NetBSD/libexec/mail.local/mail.local.c

359 lines
8.7 KiB
C

/* $NetBSD: mail.local.c,v 1.28 2016/07/21 12:29:37 shm Exp $ */
/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. 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. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1990, 1993, 1994\
The Regents of the University of California. All rights reserved.");
#if 0
static char sccsid[] = "@(#)mail.local.c 8.22 (Berkeley) 6/21/95";
#else
__RCSID("$NetBSD: mail.local.c,v 1.28 2016/07/21 12:29:37 shm Exp $");
#endif
#endif /* not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include <sysexits.h>
#include "pathnames.h"
static int deliver(int, char *, int);
__dead static void logerr(int, const char *, ...) __printflike(2, 3);
static void logwarn(const char *, ...) __printflike(1, 2);
static void notifybiff(char *);
static int store(const char *);
__dead static void usage(void);
int
main(int argc, char *argv[])
{
struct passwd *pw;
int ch, fd, eval, lockfile = 0;
uid_t uid;
const char *from;
/* use a reasonable umask */
(void) umask(0077);
openlog("mail.local", LOG_PERROR, LOG_MAIL);
from = NULL;
while ((ch = getopt(argc, argv, "ldf:r:")) != -1)
switch (ch) {
case 'd': /* backward compatible */
break;
case 'f':
case 'r': /* backward compatible */
if (from)
logerr(EX_USAGE, "multiple -f options");
from = optarg;
break;
case 'l':
lockfile++;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (!*argv)
usage();
/*
* If from not specified, use the name from getlogin() if the
* uid matches, otherwise, use the name from the password file
* corresponding to the uid.
*/
uid = getuid();
if (!from && (!(from = getlogin()) ||
!(pw = getpwnam(from)) || pw->pw_uid != uid))
from = (pw = getpwuid(uid)) ? pw->pw_name : "???";
fd = store(from);
for (eval = EX_OK; *argv; ++argv) {
int rval;
rval = deliver(fd, *argv, lockfile);
if (eval == EX_OK && rval != EX_OK)
eval = rval;
}
exit (eval);
}
static int
store(const char *from)
{
FILE *fp = NULL; /* XXX gcc */
time_t tval;
int fd, eline;
char *tn, line[2048];
tn = strdup(_PATH_LOCTMP);
if (!tn)
logerr(EX_OSERR, "not enough core");
if ((fd = mkstemp(tn)) == -1 || !(fp = fdopen(fd, "w+")))
logerr(EX_OSERR, "unable to open temporary file");
(void)unlink(tn);
free(tn);
(void)time(&tval);
(void)fprintf(fp, "From %s %s", from, ctime(&tval));
line[0] = '\0';
for (eline = 1; fgets(line, sizeof(line), stdin);) {
if (line[0] == '\n')
eline = 1;
else {
if (eline && line[0] == 'F' && !memcmp(line, "From ", 5))
(void)putc('>', fp);
eline = 0;
}
(void)fprintf(fp, "%s", line);
if (ferror(fp))
break;
}
/* If message not newline terminated, need an extra. */
if (!index(line, '\n'))
(void)putc('\n', fp);
/* Output a newline; note, empty messages are allowed. */
(void)putc('\n', fp);
(void)fflush(fp);
if (ferror(fp))
logerr(EX_OSERR, "temporary file write error");
if ((fd = dup(fd)) == -1)
logerr(EX_OSERR, "dup failed");
(void)fclose(fp);
return(fd);
}
static int
deliver(int fd, char *name, int lockfile)
{
struct stat sb, nsb;
struct passwd pwres, *pw;
char pwbuf[1024];
int created = 0, mbfd, nr, nw, off, rval=EX_OK, lfd = -1;
char biffmsg[100], buf[8*1024], path[MAXPATHLEN], lpath[MAXPATHLEN];
off_t curoff;
/*
* Disallow delivery to unknown names -- special mailboxes can be
* handled in the sendmail aliases file.
*/
if ((getpwnam_r(name, &pwres, pwbuf, sizeof(pwbuf), &pw)) != 0) {
logwarn("unable to find user %s: %s", name, strerror(errno));
return(EX_TEMPFAIL);
}
if (pw == NULL) {
logwarn("unknown name: %s", name);
return(EX_NOUSER);
}
(void)snprintf(path, sizeof path, "%s/%s", _PATH_MAILDIR, name);
if (lockfile) {
(void)snprintf(lpath, sizeof lpath, "%s/%s.lock",
_PATH_MAILDIR, name);
if((lfd = open(lpath, O_CREAT|O_WRONLY|O_EXCL,
S_IRUSR|S_IWUSR)) < 0) {
logwarn("%s: %s", lpath, strerror(errno));
return(EX_OSERR);
}
}
if ((lstat(path, &sb) != -1) &&
(sb.st_nlink != 1 || S_ISLNK(sb.st_mode))) {
logwarn("%s: linked file", path);
return(EX_OSERR);
}
if ((mbfd = open(path, O_APPEND|O_WRONLY|O_EXLOCK,
S_IRUSR|S_IWUSR)) == -1) {
/* create file */
if ((mbfd = open(path, O_APPEND|O_CREAT|O_WRONLY|O_EXLOCK,
S_IRUSR|S_IWUSR)) == -1) {
logwarn("%s: %s", path, strerror(errno));
rval = EX_OSERR;
goto bad;
}
created = 1;
} else {
/* opened existing file, check for TOCTTOU */
if (fstat(mbfd, &nsb) == -1) {
rval = EX_OSERR;
goto bad;
}
/* file is not what we expected */
if (nsb.st_ino != sb.st_ino || nsb.st_dev != sb.st_dev) {
rval = EX_OSERR;
goto bad;
}
}
if ((curoff = lseek(mbfd, 0, SEEK_END)) == (off_t)-1) {
logwarn("%s: %s", path, strerror(errno));
rval = EX_OSERR;
goto bad;
}
(void)snprintf(biffmsg, sizeof biffmsg, "%s@%lld\n", name,
(long long)curoff);
if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {
logwarn("temporary file: %s", strerror(errno));
rval = EX_OSERR;
goto bad;
}
while ((nr = read(fd, buf, sizeof(buf))) > 0)
for (off = 0; off < nr; off += nw)
if ((nw = write(mbfd, buf + off, nr - off)) < 0) {
logwarn("%s: %s", path, strerror(errno));
goto trunc;
}
if (nr < 0) {
logwarn("temporary file: %s", strerror(errno));
trunc: (void)ftruncate(mbfd, curoff);
rval = EX_OSERR;
}
/*
* Set the owner and group. Historically, binmail repeated this at
* each mail delivery. We no longer do this, assuming that if the
* ownership or permissions were changed there was a reason for doing
* so.
*/
bad:
if (lockfile) {
if (lfd >= 0) {
unlink(lpath);
close(lfd);
}
}
if (mbfd >= 0) {
if (created)
(void)fchown(mbfd, pw->pw_uid, pw->pw_gid);
(void)fsync(mbfd); /* Don't wait for update. */
(void)close(mbfd); /* Implicit unlock. */
}
if (rval == EX_OK)
notifybiff(biffmsg);
return rval;
}
void
notifybiff(char *msg)
{
static struct sockaddr_in addr;
static int f = -1;
struct hostent *hp;
struct servent *sp;
int len;
if (!addr.sin_family) {
/* Be silent if biff service not available. */
if (!(sp = getservbyname("biff", "udp")))
return;
if (!(hp = gethostbyname("localhost"))) {
logwarn("localhost: %s", strerror(errno));
return;
}
addr.sin_len = sizeof(struct sockaddr_in);
addr.sin_family = hp->h_addrtype;
addr.sin_port = sp->s_port;
memcpy(&addr.sin_addr, hp->h_addr, hp->h_length);
}
if (f < 0 && (f = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
logwarn("socket: %s", strerror(errno));
return;
}
len = strlen(msg) + 1;
if (sendto(f, msg, len, 0, (struct sockaddr *)&addr, sizeof(addr))
!= len)
logwarn("sendto biff: %s", strerror(errno));
}
static void
usage(void)
{
logerr(EX_USAGE, "usage: mail.local [-l] [-f from] user ...");
}
static void
logerr(int status, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsyslog(LOG_ERR, fmt, ap);
va_end(ap);
exit(status);
/* NOTREACHED */
}
static void
logwarn(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsyslog(LOG_ERR, fmt, ap);
va_end(ap);
return;
}