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x509.c
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x509.c
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#include "x509.h"
unsigned char * get_der_x509(char *cert_file) {
FILE *fp;
uchar *x509_cert,*x509_cert_decoded,*x509_hash;
int cert_len,x509_cert_decoded_len;
fp = open_file(cert_file,1);
x509_cert = read_key(fp,&cert_len);
x509_cert_decoded_len = base64_decode(x509_cert,cert_len,&x509_cert_decoded);
if(DEBUG){
printf("x509_certificate\n");
print_octect(x509_cert_decoded,x509_cert_decoded_len,22);
}
return x509_cert_decoded;
}
int get_public_key(unsigned char *x509_der,public_key **pu) {
int counter;
int index = 0,i,size;
int seq_size,seq_size_len;
int elems =0, seq_count = 0;
(*pu) = (public_key *)malloc(sizeof(public_key));
while(seq_count < 2) {
if(x509_der[index++] == 0x30) {
seq_size_len = x509_der[index++] & 0x3F;
index += seq_size_len;
seq_count++;
}
}
//the second sequence contains the 6 elems
while(elems!=5) {
switch(x509_der[index++]){
case 0x02: //INTEGER
case 0x30: //SEQUENCE
if(x509_der[index]<0x80){
seq_size = x509_der[index++];
} else{
seq_size_len = x509_der[index++] & 0x3F;
for (i=0;i<seq_size_len;i++){
size = x509_der[index++];
seq_size |= size << (8*(seq_size_len-(i+1)));
}
}
elems++;
index+=seq_size;
seq_size = 0;
seq_size_len = 0;
}
}
//Now index point to the sequence of sequence which contains the public key...
//contains two integers mod and exp
if(x509_der[index++] == 0x30) {
seq_size_len = x509_der[index++] & 0x3F;
index += seq_size_len;
}
if(x509_der[index++] == 0x30) {
seq_size = 0;
if(x509_der[index]<0x80){
seq_size = x509_der[index++];
} else {
seq_size_len = x509_der[index++] & 0x3F;
for (i=0;i<seq_size_len;i++){
size = x509_der[index++];
seq_size |= size << (8*(seq_size_len-(i+1)));
}
}
}
index+=seq_size;
if(x509_der[index++] == 0x3) {
seq_size_len = x509_der[index++] & 0x3F;
index += seq_size_len;
}
if(x509_der[index]==0x0)
index++;
if(x509_der[index++]==0x30) {
seq_size_len = x509_der[index++] & 0x3F;
index += seq_size_len;
}
if(x509_der[index++] == 0x02) {
//MOD
seq_size_len = 0;
seq_size = 0;
if(x509_der[index]<0x80){
seq_size = x509_der[index];
} else{
seq_size_len = x509_der[index++] & 0x3F;
for (i=0;i<seq_size_len;i++){
size = x509_der[index++];
seq_size |= size << (8*(seq_size_len-(i+1)));
}
}
if(x509_der[index]==0x0){
index++;
seq_size--;
}
(*pu)->mod_len = seq_size;
(*pu)->mod = (unsigned char *)malloc((*pu)->mod_len);
memset((*pu)->mod,0,(*pu)->mod_len);
memcpy((*pu)->mod,x509_der+index,(*pu)->mod_len);
index+=seq_size;
}
if(x509_der[index++] == 0x02) {
//EXP
seq_size_len = 0;
seq_size = 0;
if(x509_der[index]<0x80){
seq_size = x509_der[index++];
} else{
seq_size_len = x509_der[index++] & 0x3F;
for (i=0;i<seq_size_len;i++){
size = x509_der[index++];
seq_size |= size << (8*(seq_size_len-(i+1)));
}
}
(*pu)->pub_exp_len = seq_size;
(*pu)->pub_exp = (unsigned char *)malloc((*pu)->pub_exp_len);
memset((*pu)->pub_exp,0,(*pu)->pub_exp_len);
memcpy((*pu)->pub_exp,x509_der+index,(*pu)->pub_exp_len);
index+=seq_size;
}
return 1;
}