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/*
* Copyright (c) 2003,2010 Red Hat, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <security/pam_ext.h>
int
pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
const char *values[] = {
"\x72\x6f\x63\x6b",
"\x70\x61\x70\x65\x72",
"\x73\x63\x69\x73\x73\x6f\x72\x73"};
char prompt_text[32] = "";
const char *want = "";
char *response = NULL;
int debug = 0;
int ret, fd, r, i;
unsigned char c;
for (i = 0; i < argc; i++) {
if (strcmp(argv[i], "debug") == 0) {
debug = 1;
break;
}
}
r = -1;
for (i = 0; i < argc; i++) {
if (strncmp(argv[i], "throw=", 6) == 0) {
r = atol(argv[i] + 6) % 3;
break;
}
}
if (r == -1) {
r = 0;
fd = open("/dev/urandom", O_RDONLY);
if (fd != -1) {
c = 0;
do {
ret = read(fd, &c, 1);
} while ( ((ret == 1) && (c == 0xff)) ||
((ret == -1) && (errno == EINTR)) );
/* We drop 0xff here to avoid a variation on
* Bleichenbacher's attack. */
r = c / 85;
close(fd);
} else {
/* Something is wrong with /dev/urandom */
return PAM_CONV_ERR;
}
}
switch (r) {
case 0:
strcpy(prompt_text, values[0]);
want = values[1];
break;
case 1:
strcpy(prompt_text, values[1]);
want = values[2];
break;
case 2:
strcpy(prompt_text, values[2]);
want = values[0];
break;
}
if (debug) {
pam_syslog(pamh, LOG_DEBUG, "challenge is \"%s\", "
"expected response is \"%s\"", prompt_text, want);
}
ret = pam_prompt(pamh, PAM_PROMPT_ECHO_OFF, &response, "%s: ", prompt_text);
if (ret != PAM_SUCCESS) {
pam_syslog(pamh, LOG_CRIT, "conversation error");
return PAM_CONV_ERR;
}
if ((response != NULL) &&
(strcasecmp(response, want) == 0)) {
ret = PAM_SUCCESS;
} else {
ret = PAM_AUTH_ERR;
}
if (response) {
_pam_overwrite(response);
free(response);
}
return ret;
}
int
pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
return PAM_SUCCESS;
}
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