cb1
1 changed files with 113 additions and 21 deletions
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134
checkpw.c
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@ -14,10 +14,11 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> // For getopt and access to user info
#include <pwd.h> // For struct passwd and getpwuid
#include <unistd.h> // For getopt and access to user info
#include <pwd.h> // For struct passwd and getpwnam
#include <termios.h> // For terminal input settings
#define MAX_USERNAME_LEN 32
#define MAX_USERNAME_LEN 256
#define MAX_PASSWORD_LEN 256
#ifndef MIN_UID
@ -42,9 +43,15 @@ int pam_conversation(int num_msg, const struct pam_message **msg,
}
for (i = 0; i < num_msg; i++) {
if (msg[i]->msg_style == PAM_PROMPT_ECHO_OFF || msg[i]->msg_style == PAM_PROMPT_ECHO_ON) {
response[i].resp = strdup(credentials->password);
response[i].resp_retcode = 0;
switch (msg[i]->msg_style) {
case PAM_PROMPT_ECHO_ON:
case PAM_PROMPT_ECHO_OFF:
response[i].resp = strdup(credentials->password);
response[i].resp_retcode = 0;
break;
default:
free(response);
return PAM_CONV_ERR;
}
}
@ -69,6 +76,10 @@ int authenticate(const char *username, const char *password, int verbose) {
printf("PAM authentication initialized.\n");
}
retval = pam_authenticate(pamh, 0); // Attempt to authenticate
} else {
if (verbose) {
printf("pam_start failed: %s\n", pam_strerror(pamh, retval));
}
}
if (retval == PAM_SUCCESS) {
@ -76,6 +87,13 @@ int authenticate(const char *username, const char *password, int verbose) {
printf("User '%s' authenticated successfully.\n", username);
}
retval = pam_acct_mgmt(pamh, 0); // Check account validity
if (retval != PAM_SUCCESS && verbose) {
printf("pam_acct_mgmt failed: %s\n", pam_strerror(pamh, retval));
}
} else {
if (verbose) {
printf("pam_authenticate failed: %s\n", pam_strerror(pamh, retval));
}
}
if (pam_end(pamh, retval) != PAM_SUCCESS) {
@ -91,45 +109,119 @@ int authenticate(const char *username, const char *password, int verbose) {
return (retval == PAM_SUCCESS ? 0 : 1); // 0 for success, 1 for failure
}
// Function to prompt user for input, optionally hiding input
void prompt_for_input(char *buffer, size_t size, const char *prompt, int 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) {
fprintf(stderr, "Usage: %s [-u <username>] [-p <password>] [-i] [-v]\n", prog_name);
fprintf(stderr, "Options:\n");
fprintf(stderr, " -u <username> Specify username.\n");
fprintf(stderr, " -p <password> Specify password.\n");
fprintf(stderr, " -i Enable interactive mode to prompt for missing username/password.\n");
fprintf(stderr, " -v Enable verbose mode.\n");
}
int main(int argc, char *argv[]) {
char username[MAX_USERNAME_LEN];
char password[MAX_PASSWORD_LEN];
int verbose = 0; // Verbose mode flag
char username[MAX_USERNAME_LEN] = {0};
char password[MAX_PASSWORD_LEN] = {0};
int verbose = 0; // Verbose mode flag
int interactive = 0; // Interactive mode flag
int opt;
memset(username, 0, sizeof(username));
memset(password, 0, sizeof(password));
// Parse command-line arguments
while ((opt = getopt(argc, argv, "u:p:v")) != -1) {
while ((opt = getopt(argc, argv, "u:p:iv")) != -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);
fprintf(stderr, "Error: Username is too long (maximum %d characters).\n", MAX_USERNAME_LEN - 1);
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);
fprintf(stderr, "Error: Password is too long (maximum %d characters).\n", MAX_PASSWORD_LEN - 1);
exit(1);
}
strncpy(password, optarg, MAX_PASSWORD_LEN - 1);
break;
case 'i':
interactive = 1; // Enable interactive mode
break;
case 'v':
verbose = 1; // Enable verbose mode
verbose = 1; // Enable verbose mode
break;
default:
fprintf(stderr, "Usage: %s -u <username> -p <password> [-v]\n", argv[0]);
print_usage(argv[0]);
exit(1);
}
}
// Check if both username and password are provided
if (username[0] == '\0' || password[0] == '\0') {
fprintf(stderr, "Usage: %s -u <username> -p <password> [-v]\n", argv[0]);
exit(1);
// If interactive mode is enabled, prompt for missing username and/or password
if (interactive) {
if (username[0] == '\0') {
prompt_for_input(username, sizeof(username), "Username: ", 0);
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: ", 1);
if (strlen(password) == 0) {
fprintf(stderr, "Error: Password cannot be empty.\n");
exit(1);
}
}
} else {
// If not in interactive mode, ensure username and password are provided
if (username[0] == '\0' || password[0] == '\0') {
fprintf(stderr, "Error: Username and password must be provided unless interactive mode is enabled.\n");
print_usage(argv[0]);
exit(1);
}
}
// Retrieve user information from the username