Diff: axTLS/ssl/asn1.c

Revision:

0:85fceccc1a7c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/axTLS/ssl/asn1.c	Thu Sep 12 15:18:04 2013 +0000
@@ -0,0 +1,586 @@
+/*
+ * 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 };
+
+static const uint8_t rsaOID[] = {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01 };
+
+
+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;
+    int offset2 = 0, oid_len = 0;
+    uint8_t *modulus = NULL, *pub_exp = NULL;
+ 
+    if (asn1_next_obj(cert, offset, ASN1_SEQUENCE) < 0)
+        goto end_pub_key;
+    
+    offset2 = *offset;
+    if(asn1_next_obj(cert, &offset2, ASN1_SEQUENCE) < 0)
+        goto end_pub_key;
+    oid_len = asn1_next_obj(cert, &offset2, ASN1_OID);
+    if(oid_len < 0)
+        goto end_pub_key;
+    if(memcmp(rsaOID, &cert[offset2], oid_len))
+    {
+        printf("Only RSA public key algorithm is supported\n");
+        goto end_pub_key;
+    }
+    
+    if (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;
+}
+
+
+