diff options
Diffstat (limited to 'source4/heimdal/lib/gssapi/cfx.c')
| -rwxr-xr-x | source4/heimdal/lib/gssapi/cfx.c | 841 |
1 files changed, 841 insertions, 0 deletions
diff --git a/source4/heimdal/lib/gssapi/cfx.c b/source4/heimdal/lib/gssapi/cfx.c new file mode 100755 index 0000000000..75b6a8bcfa --- /dev/null +++ b/source4/heimdal/lib/gssapi/cfx.c @@ -0,0 +1,841 @@ +/* + * Copyright (c) 2003, PADL Software Pty Ltd. + * 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 PADL Software 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 PADL SOFTWARE 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 PADL SOFTWARE 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 "gssapi_locl.h" + +RCSID("$Id: cfx.c,v 1.17 2005/04/27 17:47:32 lha Exp $"); + +/* + * Implementation of draft-ietf-krb-wg-gssapi-cfx-06.txt + */ + +#define CFXSentByAcceptor (1 << 0) +#define CFXSealed (1 << 1) +#define CFXAcceptorSubkey (1 << 2) + +static krb5_error_code +wrap_length_cfx(krb5_crypto crypto, + int conf_req_flag, + size_t input_length, + size_t *output_length, + size_t *cksumsize, + u_int16_t *padlength) +{ + krb5_error_code ret; + krb5_cksumtype type; + + /* 16-byte header is always first */ + *output_length = sizeof(gss_cfx_wrap_token_desc); + *padlength = 0; + + ret = krb5_crypto_get_checksum_type(gssapi_krb5_context, crypto, &type); + if (ret) { + return ret; + } + + ret = krb5_checksumsize(gssapi_krb5_context, type, cksumsize); + if (ret) { + return ret; + } + + if (conf_req_flag) { + size_t padsize; + + /* Header is concatenated with data before encryption */ + input_length += sizeof(gss_cfx_wrap_token_desc); + + ret = krb5_crypto_getpadsize(gssapi_krb5_context, crypto, &padsize); + if (ret) { + return ret; + } + if (padsize > 1) { + /* XXX check this */ + *padlength = padsize - (input_length % padsize); + } + + /* We add the pad ourselves (noted here for completeness only) */ + input_length += *padlength; + + *output_length += krb5_get_wrapped_length(gssapi_krb5_context, + crypto, input_length); + } else { + /* Checksum is concatenated with data */ + *output_length += input_length + *cksumsize; + } + + assert(*output_length > input_length); + + return 0; +} + +OM_uint32 _gssapi_wrap_size_cfx(OM_uint32 *minor_status, + const gss_ctx_id_t context_handle, + int conf_req_flag, + gss_qop_t qop_req, + OM_uint32 req_output_size, + OM_uint32 *max_input_size, + krb5_keyblock *key) +{ + krb5_error_code ret; + krb5_crypto crypto; + u_int16_t padlength; + size_t output_length, cksumsize; + + ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + return GSS_S_FAILURE; + } + + ret = wrap_length_cfx(crypto, conf_req_flag, + req_output_size, + &output_length, &cksumsize, &padlength); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + if (output_length < req_output_size) { + *max_input_size = (req_output_size - output_length); + *max_input_size -= padlength; + } else { + /* Should this return an error? */ + *max_input_size = 0; + } + + krb5_crypto_destroy(gssapi_krb5_context, crypto); + + return GSS_S_COMPLETE; +} + +/* + * Rotate "rrc" bytes to the front or back + */ + +static krb5_error_code +rrc_rotate(void *data, size_t len, u_int16_t rrc, krb5_boolean unrotate) +{ + u_char *tmp; + size_t left; + char buf[256]; + + if (len == 0) + return 0; + + rrc %= len; + + if (rrc == 0) + return 0; + + left = len - rrc; + + if (rrc <= sizeof(buf)) { + tmp = buf; + } else { + tmp = malloc(rrc); + if (tmp == NULL) + return ENOMEM; + } + + if (unrotate) { + memcpy(tmp, data, rrc); + memmove(data, (u_char *)data + rrc, left); + memcpy((u_char *)data + left, tmp, rrc); + } else { + memcpy(tmp, (u_char *)data + left, rrc); + memmove((u_char *)data + rrc, data, left); + memcpy(data, tmp, rrc); + } + + if (rrc > sizeof(buf)) + free(tmp); + + return 0; +} + +OM_uint32 _gssapi_wrap_cfx(OM_uint32 *minor_status, + const gss_ctx_id_t context_handle, + int conf_req_flag, + gss_qop_t qop_req, + const gss_buffer_t input_message_buffer, + int *conf_state, + gss_buffer_t output_message_buffer, + krb5_keyblock *key) +{ + krb5_crypto crypto; + gss_cfx_wrap_token token; + krb5_error_code ret; + unsigned usage; + krb5_data cipher; + size_t wrapped_len, cksumsize; + u_int16_t padlength, rrc = 0; + OM_uint32 seq_number; + u_char *p; + + ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + return GSS_S_FAILURE; + } + + ret = wrap_length_cfx(crypto, conf_req_flag, + input_message_buffer->length, + &wrapped_len, &cksumsize, &padlength); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + /* Always rotate encrypted token (if any) and checksum to header */ + rrc = (conf_req_flag ? sizeof(*token) : 0) + (u_int16_t)cksumsize; + + output_message_buffer->length = wrapped_len; + output_message_buffer->value = malloc(output_message_buffer->length); + if (output_message_buffer->value == NULL) { + *minor_status = ENOMEM; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + p = output_message_buffer->value; + token = (gss_cfx_wrap_token)p; + token->TOK_ID[0] = 0x05; + token->TOK_ID[1] = 0x04; + token->Flags = 0; + token->Filler = 0xFF; + if ((context_handle->more_flags & LOCAL) == 0) + token->Flags |= CFXSentByAcceptor; + if (context_handle->more_flags & ACCEPTOR_SUBKEY) + token->Flags |= CFXAcceptorSubkey; + if (conf_req_flag) { + /* + * In Wrap tokens with confidentiality, the EC field is + * used to encode the size (in bytes) of the random filler. + */ + token->Flags |= CFXSealed; + token->EC[0] = (padlength >> 8) & 0xFF; + token->EC[1] = (padlength >> 0) & 0xFF; + } else { + /* + * In Wrap tokens without confidentiality, the EC field is + * used to encode the size (in bytes) of the trailing + * checksum. + * + * This is not used in the checksum calcuation itself, + * because the checksum length could potentially vary + * depending on the data length. + */ + token->EC[0] = 0; + token->EC[1] = 0; + } + + /* + * In Wrap tokens that provide for confidentiality, the RRC + * field in the header contains the hex value 00 00 before + * encryption. + * + * In Wrap tokens that do not provide for confidentiality, + * both the EC and RRC fields in the appended checksum + * contain the hex value 00 00 for the purpose of calculating + * the checksum. + */ + token->RRC[0] = 0; + token->RRC[1] = 0; + + HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); + krb5_auth_con_getlocalseqnumber(gssapi_krb5_context, + context_handle->auth_context, + &seq_number); + gssapi_encode_be_om_uint32(0, &token->SND_SEQ[0]); + gssapi_encode_be_om_uint32(seq_number, &token->SND_SEQ[4]); + krb5_auth_con_setlocalseqnumber(gssapi_krb5_context, + context_handle->auth_context, + ++seq_number); + HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); + + /* + * If confidentiality is requested, the token header is + * appended to the plaintext before encryption; the resulting + * token is {"header" | encrypt(plaintext | pad | "header")}. + * + * If no confidentiality is requested, the checksum is + * calculated over the plaintext concatenated with the + * token header. + */ + if (context_handle->more_flags & LOCAL) { + usage = KRB5_KU_USAGE_INITIATOR_SEAL; + } else { + usage = KRB5_KU_USAGE_ACCEPTOR_SEAL; + } + + if (conf_req_flag) { + /* + * Any necessary padding is added here to ensure that the + * encrypted token header is always at the end of the + * ciphertext. + * + * The specification does not require that the padding + * bytes are initialized. + */ + p += sizeof(*token); + memcpy(p, input_message_buffer->value, input_message_buffer->length); + memset(p + input_message_buffer->length, 0xFF, padlength); + memcpy(p + input_message_buffer->length + padlength, + token, sizeof(*token)); + + ret = krb5_encrypt(gssapi_krb5_context, crypto, + usage, p, + input_message_buffer->length + padlength + + sizeof(*token), + &cipher); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + gss_release_buffer(minor_status, output_message_buffer); + return GSS_S_FAILURE; + } + assert(sizeof(*token) + cipher.length == wrapped_len); + token->RRC[0] = (rrc >> 8) & 0xFF; + token->RRC[1] = (rrc >> 0) & 0xFF; + + ret = rrc_rotate(cipher.data, cipher.length, rrc, FALSE); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + gss_release_buffer(minor_status, output_message_buffer); + return GSS_S_FAILURE; + } + memcpy(p, cipher.data, cipher.length); + krb5_data_free(&cipher); + } else { + char *buf; + Checksum cksum; + + buf = malloc(input_message_buffer->length + sizeof(*token)); + if (buf == NULL) { + *minor_status = ENOMEM; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + gss_release_buffer(minor_status, output_message_buffer); + return GSS_S_FAILURE; + } + memcpy(buf, input_message_buffer->value, input_message_buffer->length); + memcpy(buf + input_message_buffer->length, token, sizeof(*token)); + + ret = krb5_create_checksum(gssapi_krb5_context, crypto, + usage, 0, buf, + input_message_buffer->length + + sizeof(*token), + &cksum); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + gss_release_buffer(minor_status, output_message_buffer); + free(buf); + return GSS_S_FAILURE; + } + + free(buf); + + assert(cksum.checksum.length == cksumsize); + token->EC[0] = (cksum.checksum.length >> 8) & 0xFF; + token->EC[1] = (cksum.checksum.length >> 0) & 0xFF; + token->RRC[0] = (rrc >> 8) & 0xFF; + token->RRC[1] = (rrc >> 0) & 0xFF; + + p += sizeof(*token); + memcpy(p, input_message_buffer->value, input_message_buffer->length); + memcpy(p + input_message_buffer->length, + cksum.checksum.data, cksum.checksum.length); + + ret = rrc_rotate(p, + input_message_buffer->length + cksum.checksum.length, rrc, FALSE); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + gss_release_buffer(minor_status, output_message_buffer); + free_Checksum(&cksum); + return GSS_S_FAILURE; + } + free_Checksum(&cksum); + } + + krb5_crypto_destroy(gssapi_krb5_context, crypto); + + if (conf_state != NULL) { + *conf_state = conf_req_flag; + } + + *minor_status = 0; + return GSS_S_COMPLETE; +} + +OM_uint32 _gssapi_unwrap_cfx(OM_uint32 *minor_status, + const gss_ctx_id_t context_handle, + const gss_buffer_t input_message_buffer, + gss_buffer_t output_message_buffer, + int *conf_state, + gss_qop_t *qop_state, + krb5_keyblock *key) +{ + krb5_crypto crypto; + gss_cfx_wrap_token token; + u_char token_flags; + krb5_error_code ret; + unsigned usage; + krb5_data data; + u_int16_t ec, rrc; + OM_uint32 seq_number_lo, seq_number_hi; + size_t len; + u_char *p; + + *minor_status = 0; + + if (input_message_buffer->length < sizeof(*token)) { + return GSS_S_DEFECTIVE_TOKEN; + } + + p = input_message_buffer->value; + + token = (gss_cfx_wrap_token)p; + + if (token->TOK_ID[0] != 0x05 || token->TOK_ID[1] != 0x04) { + return GSS_S_DEFECTIVE_TOKEN; + } + + /* Ignore unknown flags */ + token_flags = token->Flags & + (CFXSentByAcceptor | CFXSealed | CFXAcceptorSubkey); + + if (token_flags & CFXSentByAcceptor) { + if ((context_handle->more_flags & LOCAL) == 0) + return GSS_S_DEFECTIVE_TOKEN; + } + + if (context_handle->more_flags & ACCEPTOR_SUBKEY) { + if ((token_flags & CFXAcceptorSubkey) == 0) + return GSS_S_DEFECTIVE_TOKEN; + } else { + if (token_flags & CFXAcceptorSubkey) + return GSS_S_DEFECTIVE_TOKEN; + } + + if (token->Filler != 0xFF) { + return GSS_S_DEFECTIVE_TOKEN; + } + + if (conf_state != NULL) { + *conf_state = (token_flags & CFXSealed) ? 1 : 0; + } + + ec = (token->EC[0] << 8) | token->EC[1]; + rrc = (token->RRC[0] << 8) | token->RRC[1]; + + /* + * Check sequence number + */ + gssapi_decode_be_om_uint32(&token->SND_SEQ[0], &seq_number_hi); + gssapi_decode_be_om_uint32(&token->SND_SEQ[4], &seq_number_lo); + if (seq_number_hi) { + /* no support for 64-bit sequence numbers */ + *minor_status = ERANGE; + return GSS_S_UNSEQ_TOKEN; + } + + HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); + ret = _gssapi_msg_order_check(context_handle->order, seq_number_lo); + if (ret != 0) { + *minor_status = 0; + HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); + gss_release_buffer(minor_status, output_message_buffer); + return ret; + } + HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); + + /* + * Decrypt and/or verify checksum + */ + ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + return GSS_S_FAILURE; + } + + if (context_handle->more_flags & LOCAL) { + usage = KRB5_KU_USAGE_ACCEPTOR_SEAL; + } else { + usage = KRB5_KU_USAGE_INITIATOR_SEAL; + } + + p += sizeof(*token); + len = input_message_buffer->length; + len -= (p - (u_char *)input_message_buffer->value); + + /* Rotate by RRC; bogus to do this in-place XXX */ + *minor_status = rrc_rotate(p, len, rrc, TRUE); + if (*minor_status != 0) { + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + if (token_flags & CFXSealed) { + ret = krb5_decrypt(gssapi_krb5_context, crypto, usage, + p, len, &data); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_BAD_MIC; + } + + /* Check that there is room for the pad and token header */ + if (data.length < ec + sizeof(*token)) { + krb5_crypto_destroy(gssapi_krb5_context, crypto); + krb5_data_free(&data); + return GSS_S_DEFECTIVE_TOKEN; + } + p = data.data; + p += data.length - sizeof(*token); + + /* RRC is unprotected; don't modify input buffer */ + ((gss_cfx_wrap_token)p)->RRC[0] = token->RRC[0]; + ((gss_cfx_wrap_token)p)->RRC[1] = token->RRC[1]; + + /* Check the integrity of the header */ + if (memcmp(p, token, sizeof(*token)) != 0) { + krb5_crypto_destroy(gssapi_krb5_context, crypto); + krb5_data_free(&data); + return GSS_S_BAD_MIC; + } + + output_message_buffer->value = data.data; + output_message_buffer->length = data.length - ec - sizeof(*token); + } else { + Checksum cksum; + + /* Determine checksum type */ + ret = krb5_crypto_get_checksum_type(gssapi_krb5_context, + crypto, &cksum.cksumtype); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + cksum.checksum.length = ec; + + /* Check we have at least as much data as the checksum */ + if (len < cksum.checksum.length) { + *minor_status = ERANGE; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_BAD_MIC; + } + + /* Length now is of the plaintext only, no checksum */ + len -= cksum.checksum.length; + cksum.checksum.data = p + len; + + output_message_buffer->length = len; /* for later */ + output_message_buffer->value = malloc(len + sizeof(*token)); + if (output_message_buffer->value == NULL) { + *minor_status = ENOMEM; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + /* Checksum is over (plaintext-data | "header") */ + memcpy(output_message_buffer->value, p, len); + memcpy((u_char *)output_message_buffer->value + len, + token, sizeof(*token)); + + /* EC is not included in checksum calculation */ + token = (gss_cfx_wrap_token)((u_char *)output_message_buffer->value + + len); + token->EC[0] = 0; + token->EC[1] = 0; + token->RRC[0] = 0; + token->RRC[1] = 0; + + ret = krb5_verify_checksum(gssapi_krb5_context, crypto, + usage, + output_message_buffer->value, + len + sizeof(*token), + &cksum); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + gss_release_buffer(minor_status, output_message_buffer); + return GSS_S_BAD_MIC; + } + } + + krb5_crypto_destroy(gssapi_krb5_context, crypto); + + if (qop_state != NULL) { + *qop_state = GSS_C_QOP_DEFAULT; + } + + *minor_status = 0; + return GSS_S_COMPLETE; +} + +OM_uint32 _gssapi_mic_cfx(OM_uint32 *minor_status, + const gss_ctx_id_t context_handle, + gss_qop_t qop_req, + const gss_buffer_t message_buffer, + gss_buffer_t message_token, + krb5_keyblock *key) +{ + krb5_crypto crypto; + gss_cfx_mic_token token; + krb5_error_code ret; + unsigned usage; + Checksum cksum; + u_char *buf; + size_t len; + OM_uint32 seq_number; + + ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + return GSS_S_FAILURE; + } + + len = message_buffer->length + sizeof(*token); + buf = malloc(len); + if (buf == NULL) { + *minor_status = ENOMEM; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + memcpy(buf, message_buffer->value, message_buffer->length); + + token = (gss_cfx_mic_token)(buf + message_buffer->length); + token->TOK_ID[0] = 0x04; + token->TOK_ID[1] = 0x04; + token->Flags = 0; + if ((context_handle->more_flags & LOCAL) == 0) + token->Flags |= CFXSentByAcceptor; + if (context_handle->more_flags & ACCEPTOR_SUBKEY) + token->Flags |= CFXAcceptorSubkey; + memset(token->Filler, 0xFF, 5); + + HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); + krb5_auth_con_getlocalseqnumber(gssapi_krb5_context, + context_handle->auth_context, + &seq_number); + gssapi_encode_be_om_uint32(0, &token->SND_SEQ[0]); + gssapi_encode_be_om_uint32(seq_number, &token->SND_SEQ[4]); + krb5_auth_con_setlocalseqnumber(gssapi_krb5_context, + context_handle->auth_context, + ++seq_number); + HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); + + if (context_handle->more_flags & LOCAL) { + usage = KRB5_KU_USAGE_INITIATOR_SIGN; + } else { + usage = KRB5_KU_USAGE_ACCEPTOR_SIGN; + } + + ret = krb5_create_checksum(gssapi_krb5_context, crypto, + usage, 0, buf, len, &cksum); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + free(buf); + return GSS_S_FAILURE; + } + krb5_crypto_destroy(gssapi_krb5_context, crypto); + + /* Determine MIC length */ + message_token->length = sizeof(*token) + cksum.checksum.length; + message_token->value = malloc(message_token->length); + if (message_token->value == NULL) { + *minor_status = ENOMEM; + free_Checksum(&cksum); + free(buf); + return GSS_S_FAILURE; + } + + /* Token is { "header" | get_mic("header" | plaintext-data) } */ + memcpy(message_token->value, token, sizeof(*token)); + memcpy((u_char *)message_token->value + sizeof(*token), + cksum.checksum.data, cksum.checksum.length); + + free_Checksum(&cksum); + free(buf); + + *minor_status = 0; + return GSS_S_COMPLETE; +} + +OM_uint32 _gssapi_verify_mic_cfx(OM_uint32 *minor_status, + const gss_ctx_id_t context_handle, + const gss_buffer_t message_buffer, + const gss_buffer_t token_buffer, + gss_qop_t *qop_state, + krb5_keyblock *key) +{ + krb5_crypto crypto; + gss_cfx_mic_token token; + u_char token_flags; + krb5_error_code ret; + unsigned usage; + OM_uint32 seq_number_lo, seq_number_hi; + u_char *buf, *p; + Checksum cksum; + + *minor_status = 0; + + if (token_buffer->length < sizeof(*token)) { + return GSS_S_DEFECTIVE_TOKEN; + } + + p = token_buffer->value; + + token = (gss_cfx_mic_token)p; + + if (token->TOK_ID[0] != 0x04 || token->TOK_ID[1] != 0x04) { + return GSS_S_DEFECTIVE_TOKEN; + } + + /* Ignore unknown flags */ + token_flags = token->Flags & (CFXSentByAcceptor | CFXAcceptorSubkey); + + if (token_flags & CFXSentByAcceptor) { + if ((context_handle->more_flags & LOCAL) == 0) + return GSS_S_DEFECTIVE_TOKEN; + } + if (context_handle->more_flags & ACCEPTOR_SUBKEY) { + if ((token_flags & CFXAcceptorSubkey) == 0) + return GSS_S_DEFECTIVE_TOKEN; + } else { + if (token_flags & CFXAcceptorSubkey) + return GSS_S_DEFECTIVE_TOKEN; + } + + if (memcmp(token->Filler, "\xff\xff\xff\xff\xff", 5) != 0) { + return GSS_S_DEFECTIVE_TOKEN; + } + + /* + * Check sequence number + */ + gssapi_decode_be_om_uint32(&token->SND_SEQ[0], &seq_number_hi); + gssapi_decode_be_om_uint32(&token->SND_SEQ[4], &seq_number_lo); + if (seq_number_hi) { + *minor_status = ERANGE; + return GSS_S_UNSEQ_TOKEN; + } + + HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); + ret = _gssapi_msg_order_check(context_handle->order, seq_number_lo); + if (ret != 0) { + *minor_status = 0; + HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); + return ret; + } + HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); + + /* + * Verify checksum + */ + ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + return GSS_S_FAILURE; + } + + ret = krb5_crypto_get_checksum_type(gssapi_krb5_context, crypto, + &cksum.cksumtype); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + + cksum.checksum.data = p + sizeof(*token); + cksum.checksum.length = token_buffer->length - sizeof(*token); + + if (context_handle->more_flags & LOCAL) { + usage = KRB5_KU_USAGE_ACCEPTOR_SIGN; + } else { + usage = KRB5_KU_USAGE_INITIATOR_SIGN; + } + + buf = malloc(message_buffer->length + sizeof(*token)); + if (buf == NULL) { + *minor_status = ENOMEM; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + return GSS_S_FAILURE; + } + memcpy(buf, message_buffer->value, message_buffer->length); + memcpy(buf + message_buffer->length, token, sizeof(*token)); + + ret = krb5_verify_checksum(gssapi_krb5_context, crypto, + usage, + buf, + sizeof(*token) + message_buffer->length, + &cksum); + if (ret != 0) { + gssapi_krb5_set_error_string(); + *minor_status = ret; + krb5_crypto_destroy(gssapi_krb5_context, crypto); + free(buf); + return GSS_S_BAD_MIC; + } + + free(buf); + + if (qop_state != NULL) { + *qop_state = GSS_C_QOP_DEFAULT; + } + + return GSS_S_COMPLETE; +} |