+++ /dev/null
-/*
- * chap-new.c - New CHAP implementation.
- *
- * Copyright (c) 2003 Paul Mackerras. All rights reserved.
- *
- * 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, this list of conditions and the following disclaimer.
- *
- * 2. The name(s) of the authors of this software must not be used to
- * endorse or promote products derived from this software without
- * prior written permission.
- *
- * 3. Redistributions of any form whatsoever must retain the following
- * acknowledgment:
- * "This product includes software developed by Paul Mackerras
- * <paulus@samba.org>".
- *
- * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
- * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
- * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
- * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
- * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-#define RCSID "$Id: chap-new.c,v 1.9 2007/06/19 02:08:35 carlsonj Exp $"
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <stdlib.h>
-#include <string.h>
-#include "pppd.h"
-#include "session.h"
-#include "chap-new.h"
-#include "chap-md5.h"
-
-#ifdef PPP_WITH_CHAPMS
-#include "chap_ms.h"
-#define MDTYPE_ALL (MDTYPE_MICROSOFT_V2 | MDTYPE_MICROSOFT | MDTYPE_MD5)
-#else
-#define MDTYPE_ALL (MDTYPE_MD5)
-#endif
-
-int chap_mdtype_all = MDTYPE_ALL;
-
-/* Hook for a plugin to validate CHAP challenge */
-int (*chap_verify_hook)(char *name, char *ourname, int id,
- struct chap_digest_type *digest,
- unsigned char *challenge, unsigned char *response,
- char *message, int message_space) = NULL;
-
-/*
- * Option variables.
- */
-int chap_server_timeout_time = 3;
-int chap_max_transmits = 10;
-int chap_rechallenge_time = 0;
-int chap_client_timeout_time = 60;
-int chapms_strip_domain = 0;
-
-/*
- * Command-line options.
- */
-static option_t chap_option_list[] = {
- { "chap-restart", o_int, &chap_server_timeout_time,
- "Set timeout for CHAP (as server)", OPT_PRIO },
- { "chap-max-challenge", o_int, &chap_max_transmits,
- "Set max #xmits for challenge", OPT_PRIO },
- { "chap-interval", o_int, &chap_rechallenge_time,
- "Set interval for rechallenge", OPT_PRIO },
- { "chap-timeout", o_int, &chap_client_timeout_time,
- "Set timeout for CHAP (as client)", OPT_PRIO },
- { "chapms-strip-domain", o_bool, &chapms_strip_domain,
- "Strip the domain prefix before the Username", 1 },
- { NULL }
-};
-
-/*
- * Internal state.
- */
-static struct chap_client_state {
- int flags;
- char *name;
- struct chap_digest_type *digest;
- unsigned char priv[64]; /* private area for digest's use */
-} client;
-
-/*
- * These limits apply to challenge and response packets we send.
- * The +4 is the +1 that we actually need rounded up.
- */
-#define CHAL_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_CHALLENGE_LEN + MAXNAMELEN)
-#define RESP_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_RESPONSE_LEN + MAXNAMELEN)
-
-static struct chap_server_state {
- int flags;
- int id;
- char *name;
- struct chap_digest_type *digest;
- int challenge_xmits;
- int challenge_pktlen;
- unsigned char challenge[CHAL_MAX_PKTLEN];
- char message[256];
-} server;
-
-/* Values for flags in chap_client_state and chap_server_state */
-#define LOWERUP 1
-#define AUTH_STARTED 2
-#define AUTH_DONE 4
-#define AUTH_FAILED 8
-#define TIMEOUT_PENDING 0x10
-#define CHALLENGE_VALID 0x20
-
-/*
- * Prototypes.
- */
-static void chap_init(int unit);
-static void chap_lowerup(int unit);
-static void chap_lowerdown(int unit);
-static void chap_server_timeout(void *arg);
-static void chap_client_timeout(void *arg);
-static void chap_generate_challenge(struct chap_server_state *ss);
-static void chap_handle_response(struct chap_server_state *ss, int code,
- unsigned char *pkt, int len);
-static int chap_verify_response(char *name, char *ourname, int id,
- struct chap_digest_type *digest,
- unsigned char *challenge, unsigned char *response,
- char *message, int message_space);
-static void chap_respond(struct chap_client_state *cs, int id,
- unsigned char *pkt, int len);
-static void chap_handle_status(struct chap_client_state *cs, int code, int id,
- unsigned char *pkt, int len);
-static void chap_protrej(int unit);
-static void chap_input(int unit, unsigned char *pkt, int pktlen);
-static int chap_print_pkt(unsigned char *p, int plen,
- void (*printer)(void *, char *, ...), void *arg);
-
-/* List of digest types that we know about */
-static struct chap_digest_type *chap_digests;
-
-/*
- * chap_init - reset to initial state.
- */
-static void
-chap_init(int unit)
-{
- memset(&client, 0, sizeof(client));
- memset(&server, 0, sizeof(server));
-
- chap_md5_init();
-#ifdef PPP_WITH_CHAPMS
- chapms_init();
-#endif
-}
-
-/*
- * Add a new digest type to the list.
- */
-void
-chap_register_digest(struct chap_digest_type *dp)
-{
- dp->next = chap_digests;
- chap_digests = dp;
-}
-
-/*
- * Lookup a digest type by code
- */
-struct chap_digest_type *
-chap_find_digest(int digest_code) {
- struct chap_digest_type *dp = NULL;
- for (dp = chap_digests; dp != NULL; dp = dp->next)
- if (dp->code == digest_code)
- break;
- return dp;
-}
-
-/*
- * chap_lowerup - we can start doing stuff now.
- */
-static void
-chap_lowerup(int unit)
-{
- struct chap_client_state *cs = &client;
- struct chap_server_state *ss = &server;
-
- cs->flags |= LOWERUP;
- ss->flags |= LOWERUP;
- if (ss->flags & AUTH_STARTED)
- chap_server_timeout(ss);
-}
-
-static void
-chap_lowerdown(int unit)
-{
- struct chap_client_state *cs = &client;
- struct chap_server_state *ss = &server;
-
- if (cs->flags & TIMEOUT_PENDING)
- UNTIMEOUT(chap_client_timeout, cs);
- cs->flags = 0;
- if (ss->flags & TIMEOUT_PENDING)
- UNTIMEOUT(chap_server_timeout, ss);
- ss->flags = 0;
-}
-
-/*
- * chap_auth_peer - Start authenticating the peer.
- * If the lower layer is already up, we start sending challenges,
- * otherwise we wait for the lower layer to come up.
- */
-void
-chap_auth_peer(int unit, char *our_name, int digest_code)
-{
- struct chap_server_state *ss = &server;
- struct chap_digest_type *dp;
-
- if (ss->flags & AUTH_STARTED) {
- error("CHAP: peer authentication already started!");
- return;
- }
-
- dp = chap_find_digest(digest_code);
- if (dp == NULL)
- fatal("CHAP digest 0x%x requested but not available",
- digest_code);
-
- ss->digest = dp;
- ss->name = our_name;
- /* Start with a random ID value */
- ss->id = (unsigned char)(drand48() * 256);
- ss->flags |= AUTH_STARTED;
- if (ss->flags & LOWERUP)
- chap_server_timeout(ss);
-}
-
-/*
- * chap_auth_with_peer - Prepare to authenticate ourselves to the peer.
- * There isn't much to do until we receive a challenge.
- */
-void
-chap_auth_with_peer(int unit, char *our_name, int digest_code)
-{
- struct chap_client_state *cs = &client;
- struct chap_digest_type *dp;
-
- if (cs->flags & AUTH_STARTED) {
- error("CHAP: authentication with peer already started!");
- return;
- }
- for (dp = chap_digests; dp != NULL; dp = dp->next)
- if (dp->code == digest_code)
- break;
- if (dp == NULL)
- fatal("CHAP digest 0x%x requested but not available",
- digest_code);
-
- cs->digest = dp;
- cs->name = our_name;
- cs->flags |= AUTH_STARTED | TIMEOUT_PENDING;
- TIMEOUT(chap_client_timeout, cs, chap_client_timeout_time);
-}
-
-/*
- * chap_server_timeout - It's time to send another challenge to the peer.
- * This could be either a retransmission of a previous challenge,
- * or a new challenge to start re-authentication.
- */
-static void
-chap_server_timeout(void *arg)
-{
- struct chap_server_state *ss = arg;
-
- ss->flags &= ~TIMEOUT_PENDING;
- if ((ss->flags & CHALLENGE_VALID) == 0) {
- ss->challenge_xmits = 0;
- chap_generate_challenge(ss);
- ss->flags |= CHALLENGE_VALID;
- } else if (ss->challenge_xmits >= chap_max_transmits) {
- ss->flags &= ~CHALLENGE_VALID;
- ss->flags |= AUTH_DONE | AUTH_FAILED;
- auth_peer_fail(0, PPP_CHAP);
- return;
- }
-
- output(0, ss->challenge, ss->challenge_pktlen);
- ++ss->challenge_xmits;
- ss->flags |= TIMEOUT_PENDING;
- TIMEOUT(chap_server_timeout, arg, chap_server_timeout_time);
-}
-
-/* chap_client_timeout - Authentication with peer timed out. */
-static void
-chap_client_timeout(void *arg)
-{
- struct chap_client_state *cs = arg;
-
- cs->flags &= ~TIMEOUT_PENDING;
- cs->flags |= AUTH_DONE | AUTH_FAILED;
- error("CHAP authentication timed out");
- auth_withpeer_fail(0, PPP_CHAP);
-}
-
-/*
- * chap_generate_challenge - generate a challenge string and format
- * the challenge packet in ss->challenge_pkt.
- */
-static void
-chap_generate_challenge(struct chap_server_state *ss)
-{
- int clen = 1, nlen, len;
- unsigned char *p;
-
- p = ss->challenge;
- MAKEHEADER(p, PPP_CHAP);
- p += CHAP_HDRLEN;
- ss->digest->generate_challenge(p);
- clen = *p;
- nlen = strlen(ss->name);
- memcpy(p + 1 + clen, ss->name, nlen);
-
- len = CHAP_HDRLEN + 1 + clen + nlen;
- ss->challenge_pktlen = PPP_HDRLEN + len;
-
- p = ss->challenge + PPP_HDRLEN;
- p[0] = CHAP_CHALLENGE;
- p[1] = ++ss->id;
- p[2] = len >> 8;
- p[3] = len;
-}
-
-/*
- * chap_handle_response - check the response to our challenge.
- */
-static void
-chap_handle_response(struct chap_server_state *ss, int id,
- unsigned char *pkt, int len)
-{
- int response_len, ok, mlen;
- unsigned char *response, *p;
- char *name = NULL; /* initialized to shut gcc up */
- int (*verifier)(char *, char *, int, struct chap_digest_type *,
- unsigned char *, unsigned char *, char *, int);
- char rname[MAXNAMELEN+1];
-
- if ((ss->flags & LOWERUP) == 0)
- return;
- if (id != ss->challenge[PPP_HDRLEN+1] || len < 2)
- return;
- if (ss->flags & CHALLENGE_VALID) {
- response = pkt;
- GETCHAR(response_len, pkt);
- len -= response_len + 1; /* length of name */
- name = (char *)pkt + response_len;
- if (len < 0)
- return;
-
- if (ss->flags & TIMEOUT_PENDING) {
- ss->flags &= ~TIMEOUT_PENDING;
- UNTIMEOUT(chap_server_timeout, ss);
- }
-
- if (explicit_remote) {
- name = remote_name;
- } else {
- /* Null terminate and clean remote name. */
- slprintf(rname, sizeof(rname), "%.*v", len, name);
- name = rname;
-
- /* strip the MS domain name */
- if (chapms_strip_domain && strrchr(rname, '\\')) {
- char tmp[MAXNAMELEN+1];
-
- strcpy(tmp, strrchr(rname, '\\') + 1);
- strcpy(rname, tmp);
- }
- }
-
- if (chap_verify_hook)
- verifier = chap_verify_hook;
- else
- verifier = chap_verify_response;
- ok = (*verifier)(name, ss->name, id, ss->digest,
- ss->challenge + PPP_HDRLEN + CHAP_HDRLEN,
- response, ss->message, sizeof(ss->message));
- if (!ok || !auth_number()) {
- ss->flags |= AUTH_FAILED;
- warn("Peer %q failed CHAP authentication", name);
- }
- } else if ((ss->flags & AUTH_DONE) == 0)
- return;
-
- /* send the response */
- p = outpacket_buf;
- MAKEHEADER(p, PPP_CHAP);
- mlen = strlen(ss->message);
- len = CHAP_HDRLEN + mlen;
- p[0] = (ss->flags & AUTH_FAILED)? CHAP_FAILURE: CHAP_SUCCESS;
- p[1] = id;
- p[2] = len >> 8;
- p[3] = len;
- if (mlen > 0)
- memcpy(p + CHAP_HDRLEN, ss->message, mlen);
- output(0, outpacket_buf, PPP_HDRLEN + len);
-
- if (ss->flags & CHALLENGE_VALID) {
- ss->flags &= ~CHALLENGE_VALID;
- if (!(ss->flags & AUTH_DONE) && !(ss->flags & AUTH_FAILED)) {
- /*
- * Auth is OK, so now we need to check session restrictions
- * to ensure everything is OK, but only if we used a
- * plugin, and only if we're configured to check. This
- * allows us to do PAM checks on PPP servers that
- * authenticate against ActiveDirectory, and use AD for
- * account info (like when using Winbind integrated with
- * PAM).
- */
- if (session_mgmt &&
- session_check(name, NULL, devnam, NULL) == 0) {
- ss->flags |= AUTH_FAILED;
- warn("Peer %q failed CHAP Session verification", name);
- }
- }
- if (ss->flags & AUTH_FAILED) {
- auth_peer_fail(0, PPP_CHAP);
- } else {
- if ((ss->flags & AUTH_DONE) == 0)
- auth_peer_success(0, PPP_CHAP,
- ss->digest->code,
- name, strlen(name));
- if (chap_rechallenge_time) {
- ss->flags |= TIMEOUT_PENDING;
- TIMEOUT(chap_server_timeout, ss,
- chap_rechallenge_time);
- }
- }
- ss->flags |= AUTH_DONE;
- }
-}
-
-/*
- * chap_verify_response - check whether the peer's response matches
- * what we think it should be. Returns 1 if it does (authentication
- * succeeded), or 0 if it doesn't.
- */
-static int
-chap_verify_response(char *name, char *ourname, int id,
- struct chap_digest_type *digest,
- unsigned char *challenge, unsigned char *response,
- char *message, int message_space)
-{
- int ok;
- unsigned char secret[MAXSECRETLEN];
- int secret_len;
-
- /* Get the secret that the peer is supposed to know */
- if (!get_secret(0, name, ourname, (char *)secret, &secret_len, 1)) {
- error("No CHAP secret found for authenticating %q", name);
- return 0;
- }
-
- ok = digest->verify_response(id, name, secret, secret_len, challenge,
- response, message, message_space);
- memset(secret, 0, sizeof(secret));
-
- return ok;
-}
-
-/*
- * chap_respond - Generate and send a response to a challenge.
- */
-static void
-chap_respond(struct chap_client_state *cs, int id,
- unsigned char *pkt, int len)
-{
- int clen, nlen;
- int secret_len;
- unsigned char *p;
- unsigned char response[RESP_MAX_PKTLEN];
- char rname[MAXNAMELEN+1];
- char secret[MAXSECRETLEN+1];
-
- if ((cs->flags & (LOWERUP | AUTH_STARTED)) != (LOWERUP | AUTH_STARTED))
- return; /* not ready */
- if (len < 2 || len < pkt[0] + 1)
- return; /* too short */
- clen = pkt[0];
- nlen = len - (clen + 1);
-
- /* Null terminate and clean remote name. */
- slprintf(rname, sizeof(rname), "%.*v", nlen, pkt + clen + 1);
-
- /* Microsoft doesn't send their name back in the PPP packet */
- if (explicit_remote || (remote_name[0] != 0 && rname[0] == 0))
- strlcpy(rname, remote_name, sizeof(rname));
-
- /* get secret for authenticating ourselves with the specified host */
- if (!get_secret(0, cs->name, rname, secret, &secret_len, 0)) {
- secret_len = 0; /* assume null secret if can't find one */
- warn("No CHAP secret found for authenticating us to %q", rname);
- }
-
- p = response;
- MAKEHEADER(p, PPP_CHAP);
- p += CHAP_HDRLEN;
-
- cs->digest->make_response(p, id, cs->name, pkt,
- secret, secret_len, cs->priv);
- memset(secret, 0, secret_len);
-
- clen = *p;
- nlen = strlen(cs->name);
- memcpy(p + clen + 1, cs->name, nlen);
-
- p = response + PPP_HDRLEN;
- len = CHAP_HDRLEN + clen + 1 + nlen;
- p[0] = CHAP_RESPONSE;
- p[1] = id;
- p[2] = len >> 8;
- p[3] = len;
-
- output(0, response, PPP_HDRLEN + len);
-}
-
-static void
-chap_handle_status(struct chap_client_state *cs, int code, int id,
- unsigned char *pkt, int len)
-{
- const char *msg = NULL;
-
- if ((cs->flags & (AUTH_DONE|AUTH_STARTED|LOWERUP))
- != (AUTH_STARTED|LOWERUP))
- return;
- cs->flags |= AUTH_DONE;
-
- UNTIMEOUT(chap_client_timeout, cs);
- cs->flags &= ~TIMEOUT_PENDING;
-
- if (code == CHAP_SUCCESS) {
- /* used for MS-CHAP v2 mutual auth, yuck */
- if (cs->digest->check_success != NULL) {
- if (!(*cs->digest->check_success)(id, pkt, len))
- code = CHAP_FAILURE;
- } else
- msg = "CHAP authentication succeeded";
- } else {
- if (cs->digest->handle_failure != NULL)
- (*cs->digest->handle_failure)(pkt, len);
- else
- msg = "CHAP authentication failed";
- }
- if (msg) {
- if (len > 0)
- info("%s: %.*v", msg, len, pkt);
- else
- info("%s", msg);
- }
- if (code == CHAP_SUCCESS)
- auth_withpeer_success(0, PPP_CHAP, cs->digest->code);
- else {
- cs->flags |= AUTH_FAILED;
- error("CHAP authentication failed");
- auth_withpeer_fail(0, PPP_CHAP);
- }
-}
-
-static void
-chap_input(int unit, unsigned char *pkt, int pktlen)
-{
- struct chap_client_state *cs = &client;
- struct chap_server_state *ss = &server;
- unsigned char code, id;
- int len;
-
- if (pktlen < CHAP_HDRLEN)
- return;
- GETCHAR(code, pkt);
- GETCHAR(id, pkt);
- GETSHORT(len, pkt);
- if (len < CHAP_HDRLEN || len > pktlen)
- return;
- len -= CHAP_HDRLEN;
-
- switch (code) {
- case CHAP_CHALLENGE:
- chap_respond(cs, id, pkt, len);
- break;
- case CHAP_RESPONSE:
- chap_handle_response(ss, id, pkt, len);
- break;
- case CHAP_FAILURE:
- case CHAP_SUCCESS:
- chap_handle_status(cs, code, id, pkt, len);
- break;
- }
-}
-
-static void
-chap_protrej(int unit)
-{
- struct chap_client_state *cs = &client;
- struct chap_server_state *ss = &server;
-
- if (ss->flags & TIMEOUT_PENDING) {
- ss->flags &= ~TIMEOUT_PENDING;
- UNTIMEOUT(chap_server_timeout, ss);
- }
- if (ss->flags & AUTH_STARTED) {
- ss->flags = 0;
- auth_peer_fail(0, PPP_CHAP);
- }
- if ((cs->flags & (AUTH_STARTED|AUTH_DONE)) == AUTH_STARTED) {
- cs->flags &= ~AUTH_STARTED;
- error("CHAP authentication failed due to protocol-reject");
- auth_withpeer_fail(0, PPP_CHAP);
- }
-}
-
-/*
- * chap_print_pkt - print the contents of a CHAP packet.
- */
-static char *chap_code_names[] = {
- "Challenge", "Response", "Success", "Failure"
-};
-
-static int
-chap_print_pkt(unsigned char *p, int plen,
- void (*printer)(void *, char *, ...), void *arg)
-{
- int code, id, len;
- int clen, nlen;
- unsigned char x;
-
- if (plen < CHAP_HDRLEN)
- return 0;
- GETCHAR(code, p);
- GETCHAR(id, p);
- GETSHORT(len, p);
- if (len < CHAP_HDRLEN || len > plen)
- return 0;
-
- if (code >= 1 && code <= sizeof(chap_code_names) / sizeof(char *))
- printer(arg, " %s", chap_code_names[code-1]);
- else
- printer(arg, " code=0x%x", code);
- printer(arg, " id=0x%x", id);
- len -= CHAP_HDRLEN;
- switch (code) {
- case CHAP_CHALLENGE:
- case CHAP_RESPONSE:
- if (len < 1)
- break;
- clen = p[0];
- if (len < clen + 1)
- break;
- ++p;
- nlen = len - clen - 1;
- printer(arg, " <");
- for (; clen > 0; --clen) {
- GETCHAR(x, p);
- printer(arg, "%.2x", x);
- }
- printer(arg, ">, name = ");
- print_string((char *)p, nlen, printer, arg);
- break;
- case CHAP_FAILURE:
- case CHAP_SUCCESS:
- printer(arg, " ");
- print_string((char *)p, len, printer, arg);
- break;
- default:
- for (clen = len; clen > 0; --clen) {
- GETCHAR(x, p);
- printer(arg, " %.2x", x);
- }
- }
-
- return len + CHAP_HDRLEN;
-}
-
-struct protent chap_protent = {
- PPP_CHAP,
- chap_init,
- chap_input,
- chap_protrej,
- chap_lowerup,
- chap_lowerdown,
- NULL, /* open */
- NULL, /* close */
- chap_print_pkt,
- NULL, /* datainput */
- 1, /* enabled_flag */
- "CHAP", /* name */
- NULL, /* data_name */
- chap_option_list,
- NULL, /* check_options */
-};
projects / ppp.git / blobdiff