/*
** Copyright 2000-2018 S. Varshavchik.
** See COPYING for distribution information.
*/
#include	"config.h"
#include	"argparse.h"
#include	"spipe.h"

#include	"libcouriertls.h"
#include	"tlscache.h"
#include	"rfc1035/rfc1035.h"
#include	"soxwrap/soxwrap.h"
#include	"numlib/numlib.h"

#ifdef  getc
#undef  getc
#endif
#include	<stdio.h>
#include	<string.h>
#include	<stdlib.h>
#include	<ctype.h>
#include	<netdb.h>
#include	<signal.h>
#if HAVE_DIRENT_H
#include <dirent.h>
#define NAMLEN(dirent) strlen((dirent)->d_name)
#else
#define dirent direct
#define NAMLEN(dirent) (dirent)->d_namlen
#if HAVE_SYS_NDIR_H
#include <sys/ndir.h>
#endif
#if HAVE_SYS_DIR_H
#include <sys/dir.h>
#endif
#if HAVE_NDIR_H
#include <ndir.h>
#endif
#endif
#if	HAVE_UNISTD_H
#include	<unistd.h>
#endif
#if	HAVE_FCNTL_H
#include	<fcntl.h>
#endif
#include	<errno.h>
#if	HAVE_SYS_TYPES_H
#include	<sys/types.h>
#endif
#if	HAVE_SYS_STAT_H
#include	<sys/stat.h>
#endif
#include	<sys/socket.h>
#include	<arpa/inet.h>

#include        <time.h>
#if HAVE_SYS_TIME_H
#include        <sys/time.h>
#endif

#include	<locale.h>


/* Command-line options: */
const char *clienthost=0;
const char *clientport=0;

const char *server=0;
const char *localfd=0;
const char *remotefd=0;
const char *statusfd=0;
const char *tcpd=0;
const char *peer_verify_domain=0;
const char *fdprotocol=0;
const char *username=0;
static FILE *errfp;
static FILE *statusfp;

const char *printx509=0;

static void ssl_errmsg(const char *errmsg, void *dummy)
{
	const char *loglevel_prefix="";
	const char *tcpremoteip=getenv("TCPREMOTEIP");
	const char *errmsgpfix="";
	const char *errmsgsfix="";

	if (strncmp(errmsg, "DEBUG: ", 7) == 0)
	{
		loglevel_prefix="DEBUG: ";
		errmsg += 7;
	}

	if (tcpremoteip && *tcpremoteip)
	{
		errmsgpfix="ip=[";
		errmsgsfix="], ";
	}
	else
	{
		tcpremoteip="";
	}

	fprintf(errfp, "%s%s%s%s%s\n",
		loglevel_prefix,
		errmsgpfix, tcpremoteip, errmsgsfix,
		errmsg);
	fflush(errfp);
}

static void nonsslerror(const char *pfix)
{
	fprintf(errfp, "%s: %s\n", pfix, strerror(errno));
}

void docopy(ssl_handle ssl, int sslfd, int stdinfd, int stdoutfd)
{
	struct tls_transfer_info transfer_info;

	char from_ssl_buf[BUFSIZ], to_ssl_buf[BUFSIZ];
	char *fromptr;
	int rc;

	fd_set	fdr, fdw;
	int	maxfd=sslfd;

	if (fcntl(stdinfd, F_SETFL, O_NONBLOCK)
	    || fcntl(stdoutfd, F_SETFL, O_NONBLOCK)
	    )
	{
		nonsslerror("fcntl");
		return;
	}

	if (maxfd < stdinfd)	maxfd=stdinfd;
	if (maxfd < stdoutfd)	maxfd=stdoutfd;

	tls_transfer_init(&transfer_info);

	transfer_info.readptr=fromptr=from_ssl_buf;

	for (;;)
	{
		if (transfer_info.readptr == fromptr)
		{
			transfer_info.readptr=fromptr=from_ssl_buf;
			transfer_info.readleft=sizeof(from_ssl_buf);
		}
		else
			transfer_info.readleft=0;

		FD_ZERO(&fdr);
		FD_ZERO(&fdw);

		rc=tls_transfer(&transfer_info, ssl, sslfd, &fdr, &fdw);

		if (rc == 0)
			continue;
		if (rc < 0)
			break;

		if (!tls_inprogress(&transfer_info))
		{
			if (transfer_info.readptr > fromptr)
				FD_SET(stdoutfd, &fdw);

			if (transfer_info.writeleft == 0)
				FD_SET(stdinfd, &fdr);
		}

		if (select(maxfd+1, &fdr, &fdw, 0, 0) <= 0)
		{
			if (errno != EINTR)
			{
				nonsslerror("select");
				break;
			}
			continue;
		}

		if (FD_ISSET(stdoutfd, &fdw) &&
		    transfer_info.readptr > fromptr)
		{
			rc=write(stdoutfd, fromptr,
				 transfer_info.readptr - fromptr);

			if (rc <= 0)
				break;

			fromptr += rc;
		}

		if (FD_ISSET(stdinfd, &fdr) && transfer_info.writeleft == 0)
		{
			rc=read(stdinfd, to_ssl_buf, sizeof(to_ssl_buf));
			if (rc <= 0)
				break;

			transfer_info.writeptr=to_ssl_buf;
			transfer_info.writeleft=rc;
		}
	}

	tls_closing(&transfer_info);

	for (;;)
	{
		FD_ZERO(&fdr);
		FD_ZERO(&fdw);

		if (tls_transfer(&transfer_info, ssl, sslfd, &fdr, &fdw) < 0)
			break;

		if (select(maxfd+1, &fdr, &fdw, 0, 0) <= 0)
		{
			if (errno != EINTR)
			{
				nonsslerror("select");
				break;
			}
			continue;
		}
	}
}

struct dump_capture_subject {
	char line[1024];
	int line_size;

	int set_subject;
	int seen_subject;
	int in_subject;
	FILE *fp;
};

static void dump_to_fp(const char *p, int cnt, void *arg)
{
	struct dump_capture_subject *dcs=(struct dump_capture_subject *)arg;
	char *n, *v;
	char namebuf[64];

	if (cnt < 0)
		cnt=strlen(p);

	if (dcs->fp && fwrite(p, cnt, 1, dcs->fp) != 1)
		; /* NOOP */

	while (cnt)
	{
		if (*p != '\n')
		{
			if (dcs->line_size < sizeof(dcs->line)-1)
				dcs->line[dcs->line_size++]=*p;

			++p;
			--cnt;
			continue;
		}
		dcs->line[dcs->line_size]=0;
		++p;
		--cnt;
		dcs->line_size=0;

		if (strncmp(dcs->line, "Subject:", 8) == 0)
		{
			if (dcs->seen_subject)
				continue;

			dcs->seen_subject=1;
			dcs->in_subject=1;
			continue;
		}

		if (!dcs->in_subject)
			continue;

		if (dcs->line[0] != ' ')
		{
			dcs->in_subject=0;
			continue;
		}

		for (n=dcs->line; *n; n++)
			if (*n != ' ')
				break;

		for (v=n; *v; v++)
		{
			*v=toupper(*v);
			if (*v == '=')
			{
				*v++=0;
				break;
			}
		}

		namebuf[snprintf(namebuf, sizeof(namebuf)-1,
				 "TLS_SUBJECT_%s", n)]=0;

		if (dcs->set_subject)
			setenv(namebuf, v, 1);
	}
}

static int verify_connection(ssl_handle ssl, void *dummy)
{
	FILE	*printx509_fp=NULL;
	int	printx509_fd=0;
	char	*buf;

	struct dump_capture_subject dcs;

	memset(&dcs, 0, sizeof(dcs));

	if (printx509)
	{
		printx509_fd=atoi(printx509);

		printx509_fp=fdopen(printx509_fd, "w");
                if (!printx509_fp)
                        nonsslerror("fdopen");
	}

	dcs.fp=printx509_fp;

	dcs.set_subject=0;

	if (tls_certificate_verified(ssl))
		dcs.set_subject=1;

	tls_dump_connection_info(ssl, server ? 1:0, dump_to_fp, &dcs);

	if (printx509_fp)
	{
		fclose(printx509_fp);
	}

	if (statusfp)
	{
		fclose(statusfp);
		statusfp=NULL;
		errfp=stderr;
	}

	buf=tls_get_encryption_desc(ssl);

	setenv("TLS_CONNECTED_PROTOCOL",
	       buf ? buf:"(unknown)", 1);

	if (buf)
		free(buf);
	return 1;
}

/* ----------------------------------------------------------------------- */

static void startclient(int argn, int argc, char **argv, int fd,
	int *stdin_fd, int *stdout_fd)
{
pid_t	p;
int	streampipe[2];

	if (localfd)
	{
		*stdin_fd= *stdout_fd= atoi(localfd);
		return;
	}

	if (argn >= argc)	return;		/* Interactive */

	if (libmail_streampipe(streampipe))
	{
		nonsslerror("libmail_streampipe");
		exit(1);
	}
	if ((p=fork()) == -1)
	{
		nonsslerror("fork");
		close(streampipe[0]);
		close(streampipe[1]);
		exit(1);
	}
	if (p == 0)
	{
	char **argvec;
	int n;

		close(fd);	/* Child process doesn't need it */
		dup2(streampipe[1], 0);
		dup2(streampipe[1], 1);
		close(streampipe[0]);
		close(streampipe[1]);

		argvec=malloc(sizeof(char *)*(argc-argn+1));
		if (!argvec)
		{
			nonsslerror("malloc");
			exit(1);
		}
		for (n=0; n<argc-argn; n++)
			argvec[n]=argv[argn+n];
		argvec[n]=0;
		execvp(argvec[0], argvec);
		nonsslerror(argvec[0]);
		exit(1);
	}
	close(streampipe[1]);

	*stdin_fd= *stdout_fd= streampipe[0];
}

static int connectremote(const char *host, const char *port)
{
int	fd;

RFC1035_ADDR addr;
int	af;
RFC1035_ADDR *addrs;
unsigned	naddrs, n;

RFC1035_NETADDR addrbuf;
const struct sockaddr *saddr;
int     saddrlen;
int	port_num;

	port_num=atoi(port);
	if (port_num <= 0)
	{
	struct servent *servent;

		servent=getservbyname(port, "tcp");

		if (!servent)
		{
			fprintf(errfp, "%s: invalid port.\n", port);
			return (-1);
		}
		port_num=servent->s_port;
	}
	else
		port_num=htons(port_num);

	if (rfc1035_aton(host, &addr) == 0) /* An explicit IP addr */
	{
		if ((addrs=malloc(sizeof(addr))) == 0)
		{
			nonsslerror("malloc");
			return (-1);
		}
		memcpy(addrs, &addr, sizeof(addr));
		naddrs=1;
	}
	else
	{
		struct rfc1035_res res;
		int rc;

		rfc1035_init_resolv(&res);
		rc=rfc1035_a(&res, host, &addrs, &naddrs);
		rfc1035_destroy_resolv(&res);

		if (rc)
		{
			fprintf(errfp, "%s: not found.\n", host);
			return (-1);
		}
	}

        if ((fd=rfc1035_mksocket(SOCK_STREAM, 0, &af)) < 0)
        {
                nonsslerror("socket");
                return (-1);
        }

	for (n=0; n<naddrs; n++)
	{
		if (rfc1035_mkaddress(af, &addrbuf, addrs+n, port_num,
			&saddr, &saddrlen))	continue;

		if (sox_connect(fd, saddr, saddrlen) == 0)
			break;
	}
	free(addrs);

	if (n >= naddrs)
	{
		close(fd);
		nonsslerror("connect");
		return (-1);
	}

	return (fd);
}

static int connect_completed(ssl_handle ssl, int fd)
{
	struct tls_transfer_info transfer_info;
	tls_transfer_init(&transfer_info);

	while (tls_connecting(ssl))
	{
		fd_set	fdr, fdw;

		FD_ZERO(&fdr);
		FD_ZERO(&fdw);
		if (tls_transfer(&transfer_info, ssl,
				 fd, &fdr, &fdw) < 0)
			return (0);

		if (!tls_connecting(ssl))
			break;

		if (select(fd+1, &fdr, &fdw, 0, 0) <= 0)
		{
			if (errno != EINTR)
			{
				nonsslerror("select");
				return (0);
			}
		}
	}
	return (1);
}

static void child_handler(int signum)
{
	alarm(10);
}

static void trapexit()
{
	struct sigaction sa;

	memset(&sa, 0, sizeof(sa));

	sa.sa_handler=child_handler;
	sigaction(SIGCHLD, &sa, NULL);
}

static int dossl(int fd, int argn, int argc, char **argv)
{
	ssl_context ctx;
	ssl_handle ssl;

	int	stdin_fd, stdout_fd;
	struct tls_info info= *tls_get_default_info();

	info.peer_verify_domain=peer_verify_domain;
	info.tls_err_msg=ssl_errmsg;
	info.connect_callback= &verify_connection;
	info.app_data=NULL;

	stdin_fd=0;
	stdout_fd=1;

	ctx=tls_create(server ? 1:0, &info);
	if (ctx == 0)	return (1);

	ssl=tls_connect(ctx, fd);

	if (!ssl)
	{
		close(fd);
		tls_destroy(ctx);
		return (1);
	}

	if (!connect_completed(ssl, fd))
	{
		tls_disconnect(ssl, fd);
		close(fd);
		tls_destroy(ctx);
		return 1;
	}

	startclient(argn, argc, argv, fd, &stdin_fd, &stdout_fd);
	trapexit();

	if (username)
		libmail_changeusername(username, 0);

	docopy(ssl, fd, stdin_fd, stdout_fd);

	tls_disconnect(ssl, fd);
	close(fd);
	tls_destroy(ctx);
	return (0);
}

struct protoreadbuf {
	char buffer[512];
	char *bufptr;
	int bufleft;

	char line[256];
} ;

#define PRB_INIT(p) ( (p)->bufptr=0, (p)->bufleft=0)

static char protoread(int fd, struct protoreadbuf *prb)
{
	fd_set fds;
	struct timeval tv;

	FD_ZERO(&fds);
	FD_SET(fd, &fds);

	tv.tv_sec=60;
	tv.tv_usec=0;

	if (select(fd+1, &fds, NULL, NULL, &tv) <= 0)
	{
		nonsslerror("select");
		exit(1);
	}

	if ( (prb->bufleft=read(fd, prb->buffer, sizeof(prb->buffer))) <= 0)
	{
		errno=ECONNRESET;
		nonsslerror("read");
		exit(1);
	}

	prb->bufptr= prb->buffer;

	--prb->bufleft;
	return (*prb->bufptr++);
}

#define PRB_GETCH(fd,prb) ( (prb)->bufleft-- > 0 ? *(prb)->bufptr++:\
				protoread( (fd), (prb)))

static const char *prb_getline(int fd, struct protoreadbuf *prb)
{
	int i=0;
	char c;

	while ((c=PRB_GETCH(fd, prb)) != '\n')
	{
		if ( i < sizeof (prb->line)-1)
			prb->line[i++]=c;
	}
	prb->line[i]=0;
	return (prb->line);
}

static void prb_write(int fd, struct protoreadbuf *prb, const char *p)
{
	printf("%s", p);
	while (*p)
	{
		int l=write(fd, p, strlen(p));

		if (l <= 0)
		{
			nonsslerror("write");
			exit(1);
		}
		p += l;
	}
}

static int goodimap(const char *p)
{
	if (*p == 'x' && p[1] && isspace((int)(unsigned char)p[1]))
		++p;
	else
	{
		if (*p != '*')
			return (0);
		++p;
	}
	while (*p && isspace((int)(unsigned char)*p))
		++p;
	if (strncasecmp(p, "BAD", 3) == 0)
	{
		exit(1);
	}

	if (strncasecmp(p, "BYE", 3) == 0)
	{
		exit(1);
	}

	if (strncasecmp(p, "NO", 2) == 0)
	{
		exit(1);
	}

	return (strncasecmp(p, "OK", 2) == 0);
}

static void imap_proto(int fd)
{
	struct protoreadbuf prb;
	const char *p;

	PRB_INIT(&prb);

	do
	{
		p=prb_getline(fd, &prb);
		printf("%s\n", p);

	} while (!goodimap(p));

	prb_write(fd, &prb, "x STARTTLS\r\n");

	do
	{
		p=prb_getline(fd, &prb);
		printf("%s\n", p);
	} while (!goodimap(p));
}

static void pop3_proto(int fd)
{
	struct protoreadbuf prb;
	const char *p;

	PRB_INIT(&prb);

	p=prb_getline(fd, &prb);
	printf("%s\n", p);

	prb_write(fd, &prb, "STLS\r\n");

	p=prb_getline(fd, &prb);
	printf("%s\n", p);
}

static void smtp_proto(int fd)
{
	struct protoreadbuf prb;
	const char *p;

	char hostname[1024];

	PRB_INIT(&prb);

	do
	{
		p=prb_getline(fd, &prb);
		printf("%s\n", p);
	} while ( ! ( isdigit((int)(unsigned char)p[0]) &&
		      isdigit((int)(unsigned char)p[1]) &&
		      isdigit((int)(unsigned char)p[2]) &&
		      (p[3] == 0 || isspace((int)(unsigned char)p[3]))));
	if (strchr("123", *p) == 0)
		exit(1);

	hostname[sizeof(hostname)-1]=0;
	if (gethostname(hostname, sizeof(hostname)-1) < 0)
		strcpy(hostname, "localhost");

	prb_write(fd, &prb, "EHLO ");
	prb_write(fd, &prb, hostname);
	prb_write(fd, &prb, "\r\n");
	do
	{
		p=prb_getline(fd, &prb);
		printf("%s\n", p);
	} while ( ! ( isdigit((int)(unsigned char)p[0]) &&
		      isdigit((int)(unsigned char)p[1]) &&
		      isdigit((int)(unsigned char)p[2]) &&
		      (p[3] == 0 || isspace((int)(unsigned char)p[3]))));
	if (strchr("123", *p) == 0)
		exit(1);

	prb_write(fd, &prb, "STARTTLS\r\n");

	do
	{
		p=prb_getline(fd, &prb);
		printf("%s\n", p);
	} while ( ! ( isdigit((int)(unsigned char)p[0]) &&
		      isdigit((int)(unsigned char)p[1]) &&
		      isdigit((int)(unsigned char)p[2]) &&
		      (p[3] == 0 || isspace((int)(unsigned char)p[3]))));
	if (strchr("123", *p) == 0)
		exit(1);

}

int main(int argc, char **argv)
{
int	argn;
int	fd;
static struct args arginfo[] = {
	{ "host", &clienthost },
	{ "localfd", &localfd},
	{ "port", &clientport },
	{ "printx509", &printx509},
	{ "remotefd", &remotefd},
	{ "server", &server},
	{ "tcpd", &tcpd},
	{ "verify", &peer_verify_domain},
	{ "statusfd", &statusfd},
	{ "protocol", &fdprotocol},
	{ "user", &username},
	{0}};
void (*protocol_func)(int)=0;

	setlocale(LC_ALL, "");
	errfp=stderr;

	argn=argparse(argc, argv, arginfo);

	if (statusfd)
		statusfp=fdopen(atoi(statusfd), "w");

	if (statusfp)
		errfp=statusfp;

	if (fdprotocol)
	{
		if (strcmp(fdprotocol, "smtp") == 0)
			protocol_func= &smtp_proto;
		else if (strcmp(fdprotocol, "imap") == 0)
			protocol_func= &imap_proto;
		else if (strcmp(fdprotocol, "pop3") == 0)
			protocol_func= &pop3_proto;
		else
		{
			fprintf(stderr, "--protocol=%s - unknown protocol.\n",
				fdprotocol);
			exit(1);
		}
	}

	if (tcpd)
	{
		dup2(2, 1);
		fd=0;
	}
	else if (remotefd)
		fd=atoi(remotefd);
	else if (clienthost && clientport)
		fd=connectremote(clienthost, clientport);
	else
	{
		fprintf(errfp, "%s: specify remote location.\n",
			argv[0]);
		return (1);
	}

	if (fd < 0)	return (1);
	if (protocol_func)
		(*protocol_func)(fd);

	return (dossl(fd, argn, argc, argv));
}
