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/*
* APOP (RFC-1460) authentication mechanism.
*
* Copyright (c) 2004 Andrey Panin <pazke@donpac.ru>
*
* This software is released under the MIT license.
*/
#include "auth-common.h"
#include "mech.h"
#include "passdb.h"
#include "md5.h"
#include "buffer.h"
#include "auth-client-connection.h"
#include "auth-master-connection.h"
#include <stdio.h>
#include <unistd.h>
struct apop_auth_request {
struct auth_request auth_request;
pool_t pool;
/* requested: */
char *challenge;
/* received: */
unsigned char response_digest[16];
};
static bool verify_credentials(struct apop_auth_request *request,
const unsigned char *credentials, size_t size)
{
unsigned char digest[16];
struct md5_context ctx;
md5_init(&ctx);
md5_update(&ctx, request->challenge, strlen(request->challenge));
md5_update(&ctx, credentials, size);
md5_final(&ctx, digest);
return mem_equals_timing_safe(digest, request->response_digest, 16);
}
static void
apop_credentials_callback(enum passdb_result result,
const unsigned char *credentials, size_t size,
struct auth_request *auth_request)
{
struct apop_auth_request *request =
(struct apop_auth_request *)auth_request;
switch (result) {
case PASSDB_RESULT_OK:
if (verify_credentials(request, credentials, size))
auth_request_success(auth_request, "", 0);
else
auth_request_fail(auth_request);
break;
case PASSDB_RESULT_INTERNAL_FAILURE:
auth_request_internal_failure(auth_request);
break;
default:
auth_request_fail(auth_request);
break;
}
}
static void
mech_apop_auth_initial(struct auth_request *auth_request,
const unsigned char *data, size_t data_size)
{
struct apop_auth_request *request =
(struct apop_auth_request *)auth_request;
const unsigned char *tmp, *end, *username = NULL;
unsigned long pid, connect_uid, timestamp;
const char *error;
/* pop3-login handles sending the challenge and getting the response.
Our input here is: <challenge> \0 <username> \0 <response> */
if (data_size == 0) {
/* Should never happen */
e_info(auth_request->mech_event,
"no initial response");
auth_request_fail(auth_request);
return;
}
tmp = data;
end = data + data_size;
/* get the challenge */
while (tmp != end && *tmp != '\0')
tmp++;
request->challenge = p_strdup_until(request->pool, data, tmp);
if (tmp != end) {
/* get the username */
username = ++tmp;
while (tmp != end && *tmp != '\0')
tmp++;
} else {
/* should never happen */
e_info(auth_request->mech_event,
"malformed data");
auth_request_fail(auth_request);
return;
}
if (tmp + 1 + 16 != end) {
/* Should never happen */
e_info(auth_request->mech_event,
"malformed data");
auth_request_fail(auth_request);
return;
}
memcpy(request->response_digest, tmp + 1,
sizeof(request->response_digest));
/* the challenge must begin with trusted unique ID. we trust only
ourself, so make sure it matches our connection specific UID
which we told to client in handshake. Also require a timestamp
which is later than this process's start time. */
if (sscanf(request->challenge, "<%lx.%lx.%lx.",
&pid, &connect_uid, ×tamp) != 3 ||
connect_uid != auth_request->connect_uid ||
pid != (unsigned long)getpid() ||
(time_t)timestamp < process_start_time) {
e_info(auth_request->mech_event,
"invalid challenge");
auth_request_fail(auth_request);
return;
}
if (!auth_request_set_username(auth_request, (const char *)username,
&error)) {
e_info(auth_request->mech_event, "%s", error);
auth_request_fail(auth_request);
return;
}
auth_request_lookup_credentials(auth_request, "PLAIN",
apop_credentials_callback);
}
static struct auth_request *mech_apop_auth_new(void)
{
struct apop_auth_request *request;
pool_t pool;
pool = pool_alloconly_create(MEMPOOL_GROWING"apop_auth_request", 2048);
request = p_new(pool, struct apop_auth_request, 1);
request->pool = pool;
request->auth_request.pool = pool;
return &request->auth_request;
}
const struct mech_module mech_apop = {
"APOP",
.flags = MECH_SEC_PRIVATE | MECH_SEC_DICTIONARY | MECH_SEC_ACTIVE |
MECH_SEC_ALLOW_NULS,
.passdb_need = MECH_PASSDB_NEED_VERIFY_RESPONSE,
mech_apop_auth_new,
mech_apop_auth_initial,
NULL,
mech_generic_auth_free
};
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