/* * Copyright (c) 2006 - 2008 Kungliga Tekniska Högskolan * (Royal Institute of Technology, Stockholm, Sweden). * All rights reserved. * * Portions Copyright (c) 2010 Apple Inc. 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. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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 #include #include #include #include #include #include #include #include #include #include #define HC_DEPRECATED_CRYPTO #include "krb5-types.h" #include "crypto-headers.h" #include /*! \mainpage Heimdal NTLM library * * \section intro Introduction * * Heimdal libheimntlm library is a implementation of the NTLM * protocol, both version 1 and 2. The GSS-API mech that uses this * library adds support for transport encryption and integrity * checking. * * NTLM is a protocol for mutual authentication, its still used in * many protocol where Kerberos is not support, one example is * EAP/X802.1x mechanism LEAP from Microsoft and Cisco. * * This is a support library for the core protocol, its used in * Heimdal to implement and GSS-API mechanism. There is also support * in the KDC to do remote digest authenticiation, this to allow * services to authenticate users w/o direct access to the users ntlm * hashes (same as Kerberos arcfour enctype keys). * * More information about the NTLM protocol can found here * http://davenport.sourceforge.net/ntlm.html . * * The Heimdal projects web page: http://www.h5l.org/ * * @section ntlm_example NTLM Example * * Example to to use @ref test_ntlm.c . * * @example test_ntlm.c * * Example how to use the NTLM primitives. * */ /** @defgroup ntlm_core Heimdal NTLM library * * The NTLM core functions implement the string2key generation * function, message encode and decode function, and the hash function * functions. */ struct sec_buffer { uint16_t length; uint16_t allocated; uint32_t offset; }; static const unsigned char ntlmsigature[8] = "NTLMSSP\x00"; /* * */ #define CHECK(f, e) \ do { \ ret = f; \ if (ret != (ssize_t)(e)) { \ ret = HNTLM_ERR_DECODE; \ goto out; \ } \ } while(/*CONSTCOND*/0) static struct units ntlm_flag_units[] = { #define ntlm_flag(x) { #x, NTLM_##x } ntlm_flag(ENC_56), ntlm_flag(NEG_KEYEX), ntlm_flag(ENC_128), ntlm_flag(MBZ1), ntlm_flag(MBZ2), ntlm_flag(MBZ3), ntlm_flag(NEG_VERSION), ntlm_flag(MBZ4), ntlm_flag(NEG_TARGET_INFO), ntlm_flag(NON_NT_SESSION_KEY), ntlm_flag(MBZ5), ntlm_flag(NEG_IDENTIFY), ntlm_flag(NEG_NTLM2), ntlm_flag(TARGET_SHARE), ntlm_flag(TARGET_SERVER), ntlm_flag(TARGET_DOMAIN), ntlm_flag(NEG_ALWAYS_SIGN), ntlm_flag(MBZ6), ntlm_flag(OEM_SUPPLIED_WORKSTATION), ntlm_flag(OEM_SUPPLIED_DOMAIN), ntlm_flag(NEG_ANONYMOUS), ntlm_flag(NEG_NT_ONLY), ntlm_flag(NEG_NTLM), ntlm_flag(MBZ8), ntlm_flag(NEG_LM_KEY), ntlm_flag(NEG_DATAGRAM), ntlm_flag(NEG_SEAL), ntlm_flag(NEG_SIGN), ntlm_flag(MBZ9), ntlm_flag(NEG_TARGET), ntlm_flag(NEG_OEM), ntlm_flag(NEG_UNICODE), #undef ntlm_flag {NULL, 0} }; size_t heim_ntlm_unparse_flags(uint32_t flags, char *s, size_t len) { return unparse_flags(flags, ntlm_flag_units, s, len); } /** * heim_ntlm_free_buf frees the ntlm buffer * * @param p buffer to be freed * * @ingroup ntlm_core */ void heim_ntlm_free_buf(struct ntlm_buf *p) { if (p->data) free(p->data); p->data = NULL; p->length = 0; } static int ascii2ucs2le(const char *string, int up, struct ntlm_buf *buf) { unsigned char *p; size_t len, i; len = strlen(string); if (len / 2 > UINT_MAX) return ERANGE; buf->length = len * 2; buf->data = malloc(buf->length); if (buf->data == NULL && len != 0) { heim_ntlm_free_buf(buf); return ENOMEM; } p = buf->data; for (i = 0; i < len; i++) { unsigned char t = (unsigned char)string[i]; if (t & 0x80) { heim_ntlm_free_buf(buf); return EINVAL; } if (up) t = toupper(t); p[(i * 2) + 0] = t; p[(i * 2) + 1] = 0; } return 0; } /* * */ static krb5_error_code ret_sec_buffer(krb5_storage *sp, struct sec_buffer *buf) { krb5_error_code ret; CHECK(krb5_ret_uint16(sp, &buf->length), 0); CHECK(krb5_ret_uint16(sp, &buf->allocated), 0); CHECK(krb5_ret_uint32(sp, &buf->offset), 0); out: return ret; } static krb5_error_code store_sec_buffer(krb5_storage *sp, const struct sec_buffer *buf) { krb5_error_code ret; CHECK(krb5_store_uint16(sp, buf->length), 0); CHECK(krb5_store_uint16(sp, buf->allocated), 0); CHECK(krb5_store_uint32(sp, buf->offset), 0); out: return ret; } /* * Strings are either OEM or UNICODE. The later is encoded as ucs2 on * wire, but using utf8 in memory. */ static krb5_error_code len_string(int ucs2, const char *s) { size_t len = strlen(s); if (ucs2) len *= 2; return len; } /* * */ static krb5_error_code ret_string(krb5_storage *sp, int ucs2, size_t len, char **s) { krb5_error_code ret; *s = malloc(len + 1); if (*s == NULL) return ENOMEM; CHECK(krb5_storage_read(sp, *s, len), len); (*s)[len] = '\0'; if (ucs2) { size_t i; for (i = 0; i < len / 2; i++) { (*s)[i] = (*s)[i * 2]; if ((*s)[i * 2 + 1]) { free(*s); *s = NULL; return EINVAL; } } (*s)[i] = '\0'; } ret = 0; out: return ret; } static krb5_error_code ret_sec_string(krb5_storage *sp, int ucs2, struct sec_buffer *desc, char **s) { krb5_error_code ret = 0; CHECK(krb5_storage_seek(sp, desc->offset, SEEK_SET), desc->offset); CHECK(ret_string(sp, ucs2, desc->length, s), 0); out: return ret; } static krb5_error_code put_string(krb5_storage *sp, int ucs2, const char *s) { krb5_error_code ret; struct ntlm_buf buf; if (ucs2) { ret = ascii2ucs2le(s, 0, &buf); if (ret) return ret; } else { buf.data = rk_UNCONST(s); buf.length = strlen(s); } CHECK(krb5_storage_write(sp, buf.data, buf.length), buf.length); if (ucs2) heim_ntlm_free_buf(&buf); ret = 0; out: return ret; } /* * */ static krb5_error_code ret_buf(krb5_storage *sp, struct sec_buffer *desc, struct ntlm_buf *buf) { krb5_error_code ret; buf->data = malloc(desc->length); buf->length = desc->length; CHECK(krb5_storage_seek(sp, desc->offset, SEEK_SET), desc->offset); CHECK(krb5_storage_read(sp, buf->data, buf->length), buf->length); ret = 0; out: return ret; } static krb5_error_code put_buf(krb5_storage *sp, const struct ntlm_buf *buf) { krb5_error_code ret; CHECK(krb5_storage_write(sp, buf->data, buf->length), buf->length); ret = 0; out: return ret; } /** * Frees the ntlm_targetinfo message * * @param ti targetinfo to be freed * * @ingroup ntlm_core */ void heim_ntlm_free_targetinfo(struct ntlm_targetinfo *ti) { free(ti->servername); free(ti->domainname); free(ti->dnsdomainname); free(ti->dnsservername); free(ti->dnstreename); memset(ti, 0, sizeof(*ti)); } static int encode_ti_string(krb5_storage *out, uint16_t type, int ucs2, char *s) { krb5_error_code ret; CHECK(krb5_store_uint16(out, type), 0); CHECK(krb5_store_uint16(out, len_string(ucs2, s)), 0); CHECK(put_string(out, ucs2, s), 0); out: return ret; } /** * Encodes a ntlm_targetinfo message. * * @param ti the ntlm_targetinfo message to encode. * @param ucs2 ignored * @param data is the return buffer with the encoded message, should be * freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_encode_targetinfo(const struct ntlm_targetinfo *ti, int ucs2, struct ntlm_buf *data) { krb5_error_code ret; krb5_storage *out; data->data = NULL; data->length = 0; out = krb5_storage_emem(); if (out == NULL) return ENOMEM; krb5_storage_set_byteorder(out, KRB5_STORAGE_BYTEORDER_LE); if (ti->servername) CHECK(encode_ti_string(out, 1, ucs2, ti->servername), 0); if (ti->domainname) CHECK(encode_ti_string(out, 2, ucs2, ti->domainname), 0); if (ti->dnsservername) CHECK(encode_ti_string(out, 3, ucs2, ti->dnsservername), 0); if (ti->dnsdomainname) CHECK(encode_ti_string(out, 4, ucs2, ti->dnsdomainname), 0); if (ti->dnstreename) CHECK(encode_ti_string(out, 5, ucs2, ti->dnstreename), 0); if (ti->avflags) { CHECK(krb5_store_uint16(out, 6), 0); CHECK(krb5_store_uint16(out, 4), 0); CHECK(krb5_store_uint32(out, ti->avflags), 0); } /* end tag */ CHECK(krb5_store_int16(out, 0), 0); CHECK(krb5_store_int16(out, 0), 0); { krb5_data d; ret = krb5_storage_to_data(out, &d); data->data = d.data; data->length = d.length; } out: krb5_storage_free(out); return ret; } /** * Decodes an NTLM targetinfo message * * @param data input data buffer with the encode NTLM targetinfo message * @param ucs2 if the strings should be encoded with ucs2 (selected by flag in message). * @param ti the decoded target info, should be freed with heim_ntlm_free_targetinfo(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_decode_targetinfo(const struct ntlm_buf *data, int ucs2, struct ntlm_targetinfo *ti) { uint16_t type, len; krb5_storage *in; int ret = 0, done = 0; memset(ti, 0, sizeof(*ti)); if (data->length == 0) return 0; in = krb5_storage_from_readonly_mem(data->data, data->length); if (in == NULL) return ENOMEM; krb5_storage_set_byteorder(in, KRB5_STORAGE_BYTEORDER_LE); while (!done) { CHECK(krb5_ret_uint16(in, &type), 0); CHECK(krb5_ret_uint16(in, &len), 0); switch (type) { case 0: done = 1; break; case 1: CHECK(ret_string(in, ucs2, len, &ti->servername), 0); break; case 2: CHECK(ret_string(in, ucs2, len, &ti->domainname), 0); break; case 3: CHECK(ret_string(in, ucs2, len, &ti->dnsservername), 0); break; case 4: CHECK(ret_string(in, ucs2, len, &ti->dnsdomainname), 0); break; case 5: CHECK(ret_string(in, ucs2, len, &ti->dnstreename), 0); break; case 6: CHECK(krb5_ret_uint32(in, &ti->avflags), 0); break; default: krb5_storage_seek(in, len, SEEK_CUR); break; } } out: if (in) krb5_storage_free(in); return ret; } /** * Frees the ntlm_type1 message * * @param data message to be freed * * @ingroup ntlm_core */ void heim_ntlm_free_type1(struct ntlm_type1 *data) { if (data->domain) free(data->domain); if (data->hostname) free(data->hostname); memset(data, 0, sizeof(*data)); } int heim_ntlm_decode_type1(const struct ntlm_buf *buf, struct ntlm_type1 *data) { krb5_error_code ret; unsigned char sig[8]; uint32_t type; struct sec_buffer domain, hostname; krb5_storage *in; memset(data, 0, sizeof(*data)); in = krb5_storage_from_readonly_mem(buf->data, buf->length); if (in == NULL) { ret = ENOMEM; goto out; } krb5_storage_set_byteorder(in, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_read(in, sig, sizeof(sig)), sizeof(sig)); CHECK(memcmp(ntlmsigature, sig, sizeof(ntlmsigature)), 0); CHECK(krb5_ret_uint32(in, &type), 0); CHECK(type, 1); CHECK(krb5_ret_uint32(in, &data->flags), 0); if (data->flags & NTLM_OEM_SUPPLIED_DOMAIN) CHECK(ret_sec_buffer(in, &domain), 0); if (data->flags & NTLM_OEM_SUPPLIED_WORKSTATION) CHECK(ret_sec_buffer(in, &hostname), 0); #if 0 if (domain.offset > 32) { CHECK(krb5_ret_uint32(in, &data->os[0]), 0); CHECK(krb5_ret_uint32(in, &data->os[1]), 0); } #endif if (data->flags & NTLM_OEM_SUPPLIED_DOMAIN) CHECK(ret_sec_string(in, 0, &domain, &data->domain), 0); if (data->flags & NTLM_OEM_SUPPLIED_WORKSTATION) CHECK(ret_sec_string(in, 0, &hostname, &data->hostname), 0); out: if (in) krb5_storage_free(in); if (ret) heim_ntlm_free_type1(data); return ret; } /** * Encodes an ntlm_type1 message. * * @param type1 the ntlm_type1 message to encode. * @param data is the return buffer with the encoded message, should be * freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_encode_type1(const struct ntlm_type1 *type1, struct ntlm_buf *data) { krb5_error_code ret; struct sec_buffer domain, hostname; krb5_storage *out; uint32_t base, flags; flags = type1->flags; base = 16; if (type1->domain) { base += 8; flags |= NTLM_OEM_SUPPLIED_DOMAIN; } if (type1->hostname) { base += 8; flags |= NTLM_OEM_SUPPLIED_WORKSTATION; } if (type1->os[0]) base += 8; domain.offset = base; if (type1->domain) { domain.length = len_string(0, type1->domain); domain.allocated = domain.length; } else { domain.length = 0; domain.allocated = 0; } hostname.offset = domain.allocated + domain.offset; if (type1->hostname) { hostname.length = len_string(0, type1->hostname); hostname.allocated = hostname.length; } else { hostname.length = 0; hostname.allocated = 0; } out = krb5_storage_emem(); if (out == NULL) return ENOMEM; krb5_storage_set_byteorder(out, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_write(out, ntlmsigature, sizeof(ntlmsigature)), sizeof(ntlmsigature)); CHECK(krb5_store_uint32(out, 1), 0); CHECK(krb5_store_uint32(out, flags), 0); CHECK(store_sec_buffer(out, &domain), 0); CHECK(store_sec_buffer(out, &hostname), 0); #if 0 CHECK(krb5_store_uint32(out, type1->os[0]), 0); CHECK(krb5_store_uint32(out, type1->os[1]), 0); #endif if (type1->domain) CHECK(put_string(out, 0, type1->domain), 0); if (type1->hostname) CHECK(put_string(out, 0, type1->hostname), 0); { krb5_data d; ret = krb5_storage_to_data(out, &d); data->data = d.data; data->length = d.length; } out: krb5_storage_free(out); return ret; } /** * Frees the ntlm_type2 message * * @param data message to be freed * * @ingroup ntlm_core */ void heim_ntlm_free_type2(struct ntlm_type2 *data) { if (data->targetname) free(data->targetname); heim_ntlm_free_buf(&data->targetinfo); memset(data, 0, sizeof(*data)); } int heim_ntlm_decode_type2(const struct ntlm_buf *buf, struct ntlm_type2 *type2) { krb5_error_code ret; unsigned char sig[8]; uint32_t type, ctx[2]; struct sec_buffer targetname, targetinfo; krb5_storage *in; int ucs2 = 0; memset(type2, 0, sizeof(*type2)); in = krb5_storage_from_readonly_mem(buf->data, buf->length); if (in == NULL) { ret = ENOMEM; goto out; } krb5_storage_set_byteorder(in, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_read(in, sig, sizeof(sig)), sizeof(sig)); CHECK(memcmp(ntlmsigature, sig, sizeof(ntlmsigature)), 0); CHECK(krb5_ret_uint32(in, &type), 0); CHECK(type, 2); CHECK(ret_sec_buffer(in, &targetname), 0); CHECK(krb5_ret_uint32(in, &type2->flags), 0); if (type2->flags & NTLM_NEG_UNICODE) ucs2 = 1; CHECK(krb5_storage_read(in, type2->challenge, sizeof(type2->challenge)), sizeof(type2->challenge)); CHECK(krb5_ret_uint32(in, &ctx[0]), 0); /* context */ CHECK(krb5_ret_uint32(in, &ctx[1]), 0); CHECK(ret_sec_buffer(in, &targetinfo), 0); /* os version */ if (type2->flags & NTLM_NEG_VERSION) { CHECK(krb5_ret_uint32(in, &type2->os[0]), 0); CHECK(krb5_ret_uint32(in, &type2->os[1]), 0); } CHECK(ret_sec_string(in, ucs2, &targetname, &type2->targetname), 0); CHECK(ret_buf(in, &targetinfo, &type2->targetinfo), 0); ret = 0; out: if (in) krb5_storage_free(in); if (ret) heim_ntlm_free_type2(type2); return ret; } /** * Encodes an ntlm_type2 message. * * @param type2 the ntlm_type2 message to encode. * @param data is the return buffer with the encoded message, should be * freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_encode_type2(const struct ntlm_type2 *type2, struct ntlm_buf *data) { struct sec_buffer targetname, targetinfo; krb5_error_code ret; krb5_storage *out = NULL; uint32_t base; int ucs2 = 0; base = 48; if (type2->flags & NTLM_NEG_VERSION) base += 8; if (type2->flags & NTLM_NEG_UNICODE) ucs2 = 1; targetname.offset = base; targetname.length = len_string(ucs2, type2->targetname); targetname.allocated = targetname.length; targetinfo.offset = targetname.allocated + targetname.offset; targetinfo.length = type2->targetinfo.length; targetinfo.allocated = type2->targetinfo.length; out = krb5_storage_emem(); if (out == NULL) return ENOMEM; krb5_storage_set_byteorder(out, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_write(out, ntlmsigature, sizeof(ntlmsigature)), sizeof(ntlmsigature)); CHECK(krb5_store_uint32(out, 2), 0); CHECK(store_sec_buffer(out, &targetname), 0); CHECK(krb5_store_uint32(out, type2->flags), 0); CHECK(krb5_storage_write(out, type2->challenge, sizeof(type2->challenge)), sizeof(type2->challenge)); CHECK(krb5_store_uint32(out, 0), 0); /* context */ CHECK(krb5_store_uint32(out, 0), 0); CHECK(store_sec_buffer(out, &targetinfo), 0); /* os version */ if (type2->flags & NTLM_NEG_VERSION) { CHECK(krb5_store_uint32(out, type2->os[0]), 0); CHECK(krb5_store_uint32(out, type2->os[1]), 0); } CHECK(put_string(out, ucs2, type2->targetname), 0); CHECK(krb5_storage_write(out, type2->targetinfo.data, type2->targetinfo.length), type2->targetinfo.length); { krb5_data d; ret = krb5_storage_to_data(out, &d); data->data = d.data; data->length = d.length; } out: krb5_storage_free(out); return ret; } /** * Frees the ntlm_type3 message * * @param data message to be freed * * @ingroup ntlm_core */ void heim_ntlm_free_type3(struct ntlm_type3 *data) { heim_ntlm_free_buf(&data->lm); heim_ntlm_free_buf(&data->ntlm); if (data->targetname) free(data->targetname); if (data->username) free(data->username); if (data->ws) free(data->ws); heim_ntlm_free_buf(&data->sessionkey); memset(data, 0, sizeof(*data)); } /* * */ int heim_ntlm_decode_type3(const struct ntlm_buf *buf, int ucs2, struct ntlm_type3 *type3) { krb5_error_code ret; unsigned char sig[8]; uint32_t type; krb5_storage *in; struct sec_buffer lm, ntlm, target, username, sessionkey, ws; uint32_t min_offset = 72; memset(type3, 0, sizeof(*type3)); memset(&sessionkey, 0, sizeof(sessionkey)); in = krb5_storage_from_readonly_mem(buf->data, buf->length); if (in == NULL) { ret = ENOMEM; goto out; } krb5_storage_set_byteorder(in, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_read(in, sig, sizeof(sig)), sizeof(sig)); CHECK(memcmp(ntlmsigature, sig, sizeof(ntlmsigature)), 0); CHECK(krb5_ret_uint32(in, &type), 0); CHECK(type, 3); CHECK(ret_sec_buffer(in, &lm), 0); if (lm.allocated) min_offset = min(min_offset, lm.offset); CHECK(ret_sec_buffer(in, &ntlm), 0); if (ntlm.allocated) min_offset = min(min_offset, ntlm.offset); CHECK(ret_sec_buffer(in, &target), 0); if (target.allocated) min_offset = min(min_offset, target.offset); CHECK(ret_sec_buffer(in, &username), 0); if (username.allocated) min_offset = min(min_offset, username.offset); CHECK(ret_sec_buffer(in, &ws), 0); if (ws.allocated) min_offset = min(min_offset, ws.offset); if (min_offset > 52) { CHECK(ret_sec_buffer(in, &sessionkey), 0); min_offset = max(min_offset, sessionkey.offset); CHECK(krb5_ret_uint32(in, &type3->flags), 0); } if (min_offset > 52 + 8 + 4 + 8) { CHECK(krb5_ret_uint32(in, &type3->os[0]), 0); CHECK(krb5_ret_uint32(in, &type3->os[1]), 0); } CHECK(ret_buf(in, &lm, &type3->lm), 0); CHECK(ret_buf(in, &ntlm, &type3->ntlm), 0); CHECK(ret_sec_string(in, ucs2, &target, &type3->targetname), 0); CHECK(ret_sec_string(in, ucs2, &username, &type3->username), 0); CHECK(ret_sec_string(in, ucs2, &ws, &type3->ws), 0); if (sessionkey.offset) CHECK(ret_buf(in, &sessionkey, &type3->sessionkey), 0); out: if (in) krb5_storage_free(in); if (ret) heim_ntlm_free_type3(type3); return ret; } /** * Encodes an ntlm_type3 message. * * @param type3 the ntlm_type3 message to encode. * @param data is the return buffer with the encoded message, should be * freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_encode_type3(const struct ntlm_type3 *type3, struct ntlm_buf *data) { struct sec_buffer lm, ntlm, target, username, sessionkey, ws; krb5_error_code ret; krb5_storage *out = NULL; uint32_t base; int ucs2 = 0; memset(&lm, 0, sizeof(lm)); memset(&ntlm, 0, sizeof(ntlm)); memset(&target, 0, sizeof(target)); memset(&username, 0, sizeof(username)); memset(&ws, 0, sizeof(ws)); memset(&sessionkey, 0, sizeof(sessionkey)); base = 52; base += 8; /* sessionkey sec buf */ base += 4; /* flags */ if (type3->os[0]) { base += 8; } if (type3->flags & NTLM_NEG_UNICODE) ucs2 = 1; target.offset = base; target.length = len_string(ucs2, type3->targetname); target.allocated = target.length; username.offset = target.offset + target.allocated; username.length = len_string(ucs2, type3->username); username.allocated = username.length; ws.offset = username.offset + username.allocated; ws.length = len_string(ucs2, type3->ws); ws.allocated = ws.length; lm.offset = ws.offset + ws.allocated; lm.length = type3->lm.length; lm.allocated = type3->lm.length; ntlm.offset = lm.offset + lm.allocated; ntlm.length = type3->ntlm.length; ntlm.allocated = ntlm.length; sessionkey.offset = ntlm.offset + ntlm.allocated; sessionkey.length = type3->sessionkey.length; sessionkey.allocated = type3->sessionkey.length; out = krb5_storage_emem(); if (out == NULL) return ENOMEM; krb5_storage_set_byteorder(out, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_write(out, ntlmsigature, sizeof(ntlmsigature)), sizeof(ntlmsigature)); CHECK(krb5_store_uint32(out, 3), 0); CHECK(store_sec_buffer(out, &lm), 0); CHECK(store_sec_buffer(out, &ntlm), 0); CHECK(store_sec_buffer(out, &target), 0); CHECK(store_sec_buffer(out, &username), 0); CHECK(store_sec_buffer(out, &ws), 0); CHECK(store_sec_buffer(out, &sessionkey), 0); CHECK(krb5_store_uint32(out, type3->flags), 0); #if 0 CHECK(krb5_store_uint32(out, 0), 0); /* os0 */ CHECK(krb5_store_uint32(out, 0), 0); /* os1 */ #endif CHECK(put_string(out, ucs2, type3->targetname), 0); CHECK(put_string(out, ucs2, type3->username), 0); CHECK(put_string(out, ucs2, type3->ws), 0); CHECK(put_buf(out, &type3->lm), 0); CHECK(put_buf(out, &type3->ntlm), 0); CHECK(put_buf(out, &type3->sessionkey), 0); { krb5_data d; ret = krb5_storage_to_data(out, &d); data->data = d.data; data->length = d.length; } out: krb5_storage_free(out); return ret; } /* * */ static int splitandenc(unsigned char *hash, unsigned char *challenge, unsigned char *answer) { EVP_CIPHER_CTX *ctx; unsigned char key[8]; key[0] = hash[0]; key[1] = (hash[0] << 7) | (hash[1] >> 1); key[2] = (hash[1] << 6) | (hash[2] >> 2); key[3] = (hash[2] << 5) | (hash[3] >> 3); key[4] = (hash[3] << 4) | (hash[4] >> 4); key[5] = (hash[4] << 3) | (hash[5] >> 5); key[6] = (hash[5] << 2) | (hash[6] >> 6); key[7] = (hash[6] << 1); ctx = EVP_CIPHER_CTX_new(); if (ctx == NULL) return ENOMEM; EVP_CipherInit_ex(ctx, EVP_des_cbc(), NULL, key, NULL, 1); EVP_Cipher(ctx, answer, challenge, 8); EVP_CIPHER_CTX_free(ctx); memset(key, 0, sizeof(key)); return 0; } /** * Calculate the NTLM key, the password is assumed to be in UTF8. * * @param password password to calcute the key for. * @param key calcuted key, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_nt_key(const char *password, struct ntlm_buf *key) { struct ntlm_buf buf; EVP_MD_CTX *m; int ret; key->data = malloc(MD5_DIGEST_LENGTH); if (key->data == NULL) return ENOMEM; key->length = MD5_DIGEST_LENGTH; ret = ascii2ucs2le(password, 0, &buf); if (ret) { heim_ntlm_free_buf(key); return ret; } m = EVP_MD_CTX_create(); if (m == NULL) { heim_ntlm_free_buf(key); heim_ntlm_free_buf(&buf); return ENOMEM; } EVP_DigestInit_ex(m, EVP_md4(), NULL); EVP_DigestUpdate(m, buf.data, buf.length); EVP_DigestFinal_ex(m, key->data, NULL); EVP_MD_CTX_destroy(m); heim_ntlm_free_buf(&buf); return 0; } /** * Calculate NTLMv1 response hash * * @param key the ntlm v1 key * @param len length of key * @param challenge sent by the server * @param answer calculated answer, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_calculate_ntlm1(void *key, size_t len, unsigned char challenge[8], struct ntlm_buf *answer) { unsigned char res[21]; int ret; if (len != MD4_DIGEST_LENGTH) return HNTLM_ERR_INVALID_LENGTH; memcpy(res, key, len); memset(&res[MD4_DIGEST_LENGTH], 0, sizeof(res) - MD4_DIGEST_LENGTH); answer->data = malloc(24); if (answer->data == NULL) return ENOMEM; answer->length = 24; ret = splitandenc(&res[0], challenge, ((unsigned char *)answer->data) + 0); if (ret) goto out; ret = splitandenc(&res[7], challenge, ((unsigned char *)answer->data) + 8); if (ret) goto out; ret = splitandenc(&res[14], challenge, ((unsigned char *)answer->data) + 16); if (ret) goto out; return 0; out: heim_ntlm_free_buf(answer); return ret; } int heim_ntlm_v1_base_session(void *key, size_t len, struct ntlm_buf *session) { EVP_MD_CTX *m; session->length = MD4_DIGEST_LENGTH; session->data = malloc(session->length); if (session->data == NULL) { session->length = 0; return ENOMEM; } m = EVP_MD_CTX_create(); if (m == NULL) { heim_ntlm_free_buf(session); return ENOMEM; } EVP_DigestInit_ex(m, EVP_md4(), NULL); EVP_DigestUpdate(m, key, len); EVP_DigestFinal_ex(m, session->data, NULL); EVP_MD_CTX_destroy(m); return 0; } int heim_ntlm_v2_base_session(void *key, size_t len, struct ntlm_buf *ntlmResponse, struct ntlm_buf *session) { unsigned int hmaclen; HMAC_CTX *c; if (ntlmResponse->length <= 16) return HNTLM_ERR_INVALID_LENGTH; session->data = malloc(16); if (session->data == NULL) return ENOMEM; session->length = 16; /* Note: key is the NTLMv2 key */ c = HMAC_CTX_new(); if (c == NULL) { heim_ntlm_free_buf(session); return ENOMEM; } HMAC_Init_ex(c, key, len, EVP_md5(), NULL); HMAC_Update(c, ntlmResponse->data, 16); HMAC_Final(c, session->data, &hmaclen); HMAC_CTX_free(c); return 0; } int heim_ntlm_keyex_wrap(struct ntlm_buf *base_session, struct ntlm_buf *session, struct ntlm_buf *encryptedSession) { EVP_CIPHER_CTX *c; int ret; session->length = MD4_DIGEST_LENGTH; session->data = malloc(session->length); if (session->data == NULL) { session->length = 0; return ENOMEM; } encryptedSession->length = MD4_DIGEST_LENGTH; encryptedSession->data = malloc(encryptedSession->length); if (encryptedSession->data == NULL) { heim_ntlm_free_buf(session); encryptedSession->length = 0; return ENOMEM; } c = EVP_CIPHER_CTX_new(); if (c == NULL) { heim_ntlm_free_buf(encryptedSession); heim_ntlm_free_buf(session); return ENOMEM; } ret = EVP_CipherInit_ex(c, EVP_rc4(), NULL, base_session->data, NULL, 1); if (ret != 1) { EVP_CIPHER_CTX_free(c); heim_ntlm_free_buf(encryptedSession); heim_ntlm_free_buf(session); return HNTLM_ERR_CRYPTO; } if (RAND_bytes(session->data, session->length) != 1) { EVP_CIPHER_CTX_free(c); heim_ntlm_free_buf(encryptedSession); heim_ntlm_free_buf(session); return HNTLM_ERR_RAND; } EVP_Cipher(c, encryptedSession->data, session->data, encryptedSession->length); EVP_CIPHER_CTX_free(c); return 0; } /** * Generates an NTLMv1 session random with assosited session master key. * * @param key the ntlm v1 key * @param len length of key * @param session generated session nonce, should be freed with heim_ntlm_free_buf(). * @param master calculated session master key, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_build_ntlm1_master(void *key, size_t len, struct ntlm_buf *session, struct ntlm_buf *master) { struct ntlm_buf sess; int ret; ret = heim_ntlm_v1_base_session(key, len, &sess); if (ret) return ret; ret = heim_ntlm_keyex_wrap(&sess, session, master); heim_ntlm_free_buf(&sess); return ret; } /** * Generates an NTLMv2 session random with associated session master key. * * @param key the NTLMv2 key * @param len length of key * @param blob the NTLMv2 "blob" * @param session generated session nonce, should be freed with heim_ntlm_free_buf(). * @param master calculated session master key, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_build_ntlm2_master(void *key, size_t len, struct ntlm_buf *blob, struct ntlm_buf *session, struct ntlm_buf *master) { struct ntlm_buf sess; int ret; ret = heim_ntlm_v2_base_session(key, len, blob, &sess); if (ret) return ret; ret = heim_ntlm_keyex_wrap(&sess, session, master); heim_ntlm_free_buf(&sess); return ret; } /** * Given a key and encrypted session, unwrap the session key * * @param baseKey the sessionBaseKey * @param encryptedSession encrypted session, type3.session field. * @param session generated session nonce, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_keyex_unwrap(struct ntlm_buf *baseKey, struct ntlm_buf *encryptedSession, struct ntlm_buf *session) { EVP_CIPHER_CTX *c; memset(session, 0, sizeof(*session)); if (baseKey->length != MD4_DIGEST_LENGTH) return HNTLM_ERR_INVALID_LENGTH; session->length = MD4_DIGEST_LENGTH; session->data = malloc(session->length); if (session->data == NULL) { session->length = 0; return ENOMEM; } c = EVP_CIPHER_CTX_new(); if (c == NULL) { heim_ntlm_free_buf(session); return ENOMEM; } if (EVP_CipherInit_ex(c, EVP_rc4(), NULL, baseKey->data, NULL, 0) != 1) { EVP_CIPHER_CTX_free(c); heim_ntlm_free_buf(session); return HNTLM_ERR_CRYPTO; } EVP_Cipher(c, session->data, encryptedSession->data, session->length); EVP_CIPHER_CTX_free(c); return 0; } /** * Generates an NTLMv2 session key. * * @param key the ntlm key * @param len length of key * @param username name of the user, as sent in the message, assumed to be in UTF8. * @param target the name of the target, assumed to be in UTF8. * @param ntlmv2 the ntlmv2 session key * * @return 0 on success, or an error code on failure. * * @ingroup ntlm_core */ int heim_ntlm_ntlmv2_key(const void *key, size_t len, const char *username, const char *target, unsigned char ntlmv2[16]) { int ret; unsigned int hmaclen; HMAC_CTX *c; c = HMAC_CTX_new(); if (c == NULL) return ENOMEM; HMAC_Init_ex(c, key, len, EVP_md5(), NULL); { struct ntlm_buf buf; /* uppercase username and turn it into ucs2-le */ ret = ascii2ucs2le(username, 1, &buf); if (ret) goto out; HMAC_Update(c, buf.data, buf.length); free(buf.data); /* uppercase target and turn into ucs2-le */ ret = ascii2ucs2le(target, 1, &buf); if (ret) goto out; HMAC_Update(c, buf.data, buf.length); free(buf.data); } HMAC_Final(c, ntlmv2, &hmaclen); out: HMAC_CTX_free(c); return ret; } /* * */ #define NTTIME_EPOCH 0x019DB1DED53E8000LL static uint64_t unix2nttime(time_t unix_time) { long long wt; wt = unix_time * (uint64_t)10000000 + (uint64_t)NTTIME_EPOCH; return wt; } static time_t nt2unixtime(uint64_t t) { t = ((t - (uint64_t)NTTIME_EPOCH) / (uint64_t)10000000); if (t > (((uint64_t)(time_t)(~(uint64_t)0)) >> 1)) return 0; return (time_t)t; } /** * Calculate LMv2 response * * @param key the ntlm key * @param len length of key * @param username name of the user, as sent in the message, assumed to be in UTF8. * @param target the name of the target, assumed to be in UTF8. * @param serverchallenge challenge as sent by the server in the type2 message. * @param ntlmv2 calculated session key * @param answer ntlm response answer, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_calculate_lm2(const void *key, size_t len, const char *username, const char *target, const unsigned char serverchallenge[8], unsigned char ntlmv2[16], struct ntlm_buf *answer) { unsigned char clientchallenge[8]; int ret; if (RAND_bytes(clientchallenge, sizeof(clientchallenge)) != 1) return HNTLM_ERR_RAND; /* calculate ntlmv2 key */ heim_ntlm_ntlmv2_key(key, len, username, target, ntlmv2); answer->data = malloc(24); if (answer->data == NULL) return ENOMEM; answer->length = 24; ret = heim_ntlm_derive_ntlm2_sess(ntlmv2, clientchallenge, 8, serverchallenge, answer->data); if (ret) return ret; memcpy(((uint8_t *)answer->data) + 16, clientchallenge, 8); return 0; } /** * Calculate NTLMv2 response * * @param key the ntlm key * @param len length of key * @param username name of the user, as sent in the message, assumed to be in UTF8. * @param target the name of the target, assumed to be in UTF8. * @param serverchallenge challenge as sent by the server in the type2 message. * @param infotarget infotarget as sent by the server in the type2 message. * @param ntlmv2 calculated session key * @param answer ntlm response answer, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_calculate_ntlm2(const void *key, size_t len, const char *username, const char *target, const unsigned char serverchallenge[8], const struct ntlm_buf *infotarget, unsigned char ntlmv2[16], struct ntlm_buf *answer) { krb5_error_code ret; krb5_data data; unsigned char ntlmv2answer[16]; krb5_storage *sp; unsigned char clientchallenge[8]; uint64_t t; int code; t = unix2nttime(time(NULL)); if (RAND_bytes(clientchallenge, sizeof(clientchallenge)) != 1) return HNTLM_ERR_RAND; /* calculate ntlmv2 key */ heim_ntlm_ntlmv2_key(key, len, username, target, ntlmv2); /* calculate and build ntlmv2 answer */ sp = krb5_storage_emem(); if (sp == NULL) return ENOMEM; krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_store_uint32(sp, 0x00000101), 0); CHECK(krb5_store_uint32(sp, 0), 0); /* timestamp le 64 bit ts */ CHECK(krb5_store_uint32(sp, t & 0xffffffff), 0); CHECK(krb5_store_uint32(sp, t >> 32), 0); CHECK(krb5_storage_write(sp, clientchallenge, 8), 8); CHECK(krb5_store_uint32(sp, 0), 0); /* unknown but zero will work */ CHECK(krb5_storage_write(sp, infotarget->data, infotarget->length), infotarget->length); CHECK(krb5_store_uint32(sp, 0), 0); /* unknown but zero will work */ CHECK(krb5_storage_to_data(sp, &data), 0); krb5_storage_free(sp); sp = NULL; code = heim_ntlm_derive_ntlm2_sess(ntlmv2, data.data, data.length, serverchallenge, ntlmv2answer); if (code) { krb5_data_free(&data); return code; } sp = krb5_storage_emem(); if (sp == NULL) { krb5_data_free(&data); return ENOMEM; } CHECK(krb5_storage_write(sp, ntlmv2answer, 16), 16); CHECK(krb5_storage_write(sp, data.data, data.length), data.length); krb5_data_free(&data); CHECK(krb5_storage_to_data(sp, &data), 0); krb5_storage_free(sp); sp = NULL; answer->data = data.data; answer->length = data.length; return 0; out: if (sp) krb5_storage_free(sp); return ret; } static const int authtimediff = 3600 * 2; /* 2 hours */ /** * Verify NTLMv2 response. * * @param key the ntlm key * @param len length of key * @param username name of the user, as sent in the message, assumed to be in UTF8. * @param target the name of the target, assumed to be in UTF8. * @param now the time now (0 if the library should pick it up itself) * @param serverchallenge challenge as sent by the server in the type2 message. * @param answer ntlm response answer, should be freed with heim_ntlm_free_buf(). * @param infotarget infotarget as sent by the server in the type2 message. * @param ntlmv2 calculated session key * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_verify_ntlm2(const void *key, size_t len, const char *username, const char *target, time_t now, const unsigned char serverchallenge[8], const struct ntlm_buf *answer, struct ntlm_buf *infotarget, unsigned char ntlmv2[16]) { krb5_error_code ret; unsigned char clientanswer[16]; unsigned char clientnonce[8]; unsigned char serveranswer[16]; krb5_storage *sp; time_t authtime; uint32_t temp; uint64_t t; int code; infotarget->length = 0; infotarget->data = NULL; if (answer->length < 16) return HNTLM_ERR_INVALID_LENGTH; if (now == 0) now = time(NULL); /* calculate ntlmv2 key */ heim_ntlm_ntlmv2_key(key, len, username, target, ntlmv2); /* calculate and build ntlmv2 answer */ sp = krb5_storage_from_readonly_mem(answer->data, answer->length); if (sp == NULL) return ENOMEM; krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE); CHECK(krb5_storage_read(sp, clientanswer, 16), 16); CHECK(krb5_ret_uint32(sp, &temp), 0); CHECK(temp, 0x00000101); CHECK(krb5_ret_uint32(sp, &temp), 0); CHECK(temp, 0); /* timestamp le 64 bit ts */ CHECK(krb5_ret_uint32(sp, &temp), 0); t = temp; CHECK(krb5_ret_uint32(sp, &temp), 0); t |= ((uint64_t)temp)<< 32; authtime = nt2unixtime(t); if (abs((int)(authtime - now)) > authtimediff) { ret = HNTLM_ERR_TIME_SKEW; goto out; } /* client challenge */ CHECK(krb5_storage_read(sp, clientnonce, 8), 8); CHECK(krb5_ret_uint32(sp, &temp), 0); /* unknown */ /* should really unparse the infotarget, but lets pick up everything */ infotarget->length = answer->length - krb5_storage_seek(sp, 0, SEEK_CUR); infotarget->data = malloc(infotarget->length); if (infotarget->data == NULL) { ret = ENOMEM; goto out; } CHECK(krb5_storage_read(sp, infotarget->data, infotarget->length), infotarget->length); /* XXX remove the unknown ?? */ krb5_storage_free(sp); sp = NULL; if (answer->length < 16) { ret = HNTLM_ERR_INVALID_LENGTH; goto out; } ret = heim_ntlm_derive_ntlm2_sess(ntlmv2, ((unsigned char *)answer->data) + 16, answer->length - 16, serverchallenge, serveranswer); if (ret) goto out; if (memcmp(serveranswer, clientanswer, 16) != 0) { heim_ntlm_free_buf(infotarget); return HNTLM_ERR_AUTH; } return 0; out: heim_ntlm_free_buf(infotarget); if (sp) krb5_storage_free(sp); return ret; } /* * Calculate the NTLM2 Session Response * * @param clnt_nonce client nonce * @param svr_chal server challage * @param ntlm2_hash ntlm hash * @param lm The LM response, should be freed with heim_ntlm_free_buf(). * @param ntlm The NTLM response, should be freed with heim_ntlm_free_buf(). * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_calculate_ntlm2_sess(const unsigned char clnt_nonce[8], const unsigned char svr_chal[8], const unsigned char ntlm_hash[16], struct ntlm_buf *lm, struct ntlm_buf *ntlm) { unsigned char ntlm2_sess_hash[8]; unsigned char res[21], *resp; int code; code = heim_ntlm_calculate_ntlm2_sess_hash(clnt_nonce, svr_chal, ntlm2_sess_hash); if (code) { return code; } lm->data = malloc(24); if (lm->data == NULL) { return ENOMEM; } lm->length = 24; ntlm->data = malloc(24); if (ntlm->data == NULL) { free(lm->data); lm->data = NULL; return ENOMEM; } ntlm->length = 24; /* first setup the lm resp */ memset(lm->data, 0, 24); memcpy(lm->data, clnt_nonce, 8); memset(res, 0, sizeof(res)); memcpy(res, ntlm_hash, 16); resp = ntlm->data; code = splitandenc(&res[0], ntlm2_sess_hash, resp + 0); if (code) goto out; code = splitandenc(&res[7], ntlm2_sess_hash, resp + 8); if (code) goto out; code = splitandenc(&res[14], ntlm2_sess_hash, resp + 16); if (code) goto out; return 0; out: heim_ntlm_free_buf(ntlm); heim_ntlm_free_buf(lm); return code; } /* * Calculate the NTLM2 Session "Verifier" * * @param clnt_nonce client nonce * @param svr_chal server challage * @param hash The NTLM session verifier * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_calculate_ntlm2_sess_hash(const unsigned char clnt_nonce[8], const unsigned char svr_chal[8], unsigned char verifier[8]) { unsigned char ntlm2_sess_hash[MD5_DIGEST_LENGTH]; EVP_MD_CTX *m; m = EVP_MD_CTX_create(); if (m == NULL) return ENOMEM; EVP_DigestInit_ex(m, EVP_md5(), NULL); EVP_DigestUpdate(m, svr_chal, 8); /* session nonce part 1 */ EVP_DigestUpdate(m, clnt_nonce, 8); /* session nonce part 2 */ EVP_DigestFinal_ex(m, ntlm2_sess_hash, NULL); /* will only use first 8 bytes */ EVP_MD_CTX_destroy(m); memcpy(verifier, ntlm2_sess_hash, 8); return 0; } /* * Derive a NTLM2 session key * * @param sessionkey session key from domain controller * @param clnt_nonce client nonce * @param svr_chal server challenge * @param derivedkey salted session key * * @return In case of success 0 is return, an errors, a errno in what * went wrong. * * @ingroup ntlm_core */ int heim_ntlm_derive_ntlm2_sess(const unsigned char sessionkey[16], const unsigned char *clnt_nonce, size_t clnt_nonce_length, const unsigned char svr_chal[8], unsigned char derivedkey[16]) { unsigned int hmaclen; HMAC_CTX *c; /* HMAC(Ksession, serverchallenge || clientchallenge) */ c = HMAC_CTX_new(); if (c == NULL) return ENOMEM; HMAC_Init_ex(c, sessionkey, 16, EVP_md5(), NULL); HMAC_Update(c, svr_chal, 8); HMAC_Update(c, clnt_nonce, clnt_nonce_length); HMAC_Final(c, derivedkey, &hmaclen); HMAC_CTX_free(c); return 0; }