
/*
 * mswin_negotiate_auth: helper for Negotiate Authentication for Squid Cache
 *
 * (C)2005 Guido Serassio - Acme Consulting S.r.l.
 *
 * Authors:
 *  Guido Serassio <guido.serassio@acmeconsulting.it>
 *  Acme Consulting S.r.l., Italy <http://www.acmeconsulting.it>
 *
 * With contributions from others mentioned in the change history section
 * below.
 *
 * Based on previous work of Francesco Chemolli and Robert Collins.
 *
 * Dependencies: Windows NT4 SP4 and later.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * History:
 *
 * Version 1.0
 * 29-10-2005 Guido Serassio
 *              First release.
 *
 *
 */

#include "util.h"
#if HAVE_GETOPT_H
#include <getopt.h>
#endif
#include "negotiate.h"
#if HAVE_CTYPE_H
#include <ctype.h>
#endif

#define BUFFER_SIZE 10240

int debug_enabled = 0;
int Negotiate_packet_debug_enabled = 0;

static int have_serverblob;

/* makes a null-terminated string upper-case. Changes CONTENTS! */
void
uc(char *string)
{
    char *p = string, c;
    while ((c = *p)) {
	*p = toupper(c);
	p++;
    }
}

/* makes a null-terminated string lower-case. Changes CONTENTS! */
static void
lc(char *string)
{
    char *p = string, c;
    while ((c = *p)) {
	*p = tolower(c);
	p++;
    }
}

void
helperfail(const char *reason)
{
#if FAIL_DEBUG
    fail_debug_enabled = 1;
#endif
    SEND2("BH %s", reason);
}

/*
 * options:
 * -d enable debugging.
 * -v enable verbose NTLM packet debugging.
 */
char *my_program_name = NULL;

void
usage()
{
    fprintf(stderr,
	"Usage: %s [-d] [-v] [-h]\n"
	" -d  enable debugging.\n"
	" -v  enable verbose NTLM packet debugging.\n"
	" -h  this message\n\n",
	my_program_name);
}


void
process_options(int argc, char *argv[])
{
    int opt, had_error = 0;

    opterr = 0;
    while (-1 != (opt = getopt(argc, argv, "hdv"))) {
	switch (opt) {
	case 'd':
	    debug_enabled = 1;
	    break;
	case 'v':
	    debug_enabled = 1;
	    Negotiate_packet_debug_enabled = 1;
	    break;
	case 'h':
	    usage();
	    exit(0);
	case '?':
	    opt = optopt;
	    /* fall thru to default */
	default:
	    fprintf(stderr, "unknown option: -%c. Exiting\n", opt);
	    usage();
	    had_error = 1;
	}
    }
    if (had_error)
	exit(1);
}

int
manage_request()
{
    char buf[BUFFER_SIZE];
    char helper_command[3];
    char *c, *decoded;
    int plen, status;
    int oversized = 0;
    char *ErrorMessage;
    static char cred[SSP_MAX_CRED_LEN + 1];
    BOOL Done = FALSE;

  try_again:
    if (fgets(buf, BUFFER_SIZE, stdin) == NULL)
	return 0;

    c = memchr(buf, '\n', BUFFER_SIZE);		/* safer against overrun than strchr */
    if (c) {
	if (oversized) {
	    helperfail("illegal request received");
	    fprintf(stderr, "Illegal request received: '%s'\n", buf);
	    return 1;
	}
	*c = '\0';
    } else {
	fprintf(stderr, "No newline in '%s'\n", buf);
	oversized = 1;
	goto try_again;
    }

    if ((strlen(buf) > 3) && Negotiate_packet_debug_enabled) {
	decoded = base64_decode(buf + 3);
	strncpy(helper_command, buf, 2);
	debug("Got '%s' from Squid with data:\n", helper_command);
	hex_dump(decoded, ((strlen(buf) - 3) * 3) / 4);
    } else
	debug("Got '%s' from Squid\n", buf);

    if (memcmp(buf, "YR ", 3) == 0) {	/* refresh-request */
	/* figure out what we got */
	decoded = base64_decode(buf + 3);
	/*  Note: we don't need to manage memory at this point, since
	 *  base64_decode returns a pointer to static storage.
	 */
	if (!decoded) {		/* decoding failure, return error */
	    SEND("NA * Packet format error, couldn't base64-decode");
	    return 1;
	}
	/* Obtain server blob against SSPI */
	plen = (strlen(buf) - 3) * 3 / 4;	/* we only need it here. Optimization */
	c = (char *) SSP_MakeNegotiateBlob(decoded, plen, &Done, &status, cred);

	if (status == SSP_OK) {
	    if (Done) {
		lc(cred);	/* let's lowercase them for our convenience */
		have_serverblob = 0;
		Done = FALSE;
		if (Negotiate_packet_debug_enabled) {
		    printf("AF %s %s\n", c, cred);
		    decoded = base64_decode(c);
		    debug("sending 'AF' %s to squid with data:\n", cred);
		    hex_dump(decoded, (strlen(c) * 3) / 4);
		} else
		    SEND3("AF %s %s", c, cred);
	    } else {
		if (Negotiate_packet_debug_enabled) {
		    printf("TT %s\n", c);
		    decoded = base64_decode(c);
		    debug("sending 'TT' to squid with data:\n");
		    hex_dump(decoded, (strlen(c) * 3) / 4);
		} else {
		    SEND2("TT %s", c);
		}
		have_serverblob = 1;
	    }
	} else
	    helperfail("can't obtain server blob");
	return 1;
    }
    if (memcmp(buf, "KK ", 3) == 0) {	/* authenticate-request */
	if (!have_serverblob) {
	    helperfail("invalid server blob");
	    return 1;
	}
	/* figure out what we got */
	decoded = base64_decode(buf + 3);
	/*  Note: we don't need to manage memory at this point, since
	 *  base64_decode returns a pointer to static storage.
	 */
	if (!decoded) {		/* decoding failure, return error */
	    SEND("NA * Packet format error, couldn't base64-decode");
	    return 1;
	}
	/* check against SSPI */
	plen = (strlen(buf) - 3) * 3 / 4;	/* we only need it here. Optimization */
	c = (char *) SSP_ValidateNegotiateCredentials(decoded, plen, &Done, &status, cred);

	if (status == SSP_ERROR) {
#if FAIL_DEBUG
	    fail_debug_enabled = 1;
#endif
	    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
		FORMAT_MESSAGE_IGNORE_INSERTS,
		NULL,
		GetLastError(),
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),	/* Default language */
		(LPTSTR) & ErrorMessage,
		0,
		NULL);
	    if (ErrorMessage[strlen(ErrorMessage) - 1] == '\n')
		ErrorMessage[strlen(ErrorMessage) - 1] = '\0';
	    if (ErrorMessage[strlen(ErrorMessage) - 1] == '\r')
		ErrorMessage[strlen(ErrorMessage) - 1] = '\0';
	    SEND2("NA * %s", ErrorMessage);
	    LocalFree(ErrorMessage);
	    return 1;
	}
	if (Done) {
	    lc(cred);		/* let's lowercase them for our convenience */
	    have_serverblob = 0;
	    Done = FALSE;
	    if (Negotiate_packet_debug_enabled) {
		printf("AF %s %s\n", c, cred);
		decoded = base64_decode(c);
		debug("sending 'AF' %s to squid with data:\n", cred);
		hex_dump(decoded, (strlen(c) * 3) / 4);
	    } else {
		SEND3("AF %s %s", c, cred);
	    }
	    return 1;
	} else {
	    if (Negotiate_packet_debug_enabled) {
		printf("TT %s\n", c);
		decoded = base64_decode(c);
		debug("sending 'TT' to squid with data:\n");
		hex_dump(decoded, (strlen(c) * 3) / 4);
	    } else
		SEND2("TT %s", c);
	    return 1;
	}

    } else {			/* not an auth-request */
	helperfail("illegal request received");
	fprintf(stderr, "Illegal request received: '%s'\n", buf);
	return 1;
    }
    helperfail("detected protocol error");
    return 1;
/********* END ********/
}

int
main(int argc, char *argv[])
{
    my_program_name = argv[0];

    process_options(argc, argv);

    debug("%s build " __DATE__ ", " __TIME__ " starting up...\n", my_program_name);

    if (LoadSecurityDll(SSP_NTLM, NEGOTIATE_PACKAGE_NAME) == NULL) {
	fprintf(stderr, "FATAL, can't initialize SSPI, exiting.\n");
	exit(1);
    }
    debug("SSPI initialized OK\n");

    atexit(UnloadSecurityDll);

    /* initialize FDescs */
    setbuf(stdout, NULL);
    setbuf(stderr, NULL);

    while (manage_request()) {
	/* everything is done within manage_request */
    }
    exit(0);
}
