2 * Copyright (c) 2007, Cameron Rich
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32 * Some primitive asn methods for extraction ASN.1 data.
41 #include "crypto_misc.h"
44 #define SIG_OID_PREFIX_SIZE 8
45 #define SIG_IIS6_OID_SIZE 5
46 #define SIG_SUBJECT_ALT_NAME_SIZE 3
48 /* Must be an RSA algorithm with either SHA1 or MD5 for verifying to work */
49 static const uint8_t sig_oid_prefix[SIG_OID_PREFIX_SIZE] =
51 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01
54 static const uint8_t sig_sha1WithRSAEncrypt[SIG_IIS6_OID_SIZE] =
56 0x2b, 0x0e, 0x03, 0x02, 0x1d
59 static const uint8_t sig_subject_alt_name[SIG_SUBJECT_ALT_NAME_SIZE] =
65 static const uint8_t g_dn_types[] = { 3, 10, 11 };
67 int get_asn1_length(const uint8_t *buf, int *offset)
71 if (!(buf[*offset] & 0x80)) /* short form */
73 len = buf[(*offset)++];
77 int length_bytes = buf[(*offset)++]&0x7f;
79 for (i = 0; i < length_bytes; i++)
82 len += buf[(*offset)++];
90 * Skip the ASN1.1 object type and its length. Get ready to read the object's
93 int asn1_next_obj(const uint8_t *buf, int *offset, int obj_type)
95 if (buf[*offset] != obj_type)
98 int tmp = get_asn1_length(buf, offset);
103 * Skip over an ASN.1 object type completely. Get ready to read the next
106 int asn1_skip_obj(const uint8_t *buf, int *offset, int obj_type)
109 if (buf[*offset] != obj_type)
112 len = get_asn1_length(buf, offset);
118 * Read an integer value for ASN.1 data
119 * Note: This function allocates memory which must be freed by the user.
121 int asn1_get_int(const uint8_t *buf, int *offset, uint8_t **object)
125 if ((len = asn1_next_obj(buf, offset, ASN1_INTEGER)) < 0)
128 if (len > 1 && buf[*offset] == 0x00) /* ignore the negative byte */
134 *object = (uint8_t *)malloc(len);
135 memcpy(*object, &buf[*offset], len);
143 * Get all the RSA private key specifics from an ASN.1 encoded file
145 int asn1_get_private_key(const uint8_t *buf, int len, RSA_CTX **rsa_ctx)
148 uint8_t *modulus = NULL, *priv_exp = NULL, *pub_exp = NULL;
149 int mod_len, priv_len, pub_len;
150 #ifdef CONFIG_BIGINT_CRT
151 uint8_t *p = NULL, *q = NULL, *dP = NULL, *dQ = NULL, *qInv = NULL;
152 int p_len, q_len, dP_len, dQ_len, qInv_len;
155 /* not in der format */
156 if (buf[0] != ASN1_SEQUENCE) /* basic sanity check */
158 #ifdef CONFIG_SSL_FULL_MODE
159 printf("Error: This is not a valid ASN.1 file\n");
161 return X509_INVALID_PRIV_KEY;
164 /* Use the private key to mix up the RNG if possible. */
165 RNG_custom_init(buf, len);
167 mod_len = asn1_get_int(buf, &offset, &modulus);
168 pub_len = asn1_get_int(buf, &offset, &pub_exp);
169 priv_len = asn1_get_int(buf, &offset, &priv_exp);
171 if (mod_len <= 0 || pub_len <= 0 || priv_len <= 0)
172 return X509_INVALID_PRIV_KEY;
174 #ifdef CONFIG_BIGINT_CRT
175 p_len = asn1_get_int(buf, &offset, &p);
176 q_len = asn1_get_int(buf, &offset, &q);
177 dP_len = asn1_get_int(buf, &offset, &dP);
178 dQ_len = asn1_get_int(buf, &offset, &dQ);
179 qInv_len = asn1_get_int(buf, &offset, &qInv);
181 if (p_len <= 0 || q_len <= 0 || dP_len <= 0 || dQ_len <= 0 || qInv_len <= 0)
182 return X509_INVALID_PRIV_KEY;
184 RSA_priv_key_new(rsa_ctx,
185 modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len,
186 p, p_len, q, p_len, dP, dP_len, dQ, dQ_len, qInv, qInv_len);
194 RSA_priv_key_new(rsa_ctx,
195 modulus, mod_len, pub_exp, pub_len, priv_exp, priv_len);
205 * Get the time of a certificate. Ignore hours/minutes/seconds.
207 static int asn1_get_utc_time(const uint8_t *buf, int *offset, time_t *t)
209 int ret = X509_NOT_OK, len, t_offset;
212 if (buf[(*offset)++] != ASN1_UTC_TIME)
215 len = get_asn1_length(buf, offset);
218 memset(&tm, 0, sizeof(struct tm));
219 tm.tm_year = (buf[t_offset] - '0')*10 + (buf[t_offset+1] - '0');
221 if (tm.tm_year <= 50) /* 1951-2050 thing */
226 tm.tm_mon = (buf[t_offset+2] - '0')*10 + (buf[t_offset+3] - '0') - 1;
227 tm.tm_mday = (buf[t_offset+4] - '0')*10 + (buf[t_offset+5] - '0');
237 * Get the version type of a certificate (which we don't actually care about)
239 int asn1_version(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
241 int ret = X509_NOT_OK;
243 (*offset) += 2; /* get past explicit tag */
244 if (asn1_skip_obj(cert, offset, ASN1_INTEGER))
253 * Retrieve the notbefore and notafter certificate times.
255 int asn1_validity(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
257 return (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
258 asn1_get_utc_time(cert, offset, &x509_ctx->not_before) ||
259 asn1_get_utc_time(cert, offset, &x509_ctx->not_after));
263 * Get the components of a distinguished name
265 static int asn1_get_oid_x520(const uint8_t *buf, int *offset)
270 if ((len = asn1_next_obj(buf, offset, ASN1_OID)) < 0)
273 /* expect a sequence of 2.5.4.[x] where x is a one of distinguished name
274 components we are interested in. */
275 if (len == 3 && buf[(*offset)++] == 0x55 && buf[(*offset)++] == 0x04)
276 dn_type = buf[(*offset)++];
279 *offset += len; /* skip over it */
287 * Obtain an ASN.1 printable string type.
289 static int asn1_get_printable_str(const uint8_t *buf, int *offset, char **str)
291 int len = X509_NOT_OK;
292 int asn1_type = buf[*offset];
294 /* some certs have this awful crud in them for some reason */
295 if (asn1_type != ASN1_PRINTABLE_STR &&
296 asn1_type != ASN1_PRINTABLE_STR2 &&
297 asn1_type != ASN1_TELETEX_STR &&
298 asn1_type != ASN1_IA5_STR &&
299 asn1_type != ASN1_UNICODE_STR)
303 len = get_asn1_length(buf, offset);
305 if (asn1_type == ASN1_UNICODE_STR)
308 *str = (char *)malloc(len/2+1); /* allow for null */
310 for (i = 0; i < len; i += 2)
311 (*str)[i/2] = buf[*offset + i + 1];
313 (*str)[len/2] = 0; /* null terminate */
317 *str = (char *)malloc(len+1); /* allow for null */
318 memcpy(*str, &buf[*offset], len);
319 (*str)[len] = 0; /* null terminate */
329 * Get the subject name (or the issuer) of a certificate.
331 int asn1_name(const uint8_t *cert, int *offset, char *dn[])
333 int ret = X509_NOT_OK;
337 if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
340 while (asn1_next_obj(cert, offset, ASN1_SET) >= 0)
344 if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
345 (dn_type = asn1_get_oid_x520(cert, offset)) < 0)
350 if (asn1_get_printable_str(cert, offset, &tmp) < 0)
356 /* find the distinguished named type */
357 for (i = 0; i < X509_NUM_DN_TYPES; i++)
359 if (dn_type == g_dn_types[i])
370 if (found == 0) /* not found so get rid of it */
382 * Read the modulus and public exponent of a certificate.
384 int asn1_public_key(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
386 int ret = X509_NOT_OK, mod_len, pub_len;
387 uint8_t *modulus = NULL, *pub_exp = NULL;
389 if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0 ||
390 asn1_skip_obj(cert, offset, ASN1_SEQUENCE) ||
391 asn1_next_obj(cert, offset, ASN1_BIT_STRING) < 0)
394 (*offset)++; /* ignore the padding bit field */
396 if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
399 mod_len = asn1_get_int(cert, offset, &modulus);
400 pub_len = asn1_get_int(cert, offset, &pub_exp);
401 RSA_pub_key_new(&x509_ctx->rsa_ctx, modulus, mod_len, pub_exp, pub_len);
410 #ifdef CONFIG_SSL_CERT_VERIFICATION
412 * Read the signature of the certificate.
414 int asn1_signature(const uint8_t *cert, int *offset, X509_CTX *x509_ctx)
416 int ret = X509_NOT_OK;
418 if (cert[(*offset)++] != ASN1_BIT_STRING)
421 x509_ctx->sig_len = get_asn1_length(cert, offset)-1;
422 (*offset)++; /* ignore bit string padding bits */
423 x509_ctx->signature = (uint8_t *)malloc(x509_ctx->sig_len);
424 memcpy(x509_ctx->signature, &cert[*offset], x509_ctx->sig_len);
425 *offset += x509_ctx->sig_len;
433 * Compare 2 distinguished name components for equality
434 * @return 0 if a match
436 static int asn1_compare_dn_comp(const char *dn1, const char *dn2)
440 if (dn1 == NULL && dn2 == NULL)
443 ret = (dn1 && dn2) ? strcmp(dn1, dn2) : 1;
449 * Clean up all of the CA certificates.
451 void remove_ca_certs(CA_CERT_CTX *ca_cert_ctx)
455 if (ca_cert_ctx == NULL)
458 while (i < CONFIG_X509_MAX_CA_CERTS && ca_cert_ctx->cert[i])
460 x509_free(ca_cert_ctx->cert[i]);
461 ca_cert_ctx->cert[i++] = NULL;
468 * Compare 2 distinguished names for equality
469 * @return 0 if a match
471 int asn1_compare_dn(char * const dn1[], char * const dn2[])
475 for (i = 0; i < X509_NUM_DN_TYPES; i++)
477 if (asn1_compare_dn_comp(dn1[i], dn2[i]))
481 return 0; /* all good */
484 int asn1_find_oid(const uint8_t* cert, int* offset,
485 const uint8_t* oid, int oid_length)
488 if ((seqlen = asn1_next_obj(cert, offset, ASN1_SEQUENCE))> 0)
490 int end = *offset + seqlen;
492 while (*offset < end)
494 int type = cert[(*offset)++];
495 int length = get_asn1_length(cert, offset);
496 int noffset = *offset + length;
498 if (type == ASN1_SEQUENCE)
500 type = cert[(*offset)++];
501 length = get_asn1_length(cert, offset);
503 if (type == ASN1_OID && length == oid_length &&
504 memcmp(cert + *offset, oid, oid_length) == 0)
506 *offset += oid_length;
518 int asn1_find_subjectaltname(const uint8_t* cert, int offset)
520 if (asn1_find_oid(cert, &offset, sig_subject_alt_name,
521 SIG_SUBJECT_ALT_NAME_SIZE))
529 #endif /* CONFIG_SSL_CERT_VERIFICATION */
532 * Read the signature type of the certificate. We only support RSA-MD5 and
533 * RSA-SHA1 signature types.
535 int asn1_signature_type(const uint8_t *cert,
536 int *offset, X509_CTX *x509_ctx)
538 int ret = X509_NOT_OK, len;
540 if (cert[(*offset)++] != ASN1_OID)
543 len = get_asn1_length(cert, offset);
545 if (len == 5 && memcmp(sig_sha1WithRSAEncrypt, &cert[*offset],
546 SIG_IIS6_OID_SIZE) == 0)
548 x509_ctx->sig_type = SIG_TYPE_SHA1;
552 if (memcmp(sig_oid_prefix, &cert[*offset], SIG_OID_PREFIX_SIZE))
553 goto end_check_sig; /* unrecognised cert type */
555 x509_ctx->sig_type = cert[*offset + SIG_OID_PREFIX_SIZE];
559 asn1_skip_obj(cert, offset, ASN1_NULL); /* if it's there */