/* returns success or failure, and the keytype in *type. If we want
* to restrict the type, type can contain a type to return */
int readhostkey(const char * filename, sign_key * hostkey, int *type) {
int ret = DROPBEAR_FAILURE;
buffer *buf;
buf = buf_new(MAX_PRIVKEY_SIZE);
if (buf_readfile(buf, filename) == DROPBEAR_FAILURE) {
goto out;
}
buf_setpos(buf, 0);
addrandom(buf_getptr(buf, buf->len), buf->len);
if (buf_get_priv_key(buf, hostkey, type) == DROPBEAR_FAILURE) {
goto out;
}
ret = DROPBEAR_SUCCESS;
out:
buf_burn(buf);
buf_free(buf);
return ret;
}
/* returns success or failure */
static int readhostkey(const char * filename, sign_key * hostkey, int type) {
int ret = DROPBEAR_FAILURE;
int i;
buffer *buf;
buf = buf_new(2000);
if (buf_readfile(buf, filename) == DROPBEAR_FAILURE) {
goto out;
}
buf_setpos(buf, 0);
if (buf_get_priv_key(buf, hostkey, type) == DROPBEAR_FAILURE) {
goto out;
}
ret = DROPBEAR_SUCCESS;
out:
if (ret == DROPBEAR_FAILURE) {
for (i = 0; sshhostkey[i].name != NULL; i++) {
if (sshhostkey[i].val == type) {
sshhostkey[i].usable = 0;
break;
}
}
fprintf(stderr, "Failed reading '%s', disabling %s\n", filename,
type == DROPBEAR_SIGNKEY_DSS ? "DSS" : "RSA");
}
buf_burn(buf);
buf_free(buf);
return ret;
}
static void cleanup_buf(buffer **buf) {
if (!*buf) {
return;
}
buf_burn(*buf);
buf_free(*buf);
*buf = NULL;
}
int signkey_generate(enum signkey_type keytype, int bits, const char* filename)
{
sign_key * key = NULL;
buffer *buf = NULL;
int ret = DROPBEAR_FAILURE;
if (bits == 0)
{
bits = get_default_bits(keytype);
}
/* now we can generate the key */
key = new_sign_key();
seedrandom();
switch(keytype) {
#ifdef DROPBEAR_RSA
case DROPBEAR_SIGNKEY_RSA:
key->rsakey = gen_rsa_priv_key(bits);
break;
#endif
#ifdef DROPBEAR_DSS
case DROPBEAR_SIGNKEY_DSS:
key->dsskey = gen_dss_priv_key(bits);
break;
#endif
#ifdef DROPBEAR_ECDSA
case DROPBEAR_SIGNKEY_ECDSA_KEYGEN:
case DROPBEAR_SIGNKEY_ECDSA_NISTP521:
case DROPBEAR_SIGNKEY_ECDSA_NISTP384:
case DROPBEAR_SIGNKEY_ECDSA_NISTP256:
{
ecc_key *ecckey = gen_ecdsa_priv_key(bits);
keytype = ecdsa_signkey_type(ecckey);
*signkey_key_ptr(key, keytype) = ecckey;
}
break;
#endif
default:
dropbear_exit("Internal error");
}
seedrandom();
buf = buf_new(MAX_PRIVKEY_SIZE);
buf_put_priv_key(buf, key, keytype);
sign_key_free(key);
key = NULL;
buf_setpos(buf, 0);
ret = buf_writefile(buf, filename);
buf_burn(buf);
buf_free(buf);
buf = NULL;
return ret;
}
static int printpubfile(const char* filename) {
buffer *buf = NULL;
sign_key *key = NULL;
enum signkey_type keytype;
int ret;
int err = DROPBEAR_FAILURE;
buf = buf_new(MAX_PRIVKEY_SIZE);
ret = buf_readfile(buf, filename);
if (ret != DROPBEAR_SUCCESS) {
fprintf(stderr, "Failed reading '%s'\n", filename);
goto out;
}
key = new_sign_key();
keytype = DROPBEAR_SIGNKEY_ANY;
buf_setpos(buf, 0);
ret = buf_get_priv_key(buf, key, &keytype);
if (ret == DROPBEAR_FAILURE) {
fprintf(stderr, "Bad key in '%s'\n", filename);
goto out;
}
printpubkey(key, keytype);
err = DROPBEAR_SUCCESS;
out:
buf_burn(buf);
buf_free(buf);
buf = NULL;
if (key) {
sign_key_free(key);
key = NULL;
}
return err;
}
/* if skip_exist is set it will silently return if the key file exists */
int signkey_generate(enum signkey_type keytype, int bits, const char* filename, int skip_exist)
{
sign_key * key = NULL;
buffer *buf = NULL;
char *fn_temp = NULL;
int ret = DROPBEAR_FAILURE;
bits = signkey_generate_get_bits(keytype, bits);
/* now we can generate the key */
key = new_sign_key();
seedrandom();
switch(keytype) {
#if DROPBEAR_RSA
case DROPBEAR_SIGNKEY_RSA:
key->rsakey = gen_rsa_priv_key(bits);
break;
#endif
#if DROPBEAR_DSS
case DROPBEAR_SIGNKEY_DSS:
key->dsskey = gen_dss_priv_key(bits);
break;
#endif
#if DROPBEAR_ECDSA
case DROPBEAR_SIGNKEY_ECDSA_KEYGEN:
case DROPBEAR_SIGNKEY_ECDSA_NISTP521:
case DROPBEAR_SIGNKEY_ECDSA_NISTP384:
case DROPBEAR_SIGNKEY_ECDSA_NISTP256:
{
ecc_key *ecckey = gen_ecdsa_priv_key(bits);
keytype = ecdsa_signkey_type(ecckey);
*signkey_key_ptr(key, keytype) = ecckey;
}
break;
#endif
default:
dropbear_exit("Internal error");
}
seedrandom();
buf = buf_new(MAX_PRIVKEY_SIZE);
buf_put_priv_key(buf, key, keytype);
sign_key_free(key);
key = NULL;
buf_setpos(buf, 0);
fn_temp = m_malloc(strlen(filename) + 30);
snprintf(fn_temp, strlen(filename)+30, "%s.tmp%d", filename, getpid());
ret = buf_writefile(buf, fn_temp);
if (ret == DROPBEAR_FAILURE) {
goto out;
}
if (link(fn_temp, filename) < 0) {
/* If generating keys on connection (skipexist) it's OK to get EEXIST
- we probably just lost a race with another connection to generate the key */
if (!(skip_exist && errno == EEXIST)) {
dropbear_log(LOG_ERR, "Failed moving key file to %s: %s", filename,
strerror(errno));
/* XXX fallback to non-atomic copy for some filesystems? */
ret = DROPBEAR_FAILURE;
goto out;
}
}
out:
if (buf) {
buf_burn(buf);
buf_free(buf);
}
if (fn_temp) {
unlink(fn_temp);
m_free(fn_temp);
}
return ret;
}
