diff options
Diffstat (limited to 'ccast/axTLS/asn1.c')
-rw-r--r-- | ccast/axTLS/asn1.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/ccast/axTLS/asn1.c b/ccast/axTLS/asn1.c new file mode 100644 index 0000000..b082275 --- /dev/null +++ b/ccast/axTLS/asn1.c @@ -0,0 +1,566 @@ +/* + * Copyright (c) 2007, Cameron Rich + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * * 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. + * * Neither the name of the axTLS project 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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. + */ + +/** + * Some primitive asn methods for extraction ASN.1 data. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include "os_port.h" +#include "crypto.h" +#include "crypto_misc.h" + +#define SIG_OID_PREFIX_SIZE 8 +#define SIG_IIS6_OID_SIZE 5 +#define SIG_SUBJECT_ALT_NAME_SIZE 3 + +/* Must be an RSA algorithm with either SHA1 or MD5 for verifying to work */ +static const uint8_t sig_oid_prefix[SIG_OID_PREFIX_SIZE] = +{ + 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01 +}; + +static const uint8_t sig_sha1WithRSAEncrypt[SIG_IIS6_OID_SIZE] = +{ + 0x2b, 0x0e, 0x03, 0x02, 0x1d +}; + +static const uint8_t sig_subject_alt_name[SIG_SUBJECT_ALT_NAME_SIZE] = +{ + 0x55, 0x1d, 0x11 +}; + +/* CN, O, OU */ +static const uint8_t g_dn_types[] = { 3, 10, 11 }; + +int get_asn1_length(const uint8_t *buf, int *offset) +{ + int len, i; + + if (!(buf[*offset] & 0x80)) /* short form */ + { + len = buf[(*offset)++]; + } + else /* long form */ + { + int length_bytes = buf[(*offset)++]&0x7f; + len = 0; + for (i = 0; i < length_bytes; i++) + { + len <<= 8; + len += buf[(*offset)++]; + } + } + + return len; +} + +/** + * Skip the ASN1.1 object type and its length. Get ready to read the object's + * data. + */ +int asn1_next_obj(const uint8_t *buf, int *offset, int obj_type) +{ + if (buf[*offset] != obj_type) + return X509_NOT_OK; + (*offset)++; + return get_asn1_length(buf, offset); +} + +/** + * Skip over an ASN.1 object type completely. Get ready to read the next + * object. + */ +int asn1_skip_obj(const uint8_t *buf, int *offset, int obj_type) +{ + int len; + + if (buf[*offset] != obj_type) + return X509_NOT_OK; + (*offset)++; + len = get_asn1_length(buf, offset); + *offset += len; + return 0; +} + +/** + * Read an integer value for ASN.1 data + * Note: This function allocates memory which must be freed by the user. + */ +int asn1_get_int(const uint8_t *buf, int *offset, uint8_t **object) +{ + int len; + + if ((len = asn1_next_obj(buf, offset, ASN1_INTEGER)) < 0) + goto end_int_array; + + if (len > 1 && buf[*offset] == 0x00) /* ignore the negative byte */ + { + len--; + (*offset)++; + } + + *object = (uint8_t *)malloc(len); + memcpy(*object, &buf[*offset], len); + *offset += len; + +end_int_array: + return len; +} + +/** + * Get all the RSA private key specifics from an ASN.1 encoded file + */ +int asn1_get_private_key(const uint8_t *buf, int len, RSA_CTX **rsa_ctx) +{ + int offset = 7; + uint8_t *modulus = NULL, *priv_exp = NULL, *pub_exp = NULL; + int mod_len, priv_len, pub_len; +#ifdef CONFIG_BIGINT_CRT + uint8_t *p = NULL, *q = NULL, *dP = NULL, *dQ = NULL, *qInv = NULL; + int p_len, q_len, dP_len, dQ_len, qInv_len; +#endif + + /* not in der format */ + if (buf[0] != ASN1_SEQUENCE) /* basic sanity check */ + { +#ifdef CONFIG_SSL_FULL_MODE + printf("Error: This is not a valid ASN.1 file\n"); +#endif + return X509_INVALID_PRIV_KEY; + } + + /* Use the private key to mix up the RNG if possible. */ + RNG_custom_init(buf, len); + + mod_len = asn1_get_int(buf, &offset, &modulus); + pub_len = asn1_get_int(buf, &offset, &pub_exp); + priv_len = asn1_get_int(buf, &offset, &priv_exp); + + if (mod_len <= 0 || pub_len <= 0 || priv_len <= 0) + return X509_INVALID_PRIV_KEY; + +#ifdef CONFIG_BIGINT_CRT + p_len = asn1_get_int(buf, &offset, &p); + q_len = asn1_get_int(buf, &offset, &q); + dP_len = asn1_get_int(buf, &offset, &dP); + dQ_len = asn1_get_int(buf, &offset, &dQ); + qInv_len = asn1_get_int(buf, &offset, &qInv); + + if (p_len <= 0 || q_len <= 0 || dP_len <= 0 || dQ_len <= 0 || qInv_len <= 0) + return X509_INVALID_PRIV_KEY; + + RSA_priv_key_new(rsa_ctx, + modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len, + p, p_len, q, p_len, dP, dP_len, dQ, dQ_len, qInv, qInv_len); + + free(p); + free(q); + free(dP); + free(dQ); + free(qInv); +#else + RSA_priv_key_new(rsa_ctx, + modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len); +#endif + + free(modulus); + free(priv_exp); + free(pub_exp); + return X509_OK; +} + +/** + * Get the time of a certificate. Ignore hours/minutes/seconds. + */ +static int asn1_get_utc_time(const uint8_t *buf, int *offset, time_t *t) +{ + int ret = X509_NOT_OK, len, t_offset; + struct tm tm; + + if (buf[(*offset)++] != ASN1_UTC_TIME) + goto end_utc_time; + + len = get_asn1_length(buf, offset); + t_offset = *offset; + + memset(&tm, 0, sizeof(struct tm)); + tm.tm_year = (buf[t_offset] - '0')*10 + (buf[t_offset+1] - '0'); + + if (tm.tm_year <= 50) /* 1951-2050 thing */ + { + tm.tm_year += 100; + } + + tm.tm_mon = (buf[t_offset+2] - '0')*10 + (buf[t_offset+3] - '0') - 1; + tm.tm_mday = (buf[t_offset+4] - '0')*10 + (buf[t_offset+5] - '0'); + *t = mktime(&tm); + *offset += len; + ret = X509_OK; + +end_utc_time: + return ret; +} + +/** + * Get the version type of a certificate (which we don't actually care about) + */ +int asn1_version(const uint8_t *cert, int *offset, X509_CTX *x509_ctx) +{ + int ret = X509_NOT_OK; + + (*offset) += 2; /* get past explicit tag */ + if (asn1_skip_obj(cert, offset, ASN1_INTEGER)) + goto end_version; + + ret = X509_OK; +end_version: + return ret; +} + +/** + * Retrieve the notbefore and notafter certificate times. + */ +int asn1_validity(const uint8_t *cert, int *offset, X509_CTX *x509_ctx) +{ + return (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 || + asn1_get_utc_time(cert, offset, &x509_ctx->not_before) || + asn1_get_utc_time(cert, offset, &x509_ctx->not_after)); +} + +/** + * Get the components of a distinguished name + */ +static int asn1_get_oid_x520(const uint8_t *buf, int *offset) +{ + int dn_type = 0; + int len; + + if ((len = asn1_next_obj(buf, offset, ASN1_OID)) < 0) + goto end_oid; + + /* expect a sequence of 2.5.4.[x] where x is a one of distinguished name + components we are interested in. */ + if (len == 3 && buf[(*offset)++] == 0x55 && buf[(*offset)++] == 0x04) + dn_type = buf[(*offset)++]; + else + { + *offset += len; /* skip over it */ + } + +end_oid: + return dn_type; +} + +/** + * Obtain an ASN.1 printable string type. + */ +static int asn1_get_printable_str(const uint8_t *buf, int *offset, char **str) +{ + int len = X509_NOT_OK; + int asn1_type = buf[*offset]; + + /* some certs have this awful crud in them for some reason */ + if (asn1_type != ASN1_PRINTABLE_STR && + asn1_type != ASN1_PRINTABLE_STR2 && + asn1_type != ASN1_TELETEX_STR && + asn1_type != ASN1_IA5_STR && + asn1_type != ASN1_UNICODE_STR) + goto end_pnt_str; + + (*offset)++; + len = get_asn1_length(buf, offset); + + if (asn1_type == ASN1_UNICODE_STR) + { + int i; + *str = (char *)malloc(len/2+1); /* allow for null */ + + for (i = 0; i < len; i += 2) + (*str)[i/2] = buf[*offset + i + 1]; + + (*str)[len/2] = 0; /* null terminate */ + } + else + { + *str = (char *)malloc(len+1); /* allow for null */ + memcpy(*str, &buf[*offset], len); + (*str)[len] = 0; /* null terminate */ + } + + *offset += len; + +end_pnt_str: + return len; +} + +/** + * Get the subject name (or the issuer) of a certificate. + */ +int asn1_name(const uint8_t *cert, int *offset, char *dn[]) +{ + int ret = X509_NOT_OK; + int dn_type; + char *tmp; + + if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0) + goto end_name; + + while (asn1_next_obj(cert, offset, ASN1_SET) >= 0) + { + int i, found = 0; + + if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 || + (dn_type = asn1_get_oid_x520(cert, offset)) < 0) + goto end_name; + + tmp = NULL; + + if (asn1_get_printable_str(cert, offset, &tmp) < 0) + { + free(tmp); + goto end_name; + } + + /* find the distinguished named type */ + for (i = 0; i < X509_NUM_DN_TYPES; i++) + { + if (dn_type == g_dn_types[i]) + { + if (dn[i] == NULL) + { + dn[i] = tmp; + found = 1; + break; + } + } + } + + if (found == 0) /* not found so get rid of it */ + { + free(tmp); + } + } + + ret = X509_OK; +end_name: + return ret; +} + +/** + * Read the modulus and public exponent of a certificate. + */ +int asn1_public_key(const uint8_t *cert, int *offset, X509_CTX *x509_ctx) +{ + int ret = X509_NOT_OK, mod_len, pub_len; + uint8_t *modulus = NULL, *pub_exp = NULL; + + if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 || + asn1_skip_obj(cert, offset, ASN1_SEQUENCE) || + asn1_next_obj(cert, offset, ASN1_BIT_STRING) < 0) + goto end_pub_key; + + (*offset)++; /* ignore the padding bit field */ + + if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0) + goto end_pub_key; + + mod_len = asn1_get_int(cert, offset, &modulus); + pub_len = asn1_get_int(cert, offset, &pub_exp); + + RSA_pub_key_new(&x509_ctx->rsa_ctx, modulus, mod_len, pub_exp, pub_len); + + free(modulus); + free(pub_exp); + ret = X509_OK; + +end_pub_key: + return ret; +} + +#ifdef CONFIG_SSL_CERT_VERIFICATION +/** + * Read the signature of the certificate. + */ +int asn1_signature(const uint8_t *cert, int *offset, X509_CTX *x509_ctx) +{ + int ret = X509_NOT_OK; + + if (cert[(*offset)++] != ASN1_BIT_STRING) + goto end_sig; + + x509_ctx->sig_len = get_asn1_length(cert, offset)-1; + (*offset)++; /* ignore bit string padding bits */ + x509_ctx->signature = (uint8_t *)malloc(x509_ctx->sig_len); + memcpy(x509_ctx->signature, &cert[*offset], x509_ctx->sig_len); + *offset += x509_ctx->sig_len; + ret = X509_OK; + +end_sig: + return ret; +} + +/* + * Compare 2 distinguished name components for equality + * @return 0 if a match + */ +static int asn1_compare_dn_comp(const char *dn1, const char *dn2) +{ + int ret; + + if (dn1 == NULL && dn2 == NULL) + ret = 0; + else + ret = (dn1 && dn2) ? strcmp(dn1, dn2) : 1; + + return ret; +} + +/** + * Clean up all of the CA certificates. + */ +void remove_ca_certs(CA_CERT_CTX *ca_cert_ctx) +{ + int i = 0; + + if (ca_cert_ctx == NULL) + return; + + while (i < CONFIG_X509_MAX_CA_CERTS && ca_cert_ctx->cert[i]) + { + x509_free(ca_cert_ctx->cert[i]); + ca_cert_ctx->cert[i++] = NULL; + } + + free(ca_cert_ctx); +} + +/* + * Compare 2 distinguished names for equality + * @return 0 if a match + */ +int asn1_compare_dn(char * const dn1[], char * const dn2[]) +{ + int i; + + for (i = 0; i < X509_NUM_DN_TYPES; i++) + { + if (asn1_compare_dn_comp(dn1[i], dn2[i])) + return 1; + } + + return 0; /* all good */ +} + +int asn1_find_oid(const uint8_t* cert, int* offset, + const uint8_t* oid, int oid_length) +{ + int seqlen; + if ((seqlen = asn1_next_obj(cert, offset, ASN1_SEQUENCE))> 0) + { + int end = *offset + seqlen; + + while (*offset < end) + { + int type = cert[(*offset)++]; + int length = get_asn1_length(cert, offset); + int noffset = *offset + length; + + if (type == ASN1_SEQUENCE) + { + type = cert[(*offset)++]; + length = get_asn1_length(cert, offset); + + if (type == ASN1_OID && length == oid_length && + memcmp(cert + *offset, oid, oid_length) == 0) + { + *offset += oid_length; + return 1; + } + } + + *offset = noffset; + } + } + + return 0; +} + +int asn1_find_subjectaltname(const uint8_t* cert, int offset) +{ + if (asn1_find_oid(cert, &offset, sig_subject_alt_name, + SIG_SUBJECT_ALT_NAME_SIZE)) + { + return offset; + } + + return 0; +} + +#endif /* CONFIG_SSL_CERT_VERIFICATION */ + +/** + * Read the signature type of the certificate. We only support RSA-MD5 and + * RSA-SHA1 signature types. + */ +int asn1_signature_type(const uint8_t *cert, + int *offset, X509_CTX *x509_ctx) +{ + int ret = X509_NOT_OK, len; + + if (cert[(*offset)++] != ASN1_OID) + goto end_check_sig; + + len = get_asn1_length(cert, offset); + + if (len == 5 && memcmp(sig_sha1WithRSAEncrypt, &cert[*offset], + SIG_IIS6_OID_SIZE) == 0) + { + x509_ctx->sig_type = SIG_TYPE_SHA1; + } + else + { + if (memcmp(sig_oid_prefix, &cert[*offset], SIG_OID_PREFIX_SIZE)) + goto end_check_sig; /* unrecognised cert type */ + + x509_ctx->sig_type = cert[*offset + SIG_OID_PREFIX_SIZE]; + } + + *offset += len; + asn1_skip_obj(cert, offset, ASN1_NULL); /* if it's there */ + ret = X509_OK; + +end_check_sig: + return ret; +} + |