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-rw-r--r--usr.sbin/sendmail/src/domain.c325
1 files changed, 213 insertions, 112 deletions
diff --git a/usr.sbin/sendmail/src/domain.c b/usr.sbin/sendmail/src/domain.c
index da2a79587a62..8058330f962a 100644
--- a/usr.sbin/sendmail/src/domain.c
+++ b/usr.sbin/sendmail/src/domain.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1986 Eric P. Allman
+ * Copyright (c) 1986, 1995 Eric P. Allman
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
@@ -36,23 +36,21 @@
#ifndef lint
#if NAMED_BIND
-static char sccsid[] = "@(#)domain.c 8.19.1.1 (Berkeley) 3/6/95 (with name server)";
+static char sccsid[] = "@(#)domain.c 8.54 (Berkeley) 9/28/95 (with name server)";
#else
-static char sccsid[] = "@(#)domain.c 8.19.1.1 (Berkeley) 3/6/95 (without name server)";
+static char sccsid[] = "@(#)domain.c 8.54 (Berkeley) 9/28/95 (without name server)";
#endif
#endif /* not lint */
#if NAMED_BIND
#include <errno.h>
-#include <arpa/nameser.h>
#include <resolv.h>
-#include <netdb.h>
typedef union
{
HEADER qb1;
- char qb2[PACKETSZ];
+ u_char qb2[PACKETSZ];
} querybuf;
static char MXHostBuf[MAXMXHOSTS*PACKETSZ];
@@ -69,15 +67,17 @@ static char MXHostBuf[MAXMXHOSTS*PACKETSZ];
# define NO_DATA NO_ADDRESS
#endif
-#ifndef HEADERSZ
-# define HEADERSZ sizeof(HEADER)
+#ifndef HFIXEDSZ
+# define HFIXEDSZ 12 /* sizeof(HEADER) */
#endif
-/* don't use sizeof because sizeof(long) is different on 64-bit machines */
-#define SHORTSIZE 2 /* size of a short (really, must be 2) */
-#define LONGSIZE 4 /* size of a long (really, must be 4) */
-
#define MAXCNAMEDEPTH 10 /* maximum depth of CNAME recursion */
+
+#if defined(__RES) && (__RES >= 19940415)
+# define RES_UNC_T char *
+#else
+# define RES_UNC_T u_char *
+#endif
/*
** GETMXRR -- get MX resource records for a domain
**
@@ -96,13 +96,13 @@ static char MXHostBuf[MAXMXHOSTS*PACKETSZ];
** and 1 is returned.
*/
+int
getmxrr(host, mxhosts, droplocalhost, rcode)
char *host;
char **mxhosts;
bool droplocalhost;
int *rcode;
{
- extern int h_errno;
register u_char *eom, *cp;
register int i, j, n;
int nmx = 0;
@@ -111,11 +111,13 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
querybuf answer;
int ancount, qdcount, buflen;
bool seenlocal = FALSE;
- u_short pref, localpref, type;
+ u_short pref, type;
+ u_short localpref = 256;
char *fallbackMX = FallBackMX;
static bool firsttime = TRUE;
- STAB *st;
bool trycanon = FALSE;
+ int (*resfunc)();
+ extern int res_query(), res_search();
u_short prefer[MAXMXHOSTS];
int weight[MAXMXHOSTS];
extern bool getcanonname();
@@ -125,15 +127,14 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
if (fallbackMX != NULL)
{
- if (firsttime && res_query(FallBackMX, C_IN, T_A,
- (char *) &answer, sizeof answer) < 0)
+ if (firsttime &&
+ res_query(FallBackMX, C_IN, T_A,
+ (u_char *) &answer, sizeof answer) < 0)
{
/* this entry is bogus */
fallbackMX = FallBackMX = NULL;
}
- else if (droplocalhost &&
- (st = stab(fallbackMX, ST_CLASS, ST_FIND)) != NULL &&
- bitnset('w', st->s_class))
+ else if (droplocalhost && wordinclass(fallbackMX, 'w'))
{
/* don't use fallback for this pass */
fallbackMX = NULL;
@@ -141,12 +142,29 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
firsttime = FALSE;
}
+ *rcode = EX_OK;
+
/* efficiency hack -- numeric or non-MX lookups */
if (host[0] == '[')
goto punt;
+ /*
+ ** If we don't have MX records in our host switch, don't
+ ** try for MX records. Note that this really isn't "right",
+ ** since we might be set up to try NIS first and then DNS;
+ ** if the host is found in NIS we really shouldn't be doing
+ ** MX lookups. However, that should be a degenerate case.
+ */
+
+ if (!UseNameServer)
+ goto punt;
+ if (HasWildcardMX && ConfigLevel >= 6)
+ resfunc = res_query;
+ else
+ resfunc = res_search;
+
errno = 0;
- n = res_search(host, C_IN, T_MX, (char *)&answer, sizeof(answer));
+ n = (*resfunc)(host, C_IN, T_MX, (u_char *) &answer, sizeof(answer));
if (n < 0)
{
if (tTd(8, 1))
@@ -163,25 +181,22 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
goto punt;
case HOST_NOT_FOUND:
-#ifdef BROKEN_RES_SEARCH
- /* Ultrix resolver returns failure w/ h_errno=0 */
- case 0:
+#if BROKEN_RES_SEARCH
+ case 0: /* Ultrix resolver retns failure w/ h_errno=0 */
#endif
- /* the host just doesn't exist */
+ /* host doesn't exist in DNS; might be in /etc/hosts */
+ trycanon = TRUE;
*rcode = EX_NOHOST;
-
- if (!UseNameServer)
- {
- /* might exist in /etc/hosts */
- goto punt;
- }
- break;
+ goto punt;
case TRY_AGAIN:
/* couldn't connect to the name server */
- if (!UseNameServer && errno == ECONNREFUSED)
- goto punt;
-
+ if (fallbackMX != NULL)
+ {
+ /* name server is hosed -- push to fallback */
+ mxhosts[nmx++] = fallbackMX;
+ return nmx;
+ }
/* it might come up later; better queue it up */
*rcode = EX_TEMPFAIL;
break;
@@ -199,7 +214,7 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
/* find first satisfactory answer */
hp = (HEADER *)&answer;
- cp = (u_char *)&answer + HEADERSZ;
+ cp = (u_char *)&answer + HFIXEDSZ;
eom = (u_char *)&answer + n;
for (qdcount = ntohs(hp->qdcount); qdcount--; cp += n + QFIXEDSZ)
if ((n = dn_skipname(cp, eom)) < 0)
@@ -210,11 +225,11 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
while (--ancount >= 0 && cp < eom && nmx < MAXMXHOSTS - 1)
{
if ((n = dn_expand((u_char *)&answer,
- eom, cp, (u_char *)bp, buflen)) < 0)
+ eom, cp, (RES_UNC_T) bp, buflen)) < 0)
break;
cp += n;
GETSHORT(type, cp);
- cp += SHORTSIZE + LONGSIZE;
+ cp += INT16SZ + INT32SZ;
GETSHORT(n, cp);
if (type != T_MX)
{
@@ -226,22 +241,25 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
}
GETSHORT(pref, cp);
if ((n = dn_expand((u_char *)&answer, eom, cp,
- (u_char *)bp, buflen)) < 0)
+ (RES_UNC_T) bp, buflen)) < 0)
break;
cp += n;
- if (droplocalhost &&
- (st = stab(bp, ST_CLASS, ST_FIND)) != NULL &&
- bitnset('w', st->s_class))
+ if (wordinclass(bp, 'w'))
{
if (tTd(8, 3))
printf("found localhost (%s) in MX list, pref=%d\n",
bp, pref);
- if (!seenlocal || pref < localpref)
- localpref = pref;
- seenlocal = TRUE;
- continue;
+ if (droplocalhost)
+ {
+ if (!seenlocal || pref < localpref)
+ localpref = pref;
+ seenlocal = TRUE;
+ continue;
+ }
+ weight[nmx] = 0;
}
- weight[nmx] = mxrand(bp);
+ else
+ weight[nmx] = mxrand(bp);
prefer[nmx] = pref;
mxhosts[nmx++] = bp;
n = strlen(bp);
@@ -284,11 +302,25 @@ getmxrr(host, mxhosts, droplocalhost, rcode)
}
}
+ /* delete duplicates from list (yes, some bozos have duplicates) */
+ for (i = 0; i < nmx - 1; )
+ {
+ if (strcasecmp(mxhosts[i], mxhosts[i + 1]) != 0)
+ i++;
+ else
+ {
+ /* compress out duplicate */
+ for (j = i + 1; j < nmx; j++)
+ mxhosts[j] = mxhosts[j + 1];
+ nmx--;
+ }
+ }
+
if (nmx == 0)
{
punt:
if (seenlocal &&
- (!TryNullMXList || gethostbyname(host) == NULL))
+ (!TryNullMXList || sm_gethostbyname(host) == NULL))
{
/*
** If we have deleted all MX entries, this is
@@ -336,8 +368,8 @@ punt:
*bp++ = '.';
*bp = '\0';
}
+ nmx = 1;
}
- nmx = 1;
}
/* if we have a default lowest preference, include that */
@@ -364,6 +396,7 @@ punt:
** none.
*/
+int
mxrand(host)
register char *host;
{
@@ -391,13 +424,43 @@ mxrand(host)
}
hfunc &= 0xff;
+ hfunc++;
if (tTd(17, 9))
printf(" = %d\n", hfunc);
return hfunc;
}
/*
-** GETCANONNAME -- get the canonical name for named host
+** BESTMX -- find the best MX for a name
+**
+** This is really a hack, but I don't see any obvious way
+** to generalize it at the moment.
+*/
+
+char *
+bestmx_map_lookup(map, name, av, statp)
+ MAP *map;
+ char *name;
+ char **av;
+ int *statp;
+{
+ int nmx;
+ auto int rcode;
+ int saveopts = _res.options;
+ char *mxhosts[MAXMXHOSTS + 1];
+
+ _res.options &= ~(RES_DNSRCH|RES_DEFNAMES);
+ nmx = getmxrr(name, mxhosts, FALSE, &rcode);
+ _res.options = saveopts;
+ if (nmx <= 0)
+ return NULL;
+ if (bitset(MF_MATCHONLY, map->map_mflags))
+ return map_rewrite(map, name, strlen(name), NULL);
+ else
+ return map_rewrite(map, mxhosts[0], strlen(mxhosts[0]), av);
+}
+ /*
+** DNS_GETCANONNAME -- get the canonical name for named host using DNS
**
** This algorithm tries to be smart about wildcard MX records.
** This is hard to do because DNS doesn't tell is if we matched
@@ -419,6 +482,7 @@ mxrand(host)
** This is a value-result parameter.
** hbsize -- the size of the host buffer.
** trymx -- if set, try MX records as well as A and CNAME.
+** statp -- pointer to place to store status.
**
** Returns:
** TRUE -- if the host matched.
@@ -426,12 +490,12 @@ mxrand(host)
*/
bool
-getcanonname(host, hbsize, trymx)
+dns_getcanonname(host, hbsize, trymx, statp)
char *host;
int hbsize;
bool trymx;
+ int *statp;
{
- extern int h_errno;
register u_char *eom, *ap;
register char *cp;
register int n;
@@ -444,7 +508,7 @@ getcanonname(host, hbsize, trymx)
char **dp;
char *mxmatch;
bool amatch;
- bool gotmx;
+ bool gotmx = FALSE;
int qtype;
int loopcnt;
char *xp;
@@ -453,10 +517,13 @@ getcanonname(host, hbsize, trymx)
extern char *gethostalias();
if (tTd(8, 2))
- printf("getcanonname(%s)\n", host);
+ printf("dns_getcanonname(%s, trymx=%d)\n", host, trymx);
if ((_res.options & RES_INIT) == 0 && res_init() == -1)
- return (FALSE);
+ {
+ *statp = EX_UNAVAILABLE;
+ return FALSE;
+ }
/*
** Initialize domain search list. If there is at least one
@@ -470,10 +537,15 @@ getcanonname(host, hbsize, trymx)
loopcnt = 0;
cnameloop:
- for (cp = host, n = 0; *cp; cp++)
+ /* Check for dots in the name */
+ for (cp = host, n = 0; *cp != '\0'; cp++)
if (*cp == '.')
n++;
+ /*
+ ** If this is a simple name, determine whether it matches an
+ ** alias in the file defined by the environment variable HOSTALIASES.
+ */
if (n == 0 && (xp = gethostalias(host)) != NULL)
{
if (loopcnt++ > MAXCNAMEDEPTH)
@@ -488,6 +560,17 @@ cnameloop:
}
}
+ /*
+ ** Build the search list.
+ ** If there is at least one dot in name, start with a null
+ ** domain to search the unmodified name first.
+ ** If name does not end with a dot and search up local domain
+ ** tree desired, append each local domain component to the
+ ** search list; if name contains no dots and default domain
+ ** name is desired, append default domain name to search list;
+ ** else if name ends in a dot, remove that dot.
+ */
+
dp = searchlist;
if (n > 0)
*dp++ = "";
@@ -507,7 +590,8 @@ cnameloop:
*dp = NULL;
/*
- ** Now run through the search list for the name in question.
+ ** Now loop through the search list, appending each domain in turn
+ ** name and searching for a match.
*/
mxmatch = NULL;
@@ -518,11 +602,12 @@ cnameloop:
if (qtype == T_ANY)
gotmx = FALSE;
if (tTd(8, 5))
- printf("getcanonname: trying %s.%s (%s)\n", host, *dp,
+ printf("dns_getcanonname: trying %s.%s (%s)\n",
+ host, *dp,
qtype == T_ANY ? "ANY" : qtype == T_A ? "A" :
qtype == T_MX ? "MX" : "???");
ret = res_querydomain(host, *dp, C_IN, qtype,
- (u_char *) &answer, sizeof(answer));
+ answer.qb2, sizeof(answer.qb2));
if (ret <= 0)
{
if (tTd(8, 7))
@@ -533,6 +618,7 @@ cnameloop:
{
/* the name server seems to be down */
h_errno = TRY_AGAIN;
+ *statp = EX_TEMPFAIL;
return FALSE;
}
@@ -551,13 +637,7 @@ cnameloop:
}
}
- if (mxmatch != NULL)
- {
- /* we matched before -- use that one */
- break;
- }
-
- /* otherwise, try the next name */
+ /* definite no -- try the next domain */
dp++;
qtype = T_ANY;
continue;
@@ -566,13 +646,13 @@ cnameloop:
printf("\tYES\n");
/*
- ** This might be a bogus match. Search for A or
- ** CNAME records. If we don't have a matching
+ ** Appear to have a match. Confirm it by searching for A or
+ ** CNAME records. If we don't have a local domain
** wild card MX record, we will accept MX as well.
*/
hp = (HEADER *) &answer;
- ap = (u_char *) &answer + HEADERSZ;
+ ap = (u_char *) &answer + HFIXEDSZ;
eom = (u_char *) &answer + ret;
/* skip question part of response -- we know what we asked */
@@ -583,44 +663,66 @@ cnameloop:
if (tTd(8, 20))
printf("qdcount failure (%d)\n",
ntohs(hp->qdcount));
+ *statp = EX_SOFTWARE;
return FALSE; /* ???XXX??? */
}
}
amatch = FALSE;
- for (ancount = ntohs(hp->ancount); --ancount >= 0 && ap < eom; ap += n)
+ for (ancount = ntohs(hp->ancount); --ancount >= 0 && ap < eom;
+ ap += n)
{
n = dn_expand((u_char *) &answer, eom, ap,
- (u_char *) nbuf, sizeof nbuf);
+ (RES_UNC_T) nbuf, sizeof nbuf);
if (n < 0)
break;
ap += n;
GETSHORT(type, ap);
- ap += SHORTSIZE + LONGSIZE;
+ ap += INT16SZ + INT32SZ;
GETSHORT(n, ap);
switch (type)
{
case T_MX:
gotmx = TRUE;
- if (**dp != '\0')
+ if (**dp != '\0' && HasWildcardMX)
{
- /* got a match -- save that info */
+ /*
+ ** If we are using MX matches and have
+ ** not yet gotten one, save this one
+ ** but keep searching for an A or
+ ** CNAME match.
+ */
+
if (trymx && mxmatch == NULL)
mxmatch = *dp;
continue;
}
- /* exact MX matches are as good as an A match */
- /* fall through */
+ /*
+ ** If we did not append a domain name, this
+ ** must have been a canonical name to start
+ ** with. Even if we did append a domain name,
+ ** in the absence of a wildcard MX this must
+ ** still be a real MX match.
+ ** Such MX matches are as good as an A match,
+ ** fall through.
+ */
case T_A:
- /* good show */
+ /* Flag that a good match was found */
amatch = TRUE;
/* continue in case a CNAME also exists */
continue;
case T_CNAME:
+ if (DontExpandCnames)
+ {
+ /* got CNAME -- guaranteed canonical */
+ amatch = TRUE;
+ break;
+ }
+
if (loopcnt++ > MAXCNAMEDEPTH)
{
/*XXX should notify postmaster XXX*/
@@ -630,17 +732,18 @@ cnameloop:
{
char ebuf[MAXLINE];
- sprintf(ebuf, "Deferred: DNS failure: CNAME loop for %s",
+ sprintf(ebuf, "Deferred: DNS failure: CNAME loop for %.100s",
host);
CurEnv->e_message = newstr(ebuf);
}
h_errno = NO_RECOVERY;
+ *statp = EX_CONFIG;
return FALSE;
}
/* value points at name */
if ((ret = dn_expand((u_char *)&answer,
- eom, ap, (u_char *)nbuf, sizeof(nbuf))) < 0)
+ eom, ap, (RES_UNC_T) nbuf, sizeof(nbuf))) < 0)
break;
(void)strncpy(host, nbuf, hbsize); /* XXX */
host[hbsize - 1] = '\0';
@@ -661,14 +764,24 @@ cnameloop:
if (amatch)
{
- /* got an A record and no CNAME */
+ /*
+ ** Got a good match -- either an A, CNAME, or an
+ ** exact MX record. Save it and get out of here.
+ */
+
mxmatch = *dp;
break;
}
/*
- ** If this was a T_ANY query, we may have the info but
- ** need an explicit query. Try T_A, then T_MX.
+ ** Nothing definitive yet.
+ ** If this was a T_ANY query, we don't really know what
+ ** was returned -- it might have been a T_NS,
+ ** for example. Try T_A to be more specific
+ ** during the next pass.
+ ** If this was a T_A query and we haven't yet found a MX
+ ** match, try T_MX if allowed to do so.
+ ** Otherwise, try the next domain.
*/
if (qtype == T_ANY)
@@ -677,39 +790,51 @@ cnameloop:
qtype = T_MX;
else
{
- /* really nothing in this domain; try the next */
qtype = T_ANY;
dp++;
}
}
+ /* if nothing was found, we are done */
if (mxmatch == NULL)
+ {
+ *statp = EX_NOHOST;
return FALSE;
+ }
+
+ /*
+ ** Create canonical name and return.
+ ** If saved domain name is null, name was already canonical.
+ ** Otherwise append the saved domain name.
+ */
- /* create matching name and return */
(void) sprintf(nbuf, "%.*s%s%.*s", MAXDNAME, host,
*mxmatch == '\0' ? "" : ".",
MAXDNAME, mxmatch);
strncpy(host, nbuf, hbsize);
host[hbsize - 1] = '\0';
+ if (tTd(8, 5))
+ printf("dns_getcanonname: %s\n", host);
+ *statp = EX_OK;
return TRUE;
}
+
char *
gethostalias(host)
char *host;
{
char *fname;
FILE *fp;
- register char *p;
+ register char *p = NULL;
char buf[MAXLINE];
static char hbuf[MAXDNAME];
fname = getenv("HOSTALIASES");
- if (fname == NULL || (fp = fopen(fname, "r")) == NULL)
+ if (fname == NULL ||
+ (fp = safefopen(fname, O_RDONLY, 0, SFF_REGONLY)) == NULL)
return NULL;
- setbuf(fp, NULL);
while (fgets(buf, sizeof buf, fp) != NULL)
{
for (p = buf; p != '\0' && !(isascii(*p) && isspace(*p)); p++)
@@ -743,28 +868,4 @@ gethostalias(host)
return hbuf;
}
-
-#else /* not NAMED_BIND */
-
-#include <netdb.h>
-
-bool
-getcanonname(host, hbsize, trymx)
- char *host;
- int hbsize;
- bool trymx;
-{
- struct hostent *hp;
-
- hp = gethostbyname(host);
- if (hp == NULL)
- return (FALSE);
-
- if (strlen(hp->h_name) >= hbsize)
- return (FALSE);
-
- (void) strcpy(host, hp->h_name);
- return (TRUE);
-}
-
-#endif /* not NAMED_BIND */
+#endif /* NAMED_BIND */
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-18 20:00:48 +0000