511 lines
13 KiB
C
511 lines
13 KiB
C
/*
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* Copyright (c) 2007, Cameron Rich
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* * Neither the name of the axTLS project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* Some primitive asn methods for extraction ASN.1 data.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include "os_port.h"
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#include "crypto.h"
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#include "crypto_misc.h"
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#define SIG_OID_PREFIX_SIZE 8
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#define SIG_IIS6_OID_SIZE 5
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/* Must be an RSA algorithm with either SHA1 or MD5 for verifying to work */
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static const uint8_t sig_oid_prefix[SIG_OID_PREFIX_SIZE] =
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{
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0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01
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};
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static const uint8_t sig_iis6_oid[SIG_IIS6_OID_SIZE] =
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{
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0x2b, 0x0e, 0x03, 0x02, 0x1d
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};
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/* CN, O, OU */
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static const uint8_t g_dn_types[] = { 3, 10, 11 };
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int get_asn1_length(const uint8_t *buf, int *offset)
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{
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int len, i;
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if (!(buf[*offset] & 0x80)) /* short form */
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{
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len = buf[(*offset)++];
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}
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else /* long form */
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{
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int length_bytes = buf[(*offset)++]&0x7f;
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len = 0;
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for (i = 0; i < length_bytes; i++)
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{
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len <<= 8;
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len += buf[(*offset)++];
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}
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}
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return len;
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}
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/**
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* Skip the ASN1.1 object type and its length. Get ready to read the object's
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* data.
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*/
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int asn1_next_obj(const uint8_t *buf, int *offset, int obj_type)
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{
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if (buf[*offset] != obj_type)
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return X509_NOT_OK;
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(*offset)++;
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return get_asn1_length(buf, offset);
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}
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/**
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* Skip over an ASN.1 object type completely. Get ready to read the next
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* object.
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*/
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int asn1_skip_obj(const uint8_t *buf, int *offset, int obj_type)
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{
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int len;
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if (buf[*offset] != obj_type)
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return X509_NOT_OK;
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(*offset)++;
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len = get_asn1_length(buf, offset);
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*offset += len;
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return 0;
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}
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/**
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* Read an integer value for ASN.1 data
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* Note: This function allocates memory which must be freed by the user.
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*/
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int asn1_get_int(const uint8_t *buf, int *offset, uint8_t **object)
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{
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int len;
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if ((len = asn1_next_obj(buf, offset, ASN1_INTEGER)) < 0)
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goto end_int_array;
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if (len > 1 && buf[*offset] == 0x00) /* ignore the negative byte */
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{
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len--;
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(*offset)++;
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}
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*object = (uint8_t *)malloc(len);
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memcpy(*object, &buf[*offset], len);
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*offset += len;
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end_int_array:
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return len;
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}
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/**
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* Get all the RSA private key specifics from an ASN.1 encoded file
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*/
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int asn1_get_private_key(const uint8_t *buf, int len, RSA_CTX **rsa_ctx)
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{
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int offset = 7;
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uint8_t *modulus = NULL, *priv_exp = NULL, *pub_exp = NULL;
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int mod_len, priv_len, pub_len;
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#ifdef CONFIG_BIGINT_CRT
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uint8_t *p = NULL, *q = NULL, *dP = NULL, *dQ = NULL, *qInv = NULL;
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int p_len, q_len, dP_len, dQ_len, qInv_len;
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#endif
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/* not in der format */
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if (buf[0] != ASN1_SEQUENCE) /* basic sanity check */
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{
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#ifdef CONFIG_SSL_FULL_MODE
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printf("Error: This is not a valid ASN.1 file\n");
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#endif
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return X509_INVALID_PRIV_KEY;
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}
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/* initialise the RNG */
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RNG_initialize(buf, len);
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mod_len = asn1_get_int(buf, &offset, &modulus);
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pub_len = asn1_get_int(buf, &offset, &pub_exp);
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priv_len = asn1_get_int(buf, &offset, &priv_exp);
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if (mod_len <= 0 || pub_len <= 0 || priv_len <= 0)
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return X509_INVALID_PRIV_KEY;
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#ifdef CONFIG_BIGINT_CRT
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p_len = asn1_get_int(buf, &offset, &p);
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q_len = asn1_get_int(buf, &offset, &q);
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dP_len = asn1_get_int(buf, &offset, &dP);
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dQ_len = asn1_get_int(buf, &offset, &dQ);
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qInv_len = asn1_get_int(buf, &offset, &qInv);
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if (p_len <= 0 || q_len <= 0 || dP_len <= 0 || dQ_len <= 0 || qInv_len <= 0)
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return X509_INVALID_PRIV_KEY;
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RSA_priv_key_new(rsa_ctx,
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modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len,
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p, p_len, q, p_len, dP, dP_len, dQ, dQ_len, qInv, qInv_len);
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free(p);
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free(q);
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free(dP);
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free(dQ);
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free(qInv);
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#else
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RSA_priv_key_new(rsa_ctx,
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modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len);
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#endif
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free(modulus);
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free(priv_exp);
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free(pub_exp);
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return X509_OK;
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}
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/**
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* Get the time of a certificate. Ignore hours/minutes/seconds.
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*/
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static int asn1_get_utc_time(const uint8_t *buf, int *offset, time_t *t)
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{
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int ret = X509_NOT_OK, len, t_offset;
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struct tm tm;
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if (buf[(*offset)++] != ASN1_UTC_TIME)
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goto end_utc_time;
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len = get_asn1_length(buf, offset);
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t_offset = *offset;
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memset(&tm, 0, sizeof(struct tm));
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tm.tm_year = (buf[t_offset] - '0')*10 + (buf[t_offset+1] - '0');
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if (tm.tm_year <= 50) /* 1951-2050 thing */
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{
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tm.tm_year += 100;
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}
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tm.tm_mon = (buf[t_offset+2] - '0')*10 + (buf[t_offset+3] - '0') - 1;
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tm.tm_mday = (buf[t_offset+4] - '0')*10 + (buf[t_offset+5] - '0');
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*t = mktime(&tm);
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*offset += len;
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ret = X509_OK;
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end_utc_time:
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return ret;
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}
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/**
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* Get the version type of a certificate (which we don't actually care about)
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*/
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int asn1_version(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
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{
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int ret = X509_NOT_OK;
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(*offset) += 2; /* get past explicit tag */
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if (asn1_skip_obj(cert, offset, ASN1_INTEGER))
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goto end_version;
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ret = X509_OK;
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end_version:
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return ret;
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}
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/**
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* Retrieve the notbefore and notafter certificate times.
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*/
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int asn1_validity(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
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{
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return (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
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asn1_get_utc_time(cert, offset, &x509_ctx->not_before) ||
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asn1_get_utc_time(cert, offset, &x509_ctx->not_after));
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}
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/**
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* Get the components of a distinguished name
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*/
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static int asn1_get_oid_x520(const uint8_t *buf, int *offset)
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{
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int dn_type = 0;
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int len;
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if ((len = asn1_next_obj(buf, offset, ASN1_OID)) < 0)
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goto end_oid;
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/* expect a sequence of 2.5.4.[x] where x is a one of distinguished name
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components we are interested in. */
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if (len == 3 && buf[(*offset)++] == 0x55 && buf[(*offset)++] == 0x04)
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dn_type = buf[(*offset)++];
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else
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{
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*offset += len; /* skip over it */
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}
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end_oid:
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return dn_type;
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}
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/**
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* Obtain an ASN.1 printable string type.
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*/
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static int asn1_get_printable_str(const uint8_t *buf, int *offset, char **str)
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{
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int len = X509_NOT_OK;
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/* some certs have this awful crud in them for some reason */
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if (buf[*offset] != ASN1_PRINTABLE_STR &&
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buf[*offset] != ASN1_TELETEX_STR &&
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buf[*offset] != ASN1_IA5_STR &&
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buf[*offset] != ASN1_UNICODE_STR)
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goto end_pnt_str;
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(*offset)++;
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len = get_asn1_length(buf, offset);
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if (buf[*offset - 1] == ASN1_UNICODE_STR)
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{
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int i;
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*str = (char *)malloc(len/2+1); /* allow for null */
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for (i = 0; i < len; i += 2)
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(*str)[i/2] = buf[*offset + i + 1];
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(*str)[len/2] = 0; /* null terminate */
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}
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else
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{
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*str = (char *)malloc(len+1); /* allow for null */
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memcpy(*str, &buf[*offset], len);
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(*str)[len] = 0; /* null terminate */
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}
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*offset += len;
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end_pnt_str:
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return len;
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}
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/**
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* Get the subject name (or the issuer) of a certificate.
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*/
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int asn1_name(const uint8_t *cert, int *offset, char *dn[])
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{
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int ret = X509_NOT_OK;
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int dn_type;
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char *tmp = NULL;
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if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
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goto end_name;
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while (asn1_next_obj(cert, offset, ASN1_SET) >= 0)
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{
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int i, found = 0;
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if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
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(dn_type = asn1_get_oid_x520(cert, offset)) < 0)
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goto end_name;
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if (asn1_get_printable_str(cert, offset, &tmp) < 0)
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{
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free(tmp);
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goto end_name;
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}
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/* find the distinguished named type */
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for (i = 0; i < X509_NUM_DN_TYPES; i++)
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{
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if (dn_type == g_dn_types[i])
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{
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if (dn[i] == NULL)
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{
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dn[i] = tmp;
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found = 1;
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break;
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}
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}
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}
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if (found == 0) /* not found so get rid of it */
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{
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free(tmp);
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}
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}
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ret = X509_OK;
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end_name:
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return ret;
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}
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/**
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* Read the modulus and public exponent of a certificate.
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*/
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int asn1_public_key(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
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{
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int ret = X509_NOT_OK, mod_len, pub_len;
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uint8_t *modulus = NULL, *pub_exp = NULL;
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if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
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asn1_skip_obj(cert, offset, ASN1_SEQUENCE) ||
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asn1_next_obj(cert, offset, ASN1_BIT_STRING) < 0)
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goto end_pub_key;
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(*offset)++; /* ignore the padding bit field */
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if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
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goto end_pub_key;
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mod_len = asn1_get_int(cert, offset, &modulus);
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pub_len = asn1_get_int(cert, offset, &pub_exp);
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RSA_pub_key_new(&x509_ctx->rsa_ctx, modulus, mod_len, pub_exp, pub_len);
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free(modulus);
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free(pub_exp);
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ret = X509_OK;
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end_pub_key:
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return ret;
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}
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#ifdef CONFIG_SSL_CERT_VERIFICATION
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/**
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* Read the signature of the certificate.
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*/
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int asn1_signature(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
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{
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int ret = X509_NOT_OK;
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if (cert[(*offset)++] != ASN1_BIT_STRING)
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goto end_sig;
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x509_ctx->sig_len = get_asn1_length(cert, offset)-1;
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(*offset)++; /* ignore bit string padding bits */
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x509_ctx->signature = (uint8_t *)malloc(x509_ctx->sig_len);
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memcpy(x509_ctx->signature, &cert[*offset], x509_ctx->sig_len);
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*offset += x509_ctx->sig_len;
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ret = X509_OK;
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end_sig:
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return ret;
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}
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/*
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* Compare 2 distinguished name components for equality
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* @return 0 if a match
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*/
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static int asn1_compare_dn_comp(const char *dn1, const char *dn2)
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{
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int ret = 1;
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if ((dn1 && dn2 == NULL) || (dn1 == NULL && dn2)) goto err_no_match;
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ret = (dn1 && dn2) ? strcmp(dn1, dn2) : 0;
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err_no_match:
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return ret;
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}
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/**
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* Clean up all of the CA certificates.
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*/
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void remove_ca_certs(CA_CERT_CTX *ca_cert_ctx)
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{
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int i = 0;
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if (ca_cert_ctx == NULL)
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return;
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while (i < CONFIG_X509_MAX_CA_CERTS && ca_cert_ctx->cert[i])
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{
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x509_free(ca_cert_ctx->cert[i]);
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ca_cert_ctx->cert[i++] = NULL;
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}
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free(ca_cert_ctx);
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}
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/*
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* Compare 2 distinguished names for equality
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* @return 0 if a match
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*/
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int asn1_compare_dn(char * const dn1[], char * const dn2[])
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{
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int i;
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for (i = 0; i < X509_NUM_DN_TYPES; i++)
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{
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if (asn1_compare_dn_comp(dn1[i], dn2[i]))
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return 1;
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}
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return 0; /* all good */
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}
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#endif
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/**
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* Read the signature type of the certificate. We only support RSA-MD5 and
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* RSA-SHA1 signature types.
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*/
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int asn1_signature_type(const uint8_t *cert,
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int *offset, X509_CTX *x509_ctx)
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{
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int ret = X509_NOT_OK, len;
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if (cert[(*offset)++] != ASN1_OID)
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goto end_check_sig;
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len = get_asn1_length(cert, offset);
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if (len == 5 && memcmp(sig_iis6_oid, &cert[*offset],
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SIG_IIS6_OID_SIZE) == 0)
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{
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x509_ctx->sig_type = SIG_TYPE_SHA1;
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}
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else
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{
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if (memcmp(sig_oid_prefix, &cert[*offset], SIG_OID_PREFIX_SIZE))
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goto end_check_sig; /* unrecognised cert type */
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x509_ctx->sig_type = cert[*offset + SIG_OID_PREFIX_SIZE];
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}
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*offset += len;
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asn1_skip_obj(cert, offset, ASN1_NULL); /* if it's there */
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ret = X509_OK;
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end_check_sig:
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return ret;
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}
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