87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
#include "hash.h"
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#include "debug.h"
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// Hash a single data
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void hash_data(pub_data *data, unsigned char *buf) {
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// All three fields are concatenated into a single buffer
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int totlen = data->length + 10;
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unsigned char concat[totlen];
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concat_data(data, concat);
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// The resulting buf is hashed and put into a buffer
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unsigned char hash[SHA256_DIGEST_LENGTH];
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SHA256_CTX sha256;
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SHA256_Init(&sha256);
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SHA256_Update(&sha256, concat, totlen);
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SHA256_Final(hash, &sha256);
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// Put truncated hash into buf
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hash_trunc(hash, buf);
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}
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// Hash every data contained in data_list then return a network hash
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void hash_network(list *data_list, unsigned char *buf) {
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// Get list length to initialize concat buffer
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int concat_len = len_list(data_list) * 16;
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unsigned char *concat = (unsigned char*) malloc(concat_len);
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unsigned char hash[SHA256_DIGEST_LENGTH];
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int totlen = 0;
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list *tmp = data_list;
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// Hash every known data and concatenate it to buffer concat
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while(tmp != NULL) {
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hash_data((pub_data*) tmp->data, hash);
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concat_hash(concat, hash, totlen);
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totlen += 16;
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tmp = tmp->next;
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}
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// Hash all of concat to obtain the network hash
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SHA256_CTX sha256;
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SHA256_Init(&sha256);
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SHA256_Update(&sha256, concat, concat_len);
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SHA256_Final(hash, &sha256);
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// Put truncated hash into buf
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hash_trunc(hash, buf);
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// Get rid of concat
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free(concat);
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}
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// Truncate 32 octet hash to 16 octets
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void hash_trunc(unsigned char *hash32oct, unsigned char *buf) {
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// Copy the first 16 octets from hash32oct
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if (memcpy(buf, hash32oct, 16) == NULL) {
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print_debug(">> Truncating the hashs didn't work !");
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}
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}
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// Concat all fields of data and put them in buf
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void concat_data(pub_data *data, unsigned char *buf) {
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// Turn seqno to big endian
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uint16_t seqno = htobe16(data->seqno);
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uint64_t id = htobe64(data->id);
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if (memcpy(buf, (char*) &id, 8) == NULL) {
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print_debug(">> Concat the data (id) didn't work !");
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}
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if (memcpy(buf+8, (char*) &seqno, 2) == NULL) {
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print_debug(">> concat the data (seqno) didn't work !");
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}
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if (memcpy(buf+10, data->data, data->length) == NULL) {
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print_debug(">> Contact the data (data) didn't work !");
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}
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}
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// Concat hash2 to hash1 (hash1 is modified)
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void concat_hash(unsigned char *hash1, unsigned char *hash2, size_t size) {
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if(memcpy(hash1+size, hash2, 16) == NULL){
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print_debug(">> Concat the hash didn't work !");
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}
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}
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