srvrsmtp.c

早期freebsd实现

/*
 * Copyright (c) 1983 Eric P. Allman
 * Copyright (c) 1988, 1993
 *	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.
 */

# include "sendmail.h"

#ifndef lint
#ifdef SMTP
static char sccsid[] = "@(#)srvrsmtp.c	8.37 (Berkeley) 4/13/94 (with SMTP)";
#else
static char sccsid[] = "@(#)srvrsmtp.c	8.37 (Berkeley) 4/13/94 (without SMTP)";
#endif
#endif /* not lint */

# include <errno.h>

# ifdef SMTP

/*
**  SMTP -- run the SMTP protocol.
**
**	Parameters:
**		none.
**
**	Returns:
**		never.
**
**	Side Effects:
**		Reads commands from the input channel and processes
**			them.
*/

struct cmd
{
	char	*cmdname;	/* command name */
	int	cmdcode;	/* internal code, see below */
};

/* values for cmdcode */
# define CMDERROR	0	/* bad command */
# define CMDMAIL	1	/* mail -- designate sender */
# define CMDRCPT	2	/* rcpt -- designate recipient */
# define CMDDATA	3	/* data -- send message text */
# define CMDRSET	4	/* rset -- reset state */
# define CMDVRFY	5	/* vrfy -- verify address */
# define CMDEXPN	6	/* expn -- expand address */
# define CMDNOOP	7	/* noop -- do nothing */
# define CMDQUIT	8	/* quit -- close connection and die */
# define CMDHELO	9	/* helo -- be polite */
# define CMDHELP	10	/* help -- give usage info */
# define CMDEHLO	11	/* ehlo -- extended helo (RFC 1425) */
/* non-standard commands */
# define CMDONEX	16	/* onex -- sending one transaction only */
# define CMDVERB	17	/* verb -- go into verbose mode */
/* use this to catch and log "door handle" attempts on your system */
# define CMDLOGBOGUS	23	/* bogus command that should be logged */
/* debugging-only commands, only enabled if SMTPDEBUG is defined */
# define CMDDBGQSHOW	24	/* showq -- show send queue */
# define CMDDBGDEBUG	25	/* debug -- set debug mode */

static struct cmd	CmdTab[] =
{
	"mail",		CMDMAIL,
	"rcpt",		CMDRCPT,
	"data",		CMDDATA,
	"rset",		CMDRSET,
	"vrfy",		CMDVRFY,
	"expn",		CMDEXPN,
	"help",		CMDHELP,
	"noop",		CMDNOOP,
	"quit",		CMDQUIT,
	"helo",		CMDHELO,
	"ehlo",		CMDEHLO,
	"verb",		CMDVERB,
	"onex",		CMDONEX,
	/*
	 * remaining commands are here only
	 * to trap and log attempts to use them
	 */
	"showq",	CMDDBGQSHOW,
	"debug",	CMDDBGDEBUG,
	"wiz",		CMDLOGBOGUS,
	NULL,		CMDERROR,
};

bool	OneXact = FALSE;		/* one xaction only this run */
char	*CurSmtpClient;			/* who's at the other end of channel */

static char	*skipword();
extern char	RealUserName[];


#define MAXBADCOMMANDS	25		/* maximum number of bad commands */

smtp(e)
	register ENVELOPE *e;
{
	register char *p;
	register struct cmd *c;
	char *cmd;
	auto ADDRESS *vrfyqueue;
	ADDRESS *a;
	bool gotmail;			/* mail command received */
	bool gothello;			/* helo command received */
	bool vrfy;			/* set if this is a vrfy command */
	char *protocol;			/* sending protocol */
	char *sendinghost;		/* sending hostname */
	unsigned long msize;		/* approximate maximum message size */
	char *peerhostname;		/* name of SMTP peer or "localhost" */
	auto char *delimptr;
	char *id;
	int nrcpts;			/* number of RCPT commands */
	bool doublequeue;
	int badcommands = 0;		/* count of bad commands */
	char inp[MAXLINE];
	char cmdbuf[MAXLINE];
	extern char Version[];
	extern ENVELOPE BlankEnvelope;

	if (fileno(OutChannel) != fileno(stdout))
	{
		/* arrange for debugging output to go to remote host */
		(void) dup2(fileno(OutChannel), fileno(stdout));
	}
	settime(e);
	peerhostname = RealHostName;
	if (peerhostname == NULL)
		peerhostname = "localhost";
	CurHostName = peerhostname;
	CurSmtpClient = macvalue('_', e);
	if (CurSmtpClient == NULL)
		CurSmtpClient = CurHostName;

	setproctitle("server %s startup", CurSmtpClient);
	expand("\201e", inp, &inp[sizeof inp], e);
	if (BrokenSmtpPeers)
	{
		p = strchr(inp, '\n');
		if (p != NULL)
			*p = '\0';
		message("220 %s", inp);
	}
	else
	{
		char *q = inp;

		while (q != NULL)
		{
			p = strchr(q, '\n');
			if (p != NULL)
				*p++ = '\0';
			message("220-%s", q);
			q = p;
		}
		message("220 ESMTP spoken here");
	}
	protocol = NULL;
	sendinghost = macvalue('s', e);
	gothello = FALSE;
	gotmail = FALSE;
	for (;;)
	{
		/* arrange for backout */
		if (setjmp(TopFrame) > 0)
		{
			/* if() nesting is necessary for Cray UNICOS */
			if (InChild)
			{
				QuickAbort = FALSE;
				SuprErrs = TRUE;
				finis();
			}
		}
		QuickAbort = FALSE;
		HoldErrs = FALSE;
		LogUsrErrs = FALSE;
		e->e_flags &= ~(EF_VRFYONLY|EF_GLOBALERRS);

		/* setup for the read */
		e->e_to = NULL;
		Errors = 0;
		(void) fflush(stdout);

		/* read the input line */
		SmtpPhase = "server cmd read";
		setproctitle("server %s cmd read", CurHostName);
		p = sfgets(inp, sizeof inp, InChannel, TimeOuts.to_nextcommand,
				SmtpPhase);

		/* handle errors */
		if (p == NULL)
		{
			/* end of file, just die */
			disconnect(1, e);
			message("421 %s Lost input channel from %s",
				MyHostName, CurSmtpClient);
#ifdef LOG
			if (LogLevel > (gotmail ? 1 : 19))
				syslog(LOG_NOTICE, "lost input channel from %s",
					CurSmtpClient);
#endif
			if (InChild)
				ExitStat = EX_QUIT;
			finis();
		}

		/* clean up end of line */
		fixcrlf(inp, TRUE);

		/* echo command to transcript */
		if (e->e_xfp != NULL)
			fprintf(e->e_xfp, "<<< %s\n", inp);

		if (e->e_id == NULL)
			setproctitle("%s: %.80s", CurSmtpClient, inp);
		else
			setproctitle("%s %s: %.80s", e->e_id, CurSmtpClient, inp);

		/* break off command */
		for (p = inp; isascii(*p) && isspace(*p); p++)
			continue;
		cmd = cmdbuf;
		while (*p != '\0' &&
		       !(isascii(*p) && isspace(*p)) &&
		       cmd < &cmdbuf[sizeof cmdbuf - 2])
			*cmd++ = *p++;
		*cmd = '\0';

		/* throw away leading whitespace */
		while (isascii(*p) && isspace(*p))
			p++;

		/* decode command */
		for (c = CmdTab; c->cmdname != NULL; c++)
		{
			if (!strcasecmp(c->cmdname, cmdbuf))
				break;
		}

		/* reset errors */
		errno = 0;

		/* process command */
		switch (c->cmdcode)
		{
		  case CMDHELO:		/* hello -- introduce yourself */
		  case CMDEHLO:		/* extended hello */
			if (c->cmdcode == CMDEHLO)
			{
				protocol = "ESMTP";
				SmtpPhase = "server EHLO";
			}
			else
			{
				protocol = "SMTP";
				SmtpPhase = "server HELO";
			}
			sendinghost = newstr(p);
			gothello = TRUE;
			if (c->cmdcode != CMDEHLO)
			{
				/* print old message and be done with it */
				message("250 %s Hello %s, pleased to meet you",
					MyHostName, CurSmtpClient);
				break;
			}
			
			/* print extended message and brag */
			message("250-%s Hello %s, pleased to meet you",
				MyHostName, CurSmtpClient);
			if (!bitset(PRIV_NOEXPN, PrivacyFlags))
				message("250-EXPN");
			if (MaxMessageSize > 0)
				message("250-SIZE %ld", MaxMessageSize);
			else
				message("250-SIZE");
			message("250 HELP");
			break;

		  case CMDMAIL:		/* mail -- designate sender */
			SmtpPhase = "server MAIL";

			/* check for validity of this command */
			if (!gothello)
			{
				/* set sending host to our known value */
				if (sendinghost == NULL)
					sendinghost = peerhostname;

				if (bitset(PRIV_NEEDMAILHELO, PrivacyFlags))
				{
					message("503 Polite people say HELO first");
					break;
				}
			}
			if (gotmail)
			{
				message("503 Sender already specified");
				if (InChild)
					finis();
				break;
			}
			if (InChild)
			{
				errno = 0;
				syserr("503 Nested MAIL command: MAIL %s", p);
				finis();
			}

			/* fork a subprocess to process this command */
			if (runinchild("SMTP-MAIL", e) > 0)
				break;
			if (!gothello)
			{
				auth_warning(e,
					"Host %s didn't use HELO protocol",
					peerhostname);
			}
#ifdef PICKY_HELO_CHECK
			if (strcasecmp(sendinghost, peerhostname) != 0 &&
			    (strcasecmp(peerhostname, "localhost") != 0 ||
			     strcasecmp(sendinghost, MyHostName) != 0))
			{
				auth_warning(e, "Host %s claimed to be %s",
					peerhostname, sendinghost);
			}
#endif

			if (protocol == NULL)
				protocol = "SMTP";
			define('r', protocol, e);
			define('s', sendinghost, e);
			initsys(e);
			nrcpts = 0;
			e->e_flags |= EF_LOGSENDER;
			setproctitle("%s %s: %.80s", e->e_id, CurSmtpClient, inp);

			/* child -- go do the processing */
			p = skipword(p, "from");
			if (p == NULL)
				break;
			if (setjmp(TopFrame) > 0)
			{
				/* this failed -- undo work */
				if (InChild)
				{
					QuickAbort = FALSE;
					SuprErrs = TRUE;
					e->e_flags &= ~EF_FATALERRS;
					finis();
				}
				break;
			}
			QuickAbort = TRUE;

			/* must parse sender first */
			delimptr = NULL;
			setsender(p, e, &delimptr, FALSE);
			p = delimptr;
			if (p != NULL && *p != '\0')
				*p++ = '\0';

			/* check for possible spoofing */
			if (RealUid != 0 && OpMode == MD_SMTP &&
			    (e->e_from.q_mailer != LocalMailer &&
			     strcmp(e->e_from.q_user, RealUserName) != 0))
			{
				auth_warning(e, "%s owned process doing -bs",
					RealUserName);
			}

			/* now parse ESMTP arguments */
			msize = 0;
			while (p != NULL && *p != '\0')
			{
				char *kp;
				char *vp = NULL;

				/* locate the beginning of the keyword */
				while (isascii(*p) && isspace(*p))
					p++;
				if (*p == '\0')
					break;
				kp = p;

				/* skip to the value portion */
				while (isascii(*p) && isalnum(*p) || *p == '-')
					p++;
				if (*p == '=')
				{
					*p++ = '\0';
					vp = p;

					/* skip to the end of the value */
					while (*p != '\0' && *p != ' ' &&
					       !(isascii(*p) && iscntrl(*p)) &&
					       *p != '=')
						p++;
				}

				if (*p != '\0')
					*p++ = '\0';

				if (tTd(19, 1))
					printf("MAIL: got arg %s=\"%s\"\n", kp,
						vp == NULL ? "<null>" : vp);

				if (strcasecmp(kp, "size") == 0)
				{
					if (vp == NULL)
					{
						usrerr("501 SIZE requires a value");
						/* NOTREACHED */
					}
# ifdef __STDC__
					msize = strtoul(vp, (char **) NULL, 10);
# else
					msize = strtol(vp, (char **) NULL, 10);
# endif
				}
				else if (strcasecmp(kp, "body") == 0)
				{
					if (vp == NULL)
					{
						usrerr("501 BODY requires a value");
						/* NOTREACHED */
					}
# ifdef MIME
					if (strcasecmp(vp, "8bitmime") == 0)
					{
						e->e_bodytype = "8BITMIME";
						SevenBit = FALSE;
					}
					else if (strcasecmp(vp, "7bit") == 0)
					{
						e->e_bodytype = "7BIT";
						SevenBit = TRUE;
					}
					else
					{
						usrerr("501 Unknown BODY type %s",
							vp);
					}
# endif
				}
				else
				{
					usrerr("501 %s parameter unrecognized", kp);
					/* NOTREACHED */
				}
			}

			if (MaxMessageSize > 0 && msize > MaxMessageSize)
			{
				usrerr("552 Message size exceeds fixed maximum message size (%ld)",
					MaxMessageSize);
				/* NOTREACHED */
			}
				
			if (!enoughspace(msize))
			{
				message("452 Insufficient disk space; try again later");
				break;
			}
			message("250 Sender ok");
			gotmail = TRUE;
			break;

		  case CMDRCPT:		/* rcpt -- designate recipient */
			if (!gotmail)
			{
				usrerr("503 Need MAIL before RCPT");
				break;
			}
			SmtpPhase = "server RCPT";
			if (setjmp(TopFrame) > 0)
			{
				e->e_flags &= ~EF_FATALERRS;
				break;
			}
			QuickAbort = TRUE;
			LogUsrErrs = TRUE;

			if (e->e_sendmode != SM_DELIVER)
				e->e_flags |= EF_VRFYONLY;

			p = skipword(p, "to");