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/*
* Copyright 2001 by the Massachusetts Institute of Technology.
* Copyright 1993 by OpenVision Technologies, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appears in all copies and
* that both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of OpenVision not be used
* in advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. OpenVision makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Copyright (C) 1998 by the FundsXpress, INC.
*
* All rights reserved.
*
* Export of this software from the United States of America may require
* a specific license from the United States Government. It is the
* responsibility of any person or organization contemplating export to
* obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of FundsXpress. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. FundsXpress makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "gssapiP_krb5.h"
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <assert.h>
/* message_buffer is an input if SIGN, output if SEAL, and ignored if DEL_CTX
conf_state is only valid if SEAL. */
static OM_uint32
kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer,
conf_state, qop_state, toktype)
krb5_context context;
OM_uint32 *minor_status;
krb5_gss_ctx_id_rec *ctx;
unsigned char *ptr;
int bodysize;
gss_buffer_t message_buffer;
int *conf_state;
int *qop_state;
int toktype;
{
krb5_error_code code;
int conflen = 0;
int signalg;
int sealalg;
gss_buffer_desc token;
krb5_checksum cksum;
krb5_checksum md5cksum;
krb5_data plaind;
char *data_ptr;
krb5_timestamp now;
unsigned char *plain;
int cksum_len = 0;
int plainlen;
int direction;
krb5_ui_4 seqnum;
OM_uint32 retval;
size_t sumlen;
krb5_keyusage sign_usage = KG_USAGE_SIGN;
if (toktype == KG_TOK_SEAL_MSG) {
message_buffer->length = 0;
message_buffer->value = NULL;
}
/* get the sign and seal algorithms */
signalg = ptr[0] + (ptr[1]<<8);
sealalg = ptr[2] + (ptr[3]<<8);
/* Sanity checks */
if ((ptr[4] != 0xff) || (ptr[5] != 0xff)) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
if ((toktype != KG_TOK_SEAL_MSG) &&
(sealalg != 0xffff)) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
/* in the current spec, there is only one valid seal algorithm per
key type, so a simple comparison is ok */
if ((toktype == KG_TOK_SEAL_MSG) &&
!((sealalg == 0xffff) ||
(sealalg == ctx->sealalg))) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
/* there are several mappings of seal algorithms to sign algorithms,
but few enough that we can try them all. */
if ((ctx->sealalg == SEAL_ALG_NONE && signalg > 1) ||
(ctx->sealalg == SEAL_ALG_1 && signalg != SGN_ALG_3) ||
(ctx->sealalg == SEAL_ALG_DES3KD &&
signalg != SGN_ALG_HMAC_SHA1_DES3_KD)||
(ctx->sealalg == SEAL_ALG_MICROSOFT_RC4 &&
signalg != SGN_ALG_HMAC_MD5)) {
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
switch (signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_MD2_5:
case SGN_ALG_HMAC_MD5:
cksum_len = 8;
if (toktype != KG_TOK_SEAL_MSG)
sign_usage = 15;
break;
case SGN_ALG_3:
cksum_len = 16;
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
cksum_len = 20;
break;
default:
*minor_status = 0;
return GSS_S_DEFECTIVE_TOKEN;
}
/* get the token parameters */
if ((code = kg_get_seq_num(context, ctx->seq, ptr+14, ptr+6, &direction,
&seqnum))) {
*minor_status = code;
return(GSS_S_BAD_SIG);
}
/* decode the message, if SEAL */
if (toktype == KG_TOK_SEAL_MSG) {
int tmsglen = bodysize-(14+cksum_len);
if (sealalg != 0xffff) {
if ((plain = (unsigned char *) xmalloc(tmsglen)) == NULL) {
*minor_status = ENOMEM;
return(GSS_S_FAILURE);
}
if (ctx->enc->enctype == ENCTYPE_ARCFOUR_HMAC) {
unsigned char bigend_seqnum[4];
krb5_keyblock *enc_key;
int i;
bigend_seqnum[0] = (seqnum>>24) & 0xff;
bigend_seqnum[1] = (seqnum>>16) & 0xff;
bigend_seqnum[2] = (seqnum>>8) & 0xff;
bigend_seqnum[3] = seqnum & 0xff;
code = krb5_copy_keyblock (context, ctx->enc, &enc_key);
if (code)
{
xfree(plain);
*minor_status = code;
return(GSS_S_FAILURE);
}
assert (enc_key->length == 16);
for (i = 0; i <= 15; i++)
((char *) enc_key->contents)[i] ^=0xf0;
code = kg_arcfour_docrypt (enc_key, 0,
&bigend_seqnum[0], 4,
ptr+14+cksum_len, tmsglen,
plain);
krb5_free_keyblock (context, enc_key);
} else {
code = kg_decrypt(context, ctx->enc, KG_USAGE_SEAL, NULL,
ptr+14+cksum_len, plain, tmsglen);
}
if (code) {
xfree(plain);
*minor_status = code;
return(GSS_S_FAILURE);
}
} else {
plain = ptr+14+cksum_len;
}
plainlen = tmsglen;
if ((sealalg == 0xffff) && ctx->big_endian) {
token.length = tmsglen;
} else {
conflen = kg_confounder_size(context, ctx->enc);
token.length = tmsglen - conflen - plain[tmsglen-1];
}
if (token.length) {
if ((token.value = (void *) xmalloc(token.length)) == NULL) {
if (sealalg != 0xffff)
xfree(plain);
*minor_status = ENOMEM;
return(GSS_S_FAILURE);
}
memcpy(token.value, plain+conflen, token.length);
} else {
token.value = NULL;
}
} else if (toktype == KG_TOK_SIGN_MSG) {
token = *message_buffer;
plain = token.value;
plainlen = token.length;
} else {
token.length = 0;
token.value = NULL;
plain = token.value;
plainlen = token.length;
}
/* compute the checksum of the message */
/* initialize the the cksum */
switch (signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_MD2_5:
case SGN_ALG_DES_MAC:
case SGN_ALG_3:
md5cksum.checksum_type = CKSUMTYPE_RSA_MD5;
break;
case SGN_ALG_HMAC_MD5:
md5cksum.checksum_type = CKSUMTYPE_HMAC_MD5_ARCFOUR;
break;
case SGN_ALG_HMAC_SHA1_DES3_KD:
md5cksum.checksum_type = CKSUMTYPE_HMAC_SHA1_DES3;
break;
default:
abort ();
}
code = krb5_c_checksum_length(context, md5cksum.checksum_type, &sumlen);
if (code)
return(code);
md5cksum.length = sumlen;
switch (signalg) {
case SGN_ALG_DES_MAC_MD5:
case SGN_ALG_3:
/* compute the checksum of the message */
/* 8 = bytes of token body to be checksummed according to spec */
if (! (data_ptr = (void *)
xmalloc(8 + (ctx->big_endian ? token.length : plainlen)))) {
if (sealalg != 0xffff)
xfree(plain);
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = ENOMEM;
return(GSS_S_FAILURE);
}
(void) memcpy(data_ptr, ptr-2, 8);
if (ctx->big_endian)
(void) memcpy(data_ptr+8, token.value, token.length);
else
(void) memcpy(data_ptr+8, plain, plainlen);
plaind.length = 8 + (ctx->big_endian ? token.length : plainlen);
plaind.data = data_ptr;
code = krb5_c_make_checksum(context, md5cksum.checksum_type,
ctx->seq, sign_usage,
&plaind, &md5cksum);
xfree(data_ptr);
if (code) {
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = code;
return(GSS_S_FAILURE);
}
if ((code = kg_encrypt(context, ctx->seq, KG_USAGE_SEAL,
(g_OID_equal(ctx->mech_used, gss_mech_krb5_old) ?
ctx->seq->contents : NULL),
md5cksum.contents, md5cksum.contents, 16))) {
krb5_free_checksum_contents(context, &md5cksum);
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = code;
return GSS_S_FAILURE;
}
if (signalg == 0)
cksum.length = 8;
else
cksum.length = 16;
cksum.contents = md5cksum.contents + 16 - cksum.length;
code = memcmp(cksum.contents, ptr+14, cksum.length);
break;
case SGN_ALG_MD2_5:
if (!ctx->seed_init &&
(code = kg_make_seed(context, ctx->subkey, ctx->seed))) {
krb5_free_checksum_contents(context, &md5cksum);
if (sealalg != 0xffff)
xfree(plain);
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = code;
return GSS_S_FAILURE;
}
if (! (data_ptr = (void *)
xmalloc(sizeof(ctx->seed) + 8 +
(ctx->big_endian ? token.length : plainlen)))) {
krb5_free_checksum_contents(context, &md5cksum);
if (sealalg == 0)
xfree(plain);
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = ENOMEM;
return(GSS_S_FAILURE);
}
(void) memcpy(data_ptr, ptr-2, 8);
(void) memcpy(data_ptr+8, ctx->seed, sizeof(ctx->seed));
if (ctx->big_endian)
(void) memcpy(data_ptr+8+sizeof(ctx->seed),
token.value, token.length);
else
(void) memcpy(data_ptr+8+sizeof(ctx->seed),
plain, plainlen);
plaind.length = 8 + sizeof(ctx->seed) +
(ctx->big_endian ? token.length : plainlen);
plaind.data = data_ptr;
krb5_free_checksum_contents(context, &md5cksum);
code = krb5_c_make_checksum(context, md5cksum.checksum_type,
ctx->seq, sign_usage,
&plaind, &md5cksum);
xfree(data_ptr);
if (code) {
if (sealalg == 0)
xfree(plain);
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = code;
return(GSS_S_FAILURE);
}
code = memcmp(md5cksum.contents, ptr+14, 8);
/* Falls through to defective-token?? */
default:
*minor_status = 0;
return(GSS_S_DEFECTIVE_TOKEN);
case SGN_ALG_HMAC_SHA1_DES3_KD:
case SGN_ALG_HMAC_MD5:
/* compute the checksum of the message */
/* 8 = bytes of token body to be checksummed according to spec */
if (! (data_ptr = (void *)
xmalloc(8 + (ctx->big_endian ? token.length : plainlen)))) {
if (sealalg != 0xffff)
xfree(plain);
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = ENOMEM;
return(GSS_S_FAILURE);
}
(void) memcpy(data_ptr, ptr-2, 8);
if (ctx->big_endian)
(void) memcpy(data_ptr+8, token.value, token.length);
else
(void) memcpy(data_ptr+8, plain, plainlen);
plaind.length = 8 + (ctx->big_endian ? token.length : plainlen);
plaind.data = data_ptr;
code = krb5_c_make_checksum(context, md5cksum.checksum_type,
ctx->seq, sign_usage,
&plaind, &md5cksum);
xfree(data_ptr);
if (code) {
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = code;
return(GSS_S_FAILURE);
}
code = memcmp(md5cksum.contents, ptr+14, cksum_len);
break;
}
krb5_free_checksum_contents(context, &md5cksum);
if (sealalg != 0xffff)
xfree(plain);
/* compare the computed checksum against the transmitted checksum */
if (code) {
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = 0;
return(GSS_S_BAD_SIG);
}
/* it got through unscathed. Make sure the context is unexpired */
if (toktype == KG_TOK_SEAL_MSG)
*message_buffer = token;
if (conf_state)
*conf_state = (sealalg != 0xffff);
if (qop_state)
*qop_state = GSS_C_QOP_DEFAULT;
if ((code = krb5_timeofday(context, &now))) {
*minor_status = code;
return(GSS_S_FAILURE);
}
if (now > ctx->endtime) {
*minor_status = 0;
return(GSS_S_CONTEXT_EXPIRED);
}
/* do sequencing checks */
if ((ctx->initiate && direction != 0xff) ||
(!ctx->initiate && direction != 0)) {
if (toktype == KG_TOK_SEAL_MSG)
xfree(token.value);
*minor_status = G_BAD_DIRECTION;
return(GSS_S_BAD_SIG);
}
retval = g_order_check(&(ctx->seqstate), seqnum);
/* success or ordering violation */
*minor_status = 0;
return(retval);
}
/* message_buffer is an input if SIGN, output if SEAL, and ignored if DEL_CTX
conf_state is only valid if SEAL. */
OM_uint32
kg_unseal(context, minor_status, context_handle, input_token_buffer,
message_buffer, conf_state, qop_state, toktype)
krb5_context context;
OM_uint32 *minor_status;
gss_ctx_id_t context_handle;
gss_buffer_t input_token_buffer;
gss_buffer_t message_buffer;
int *conf_state;
int *qop_state;
int toktype;
{
krb5_gss_ctx_id_rec *ctx;
unsigned char *ptr;
unsigned int bodysize;
int err;
int toktype2;
/* validate the context handle */
if (! kg_validate_ctx_id(context_handle)) {
*minor_status = (OM_uint32) G_VALIDATE_FAILED;
return(GSS_S_NO_CONTEXT);
}
ctx = (krb5_gss_ctx_id_rec *) context_handle;
if (! ctx->established) {
*minor_status = KG_CTX_INCOMPLETE;
return(GSS_S_NO_CONTEXT);
}
/* parse the token, leave the data in message_buffer, setting conf_state */
/* verify the header */
ptr = (unsigned char *) input_token_buffer->value;
if (ctx->proto)
switch (toktype) {
case KG_TOK_SIGN_MSG:
toktype2 = 0x0404;
break;
case KG_TOK_SEAL_MSG:
toktype2 = 0x0504;
break;
case KG_TOK_DEL_CTX:
toktype2 = 0x0405;
break;
default:
toktype2 = toktype;
break;
}
else
toktype2 = toktype;
err = g_verify_token_header((gss_OID) ctx->mech_used,
&bodysize, &ptr, toktype2,
input_token_buffer->length,
!ctx->proto);
if (err) {
*minor_status = err;
return GSS_S_DEFECTIVE_TOKEN;
}
if (ctx->proto == 0)
return kg_unseal_v1(context, minor_status, ctx, ptr, bodysize,
message_buffer, conf_state, qop_state,
toktype);
else
return gss_krb5int_unseal_token_v3(context, minor_status, ctx,
ptr, bodysize, message_buffer,
conf_state, qop_state, toktype);
}
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