HardenedBSD/usr.sbin/ppp/chap.c
Brian Somers 442f849547 o Split the two IPCP queues into three - one for FSM data
(LCP/CCP/IPCP), one for urgent IP traffic and one for
  everything else.
o Add the ``set urgent'' command for adjusting the list of
  urgent port numbers.  The default urgent ports are 21, 22,
  23, 513, 514, 543 and 544 (Ports 80 and 81 have been
  removed from the default priority list).
o Increase the buffered packet threshold from 20 to 30.
o Report the number of packets in the IP output queue and the
  list of urgent ports under ``show ipcp''.
1999-09-04 00:00:21 +00:00

775 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 "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_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();
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(geteuid());
argc = command_Interpret(prog, strlen(prog), argv);
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 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;
#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;
}
mbuf_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 = 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) {
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);
}
mbuf_Free(bp);
return NULL;
}