68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
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/* $Header: https://svn.ita.chalmers.se/repos/security/edu/course/computer_security/trunk/lab/login_linux/makepass.c 584 2013-01-19 10:30:22Z pk@CHALMERS.SE $ */
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/* makepass.c - Make a UNIX password */
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/* compile with: gcc -o makepass makepass.c -lcrypt */
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/* usage: "makepass 'salt'" */
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#include <crypt.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <strings.h>
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#include <unistd.h>
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int is_salt(char *salt) {
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char salts[] =
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"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789./";
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return strlen(salt) == 2 && strchr(salts, salt[0]) != 0
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&& strchr(salts, salt[1]) != 0 && salt[0] != '\0' && salt[1] != '\0';
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}
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int main(int argc, char *argv[]) {
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char *clear;
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char clear1[9];
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char *clear2;
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if (argc != 2) {
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fprintf(stderr, "Usage: %s salt\n", argv[0]);
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return 1;
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}
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if (!is_salt(argv[1])) {
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fprintf(stderr, "(%s) is illegal salt!\n", argv[1]);
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return 2;
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}
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clear = getpass("Password: ");
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if (clear == NULL) {
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bzero(clear, 8);
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fprintf(stderr, "Not a tty!");
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return 3;
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}
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strncpy(clear1, clear, 8);
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bzero(clear, 8);
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clear2 = getpass("Re-enter password: ");
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if (clear2 == NULL) {
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bzero(clear2, 8);
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fprintf(stderr, "Not a tty!");
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return 3;
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}
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if (strcmp(clear1, clear2) != 0) {
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fprintf(stderr, "Sorry, passwords don't match.\n");
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bzero(clear1, 8);
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bzero(clear2, 8);
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return 4;
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}
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printf("Encrypted password: \"%s\"\n", crypt(clear1, argv[1]));
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bzero(clear1, 8);
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bzero(clear2, 8);
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return 0;
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}
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