/* * PPP CHAP Module * * Written by Toshiharu OHNO (tony-o@iij.ad.jp) * * Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd. * * Redistribution and use in source and binary forms are permitted * provided that the above copyright notice and this paragraph are * duplicated in all such forms and that any documentation, * advertising materials, and other materials related to such * distribution and use acknowledge that the software was developed * by the Internet Initiative Japan, Inc. The name of the * IIJ may not be used to endorse or promote products derived * from this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * $Id: chap.c,v 1.49 1999/04/21 08:03:51 brian Exp $ * * TODO: */ #include #include #include #include #include #include #include #ifdef HAVE_DES #include #endif #include #include #include #include #include #include #include #include #include "layer.h" #include "mbuf.h" #include "log.h" #include "defs.h" #include "timer.h" #include "fsm.h" #include "proto.h" #include "lcp.h" #include "lqr.h" #include "hdlc.h" #include "auth.h" #include "async.h" #include "throughput.h" #include "descriptor.h" #include "chap.h" #include "iplist.h" #include "slcompress.h" #include "ipcp.h" #include "filter.h" #include "ccp.h" #include "link.h" #include "physical.h" #include "mp.h" #ifndef NORADIUS #include "radius.h" #endif #include "bundle.h" #include "chat.h" #include "cbcp.h" #include "command.h" #include "datalink.h" #ifdef HAVE_DES #include "chap_ms.h" #endif static const char *chapcodes[] = { "???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE" }; #define MAXCHAPCODE (sizeof chapcodes / sizeof chapcodes[0] - 1) static void ChapOutput(struct physical *physical, u_int code, u_int id, const u_char *ptr, int count, const char *text) { int plen; struct fsmheader lh; struct mbuf *bp; plen = sizeof(struct fsmheader) + count; lh.code = code; lh.id = id; lh.length = htons(plen); bp = mbuf_Alloc(plen, MB_FSM); memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader)); if (count) memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count); log_DumpBp(LogDEBUG, "ChapOutput", bp); if (text == NULL) log_Printf(LogPHASE, "Chap Output: %s\n", chapcodes[code]); else log_Printf(LogPHASE, "Chap Output: %s (%s)\n", chapcodes[code], text); link_PushPacket(&physical->link, bp, physical->dl->bundle, PRI_LINK, PROTO_CHAP); } static char * chap_BuildAnswer(char *name, char *key, u_char id, char *challenge, u_char type #ifdef HAVE_DES , int lanman #endif ) { char *result, *digest; size_t nlen, klen; nlen = strlen(name); klen = strlen(key); #ifdef HAVE_DES if (type == 0x80) { char expkey[AUTHLEN << 2]; MD4_CTX MD4context; int f; if ((result = malloc(1 + nlen + MS_CHAP_RESPONSE_LEN)) == NULL) return result; digest = result; /* the response */ *digest++ = MS_CHAP_RESPONSE_LEN; /* 49 */ memcpy(digest + MS_CHAP_RESPONSE_LEN, name, nlen); if (lanman) { memset(digest + 24, '\0', 25); mschap_LANMan(digest, challenge + 1, key); /* LANMan response */ } else { memset(digest, '\0', 25); digest += 24; for (f = 0; f < klen; f++) { expkey[2*f] = key[f]; expkey[2*f+1] = '\0'; } /* * ----------- * expkey = | k\0e\0y\0 | * ----------- */ MD4Init(&MD4context); MD4Update(&MD4context, expkey, klen << 1); MD4Final(digest, &MD4context); /* * ---- -------- ---------------- ------- ------ * result = | 49 | LANMan | 16 byte digest | 9 * ? | name | * ---- -------- ---------------- ------- ------ */ mschap_NT(digest, challenge + 1); } /* * ---- -------- ------------- ----- ------ * | | struct MS_ChapResponse24 | | * result = | 49 | LANMan | NT digest | 0/1 | name | * ---- -------- ------------- ----- ------ * where only one of LANMan & NT digest are set. */ } else #endif if ((result = malloc(nlen + 17)) != NULL) { /* Normal MD5 stuff */ MD5_CTX MD5context; digest = result; *digest++ = 16; /* value size */ MD5Init(&MD5context); MD5Update(&MD5context, &id, 1); MD5Update(&MD5context, key, klen); MD5Update(&MD5context, challenge + 1, *challenge); MD5Final(digest, &MD5context); memcpy(digest + 16, name, nlen); /* * ---- -------- ------ * result = | 16 | digest | name | * ---- -------- ------ */ } return result; } static void chap_StartChild(struct chap *chap, char *prog, const char *name) { char *argv[MAXARGS], *nargv[MAXARGS]; int argc, fd; int in[2], out[2]; if (chap->child.fd != -1) { log_Printf(LogWARN, "Chap: %s: Program already running\n", prog); return; } if (pipe(in) == -1) { log_Printf(LogERROR, "Chap: pipe: %s\n", strerror(errno)); return; } if (pipe(out) == -1) { log_Printf(LogERROR, "Chap: pipe: %s\n", strerror(errno)); close(in[0]); close(in[1]); return; } switch ((chap->child.pid = fork())) { case -1: log_Printf(LogERROR, "Chap: fork: %s\n", strerror(errno)); close(in[0]); close(in[1]); close(out[0]); close(out[1]); chap->child.pid = 0; return; case 0: timer_TermService(); close(in[1]); close(out[0]); if (out[1] == STDIN_FILENO) { fd = dup(out[1]); close(out[1]); out[1] = fd; } dup2(in[0], STDIN_FILENO); dup2(out[1], STDOUT_FILENO); if ((fd = open(_PATH_DEVNULL, O_RDWR)) == -1) { log_Printf(LogALERT, "Chap: Failed to open %s: %s\n", _PATH_DEVNULL, strerror(errno)); exit(1); } dup2(fd, STDERR_FILENO); fcntl(3, F_SETFD, 1); /* Set close-on-exec flag */ setuid(geteuid()); argc = command_Interpret(prog, strlen(prog), argv); command_Expand(nargv, argc, (char const *const *)argv, chap->auth.physical->dl->bundle, 0); execvp(nargv[0], nargv); log_Printf(LogWARN, "exec() of %s failed: %s\n", nargv[0], strerror(errno)); exit(255); default: close(in[0]); close(out[1]); chap->child.fd = out[0]; chap->child.buf.len = 0; write(in[1], chap->auth.in.name, strlen(chap->auth.in.name)); write(in[1], "\n", 1); write(in[1], chap->challenge.peer + 1, *chap->challenge.peer); write(in[1], "\n", 1); write(in[1], name, strlen(name)); write(in[1], "\n", 1); close(in[1]); break; } } static void chap_Cleanup(struct chap *chap, int sig) { if (chap->child.pid) { int status; close(chap->child.fd); chap->child.fd = -1; if (sig) kill(chap->child.pid, SIGTERM); chap->child.pid = 0; chap->child.buf.len = 0; if (wait(&status) == -1) log_Printf(LogERROR, "Chap: wait: %s\n", strerror(errno)); else if (WIFSIGNALED(status)) log_Printf(LogWARN, "Chap: Child received signal %d\n", WTERMSIG(status)); else if (WIFEXITED(status) && WEXITSTATUS(status)) log_Printf(LogERROR, "Chap: Child exited %d\n", WEXITSTATUS(status)); } *chap->challenge.local = *chap->challenge.peer = '\0'; #ifdef HAVE_DES chap->peertries = 0; #endif } static void chap_Respond(struct chap *chap, char *name, char *key, u_char type #ifdef HAVE_DES , int lm #endif ) { u_char *ans; ans = chap_BuildAnswer(name, key, chap->auth.id, chap->challenge.peer, type #ifdef HAVE_DES , lm #endif ); if (ans) { ChapOutput(chap->auth.physical, CHAP_RESPONSE, chap->auth.id, ans, *ans + 1 + strlen(name), name); #ifdef HAVE_DES chap->NTRespSent = !lm; #endif free(ans); } else ChapOutput(chap->auth.physical, CHAP_FAILURE, chap->auth.id, "Out of memory!", 14, NULL); } static int chap_UpdateSet(struct descriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n) { struct chap *chap = descriptor2chap(d); if (r && chap && chap->child.fd != -1) { FD_SET(chap->child.fd, r); if (*n < chap->child.fd + 1) *n = chap->child.fd + 1; log_Printf(LogTIMER, "Chap: fdset(r) %d\n", chap->child.fd); return 1; } return 0; } static int chap_IsSet(struct descriptor *d, const fd_set *fdset) { struct chap *chap = descriptor2chap(d); return chap && chap->child.fd != -1 && FD_ISSET(chap->child.fd, fdset); } static void chap_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset) { struct chap *chap = descriptor2chap(d); int got; got = read(chap->child.fd, chap->child.buf.ptr + chap->child.buf.len, sizeof chap->child.buf.ptr - chap->child.buf.len - 1); if (got == -1) { log_Printf(LogERROR, "Chap: Read: %s\n", strerror(errno)); chap_Cleanup(chap, SIGTERM); } else if (got == 0) { log_Printf(LogWARN, "Chap: Read: Child terminated connection\n"); chap_Cleanup(chap, SIGTERM); } else { char *name, *key, *end; chap->child.buf.len += got; chap->child.buf.ptr[chap->child.buf.len] = '\0'; name = chap->child.buf.ptr; name += strspn(name, " \t"); if ((key = strchr(name, '\n')) == NULL) end = NULL; else end = strchr(++key, '\n'); if (end == NULL) { if (chap->child.buf.len == sizeof chap->child.buf.ptr - 1) { log_Printf(LogWARN, "Chap: Read: Input buffer overflow\n"); chap_Cleanup(chap, SIGTERM); } } else { #ifdef HAVE_DES int lanman = chap->auth.physical->link.lcp.his_authtype == 0x80 && ((chap->NTRespSent && IsAccepted(chap->auth.physical->link.lcp.cfg.chap80lm)) || !IsAccepted(chap->auth.physical->link.lcp.cfg.chap80nt)); #endif while (end >= name && strchr(" \t\r\n", *end)) *end-- = '\0'; end = key - 1; while (end >= name && strchr(" \t\r\n", *end)) *end-- = '\0'; key += strspn(key, " \t"); chap_Respond(chap, name, key, chap->auth.physical->link.lcp.his_authtype #ifdef HAVE_DES , lanman #endif ); chap_Cleanup(chap, 0); } } } static int chap_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset) { /* We never want to write here ! */ log_Printf(LogALERT, "chap_Write: Internal error: Bad call !\n"); return 0; } static void chap_Challenge(struct authinfo *authp) { struct chap *chap = auth2chap(authp); int len, i; char *cp; len = strlen(authp->physical->dl->bundle->cfg.auth.name); if (!*chap->challenge.local) { randinit(); cp = chap->challenge.local; #ifndef NORADIUS if (*authp->physical->dl->bundle->radius.cfg.file) { /* For radius, our challenge is 16 readable NUL terminated bytes :*/ *cp++ = 16; for (i = 0; i < 16; i++) *cp++ = (random() % 10) + '0'; } else #endif { #ifdef HAVE_DES if (authp->physical->link.lcp.want_authtype == 0x80) *cp++ = 8; /* MS does 8 byte callenges :-/ */ else #endif *cp++ = random() % (CHAPCHALLENGELEN-16) + 16; for (i = 0; i < *chap->challenge.local; i++) *cp++ = random() & 0xff; } memcpy(cp, authp->physical->dl->bundle->cfg.auth.name, len); } ChapOutput(authp->physical, CHAP_CHALLENGE, authp->id, chap->challenge.local, 1 + *chap->challenge.local + len, NULL); } static void chap_Success(struct authinfo *authp) { datalink_GotAuthname(authp->physical->dl, authp->in.name); ChapOutput(authp->physical, CHAP_SUCCESS, authp->id, "Welcome!!", 10, NULL); authp->physical->link.lcp.auth_ineed = 0; if (Enabled(authp->physical->dl->bundle, OPT_UTMP)) physical_Login(authp->physical, authp->in.name); if (authp->physical->link.lcp.auth_iwait == 0) /* * Either I didn't need to authenticate, or I've already been * told that I got the answer right. */ datalink_AuthOk(authp->physical->dl); } static void chap_Failure(struct authinfo *authp) { ChapOutput(authp->physical, CHAP_FAILURE, authp->id, "Invalid!!", 9, NULL); datalink_AuthNotOk(authp->physical->dl); } static int chap_Cmp(u_char type, char *myans, int mylen, char *hisans, int hislen #ifdef HAVE_DES , int lm #endif ) { if (mylen != hislen) return 0; #ifdef HAVE_DES else if (type == 0x80) { int off = lm ? 0 : 24; if (memcmp(myans + off, hisans + off, 24)) return 0; } #endif else if (memcmp(myans, hisans, mylen)) return 0; return 1; } #ifdef HAVE_DES static int chap_HaveAnotherGo(struct chap *chap) { if (++chap->peertries < 3) { /* Give the peer another shot */ *chap->challenge.local = '\0'; chap_Challenge(&chap->auth); return 1; } return 0; } #endif void chap_Init(struct chap *chap, struct physical *p) { chap->desc.type = CHAP_DESCRIPTOR; chap->desc.UpdateSet = chap_UpdateSet; chap->desc.IsSet = chap_IsSet; chap->desc.Read = chap_Read; chap->desc.Write = chap_Write; chap->child.pid = 0; chap->child.fd = -1; auth_Init(&chap->auth, p, chap_Challenge, chap_Success, chap_Failure); *chap->challenge.local = *chap->challenge.peer = '\0'; #ifdef HAVE_DES chap->NTRespSent = 0; chap->peertries = 0; #endif } void chap_ReInit(struct chap *chap) { chap_Cleanup(chap, SIGTERM); } struct mbuf * chap_Input(struct bundle *bundle, struct link *l, struct mbuf *bp) { struct physical *p = link2physical(l); struct chap *chap = &p->dl->chap; char *name, *key, *ans; int len, nlen; u_char alen, end; #ifdef HAVE_DES int lanman; #endif if (p == NULL) { log_Printf(LogERROR, "chap_Input: Not a physical link - dropped\n"); mbuf_Free(bp); return NULL; } if (bundle_Phase(bundle) != PHASE_NETWORK && bundle_Phase(bundle) != PHASE_AUTHENTICATE) { log_Printf(LogPHASE, "Unexpected chap input - dropped !\n"); mbuf_Free(bp); return NULL; } if ((bp = auth_ReadHeader(&chap->auth, bp)) == NULL && ntohs(chap->auth.in.hdr.length) == 0) log_Printf(LogWARN, "Chap Input: Truncated header !\n"); else if (chap->auth.in.hdr.code == 0 || chap->auth.in.hdr.code > MAXCHAPCODE) log_Printf(LogPHASE, "Chap Input: %d: Bad CHAP code !\n", chap->auth.in.hdr.code); else { len = mbuf_Length(bp); ans = NULL; if (chap->auth.in.hdr.code != CHAP_CHALLENGE && chap->auth.id != chap->auth.in.hdr.id && Enabled(bundle, OPT_IDCHECK)) { /* Wrong conversation dude ! */ log_Printf(LogPHASE, "Chap Input: %s dropped (got id %d, not %d)\n", chapcodes[chap->auth.in.hdr.code], chap->auth.in.hdr.id, chap->auth.id); mbuf_Free(bp); return NULL; } chap->auth.id = chap->auth.in.hdr.id; /* We respond with this id */ #ifdef HAVE_DES lanman = 0; #endif switch (chap->auth.in.hdr.code) { case CHAP_CHALLENGE: bp = mbuf_Read(bp, &alen, 1); len -= alen + 1; if (len < 0) { log_Printf(LogERROR, "Chap Input: Truncated challenge !\n"); mbuf_Free(bp); return NULL; } *chap->challenge.peer = alen; bp = mbuf_Read(bp, chap->challenge.peer + 1, alen); bp = auth_ReadName(&chap->auth, bp, len); #ifdef HAVE_DES lanman = p->link.lcp.his_authtype == 0x80 && ((chap->NTRespSent && IsAccepted(p->link.lcp.cfg.chap80lm)) || !IsAccepted(p->link.lcp.cfg.chap80nt)); #endif break; case CHAP_RESPONSE: auth_StopTimer(&chap->auth); bp = mbuf_Read(bp, &alen, 1); len -= alen + 1; if (len < 0) { log_Printf(LogERROR, "Chap Input: Truncated response !\n"); mbuf_Free(bp); return NULL; } if ((ans = malloc(alen + 2)) == NULL) { log_Printf(LogERROR, "Chap Input: Out of memory !\n"); mbuf_Free(bp); return NULL; } *ans = chap->auth.id; bp = mbuf_Read(bp, ans + 1, alen); ans[alen+1] = '\0'; bp = auth_ReadName(&chap->auth, bp, len); #ifdef HAVE_DES lanman = alen == 49 && ans[alen] == 0; #endif break; case CHAP_SUCCESS: case CHAP_FAILURE: /* chap->auth.in.name is already set up at CHALLENGE time */ if ((ans = malloc(len + 1)) == NULL) { log_Printf(LogERROR, "Chap Input: Out of memory !\n"); mbuf_Free(bp); return NULL; } bp = mbuf_Read(bp, ans, len); ans[len] = '\0'; break; } switch (chap->auth.in.hdr.code) { case CHAP_CHALLENGE: case CHAP_RESPONSE: if (*chap->auth.in.name) log_Printf(LogPHASE, "Chap Input: %s (%d bytes from %s%s)\n", chapcodes[chap->auth.in.hdr.code], alen, chap->auth.in.name, #ifdef HAVE_DES lanman && chap->auth.in.hdr.code == CHAP_RESPONSE ? " - lanman" : #endif ""); else log_Printf(LogPHASE, "Chap Input: %s (%d bytes%s)\n", chapcodes[chap->auth.in.hdr.code], alen, #ifdef HAVE_DES lanman && chap->auth.in.hdr.code == CHAP_RESPONSE ? " - lanman" : #endif ""); break; case CHAP_SUCCESS: case CHAP_FAILURE: if (*ans) log_Printf(LogPHASE, "Chap Input: %s (%s)\n", chapcodes[chap->auth.in.hdr.code], ans); else log_Printf(LogPHASE, "Chap Input: %s\n", chapcodes[chap->auth.in.hdr.code]); break; } switch (chap->auth.in.hdr.code) { case CHAP_CHALLENGE: if (*bundle->cfg.auth.key == '!') chap_StartChild(chap, bundle->cfg.auth.key + 1, bundle->cfg.auth.name); else chap_Respond(chap, bundle->cfg.auth.name, bundle->cfg.auth.key, p->link.lcp.his_authtype #ifdef HAVE_DES , lanman #endif ); break; case CHAP_RESPONSE: name = chap->auth.in.name; nlen = strlen(name); #ifndef NORADIUS if (*bundle->radius.cfg.file) { end = chap->challenge.local[*chap->challenge.local+1]; chap->challenge.local[*chap->challenge.local+1] = '\0'; radius_Authenticate(&bundle->radius, &chap->auth, chap->auth.in.name, ans, chap->challenge.local + 1); chap->challenge.local[*chap->challenge.local+1] = end; } else #endif { key = auth_GetSecret(bundle, name, nlen, p); if (key) { char *myans; #ifdef HAVE_DES if (lanman && !IsEnabled(p->link.lcp.cfg.chap80lm)) { log_Printf(LogPHASE, "Auth failure: LANMan not enabled\n"); if (chap_HaveAnotherGo(chap)) break; key = NULL; } else if (!lanman && !IsEnabled(p->link.lcp.cfg.chap80nt) && p->link.lcp.want_authtype == 0x80) { log_Printf(LogPHASE, "Auth failure: mschap not enabled\n"); if (chap_HaveAnotherGo(chap)) break; key = NULL; } else #endif { myans = chap_BuildAnswer(name, key, chap->auth.id, chap->challenge.local, p->link.lcp.want_authtype #ifdef HAVE_DES , lanman #endif ); if (myans == NULL) key = NULL; else { if (!chap_Cmp(p->link.lcp.want_authtype, myans + 1, *myans, ans + 1, alen #ifdef HAVE_DES , lanman #endif )) key = NULL; free(myans); } } } if (key) chap_Success(&chap->auth); else chap_Failure(&chap->auth); } break; case CHAP_SUCCESS: if (p->link.lcp.auth_iwait == PROTO_CHAP) { p->link.lcp.auth_iwait = 0; if (p->link.lcp.auth_ineed == 0) /* * We've succeeded in our ``login'' * If we're not expecting the peer to authenticate (or he already * has), proceed to network phase. */ datalink_AuthOk(p->dl); } break; case CHAP_FAILURE: datalink_AuthNotOk(p->dl); break; } free(ans); } mbuf_Free(bp); return NULL; }