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vty_auth.c
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vty_auth.c
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#include "config.h"
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <security/pam_appl.h>
#include <security/pam_misc.h>
#include "utils.h"
#include "vty_auth.h"
#include "vty_utils.h"
static int knet_pam_misc_conv(int num_msg, const struct pam_message **msgm,
struct pam_response **response, void *appdata_ptr)
{
int count = 0;
struct pam_response *reply;
int vty_sock = *(int *)appdata_ptr;
if (num_msg <= 0)
return PAM_CONV_ERR;
reply = (struct pam_response *) calloc(num_msg, sizeof(struct pam_response));
if (reply == NULL)
return PAM_CONV_ERR;
for (count=0; count < num_msg; ++count) {
unsigned char readbuf[VTY_MAX_BUFFER_SIZE];
char *string=NULL;
int nc;
memset(readbuf, 0, sizeof(readbuf));
switch (msgm[count]->msg_style) {
case PAM_PROMPT_ECHO_OFF:
if (knet_vty_set_echo(vty_sock, 0) < 0) {
knet_vty_write(vty_sock, "Unable to turn off terminal/telnet echo");
goto failed_conversation;
}
knet_vty_write(vty_sock, "%s", msgm[count]->msg);
nc = knet_vty_read(vty_sock, readbuf, sizeof(readbuf));
if (nc < 0)
goto failed_conversation;
if (knet_vty_set_echo(vty_sock, 1) < 0) {
/* doesn't really make a lot of sense tho.... */
knet_vty_write(vty_sock, "Unable to turn on terminal/telnet echo");
goto failed_conversation;
}
knet_vty_write(vty_sock, "\n");
readbuf[nc-2] = 0;
string = strdup((const char*)readbuf);
if (!string)
goto failed_conversation;
break;
case PAM_PROMPT_ECHO_ON:
knet_vty_write(vty_sock, "\n%s", msgm[count]->msg);
nc = knet_vty_read(vty_sock, readbuf, sizeof(readbuf));
if (nc < 0)
goto failed_conversation;
readbuf[nc-2] = 0;
string = strdup((const char*)readbuf);
if (!string)
goto failed_conversation;
break;
case PAM_ERROR_MSG:
log_error("Received PAM error message %s", msgm[count]->msg);
knet_vty_write(vty_sock, "%s", msgm[count]->msg);
break;
case PAM_TEXT_INFO:
log_error("Received PAM text info: %s", msgm[count]->msg);
knet_vty_write(vty_sock, "%s", msgm[count]->msg);
break;
default:
log_error("Unknown PAM conversation message");
knet_vty_write(vty_sock, "Unknown PAM conversation message");
goto failed_conversation;
}
if (string) {
reply[count].resp_retcode = 0;
reply[count].resp = string;
string = NULL;
}
}
*response = reply;
reply = NULL;
return PAM_SUCCESS;
failed_conversation:
log_error("PAM conversation error");
knet_vty_write(vty_sock, "PAM conversation error");
if (reply) {
for (count=0; count < num_msg; ++count) {
if (reply[count].resp == NULL)
continue;
switch (msgm[count]->msg_style) {
case PAM_PROMPT_ECHO_ON:
case PAM_PROMPT_ECHO_OFF:
_pam_overwrite(reply[count].resp);
free(reply[count].resp);
break;
case PAM_BINARY_PROMPT:
{
void *bt_ptr = reply[count].resp;
pam_binary_handler_free(appdata_ptr, bt_ptr);
break;
}
case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
free(reply[count].resp);
}
}
free(reply);
reply = NULL;
}
return PAM_CONV_ERR;
}
#define AUTH_MAX_RETRY 3
int knet_vty_auth_user(int vty_sock)
{
pam_handle_t *pamh=NULL;
struct pam_conv conv;
int err;
int retry = 1;
conv.conv = knet_pam_misc_conv;
conv.appdata_ptr = (void *)&vty_sock;
retry_auth:
err = pam_start("kronosnet", NULL, &conv, &pamh);
if (err != PAM_SUCCESS)
goto out_clean;
err = pam_authenticate(pamh, 0);
if (err != PAM_SUCCESS)
goto out_clean;
err = pam_acct_mgmt(pamh, 0);
if (err != PAM_SUCCESS)
goto out_clean;
out_clean:
if (pamh) {
pam_end(pamh, err);
pamh = NULL;
}
if ((err != PAM_SUCCESS) && (retry < AUTH_MAX_RETRY)) {
retry++;
goto retry_auth;
}
if ((err != PAM_SUCCESS) && (retry = AUTH_MAX_RETRY))
knet_vty_write(vty_sock, "%s", pam_strerror(pamh, err));
knet_vty_write(vty_sock, "\n");
return err;
}