diff options
Diffstat (limited to 'lib/gssapi/verify_mic.c')
| -rw-r--r-- | lib/gssapi/verify_mic.c | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/lib/gssapi/verify_mic.c b/lib/gssapi/verify_mic.c new file mode 100644 index 0000000..aef2d07 --- /dev/null +++ b/lib/gssapi/verify_mic.c @@ -0,0 +1,322 @@ +/* + * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan + * (Royal Institute of Technology, Stockholm, Sweden). + * 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 "gssapi_locl.h" + +RCSID("$Id: verify_mic.c,v 1.18.2.4 2003/09/18 22:05:34 lha Exp $"); + +static OM_uint32 +verify_mic_des + (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, + char *type + ) +{ + u_char *p; + MD5_CTX md5; + u_char hash[16], seq_data[8]; + des_key_schedule schedule; + des_cblock zero; + des_cblock deskey; + int32_t seq_number; + OM_uint32 ret; + + p = token_buffer->value; + ret = gssapi_krb5_verify_header (&p, + token_buffer->length, + type); + if (ret) + return ret; + + if (memcmp(p, "\x00\x00", 2) != 0) + return GSS_S_BAD_SIG; + p += 2; + if (memcmp (p, "\xff\xff\xff\xff", 4) != 0) + return GSS_S_BAD_MIC; + p += 4; + p += 16; + + /* verify checksum */ + MD5_Init (&md5); + MD5_Update (&md5, p - 24, 8); + MD5_Update (&md5, message_buffer->value, + message_buffer->length); + MD5_Final (hash, &md5); + + memset (&zero, 0, sizeof(zero)); + memcpy (&deskey, key->keyvalue.data, sizeof(deskey)); + + des_set_key (&deskey, schedule); + des_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash), + schedule, &zero); + if (memcmp (p - 8, hash, 8) != 0) { + memset (deskey, 0, sizeof(deskey)); + memset (schedule, 0, sizeof(schedule)); + return GSS_S_BAD_MIC; + } + + /* verify sequence number */ + + krb5_auth_getremoteseqnumber (gssapi_krb5_context, + context_handle->auth_context, + &seq_number); + seq_data[0] = (seq_number >> 0) & 0xFF; + seq_data[1] = (seq_number >> 8) & 0xFF; + seq_data[2] = (seq_number >> 16) & 0xFF; + seq_data[3] = (seq_number >> 24) & 0xFF; + memset (seq_data + 4, + (context_handle->more_flags & LOCAL) ? 0xFF : 0, + 4); + + p -= 16; + des_set_key (&deskey, schedule); + des_cbc_encrypt ((void *)p, (void *)p, 8, + schedule, (des_cblock *)hash, DES_DECRYPT); + + memset (deskey, 0, sizeof(deskey)); + memset (schedule, 0, sizeof(schedule)); + + if (memcmp (p, seq_data, 8) != 0) { + return GSS_S_BAD_MIC; + } + + krb5_auth_con_setremoteseqnumber (gssapi_krb5_context, + context_handle->auth_context, + ++seq_number); + + return GSS_S_COMPLETE; +} + +static OM_uint32 +verify_mic_des3 + (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, + char *type + ) +{ + u_char *p; + u_char seq[8]; + int32_t seq_number; + OM_uint32 ret; + krb5_crypto crypto; + krb5_data seq_data; + int cmp, docompat; + Checksum csum; + char *tmp; + char ivec[8]; + + p = token_buffer->value; + ret = gssapi_krb5_verify_header (&p, + token_buffer->length, + type); + if (ret) + return ret; + + if (memcmp(p, "\x04\x00", 2) != 0) /* SGN_ALG = HMAC SHA1 DES3-KD */ + return GSS_S_BAD_SIG; + p += 2; + if (memcmp (p, "\xff\xff\xff\xff", 4) != 0) + return GSS_S_BAD_MIC; + p += 4; + + ret = krb5_crypto_init(gssapi_krb5_context, key, + ETYPE_DES3_CBC_NONE, &crypto); + if (ret){ + gssapi_krb5_set_error_string (); + *minor_status = ret; + return GSS_S_FAILURE; + } + + /* verify sequence number */ + docompat = 0; +retry: + if (docompat) + memset(ivec, 0, 8); + else + memcpy(ivec, p + 8, 8); + + ret = krb5_decrypt_ivec (gssapi_krb5_context, + crypto, + KRB5_KU_USAGE_SEQ, + p, 8, &seq_data, ivec); + if (ret) { + if (docompat++) { + gssapi_krb5_set_error_string (); + krb5_crypto_destroy (gssapi_krb5_context, crypto); + *minor_status = ret; + return GSS_S_FAILURE; + } else + goto retry; + } + + if (seq_data.length != 8) { + krb5_data_free (&seq_data); + if (docompat++) { + krb5_crypto_destroy (gssapi_krb5_context, crypto); + return GSS_S_BAD_MIC; + } else + goto retry; + } + + krb5_auth_getremoteseqnumber (gssapi_krb5_context, + context_handle->auth_context, + &seq_number); + seq[0] = (seq_number >> 0) & 0xFF; + seq[1] = (seq_number >> 8) & 0xFF; + seq[2] = (seq_number >> 16) & 0xFF; + seq[3] = (seq_number >> 24) & 0xFF; + memset (seq + 4, + (context_handle->more_flags & LOCAL) ? 0xFF : 0, + 4); + cmp = memcmp (seq, seq_data.data, seq_data.length); + krb5_data_free (&seq_data); + if (cmp != 0) { + if (docompat++) { + krb5_crypto_destroy (gssapi_krb5_context, crypto); + return GSS_S_BAD_MIC; + } else + goto retry; + } + + /* verify checksum */ + + tmp = malloc (message_buffer->length + 8); + if (tmp == NULL) { + krb5_crypto_destroy (gssapi_krb5_context, crypto); + *minor_status = ENOMEM; + return GSS_S_FAILURE; + } + + memcpy (tmp, p - 8, 8); + memcpy (tmp + 8, message_buffer->value, message_buffer->length); + + csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3; + csum.checksum.length = 20; + csum.checksum.data = p + 8; + + ret = krb5_verify_checksum (gssapi_krb5_context, crypto, + KRB5_KU_USAGE_SIGN, + tmp, message_buffer->length + 8, + &csum); + free (tmp); + if (ret) { + gssapi_krb5_set_error_string (); + krb5_crypto_destroy (gssapi_krb5_context, crypto); + *minor_status = ret; + return GSS_S_BAD_MIC; + } + + krb5_auth_con_setremoteseqnumber (gssapi_krb5_context, + context_handle->auth_context, + ++seq_number); + + krb5_crypto_destroy (gssapi_krb5_context, crypto); + return GSS_S_COMPLETE; +} + +OM_uint32 +gss_verify_mic_internal + (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, + char * type + ) +{ + krb5_keyblock *key; + OM_uint32 ret; + krb5_keytype keytype; + + ret = gss_krb5_get_remotekey(context_handle, &key); + if (ret) { + gssapi_krb5_set_error_string (); + *minor_status = ret; + return GSS_S_FAILURE; + } + *minor_status = 0; + krb5_enctype_to_keytype (gssapi_krb5_context, key->keytype, &keytype); + switch (keytype) { + case KEYTYPE_DES : + ret = verify_mic_des (minor_status, context_handle, + message_buffer, token_buffer, qop_state, key, + type); + break; + case KEYTYPE_DES3 : + ret = verify_mic_des3 (minor_status, context_handle, + message_buffer, token_buffer, qop_state, key, + type); + break; + case KEYTYPE_ARCFOUR : + ret = _gssapi_verify_mic_arcfour (minor_status, context_handle, + message_buffer, token_buffer, + qop_state, key, type); + break; + default : + *minor_status = KRB5_PROG_ETYPE_NOSUPP; + ret = GSS_S_FAILURE; + break; + } + krb5_free_keyblock (gssapi_krb5_context, key); + + return ret; +} + +OM_uint32 +gss_verify_mic + (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 + ) +{ + OM_uint32 ret; + + if (qop_state != NULL) + *qop_state = GSS_C_QOP_DEFAULT; + + ret = gss_verify_mic_internal(minor_status, context_handle, + message_buffer, token_buffer, + qop_state, "\x01\x01"); + + return ret; +} |
