freebsd-skq/usr.sbin/ppp/chap.c
Brian Somers a2240f353a Allow leading ``!'' characters in authkeys and chat scripts to
be doubled up to mean a single literaly ``!''.
2000-08-09 19:29:50 +00:00

785 lines
21 KiB
C

/*
* 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.
*
* $FreeBSD$
*
* TODO:
*/
#include <sys/param.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <sys/un.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_DES
#include <md4.h>
#endif
#include <md5.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <termios.h>
#include <unistd.h>
#include "layer.h"
#include "mbuf.h"
#include "log.h"
#include "defs.h"
#include "timer.h"
#include "fsm.h"
#include "proto.h"
#include "lqr.h"
#include "hdlc.h"
#include "lcp.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
#include "id.h"
static const char * const 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 = m_get(plen, MB_CHAPOUT);
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,
LINK_QUEUES(&physical->link) - 1, 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];
pid_t pid;
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;
}
pid = getpid();
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();
if ((argc = command_Interpret(prog, strlen(prog), argv)) <= 0) {
if (argc < 0) {
log_Printf(LogWARN, "CHAP: Invalid command syntax\n");
_exit(255);
}
_exit(0);
}
close(in[1]);
close(out[0]);
if (out[1] == STDIN_FILENO)
out[1] = dup(out[1]);
dup2(in[0], STDIN_FILENO);
dup2(out[1], STDOUT_FILENO);
close(STDERR_FILENO);
if (open(_PATH_DEVNULL, O_RDWR) != STDERR_FILENO) {
log_Printf(LogALERT, "Chap: Failed to open %s: %s\n",
_PATH_DEVNULL, strerror(errno));
exit(1);
}
for (fd = getdtablesize(); fd > STDERR_FILENO; fd--)
fcntl(fd, F_SETFD, 1);
setuid(ID0realuid());
command_Expand(nargv, argc, (char const *const *)argv,
chap->auth.physical->dl->bundle, 0, pid);
execvp(nargv[0], nargv);
printf("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 fdescriptor *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 fdescriptor *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 fdescriptor *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 fdescriptor *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;
#ifdef HAVE_DES
int lanman;
#endif
if (p == NULL) {
log_Printf(LogERROR, "chap_Input: Not a physical link - dropped\n");
m_freem(bp);
return NULL;
}
if (bundle_Phase(bundle) != PHASE_NETWORK &&
bundle_Phase(bundle) != PHASE_AUTHENTICATE) {
log_Printf(LogPHASE, "Unexpected chap input - dropped !\n");
m_freem(bp);
return NULL;
}
m_settype(bp, MB_CHAPIN);
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 = m_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);
m_freem(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");
m_freem(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");
m_freem(bp);
return NULL;
}
if ((ans = malloc(alen + 2)) == NULL) {
log_Printf(LogERROR, "Chap Input: Out of memory !\n");
m_freem(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");
m_freem(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 == '!' && bundle->cfg.auth.key[1] != '!')
chap_StartChild(chap, bundle->cfg.auth.key + 1,
bundle->cfg.auth.name);
else
chap_Respond(chap, bundle->cfg.auth.name, bundle->cfg.auth.key +
(*bundle->cfg.auth.key == '!' ? 1 : 0),
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) {
u_char end;
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);
}
m_freem(bp);
return NULL;
}