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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:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* 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.
* Neither the name of Red Hat, Inc., nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#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;
}
}
strcpy(prompt_text, values[(r % 3)]);
want = values[((r + 1) % 3)];
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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