/*
 *
 *
 *
 * ldap_backend.c
 * AUTHOR: Flavio Pescuma, MARA Systems AB <flavio@marasystems.com>
 */

#define LDAP_DEPRECATED 1

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include "ldap_backend.h"

#ifdef _SQUID_MSWIN_		/* Native Windows port and MinGW */

#define snprintf _snprintf
#include <windows.h>
#include <winldap.h>
#ifndef LDAPAPI
#define LDAPAPI __cdecl
#endif
#ifdef LDAP_VERSION3
#ifndef LDAP_OPT_X_TLS
#define LDAP_OPT_X_TLS 0x6000
#endif
/* Some tricks to allow dynamic bind with ldap_start_tls_s entry point at
 * run time.
 */
#undef ldap_start_tls_s
#if LDAP_UNICODE
#define LDAP_START_TLS_S "ldap_start_tls_sW"
typedef WINLDAPAPI ULONG(LDAPAPI * PFldap_start_tls_s) (IN PLDAP, OUT PULONG, OUT LDAPMessage **, IN PLDAPControlW *, IN PLDAPControlW *);
#else
#define LDAP_START_TLS_S "ldap_start_tls_sA"
typedef WINLDAPAPI ULONG(LDAPAPI * PFldap_start_tls_s) (IN PLDAP, OUT PULONG, OUT LDAPMessage **, IN PLDAPControlA *, IN PLDAPControlA *);
#endif /* LDAP_UNICODE */
PFldap_start_tls_s Win32_ldap_start_tls_s;
#define ldap_start_tls_s(l,s,c) Win32_ldap_start_tls_s(l,NULL,NULL,s,c)
#endif /* LDAP_VERSION3 */

#else

#include <lber.h>
#include <ldap.h>

#endif
#define PROGRAM_NAME "digest_pw_auth(LDAP_backend)"

/* Globals */

static LDAP *ld = NULL;
static char *passattr = NULL;
static char *ldapServer = NULL;
static char *userbasedn = NULL;
static char *userdnattr = NULL;
static char *usersearchfilter = NULL;
static char *binddn = NULL;
static char *bindpasswd = NULL;
static char *delimiter = ":";
static int encrpass = 0;
static int searchscope = LDAP_SCOPE_SUBTREE;
static int persistent = 0;
static int noreferrals = 0;
static int debug = 0;
static int port = LDAP_PORT;
static int strip_nt_domain = 0;
static int aliasderef = LDAP_DEREF_NEVER;
#if defined(NETSCAPE_SSL)
static char *sslpath = NULL;
static int sslinit = 0;
#endif
static int connect_timeout = 0;
static int timelimit = LDAP_NO_LIMIT;

#ifdef LDAP_VERSION3
/* Added for TLS support and version 3 */
static int use_tls = 0;
static int version = -1;
#endif

static void ldapconnect(void);
static int readSecret(char *filename);

/* Yuck.. we need to glue to different versions of the API */

#if defined(LDAP_API_VERSION) && LDAP_API_VERSION > 1823
static void
squid_ldap_set_aliasderef(int deref)
{
    ldap_set_option(ld, LDAP_OPT_DEREF, &deref);
}
static void
squid_ldap_set_referrals(int referrals)
{
    int *value = referrals ? LDAP_OPT_ON : LDAP_OPT_OFF;
    ldap_set_option(ld, LDAP_OPT_REFERRALS, value);
}
static void
squid_ldap_set_timelimit(int timelimit)
{
    ldap_set_option(ld, LDAP_OPT_TIMELIMIT, &timelimit);
}
static void
squid_ldap_set_connect_timeout(int timelimit)
{
#if defined(LDAP_OPT_NETWORK_TIMEOUT)
    struct timeval tv;
    tv.tv_sec = timelimit;
    tv.tv_usec = 0;
    ldap_set_option(ld, LDAP_OPT_NETWORK_TIMEOUT, &tv);
#elif defined(LDAP_X_OPT_CONNECT_TIMEOUT)
    timelimit *= 1000;
    ldap_set_option(ld, LDAP_X_OPT_CONNECT_TIMEOUT, &timelimit);
#endif
}

#else
static int
squid_ldap_errno(LDAP * ld)
{
    return ld->ld_errno;
}
static void
squid_ldap_set_aliasderef(int deref)
{
    ld->ld_deref = deref;
}
static void
squid_ldap_set_referrals(int referrals)
{
    if (referrals)
	ld->ld_options |= ~LDAP_OPT_REFERRALS;
    else
	ld->ld_options &= ~LDAP_OPT_REFERRALS;
}
static void
squid_ldap_set_timelimit(int timelimit)
{
    ld->ld_timelimit = timelimit;
}
static void
squid_ldap_set_connect_timeout(int timelimit)
{
    fprintf(stderr, "Connect timeouts not supported in your LDAP library\n");
}
static void
squid_ldap_memfree(char *p)
{
    free(p);
}

#endif

#ifdef LDAP_API_FEATURE_X_OPENLDAP
#if LDAP_VENDOR_VERSION > 194
#define HAS_URI_SUPPORT 1
#endif
#endif

static int
ldap_escape_value(char *escaped, int size, const char *src)
{
    int n = 0;
    while (size > 4 && *src) {
	switch (*src) {
	case '*':
	case '(':
	case ')':
	case '\\':
	    n += 3;
	    size -= 3;
	    if (size > 0) {
		*escaped++ = '\\';
		snprintf(escaped, 3, "%02x", (int) *src++);
		escaped += 2;
	    }
	    break;
	default:
	    *escaped++ = *src++;
	    n++;
	    size--;
	}
    }
    *escaped = '\0';
    return n;
}

static char *
getpassword(char *login, char *realm)
{
    LDAPMessage *res = NULL;
    LDAPMessage *entry;
    char **values = NULL;
    char **value = NULL;
    char *password = NULL;
    int retry = 0;
    char filter[8192];
    char searchbase[8192];
    int rc = -1;
    if (ld) {
	if (usersearchfilter) {
	    char escaped_login[1024];
	    snprintf(searchbase, sizeof(searchbase), "%s", userbasedn);
	    ldap_escape_value(escaped_login, sizeof(escaped_login), login);
	    snprintf(filter, sizeof(filter), usersearchfilter, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login, escaped_login);

	  retrysrch:
	    if (debug)
		fprintf(stderr, "user filter '%s', searchbase '%s'\n", filter, searchbase);

	    rc = ldap_search_s(ld, searchbase, searchscope, filter, NULL, 0, &res);
	    if (rc != LDAP_SUCCESS) {
		if (noreferrals && rc == LDAP_PARTIAL_RESULTS) {
		    /* Everything is fine. This is expected when referrals
		     * are disabled.
		     */
		    rc = LDAP_SUCCESS;
		} else {
		    fprintf(stderr, PROGRAM_NAME " WARNING, LDAP search error '%s'\n", ldap_err2string(rc));
#if defined(NETSCAPE_SSL)
		    if (sslpath && ((rc == LDAP_SERVER_DOWN) || (rc == LDAP_CONNECT_ERROR))) {
			int sslerr = PORT_GetError();
			fprintf(stderr, PROGRAM_NAME ": WARNING, SSL error %d (%s)\n", sslerr, ldapssl_err2string(sslerr));
		    }
#endif
		    fprintf(stderr, PROGRAM_NAME " WARNING, LDAP search error, trying to recover'%s'\n", ldap_err2string(rc));
		    ldap_msgfree(res);
		    /* try to connect to the LDAP server agin, maybe my persisten conexion failed. */
		    if (!retry) {
			retry++;
			ldap_unbind(ld);
			ld = NULL;
			ldapconnect();
			goto retrysrch;
		    }
		    return NULL;

		}
	    }
	} else if (userdnattr) {
	    sprintf(searchbase, "%s=%s, %s", userdnattr, login, userbasedn);

	  retrydnattr:
	    if (debug)
		fprintf(stderr, "searchbase '%s'\n", searchbase);
	    rc = ldap_search_s(ld, searchbase, searchscope, NULL, NULL, 0, &res);
	}
	if (rc == LDAP_SUCCESS) {
	    entry = ldap_first_entry(ld, res);
	    if (entry)
		values = ldap_get_values(ld, entry, passattr);
	    else {
		ldap_msgfree(res);
		return NULL;
	    }
	    if (!values) {
		if (debug)
		    printf("No attribute value found\n");
		ldap_msgfree(res);
		return NULL;
	    }
	    value = values;
	    while (*value) {
		if (encrpass) {
		    if (strcmp(strtok(*value, delimiter), realm) == 0) {
			password = strtok(NULL, delimiter);
			break;
		    }
		} else {
		    password = *value;
		    break;
		}
		value++;
	    }
	    if (debug)
		printf("password: %s\n", password);
	    if (password)
		password = strdup(password);
	    ldap_value_free(values);
	    ldap_msgfree(res);
	    return password;
	} else {
	    fprintf(stderr, PROGRAM_NAME " WARNING, LDAP error '%s'\n", ldap_err2string(rc));
	    /* try to connect to the LDAP server agin, maybe my persisten conexion failed. */
	    if (!retry) {
		retry++;
		ldap_unbind(ld);
		ld = NULL;
		ldapconnect();
		goto retrydnattr;
	    }
	    return NULL;
	}
    }
    return NULL;
}



static void
ldapconnect(void)
{
    int rc;

/* On Windows ldap_start_tls_s is available starting from Windows XP, 
 * so we need to bind at run-time with the function entry point
 */
#ifdef _SQUID_MSWIN_
    if (use_tls) {

	HMODULE WLDAP32Handle;

	WLDAP32Handle = GetModuleHandle("wldap32");
	if ((Win32_ldap_start_tls_s = (PFldap_start_tls_s) GetProcAddress(WLDAP32Handle, LDAP_START_TLS_S)) == NULL) {
	    fprintf(stderr, PROGRAM_NAME ": ERROR: TLS (-Z) not supported on this platform.\n");
	    exit(1);
	}
    }
#endif

    if (ld == NULL) {
#if HAS_URI_SUPPORT
	if (strstr(ldapServer, "://") != NULL) {
	    rc = ldap_initialize(&ld, ldapServer);
	    if (rc != LDAP_SUCCESS) {
		fprintf(stderr, "\nUnable to connect to LDAPURI:%s\n", ldapServer);
	    }
	} else
#endif
#if NETSCAPE_SSL
	if (sslpath) {
	    if (!sslinit && (ldapssl_client_init(sslpath, NULL) != LDAP_SUCCESS)) {
		fprintf(stderr, "\nUnable to initialise SSL with cert path %s\n",
		    sslpath);
		exit(1);
	    } else {
		sslinit++;
	    }
	    if ((ld = ldapssl_init(ldapServer, port, 1)) == NULL) {
		fprintf(stderr, "\nUnable to connect to SSL LDAP server: %s port:%d\n",
		    ldapServer, port);
		exit(1);
	    }
	} else
#endif
	if ((ld = ldap_init(ldapServer, port)) == NULL) {
	    fprintf(stderr, "\nUnable to connect to LDAP server:%s port:%d\n", ldapServer, port);
	}
	if (connect_timeout)
	    squid_ldap_set_connect_timeout(connect_timeout);

#ifdef LDAP_VERSION3
	if (version == -1) {
	    version = LDAP_VERSION2;
	}
	if (ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, &version)
	    != LDAP_SUCCESS) {
	    fprintf(stderr, "Could not set LDAP_OPT_PROTOCOL_VERSION %d\n",
		version);
	    ldap_unbind(ld);
	    ld = NULL;
	}
	if (use_tls) {
#ifdef LDAP_OPT_X_TLS
	    if ((version == LDAP_VERSION3) && (ldap_start_tls_s(ld, NULL, NULL) == LDAP_SUCCESS)) {
		fprintf(stderr, "Could not Activate TLS connection\n");
		ldap_unbind(ld);
		ld = NULL;
	    }
#else
	    fprintf(stderr, "TLS not supported with your LDAP library\n");
	    ldap_unbind(ld);
	    ld = NULL;
#endif
	}
#endif
	squid_ldap_set_timelimit(timelimit);
	squid_ldap_set_referrals(!noreferrals);
	squid_ldap_set_aliasderef(aliasderef);
	if (binddn && bindpasswd && *binddn && *bindpasswd) {
	    rc = ldap_simple_bind_s(ld, binddn, bindpasswd);
	    if (rc != LDAP_SUCCESS) {
		fprintf(stderr, PROGRAM_NAME " WARNING, could not bind to binddn '%s'\n", ldap_err2string(rc));
		ldap_unbind(ld);
		ld = NULL;
	    }
	}
	if (debug)
	    fprintf(stderr, "Connected OK\n");
    }
}
int
LDAPArguments(int argc, char **argv)
{
    setbuf(stdout, NULL);

    while (argc > 1 && argv[1][0] == '-') {
	char *value = "";
	char option = argv[1][1];
	switch (option) {
	case 'P':
	case 'R':
	case 'z':
	case 'Z':
	case 'g':
	case 'e':
	case 'S':
	    break;
	default:
	    if (strlen(argv[1]) > 2) {
		value = argv[1] + 2;
	    } else if (argc > 2) {
		value = argv[2];
		argv++;
		argc--;
	    } else
		value = "";
	    break;
	}
	argv++;
	argc--;
	switch (option) {
	case 'H':
#if !HAS_URI_SUPPORT
	    fprintf(stderr, "ERROR: Your LDAP library does not have URI support\n");
	    return 1;
#endif
	    /* Fall thru to -h */
	case 'h':
	    if (ldapServer) {
		int len = strlen(ldapServer) + 1 + strlen(value) + 1;
		char *newhost = malloc(len);
		snprintf(newhost, len, "%s %s", ldapServer, value);
		free(ldapServer);
		ldapServer = newhost;
	    } else {
		ldapServer = strdup(value);
	    }
	    break;
	case 'A':
	    passattr = value;
	    break;
	case 'e':
	    encrpass = 1;
	    break;
	case 'l':
	    delimiter = value;
	    break;
	case 'b':
	    userbasedn = value;
	    break;
	case 'F':
	    usersearchfilter = value;
	    break;
	case 'u':
	    userdnattr = value;
	    break;
	case 's':
	    if (strcmp(value, "base") == 0)
		searchscope = LDAP_SCOPE_BASE;
	    else if (strcmp(value, "one") == 0)
		searchscope = LDAP_SCOPE_ONELEVEL;
	    else if (strcmp(value, "sub") == 0)
		searchscope = LDAP_SCOPE_SUBTREE;
	    else {
		fprintf(stderr, PROGRAM_NAME " ERROR: Unknown search scope '%s'\n", value);
		return 1;
	    }
	    break;
	case 'S':
#if defined(NETSCAPE_SSL)
	    sslpath = value;
	    if (port == LDAP_PORT)
		port = LDAPS_PORT;
#else
	    fprintf(stderr, PROGRAM_NAME " ERROR: -E unsupported with this LDAP library\n");
	    return 1;
#endif
	    break;
	case 'c':
	    connect_timeout = atoi(value);
	    break;
	case 't':
	    timelimit = atoi(value);
	    break;
	case 'a':
	    if (strcmp(value, "never") == 0)
		aliasderef = LDAP_DEREF_NEVER;
	    else if (strcmp(value, "always") == 0)
		aliasderef = LDAP_DEREF_ALWAYS;
	    else if (strcmp(value, "search") == 0)
		aliasderef = LDAP_DEREF_SEARCHING;
	    else if (strcmp(value, "find") == 0)
		aliasderef = LDAP_DEREF_FINDING;
	    else {
		fprintf(stderr, PROGRAM_NAME " ERROR: Unknown alias dereference method '%s'\n", value);
		return 1;
	    }
	    break;
	case 'D':
	    binddn = value;
	    break;
	case 'w':
	    bindpasswd = value;
	    break;
	case 'W':
	    readSecret(value);
	    break;
	case 'P':
	    persistent = !persistent;
	    break;
	case 'p':
	    port = atoi(value);
	    break;
	case 'R':
	    noreferrals = !noreferrals;
	    break;
#ifdef LDAP_VERSION3
	case 'v':
	    switch (atoi(value)) {
	    case 2:
		version = LDAP_VERSION2;
		break;
	    case 3:
		version = LDAP_VERSION3;
		break;
	    default:
		fprintf(stderr, "Protocol version should be 2 or 3\n");
		return 1;
	    }
	    break;
	case 'Z':
	    if (version == LDAP_VERSION2) {
		fprintf(stderr, "TLS (-Z) is incompatible with version %d\n",
		    version);
		return 1;
	    }
	    version = LDAP_VERSION3;
	    use_tls = 1;
	    break;
#endif
	case 'd':
	    debug = 1;
	    break;
	case 'E':
	    strip_nt_domain = 1;
	    break;
	default:
	    fprintf(stderr, PROGRAM_NAME " ERROR: Unknown command line option '%c'\n", option);
	    return 1;
	}
    }

    while (argc > 1) {
	char *value = argv[1];
	if (ldapServer) {
	    int len = strlen(ldapServer) + 1 + strlen(value) + 1;
	    char *newhost = malloc(len);
	    snprintf(newhost, len, "%s %s", ldapServer, value);
	    free(ldapServer);
	    ldapServer = newhost;
	} else {
	    ldapServer = strdup(value);
	}
	argc--;
	argv++;
    }

    if (!ldapServer)
	ldapServer = "localhost";

    if (!userbasedn || !passattr) {
	fprintf(stderr, "Usage: " PROGRAM_NAME " -b basedn -f filter [options] ldap_server_name\n\n");
	fprintf(stderr, "\t-A password attribute(REQUIRED)\t\tUser attribute that contains the password\n");
	fprintf(stderr, "\t-l password realm delimiter(REQUIRED)\tCharater(s) that devides the password attribute\n\t\t\t\t\t\tin realm and password tokens, default ':' realm:password\n");
	fprintf(stderr, "\t-b basedn (REQUIRED)\t\t\tbase dn under where to search for users\n");
	fprintf(stderr, "\t-e Encrypted passwords(REQUIRED)\tPassword are stored encrypted using HHA1\n");
	fprintf(stderr, "\t-F filter\t\t\t\tuser search filter pattern. %%s = login\n");
	fprintf(stderr, "\t-u attribute\t\t\t\tattribute to use in combination with the basedn to create the user DN\n");
	fprintf(stderr, "\t-s base|one|sub\t\t\t\tsearch scope\n");
	fprintf(stderr, "\t-D binddn\t\t\t\tDN to bind as to perform searches\n");
	fprintf(stderr, "\t-w bindpasswd\t\t\t\tpassword for binddn\n");
	fprintf(stderr, "\t-W secretfile\t\t\t\tread password for binddn from file secretfile\n");
#if HAS_URI_SUPPORT
	fprintf(stderr, "\t-H URI\t\t\t\t\tLDAPURI (defaults to ldap://localhost)\n");
#endif
	fprintf(stderr, "\t-h server\t\t\t\tLDAP server (defaults to localhost)\n");
	fprintf(stderr, "\t-p port\t\t\t\t\tLDAP server port (defaults to %d)\n", LDAP_PORT);
	fprintf(stderr, "\t-P\t\t\t\t\tpersistent LDAP connection\n");
#if defined(NETSCAPE_SSL)
	fprintf(stderr, "\t-E sslcertpath\t\t\t\tenable LDAP over SSL\n");
#endif
	fprintf(stderr, "\t-c timeout\t\t\t\tconnect timeout\n");
	fprintf(stderr, "\t-t timelimit\t\t\t\tsearch time limit\n");
	fprintf(stderr, "\t-R\t\t\t\t\tdo not follow referrals\n");
	fprintf(stderr, "\t-a never|always|search|find\t\twhen to dereference aliases\n");
#ifdef LDAP_VERSION3
	fprintf(stderr, "\t-v 2|3\t\t\t\t\tLDAP version\n");
	fprintf(stderr, "\t-Z\t\t\t\t\tTLS encrypt the LDAP connection, requires\n\t\t\t\tLDAP version 3\n");
#endif
	fprintf(stderr, "\t-S\t\t\t\t\tStrip NT domain from usernames\n");
	fprintf(stderr, "\n");
	fprintf(stderr, "\tIf you need to bind as a user to perform searches then use the\n\t-D binddn -w bindpasswd or -D binddn -W secretfile options\n\n");
	return -1;
    }
    return 0;
}
static int
readSecret(char *filename)
{
    char buf[BUFSIZ];
    char *e = 0;
    FILE *f;

    if (!(f = fopen(filename, "r"))) {
	fprintf(stderr, PROGRAM_NAME " ERROR: Can not read secret file %s\n", filename);
	return 1;
    }
    if (!fgets(buf, sizeof(buf) - 1, f)) {
	fprintf(stderr, PROGRAM_NAME " ERROR: Secret file %s is empty\n", filename);
	fclose(f);
	return 1;
    }
    /* strip whitespaces on end */
    if ((e = strrchr(buf, '\n')))
	*e = 0;
    if ((e = strrchr(buf, '\r')))
	*e = 0;

    bindpasswd = (char *) calloc(sizeof(char), strlen(buf) + 1);
    if (bindpasswd) {
	strcpy(bindpasswd, buf);
    } else {
	fprintf(stderr, PROGRAM_NAME " ERROR: can not allocate memory\n");
    }

    fclose(f);

    return 0;
}

void
LDAPHHA1(RequestData * requestData)
{
    char *password = "";
    ldapconnect();
    password = getpassword(requestData->user, requestData->realm);
    if (password != NULL) {
	if (encrpass)
	    xstrncpy(requestData->HHA1, &password[6], sizeof(requestData->HHA1));
	else {
	    HASH HA1;
	    DigestCalcHA1("md5", requestData->user, requestData->realm, password, NULL, NULL, HA1, requestData->HHA1);
	}
	free(password);
    } else {
	requestData->error = -1;
    }

}
