micro-utils/libmu/pw_check.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include "pw_check.h"
#include "config.h"

void dec_salt(void) {
	size_t i;
	for (i = 0; i < sizeof(MU_SALT_ENC) / sizeof(int); i++)
		MU_SALT_BUF[i] = (char)MU_SALT_ENC[i];

	MU_SALT_BUF[i + 1] = '\0';
}

char *enc_password(const char *prog_name, const char *pass, const char *salt) {
	if (salt == NULL)
		dec_salt();

	char *cpass = crypt(pass, (salt == NULL) ? MU_SALT_BUF : salt);
	if (cpass == NULL) {
		if (prog_name != NULL)
			fprintf(stderr, "%s: %s\n", prog_name, strerror(errno));

		return NULL;
	}

	return cpass;
}

int pw_check(const char *prog_name, const struct passwd *pw, const char *pass) {
	if (pw->pw_passwd[0] == '\0' && pass[0] == '\0')
		return 0;

	if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*') {
		if (prog_name != NULL)
			fprintf(stderr, "%s: Access denied\n", prog_name);

		return 1;
	}

	char *cpass = enc_password(prog_name, pass, NULL);
	if (cpass == NULL)
		return 1;

	if (!strcmp(pw->pw_passwd, cpass))
		return 0;

	if (prog_name != NULL)
		fprintf(stderr, "%s: Incorrect password\n", prog_name);

	return 1;
}