static void
mac_setup_by_alg(Mac *mac, const struct macalg *macalg)
{
mac->type = macalg->type;
if (mac->type == SSH_DIGEST) {
if ((mac->hmac_ctx = ssh_hmac_start(macalg->alg)) == NULL)
fatal("ssh_hmac_start(alg=%d) failed", macalg->alg);
mac->key_len = mac->mac_len = ssh_hmac_bytes(macalg->alg);
} else {
mac->mac_len = macalg->len / 8;
mac->key_len = macalg->key_len / 8;
mac->umac_ctx = NULL;
}
if (macalg->truncatebits != 0)
mac->mac_len = macalg->truncatebits / 8;
mac->etm = macalg->etm;
}
/* cc -DTEST hmac.c digest.c buffer.c cleanup.c fatal.c log.c xmalloc.c -lcrypto */
static void
hmac_test(void *key, size_t klen, void *m, size_t mlen, u_char *e, size_t elen)
{
struct ssh_hmac_ctx *ctx;
size_t i;
u_char digest[16];
if ((ctx = ssh_hmac_start(SSH_DIGEST_MD5)) == NULL)
printf("ssh_hmac_start failed");
if (ssh_hmac_init(ctx, key, klen) < 0 ||
ssh_hmac_update(ctx, m, mlen) < 0 ||
ssh_hmac_final(ctx, digest, sizeof(digest)) < 0)
printf("ssh_hmac_xxx failed");
ssh_hmac_free(ctx);
if (memcmp(e, digest, elen)) {
for (i = 0; i < elen; i++)
printf("[%zd] %2.2x %2.2x\n", i, e[i], digest[i]);
printf("mismatch\n");
} else
printf("ok\n");
}
char *
host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
{
struct ssh_hmac_ctx *ctx;
u_char salt[256], result[256];
char uu_salt[512], uu_result[512];
static char encoded[1024];
u_int i, len;
len = ssh_digest_bytes(SSH_DIGEST_SHA1);
if (name_from_hostfile == NULL) {
/* Create new salt */
for (i = 0; i < len; i++)
salt[i] = arc4random();
} else {
/* Extract salt from known host entry */
if (extract_salt(name_from_hostfile, src_len, salt,
sizeof(salt)) == -1)
return (NULL);
}
if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL ||
ssh_hmac_init(ctx, salt, len) < 0 ||
ssh_hmac_update(ctx, host, strlen(host)) < 0 ||
ssh_hmac_final(ctx, result, sizeof(result)))
fatal("%s: ssh_hmac failed", __func__);
ssh_hmac_free(ctx);
if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
__b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
fatal("%s: __b64_ntop failed", __func__);
snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
HASH_DELIM, uu_result);
return (encoded);
}
