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|
/*-
* Copyright (c) 1990 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1990 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */
#ifndef lint
/*static char sccsid[] = "from: @(#)mail.local.c 5.6 (Berkeley) 6/19/91";*/
static char rcsid[] = "$Id: mail.local.c,v 1.11 1997/01/17 07:12:03 millert Exp $";
#endif /* not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/signal.h>
#include <syslog.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "pathnames.h"
#define FATAL 1
#define NOTFATAL 0
int deliver __P((int, char *, int));
void err __P((int, const char *, ...));
void notifybiff __P((char *));
int store __P((char *));
void usage __P((void));
int dohold __P((void));
int getlock __P((char *, struct passwd *));
void rellock __P((void));
int
main(argc, argv)
int argc;
char **argv;
{
extern int optind;
extern char *optarg;
struct passwd *pw;
int ch, fd, eval, lockfile=1, holdme=0;
uid_t uid;
char *from;
openlog("mail.local", LOG_PERROR, LOG_MAIL);
from = NULL;
while ((ch = getopt(argc, argv, "lLdf:r:")) != -1)
switch(ch) {
case 'd': /* backward compatible */
break;
case 'f':
case 'r': /* backward compatible */
if (from)
err(FATAL, "multiple -f options");
from = optarg;
break;
case 'l':
lockfile=1;
break;
case 'L':
lockfile=0;
break;
case 'H':
holdme=1;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (!*argv)
usage();
if (holdme)
exit(dohold());
/*
* 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 = 0; *argv; ++argv)
eval |= deliver(fd, *argv, lockfile);
exit(eval);
}
void
unhold()
{
rellock();
exit(0);
}
int
dohold()
{
struct passwd *pw;
char *from, c;
int holdfd;
signal(SIGTERM, unhold);
signal(SIGINT, unhold);
signal(SIGHUP, unhold);
from = getlogin();
if (from) {
pw = getpwnam(from);
if (pw == NULL)
return (1);
} else {
pw = getpwuid(getuid());
if (pw)
from = pw->pw_name;
else
return (1);
}
holdfd = getlock(from, pw);
if (holdfd == -1)
return (1);
while (read(0, &c, 1) == -1 && errno == EINTR)
;
rellock();
return (0);
}
int
store(from)
char *from;
{
FILE *fp;
time_t tval;
int fd, eline;
char *tn, line[2048];
if ((tn = strdup(_PATH_LOCTMP)) == NULL)
err(FATAL, "unable to allocate memory");
if ((fd = mkstemp(tn)) == -1 || !(fp = fdopen(fd, "w+")))
err(FATAL, "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' && !bcmp(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 (!strchr(line, '\n'))
(void)putc('\n', fp);
/* Output a newline; note, empty messages are allowed. */
(void)putc('\n', fp);
(void)fflush(fp);
if (ferror(fp))
err(FATAL, "temporary file write error");
return(fd);
}
void
baditem(path)
char *path;
{
char npath[MAXPATHLEN];
if (unlink(path) == 0)
return;
snprintf(npath, sizeof npath, "%s/XXXXXXXXX", _PATH_MAILDIR);
if (mktemp(npath) == NULL)
return;
if (rename(path, npath) != -1)
err(NOTFATAL, "nasty spool item %s renamed to %s",
path, npath);
/* XXX if we fail to rename, another attempt will happen later */
}
char lpath[MAXPATHLEN];
void
rellock()
{
if (lpath[0])
unlink(lpath);
}
int
getlock(name, pw)
char *name;
struct passwd *pw;
{
struct stat sb, fsb;
int lfd=-1;
char buf[8*1024];
int tries = 0;
(void)snprintf(lpath, sizeof lpath, "%s/%s.lock",
_PATH_MAILDIR, name);
if (stat(_PATH_MAILDIR, &sb) != -1 &&
(sb.st_mode & S_IWOTH) == S_IWOTH) {
/*
* We have a writeable spool, deal with it as
* securely as possible.
*/
time_t ctim = -1;
seteuid(pw->pw_uid);
if (lstat(lpath, &sb) != -1)
ctim = sb.st_ctime;
while (1) {
/*
* Deal with existing user.lock files
* or directories or symbolic links that
* should not be here.
*/
if (readlink(lpath, buf, sizeof buf) != -1) {
if (lstat(lpath, &sb) != -1 &&
S_ISLNK(fsb.st_mode)) {
seteuid(sb.st_uid);
unlink(lpath);
seteuid(pw->pw_uid);
}
goto again;
}
if ((lfd = open(lpath, O_CREAT|O_WRONLY|O_EXCL|O_EXLOCK,
S_IRUSR|S_IWUSR)) != -1)
break;
again:
if (tries > 10) {
err(NOTFATAL, "%s: %s", lpath,
strerror(errno));
seteuid(0);
return(-1);
}
if (tries > 9 &&
(lfd = open(lpath, O_WRONLY|O_EXLOCK, 0)) != -1) {
if (fstat(lfd, &fsb) != -1 &&
lstat(lpath, &sb) != -1) {
if (fsb.st_dev == sb.st_dev &&
fsb.st_ino == sb.st_ino &&
ctim == fsb.st_ctime ) {
seteuid(fsb.st_uid);
baditem(lpath);
seteuid(pw->pw_uid);
}
}
}
sleep(1 << tries);
tries++;
continue;
}
seteuid(0);
} else {
/*
* Only root can write the spool directory.
*/
if ((lfd = open(lpath, O_CREAT|O_WRONLY|O_EXCL,
S_IRUSR|S_IWUSR)) < 0) {
err(NOTFATAL, "%s: %s", lpath, strerror(errno));
return(-1);
}
}
return (lfd);
}
int
deliver(fd, name, lockfile)
int fd;
char *name;
int lockfile;
{
struct stat sb, fsb;
struct passwd *pw;
int mbfd=-1, nr, nw, off, rval=1, lfd=-1;
char biffmsg[100], buf[8*1024], path[MAXPATHLEN];
off_t curoff;
/*
* Disallow delivery to unknown names -- special mailboxes can be
* handled in the sendmail aliases file.
*/
if (!(pw = getpwnam(name))) {
err(NOTFATAL, "unknown name: %s", name);
return(1);
}
(void)snprintf(path, sizeof path, "%s/%s", _PATH_MAILDIR, name);
if (lockfile) {
lfd = getlock(name, pw);
if (lfd == -1)
return (1);
}
/* after this point, always exit via bad to remove lockfile */
retry:
if (lstat(path, &sb)) {
if (errno != ENOENT) {
err(NOTFATAL, "%s: %s", path, strerror(errno));
goto bad;
}
if ((mbfd = open(path, O_APPEND|O_CREAT|O_EXCL|O_WRONLY|O_EXLOCK,
S_IRUSR|S_IWUSR)) < 0) {
if (errno == EEXIST) {
/* file appeared since lstat */
goto retry;
} else {
err(NOTFATAL, "%s: %s", path, strerror(errno));
goto bad;
}
}
/*
* 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.
*/
if (fchown(mbfd, pw->pw_uid, pw->pw_gid) < 0) {
err(NOTFATAL, "chown %u:%u: %s",
pw->pw_uid, pw->pw_gid, name);
goto bad;
}
} else {
if (sb.st_nlink != 1 || S_ISLNK(sb.st_mode)) {
err(NOTFATAL, "%s: linked file", path);
goto bad;
}
if ((mbfd = open(path, O_APPEND|O_WRONLY|O_EXLOCK,
S_IRUSR|S_IWUSR)) < 0) {
err(NOTFATAL, "%s: %s", path, strerror(errno));
goto bad;
}
if (fstat(mbfd, &fsb)) {
/* relating error to path may be bad style */
err(NOTFATAL, "%s: %s", path, strerror(errno));
goto bad;
}
if (sb.st_dev != fsb.st_dev || sb.st_ino != fsb.st_ino) {
err(NOTFATAL, "%s: changed after open", path);
goto bad;
}
/* paranoia? */
if (fsb.st_nlink != 1 || S_ISLNK(fsb.st_mode)) {
err(NOTFATAL, "%s: linked file", path);
goto bad;
}
}
curoff = lseek(mbfd, 0, SEEK_END);
(void)snprintf(biffmsg, sizeof biffmsg, "%s@%qd\n", name, curoff);
if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {
err(FATAL, "temporary file: %s", strerror(errno));
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) {
err(NOTFATAL, "%s: %s", path, strerror(errno));
(void)ftruncate(mbfd, curoff);
goto bad;
}
if (nr == 0) {
rval = 0;
} else {
err(FATAL, "temporary file: %s", strerror(errno));
(void)ftruncate(mbfd, curoff);
}
bad:
if (lfd != -1) {
rellock();
close(lfd);
}
if (mbfd != -1) {
(void)fsync(mbfd); /* Don't wait for update. */
(void)close(mbfd); /* Implicit unlock. */
}
if (!rval)
notifybiff(biffmsg);
return(rval);
}
void
notifybiff(msg)
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"))) {
err(NOTFATAL, "localhost: %s", strerror(errno));
return;
}
addr.sin_len = sizeof(struct sockaddr_in);
addr.sin_family = hp->h_addrtype;
addr.sin_port = sp->s_port;
bcopy(hp->h_addr, &addr.sin_addr, hp->h_length);
}
if (f < 0 && (f = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
err(NOTFATAL, "socket: %s", strerror(errno));
return;
}
len = strlen(msg) + 1;
if (sendto(f, msg, len, 0, (struct sockaddr *)&addr, sizeof(addr))
!= len)
err(NOTFATAL, "sendto biff: %s", strerror(errno));
}
void
usage()
{
err(FATAL, "usage: mail.local [-f from] user ...");
}
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
void
#if __STDC__
err(int isfatal, const char *fmt, ...)
#else
err(isfatal, fmt)
int isfatal;
char *fmt;
va_dcl
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
vsyslog(LOG_ERR, fmt, ap);
va_end(ap);
if (isfatal)
exit(1);
}
|