/* this is a public key in openssh's format */
static ssh_string make_rsa1_string(ssh_string e, ssh_string n){
ssh_buffer buffer = NULL;
ssh_string rsa = NULL;
ssh_string ret = NULL;
buffer = ssh_buffer_new();
rsa = ssh_string_from_char("ssh-rsa1");
if (buffer_add_ssh_string(buffer, rsa) < 0) {
goto error;
}
if (buffer_add_ssh_string(buffer, e) < 0) {
goto error;
}
if (buffer_add_ssh_string(buffer, n) < 0) {
goto error;
}
ret = ssh_string_new(ssh_buffer_get_len(buffer));
if (ret == NULL) {
goto error;
}
ssh_string_fill(ret, ssh_buffer_get_begin(buffer), ssh_buffer_get_len(buffer));
error:
ssh_buffer_free(buffer);
ssh_string_free(rsa);
return ret;
}
static int asn1_check_sequence(ssh_buffer_t * buffer) {
unsigned char *j = NULL;
unsigned char tmp;
int i;
uint32_t size;
uint32_t padding;
if (buffer_get_data(buffer, &tmp, 1) == 0 || tmp != ASN1_SEQUENCE) {
return 0;
}
size = asn1_get_len(buffer);
if ((padding = ssh_buffer_get_len(buffer) - buffer->pos - size) > 0) {
for (i = ssh_buffer_get_len(buffer) - buffer->pos - size,
j = (unsigned char*)ssh_buffer_get_begin(buffer) + size + buffer->pos;
i;
i--, j++)
{
if (*j != padding) { /* padding is allowed */
return 0; /* but nothing else */
}
}
}
return 1;
}
static int privatekey_decrypt(int algo, int mode, unsigned int key_len,
unsigned char *iv, unsigned int iv_len,
ssh_buffer_t * data, ssh_auth_callback cb,
void *userdata,
const char *desc)
{
char passphrase[MAX_PASSPHRASE_SIZE] = {0};
unsigned char key[MAX_KEY_SIZE] = {0};
unsigned char *tmp = NULL;
gcry_cipher_hd_t cipher;
int rc = -1;
if (!algo) {
return -1;
}
if (cb) {
rc = (*cb)(desc, passphrase, MAX_PASSPHRASE_SIZE, 0, 0, userdata);
if (rc < 0) {
return -1;
}
} else if (cb == NULL && userdata != NULL) {
snprintf(passphrase, MAX_PASSPHRASE_SIZE, "%s", (char *) userdata);
}
if (passphrase_to_key(passphrase, strlen(passphrase), iv, key, key_len) < 0) {
return -1;
}
if (gcry_cipher_open(&cipher, algo, mode, 0)
|| gcry_cipher_setkey(cipher, key, key_len)
|| gcry_cipher_setiv(cipher, iv, iv_len)
|| (tmp = malloc(ssh_buffer_get_len(data) * sizeof (char))) == NULL
|| gcry_cipher_decrypt(cipher, tmp, ssh_buffer_get_len(data),
ssh_buffer_get_begin(data), ssh_buffer_get_len(data))) {
gcry_cipher_close(cipher);
return -1;
}
memcpy(ssh_buffer_get_begin(data), tmp, ssh_buffer_get_len(data));
SAFE_FREE(tmp);
gcry_cipher_close(cipher);
return 0;
}
static int ssh_gssapi_send_mic(ssh_session session){
OM_uint32 maj_stat, min_stat;
gss_buffer_desc mic_buf = GSS_C_EMPTY_BUFFER;
gss_buffer_desc mic_token_buf = GSS_C_EMPTY_BUFFER;
ssh_buffer mic_buffer;
int rc;
SSH_LOG(SSH_LOG_PACKET,"Sending SSH_MSG_USERAUTH_GSSAPI_MIC");
mic_buffer = ssh_gssapi_build_mic(session);
if (mic_buffer == NULL) {
ssh_set_error_oom(session);
return SSH_ERROR;
}
mic_buf.length = ssh_buffer_get_len(mic_buffer);
mic_buf.value = ssh_buffer_get_begin(mic_buffer);
maj_stat = gss_get_mic(&min_stat,session->gssapi->ctx, GSS_C_QOP_DEFAULT, &mic_buf, &mic_token_buf);
if (GSS_ERROR(maj_stat)){
ssh_buffer_free(mic_buffer);
ssh_gssapi_log_error(0, "generating MIC", maj_stat);
return SSH_ERROR;
}
rc = buffer_add_u8(session->out_buffer, SSH2_MSG_USERAUTH_GSSAPI_MIC);
if (rc < 0) {
ssh_buffer_free(mic_buffer);
ssh_set_error_oom(session);
return SSH_ERROR;
}
rc = buffer_add_u32(session->out_buffer, htonl(mic_token_buf.length));
if (rc < 0) {
ssh_buffer_free(mic_buffer);
ssh_set_error_oom(session);
return SSH_ERROR;
}
rc = buffer_add_data(session->out_buffer, mic_token_buf.value, mic_token_buf.length);
ssh_buffer_free(mic_buffer);
if (rc < 0) {
ssh_set_error_oom(session);
return SSH_ERROR;
}
return packet_send(session);
}
static int ssh_gssapi_send_mic(ssh_session session){
OM_uint32 maj_stat, min_stat;
gss_buffer_desc mic_buf = GSS_C_EMPTY_BUFFER;
gss_buffer_desc mic_token_buf = GSS_C_EMPTY_BUFFER;
ssh_buffer mic_buffer;
int rc;
SSH_LOG(SSH_LOG_PACKET,"Sending SSH_MSG_USERAUTH_GSSAPI_MIC");
mic_buffer = ssh_gssapi_build_mic(session);
if (mic_buffer == NULL) {
ssh_set_error_oom(session);
return SSH_ERROR;
}
mic_buf.length = ssh_buffer_get_len(mic_buffer);
mic_buf.value = ssh_buffer_get_begin(mic_buffer);
maj_stat = gss_get_mic(&min_stat,session->gssapi->ctx, GSS_C_QOP_DEFAULT, &mic_buf, &mic_token_buf);
if (GSS_ERROR(maj_stat)){
ssh_buffer_free(mic_buffer);
ssh_gssapi_log_error(SSH_LOG_PROTOCOL, "generating MIC", maj_stat);
return SSH_ERROR;
}
rc = ssh_buffer_pack(session->out_buffer,
"bdP",
SSH2_MSG_USERAUTH_GSSAPI_MIC,
mic_token_buf.length,
(size_t)mic_token_buf.length, mic_token_buf.value);
if (rc != SSH_OK) {
ssh_buffer_free(mic_buffer);
ssh_set_error_oom(session);
return SSH_ERROR;
}
return packet_send(session);
}
/*
* This function signs the session id as a string then
* the content of sigbuf */
ssh_string ssh_pki_do_sign(ssh_session session,
ssh_buffer sigbuf,
const ssh_key privkey) {
struct ssh_crypto_struct *crypto =
session->current_crypto ? session->current_crypto :
session->next_crypto;
ssh_signature sig = NULL;
ssh_string sig_blob;
ssh_string session_id;
int rc;
if (privkey == NULL || !ssh_key_is_private(privkey)) {
return NULL;
}
session_id = ssh_string_new(crypto->digest_len);
if (session_id == NULL) {
return NULL;
}
ssh_string_fill(session_id, crypto->session_id, crypto->digest_len);
if (privkey->type == SSH_KEYTYPE_ECDSA) {
#ifdef HAVE_ECC
unsigned char ehash[EVP_DIGEST_LEN] = {0};
uint32_t elen;
EVPCTX ctx;
ctx = evp_init(privkey->ecdsa_nid);
if (ctx == NULL) {
ssh_string_free(session_id);
return NULL;
}
evp_update(ctx, session_id, ssh_string_len(session_id) + 4);
evp_update(ctx, buffer_get_rest(sigbuf), buffer_get_rest_len(sigbuf));
evp_final(ctx, ehash, &elen);
#ifdef DEBUG_CRYPTO
ssh_print_hexa("Hash being signed", ehash, elen);
#endif
sig = pki_do_sign(privkey, ehash, elen);
#endif
} else if (privkey->type == SSH_KEYTYPE_ED25519){
ssh_buffer buf;
buf = ssh_buffer_new();
if (buf == NULL) {
ssh_string_free(session_id);
return NULL;
}
ssh_buffer_set_secure(buf);
rc = ssh_buffer_pack(buf,
"SP",
session_id,
buffer_get_rest_len(sigbuf), buffer_get_rest(sigbuf));
if (rc != SSH_OK) {
ssh_string_free(session_id);
ssh_buffer_free(buf);
return NULL;
}
sig = pki_do_sign(privkey,
ssh_buffer_get_begin(buf),
ssh_buffer_get_len(buf));
ssh_buffer_free(buf);
} else {
unsigned char hash[SHA_DIGEST_LEN] = {0};
SHACTX ctx;
ctx = sha1_init();
if (ctx == NULL) {
ssh_string_free(session_id);
return NULL;
}
sha1_update(ctx, session_id, ssh_string_len(session_id) + 4);
sha1_update(ctx, buffer_get_rest(sigbuf), buffer_get_rest_len(sigbuf));
sha1_final(hash, ctx);
#ifdef DEBUG_CRYPTO
ssh_print_hexa("Hash being signed", hash, SHA_DIGEST_LEN);
#endif
sig = pki_do_sign(privkey, hash, SHA_DIGEST_LEN);
}
ssh_string_free(session_id);
if (sig == NULL) {
return NULL;
}
rc = ssh_pki_export_signature_blob(sig, &sig_blob);
ssh_signature_free(sig);
if (rc < 0) {
return NULL;
}
return sig_blob;
}
int make_sessionid(ssh_session session) {
ssh_string num = NULL;
ssh_buffer server_hash = NULL;
ssh_buffer client_hash = NULL;
ssh_buffer buf = NULL;
int rc = SSH_ERROR;
buf = ssh_buffer_new();
if (buf == NULL) {
return rc;
}
rc = ssh_buffer_pack(buf,
"ss",
session->clientbanner,
session->serverbanner);
if (rc == SSH_ERROR) {
goto error;
}
if (session->client) {
server_hash = session->in_hashbuf;
client_hash = session->out_hashbuf;
} else {
server_hash = session->out_hashbuf;
client_hash = session->in_hashbuf;
}
/*
* Handle the two final fields for the KEXINIT message (RFC 4253 7.1):
*
* boolean first_kex_packet_follows
* uint32 0 (reserved for future extension)
*/
rc = buffer_add_u8(server_hash, 0);
if (rc < 0) {
goto error;
}
rc = buffer_add_u32(server_hash, 0);
if (rc < 0) {
goto error;
}
/* These fields are handled for the server case in ssh_packet_kexinit. */
if (session->client) {
rc = buffer_add_u8(client_hash, 0);
if (rc < 0) {
goto error;
}
rc = buffer_add_u32(client_hash, 0);
if (rc < 0) {
goto error;
}
}
rc = ssh_buffer_pack(buf,
"dPdPS",
buffer_get_rest_len(client_hash),
buffer_get_rest_len(client_hash),
buffer_get_rest(client_hash),
buffer_get_rest_len(server_hash),
buffer_get_rest_len(server_hash),
buffer_get_rest(server_hash),
session->next_crypto->server_pubkey);
if(rc != SSH_OK){
goto error;
}
if (session->next_crypto->kex_type == SSH_KEX_DH_GROUP1_SHA1 ||
session->next_crypto->kex_type == SSH_KEX_DH_GROUP14_SHA1) {
rc = ssh_buffer_pack(buf,
"BB",
session->next_crypto->e,
session->next_crypto->f);
if (rc != SSH_OK) {
goto error;
}
#ifdef HAVE_ECDH
} else if (session->next_crypto->kex_type == SSH_KEX_ECDH_SHA2_NISTP256) {
if (session->next_crypto->ecdh_client_pubkey == NULL ||
session->next_crypto->ecdh_server_pubkey == NULL) {
SSH_LOG(SSH_LOG_WARNING, "ECDH parameted missing");
goto error;
}
rc = ssh_buffer_pack(buf,
"SS",
session->next_crypto->ecdh_client_pubkey,
session->next_crypto->ecdh_server_pubkey);
if (rc != SSH_OK) {
goto error;
}
#endif
#ifdef HAVE_CURVE25519
} else if (session->next_crypto->kex_type == SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG) {
rc = ssh_buffer_pack(buf,
"dPdP",
CURVE25519_PUBKEY_SIZE,
(size_t)CURVE25519_PUBKEY_SIZE, session->next_crypto->curve25519_client_pubkey,
CURVE25519_PUBKEY_SIZE,
(size_t)CURVE25519_PUBKEY_SIZE, session->next_crypto->curve25519_server_pubkey);
if (rc != SSH_OK) {
goto error;
}
#endif
}
rc = ssh_buffer_pack(buf, "B", session->next_crypto->k);
if (rc != SSH_OK) {
goto error;
}
#ifdef DEBUG_CRYPTO
ssh_print_hexa("hash buffer", ssh_buffer_get_begin(buf), ssh_buffer_get_len(buf));
#endif
switch (session->next_crypto->kex_type) {
case SSH_KEX_DH_GROUP1_SHA1:
case SSH_KEX_DH_GROUP14_SHA1:
session->next_crypto->digest_len = SHA_DIGEST_LENGTH;
session->next_crypto->mac_type = SSH_MAC_SHA1;
session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len);
if (session->next_crypto->secret_hash == NULL) {
ssh_set_error_oom(session);
goto error;
}
sha1(buffer_get_rest(buf), buffer_get_rest_len(buf),
session->next_crypto->secret_hash);
break;
case SSH_KEX_ECDH_SHA2_NISTP256:
case SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG:
session->next_crypto->digest_len = SHA256_DIGEST_LENGTH;
session->next_crypto->mac_type = SSH_MAC_SHA256;
session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len);
if (session->next_crypto->secret_hash == NULL) {
ssh_set_error_oom(session);
goto error;
}
sha256(buffer_get_rest(buf), buffer_get_rest_len(buf),
session->next_crypto->secret_hash);
break;
}
/* During the first kex, secret hash and session ID are equal. However, after
* a key re-exchange, a new secret hash is calculated. This hash will not replace
* but complement existing session id.
*/
if (!session->next_crypto->session_id) {
session->next_crypto->session_id = malloc(session->next_crypto->digest_len);
if (session->next_crypto->session_id == NULL) {
ssh_set_error_oom(session);
goto error;
}
memcpy(session->next_crypto->session_id, session->next_crypto->secret_hash,
session->next_crypto->digest_len);
}
#ifdef DEBUG_CRYPTO
printf("Session hash: \n");
ssh_print_hexa("secret hash", session->next_crypto->secret_hash, session->next_crypto->digest_len);
ssh_print_hexa("session id", session->next_crypto->session_id, session->next_crypto->digest_len);
#endif
rc = SSH_OK;
error:
ssh_buffer_free(buf);
ssh_buffer_free(client_hash);
ssh_buffer_free(server_hash);
session->in_hashbuf = NULL;
session->out_hashbuf = NULL;
ssh_string_free(num);
return rc;
}
/** @internal
* @handles a data received event. It then calls the handlers for the different packet types
* or and exception handler callback.
* @param user pointer to current ssh_session
* @param data pointer to the data received
* @len length of data received. It might not be enough for a complete packet
* @returns number of bytes read and processed.
*/
int ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user){
ssh_session session=(ssh_session) user;
unsigned int blocksize = (session->current_crypto ?
session->current_crypto->in_cipher->blocksize : 8);
int current_macsize = session->current_crypto ? macsize : 0;
unsigned char mac[30] = {0};
char buffer[16] = {0};
void *packet=NULL;
int to_be_read;
int rc;
uint32_t len;
uint8_t padding;
size_t processed=0; /* number of byte processed from the callback */
enter_function();
switch(session->packet_state) {
case PACKET_STATE_INIT:
if(receivedlen < blocksize){
/* We didn't receive enough data to read at least one block size, give up */
leave_function();
return 0;
}
memset(&session->in_packet, 0, sizeof(PACKET));
if (session->in_buffer) {
if (buffer_reinit(session->in_buffer) < 0) {
goto error;
}
} else {
session->in_buffer = ssh_buffer_new();
if (session->in_buffer == NULL) {
goto error;
}
}
memcpy(buffer,data,blocksize);
processed += blocksize;
len = packet_decrypt_len(session, buffer);
if (buffer_add_data(session->in_buffer, buffer, blocksize) < 0) {
goto error;
}
if(len > MAX_PACKET_LEN) {
ssh_set_error(session, SSH_FATAL,
"read_packet(): Packet len too high(%u %.4x)", len, len);
goto error;
}
to_be_read = len - blocksize + sizeof(uint32_t);
if (to_be_read < 0) {
/* remote sshd sends invalid sizes? */
ssh_set_error(session, SSH_FATAL,
"given numbers of bytes left to be read < 0 (%d)!", to_be_read);
goto error;
}
/* saves the status of the current operations */
session->in_packet.len = len;
session->packet_state = PACKET_STATE_SIZEREAD;
case PACKET_STATE_SIZEREAD:
len = session->in_packet.len;
to_be_read = len - blocksize + sizeof(uint32_t) + current_macsize;
/* if to_be_read is zero, the whole packet was blocksize bytes. */
if (to_be_read != 0) {
if(receivedlen - processed < (unsigned int)to_be_read){
/* give up, not enough data in buffer */
return processed;
}
packet = (unsigned char *)data + processed;
// ssh_socket_read(session->socket,packet,to_be_read-current_macsize);
ssh_log(session,SSH_LOG_PACKET,"Read a %d bytes packet",len);
if (buffer_add_data(session->in_buffer, packet,
to_be_read - current_macsize) < 0) {
goto error;
}
processed += to_be_read - current_macsize;
}
if (session->current_crypto) {
/*
* decrypt the rest of the packet (blocksize bytes already
* have been decrypted)
*/
if (packet_decrypt(session,
((uint8_t*)buffer_get_rest(session->in_buffer) + blocksize),
buffer_get_rest_len(session->in_buffer) - blocksize) < 0) {
ssh_set_error(session, SSH_FATAL, "Decrypt error");
goto error;
}
/* copy the last part from the incoming buffer */
memcpy(mac,(unsigned char *)packet + to_be_read - current_macsize, macsize);
if (packet_hmac_verify(session, session->in_buffer, mac) < 0) {
ssh_set_error(session, SSH_FATAL, "HMAC error");
goto error;
}
processed += current_macsize;
}
/* skip the size field which has been processed before */
buffer_pass_bytes(session->in_buffer, sizeof(uint32_t));
if (buffer_get_u8(session->in_buffer, &padding) == 0) {
ssh_set_error(session, SSH_FATAL, "Packet too short to read padding");
goto error;
}
ssh_log(session, SSH_LOG_PACKET,
"%hhd bytes padding, %d bytes left in buffer",
padding, buffer_get_rest_len(session->in_buffer));
if (padding > buffer_get_rest_len(session->in_buffer)) {
ssh_set_error(session, SSH_FATAL,
"Invalid padding: %d (%d resting)",
padding,
buffer_get_rest_len(session->in_buffer));
#ifdef DEBUG_CRYPTO
ssh_print_hexa("incrimined packet",
ssh_buffer_get_begin(session->in_buffer),
ssh_buffer_get_len(session->in_buffer));
#endif
goto error;
}
buffer_pass_bytes_end(session->in_buffer, padding);
ssh_log(session, SSH_LOG_PACKET,
"After padding, %d bytes left in buffer",
buffer_get_rest_len(session->in_buffer));
#if defined(HAVE_LIBZ) && defined(WITH_LIBZ)
if (session->current_crypto
&& session->current_crypto->do_compress_in
&& buffer_get_rest_len(session->in_buffer)) {
ssh_log(session, SSH_LOG_PACKET, "Decompressing in_buffer ...");
if (decompress_buffer(session, session->in_buffer,MAX_PACKET_LEN) < 0) {
goto error;
}
}
#endif
session->recv_seq++;
/* We don't want to rewrite a new packet while still executing the packet callbacks */
session->packet_state = PACKET_STATE_PROCESSING;
ssh_packet_parse_type(session);
/* execute callbacks */
ssh_packet_process(session, session->in_packet.type);
session->packet_state = PACKET_STATE_INIT;
if(processed < receivedlen){
/* Handle a potential packet left in socket buffer */
ssh_log(session,SSH_LOG_PACKET,"Processing %" PRIdS " bytes left in socket buffer",
receivedlen-processed);
rc = ssh_packet_socket_callback((char *)data + processed,
receivedlen - processed,user);
processed += rc;
}
leave_function();
return processed;
case PACKET_STATE_PROCESSING:
ssh_log(session, SSH_LOG_RARE, "Nested packet processing. Delaying.");
return 0;
}
ssh_set_error(session, SSH_FATAL,
"Invalid state into packet_read2(): %d",
session->packet_state);
error:
leave_function();
return processed;
}
static ssh_buffer_t * privatekey_string_to_buffer(const char *pkey, int type,
ssh_auth_callback cb, void *userdata, const char *desc) {
ssh_buffer_t * buffer = NULL;
ssh_buffer_t * out = NULL;
const char *p;
unsigned char *iv = NULL;
const char *header_begin;
const char *header_end;
unsigned int header_begin_size;
unsigned int header_end_size;
unsigned int key_len = 0;
unsigned int iv_len = 0;
int algo = 0;
int mode = 0;
int len;
buffer = ssh_buffer_new();
if (buffer == NULL) {
return NULL;
}
switch(type) {
case SSH_KEYTYPE_DSS:
header_begin = DSA_HEADER_BEGIN;
header_end = DSA_HEADER_END;
break;
case SSH_KEYTYPE_RSA:
header_begin = RSA_HEADER_BEGIN;
header_end = RSA_HEADER_END;
break;
default:
ssh_buffer_free(buffer);
return NULL;
}
header_begin_size = strlen(header_begin);
header_end_size = strlen(header_end);
p = pkey;
len = 0;
get_next_line(p, len);
while(len > 0 && strncmp(p, header_begin, header_begin_size)) {
/* skip line */
get_next_line(p, len);
}
if(len < 0) {
/* no header found */
return NULL;
}
/* skip header line */
get_next_line(p, len);
if (len > 11 && strncmp("Proc-Type: 4,ENCRYPTED", p, 11) == 0) {
/* skip line */
get_next_line(p, len);
if (len > 10 && strncmp("DEK-Info: ", p, 10) == 0) {
p += 10;
len = 0;
get_next_line(p, len);
if (privatekey_dek_header(p, len, &algo, &mode, &key_len,
&iv, &iv_len) < 0) {
ssh_buffer_free(buffer);
SAFE_FREE(iv);
return NULL;
}
} else {
ssh_buffer_free(buffer);
SAFE_FREE(iv);
return NULL;
}
} else {
if(len > 0) {
if (buffer_add_data(buffer, p, len) < 0) {
ssh_buffer_free(buffer);
SAFE_FREE(iv);
return NULL;
}
}
}
get_next_line(p, len);
while(len > 0 && strncmp(p, header_end, header_end_size) != 0) {
if (buffer_add_data(buffer, p, len) < 0) {
ssh_buffer_free(buffer);
SAFE_FREE(iv);
return NULL;
}
get_next_line(p, len);
}
if (len == -1 || strncmp(p, header_end, header_end_size) != 0) {
ssh_buffer_free(buffer);
SAFE_FREE(iv);
return NULL;
}
if (buffer_add_data(buffer, "\0", 1) < 0) {
ssh_buffer_free(buffer);
SAFE_FREE(iv);
return NULL;
}
out = base64_to_bin(ssh_buffer_get_begin(buffer));
ssh_buffer_free(buffer);
if (out == NULL) {
SAFE_FREE(iv);
return NULL;
}
if (algo) {
if (privatekey_decrypt(algo, mode, key_len, iv, iv_len, out,
cb, userdata, desc) < 0) {
ssh_buffer_free(out);
SAFE_FREE(iv);
return NULL;
}
}
SAFE_FREE(iv);
return out;
}
int make_sessionid(ssh_session session) {
SHACTX ctx;
ssh_string num = NULL;
ssh_string str = NULL;
ssh_buffer server_hash = NULL;
ssh_buffer client_hash = NULL;
ssh_buffer buf = NULL;
uint32_t len;
int rc = SSH_ERROR;
enter_function();
ctx = sha1_init();
if (ctx == NULL) {
return rc;
}
buf = ssh_buffer_new();
if (buf == NULL) {
return rc;
}
str = ssh_string_from_char(session->clientbanner);
if (str == NULL) {
goto error;
}
if (buffer_add_ssh_string(buf, str) < 0) {
goto error;
}
ssh_string_free(str);
str = ssh_string_from_char(session->serverbanner);
if (str == NULL) {
goto error;
}
if (buffer_add_ssh_string(buf, str) < 0) {
goto error;
}
if (session->client) {
server_hash = session->in_hashbuf;
client_hash = session->out_hashbuf;
} else {
server_hash = session->out_hashbuf;
client_hash = session->in_hashbuf;
}
if (buffer_add_u32(server_hash, 0) < 0) {
goto error;
}
if (buffer_add_u8(server_hash, 0) < 0) {
goto error;
}
if (buffer_add_u32(client_hash, 0) < 0) {
goto error;
}
if (buffer_add_u8(client_hash, 0) < 0) {
goto error;
}
len = ntohl(buffer_get_rest_len(client_hash));
if (buffer_add_u32(buf,len) < 0) {
goto error;
}
if (buffer_add_data(buf, buffer_get_rest(client_hash),
buffer_get_rest_len(client_hash)) < 0) {
goto error;
}
len = ntohl(buffer_get_rest_len(server_hash));
if (buffer_add_u32(buf, len) < 0) {
goto error;
}
if (buffer_add_data(buf, buffer_get_rest(server_hash),
buffer_get_rest_len(server_hash)) < 0) {
goto error;
}
len = ssh_string_len(session->next_crypto->server_pubkey) + 4;
if (buffer_add_data(buf, session->next_crypto->server_pubkey, len) < 0) {
goto error;
}
num = make_bignum_string(session->next_crypto->e);
if (num == NULL) {
goto error;
}
len = ssh_string_len(num) + 4;
if (buffer_add_data(buf, num, len) < 0) {
goto error;
}
ssh_string_free(num);
num = make_bignum_string(session->next_crypto->f);
if (num == NULL) {
goto error;
}
len = ssh_string_len(num) + 4;
if (buffer_add_data(buf, num, len) < 0) {
goto error;
}
ssh_string_free(num);
num = make_bignum_string(session->next_crypto->k);
if (num == NULL) {
goto error;
}
len = ssh_string_len(num) + 4;
if (buffer_add_data(buf, num, len) < 0) {
goto error;
}
#ifdef DEBUG_CRYPTO
ssh_print_hexa("hash buffer", ssh_buffer_get_begin(buf), ssh_buffer_get_len(buf));
#endif
sha1_update(ctx, buffer_get_rest(buf), buffer_get_rest_len(buf));
sha1_final(session->next_crypto->session_id, ctx);
#ifdef DEBUG_CRYPTO
printf("Session hash: ");
ssh_print_hexa("session id", session->next_crypto->session_id, SHA_DIGEST_LEN);
#endif
rc = SSH_OK;
error:
ssh_buffer_free(buf);
ssh_buffer_free(client_hash);
ssh_buffer_free(server_hash);
session->in_hashbuf = NULL;
session->out_hashbuf = NULL;
ssh_string_free(str);
ssh_string_free(num);
leave_function();
return rc;
}
int ssh_packet_socket_callback1(const void *data, size_t receivedlen, void *user) {
void *packet = NULL;
int to_be_read;
size_t processed=0;
uint32_t padding;
uint32_t crc;
uint32_t len;
ssh_session session=(ssh_session)user;
switch (session->packet_state){
case PACKET_STATE_INIT:
memset(&session->in_packet, 0, sizeof(PACKET));
if (session->in_buffer) {
if (buffer_reinit(session->in_buffer) < 0) {
goto error;
}
} else {
session->in_buffer = ssh_buffer_new();
if (session->in_buffer == NULL) {
goto error;
}
}
/* must have at least enough bytes for size */
if(receivedlen < sizeof(uint32_t)){
return 0;
}
memcpy(&len,data,sizeof(uint32_t));
processed += sizeof(uint32_t);
/* len is not encrypted */
len = ntohl(len);
if (len > MAX_PACKET_LEN) {
ssh_set_error(session, SSH_FATAL,
"read_packet(): Packet len too high (%u %.8x)", len, len);
goto error;
}
ssh_log(session, SSH_LOG_PACKET, "Reading a %d bytes packet", len);
session->in_packet.len = len;
session->packet_state = PACKET_STATE_SIZEREAD;
case PACKET_STATE_SIZEREAD:
len = session->in_packet.len;
/* SSH-1 has a fixed padding lenght */
padding = 8 - (len % 8);
to_be_read = len + padding;
if(to_be_read + processed > receivedlen){
/* wait for rest of packet */
return processed;
}
/* it is _not_ possible that to_be_read be < 8. */
packet = (char *)data + processed;
if (buffer_add_data(session->in_buffer,packet,to_be_read) < 0) {
SAFE_FREE(packet);
goto error;
}
processed += to_be_read;
#ifdef DEBUG_CRYPTO
ssh_print_hexa("read packet:", ssh_buffer_get_begin(session->in_buffer),
ssh_buffer_get_len(session->in_buffer));
#endif
if (session->current_crypto) {
/*
* We decrypt everything, missing the lenght part (which was
* previously read, unencrypted, and is not part of the buffer
*/
if (packet_decrypt(session,
ssh_buffer_get_begin(session->in_buffer),
ssh_buffer_get_len(session->in_buffer)) < 0) {
ssh_set_error(session, SSH_FATAL, "Packet decrypt error");
goto error;
}
}
#ifdef DEBUG_CRYPTO
ssh_print_hexa("read packet decrypted:", ssh_buffer_get_begin(session->in_buffer),
ssh_buffer_get_len(session->in_buffer));
#endif
ssh_log(session, SSH_LOG_PACKET, "%d bytes padding", padding);
if(((len + padding) != buffer_get_rest_len(session->in_buffer)) ||
((len + padding) < sizeof(uint32_t))) {
ssh_log(session, SSH_LOG_RARE, "no crc32 in packet");
ssh_set_error(session, SSH_FATAL, "no crc32 in packet");
goto error;
}
memcpy(&crc,
(unsigned char *)buffer_get_rest(session->in_buffer) + (len+padding) - sizeof(uint32_t),
sizeof(uint32_t));
buffer_pass_bytes_end(session->in_buffer, sizeof(uint32_t));
crc = ntohl(crc);
if (ssh_crc32(buffer_get_rest(session->in_buffer),
(len + padding) - sizeof(uint32_t)) != crc) {
#ifdef DEBUG_CRYPTO
ssh_print_hexa("crc32 on",buffer_get_rest(session->in_buffer),
len + padding - sizeof(uint32_t));
#endif
ssh_log(session, SSH_LOG_RARE, "Invalid crc32");
ssh_set_error(session, SSH_FATAL,
"Invalid crc32: expected %.8x, got %.8x",
crc,
ssh_crc32(buffer_get_rest(session->in_buffer),
len + padding - sizeof(uint32_t)));
goto error;
}
/* pass the padding */
buffer_pass_bytes(session->in_buffer, padding);
ssh_log(session, SSH_LOG_PACKET, "The packet is valid");
/* TODO FIXME
#if defined(HAVE_LIBZ) && defined(WITH_LIBZ)
if(session->current_crypto && session->current_crypto->do_compress_in){
decompress_buffer(session,session->in_buffer);
}
#endif
*/
session->recv_seq++;
/* We don't want to rewrite a new packet while still executing the packet callbacks */
session->packet_state = PACKET_STATE_PROCESSING;
ssh_packet_parse_type(session);
/* execute callbacks */
ssh_packet_process(session, session->in_packet.type);
session->packet_state = PACKET_STATE_INIT;
if(processed < receivedlen){
int rc;
/* Handle a potential packet left in socket buffer */
ssh_log(session,SSH_LOG_PACKET,"Processing %" PRIdS " bytes left in socket buffer",
receivedlen-processed);
rc = ssh_packet_socket_callback1((char *)data + processed,
receivedlen - processed,user);
processed += rc;
}
return processed;
case PACKET_STATE_PROCESSING:
ssh_log(session, SSH_LOG_RARE, "Nested packet processing. Delaying.");
return 0;
}
error:
session->session_state=SSH_SESSION_STATE_ERROR;
return processed;
}
int packet_send1(ssh_session session) {
unsigned int blocksize = (session->current_crypto ?
session->current_crypto->out_cipher->blocksize : 8);
uint32_t currentlen = ssh_buffer_get_len(session->out_buffer) + sizeof(uint32_t);
char padstring[32] = {0};
int rc = SSH_ERROR;
uint32_t finallen;
uint32_t crc;
uint8_t padding;
ssh_log(session,SSH_LOG_PACKET,"Sending a %d bytes long packet",currentlen);
/* TODO FIXME
#if defined(HAVE_LIBZ) && defined(WITH_LIBZ)
if (session->current_crypto && session->current_crypto->do_compress_out) {
if (compress_buffer(session, session->out_buffer) < 0) {
goto error;
}
currentlen = buffer_get_len(session->out_buffer);
}
#endif
*/
padding = blocksize - (currentlen % blocksize);
if (session->current_crypto) {
ssh_get_random(padstring, padding, 0);
} else {
memset(padstring, 0, padding);
}
finallen = htonl(currentlen);
ssh_log(session, SSH_LOG_PACKET,
"%d bytes after comp + %d padding bytes = %d bytes packet",
currentlen, padding, ntohl(finallen));
if (buffer_prepend_data(session->out_buffer, &padstring, padding) < 0) {
goto error;
}
if (buffer_prepend_data(session->out_buffer, &finallen, sizeof(uint32_t)) < 0) {
goto error;
}
crc = ssh_crc32((char *)ssh_buffer_get_begin(session->out_buffer) + sizeof(uint32_t),
ssh_buffer_get_len(session->out_buffer) - sizeof(uint32_t));
if (buffer_add_u32(session->out_buffer, ntohl(crc)) < 0) {
goto error;
}
#ifdef DEBUG_CRYPTO
ssh_print_hexa("Clear packet", ssh_buffer_get_begin(session->out_buffer),
ssh_buffer_get_len(session->out_buffer));
#endif
packet_encrypt(session, (unsigned char *)ssh_buffer_get_begin(session->out_buffer) + sizeof(uint32_t),
ssh_buffer_get_len(session->out_buffer) - sizeof(uint32_t));
#ifdef DEBUG_CRYPTO
ssh_print_hexa("encrypted packet",ssh_buffer_get_begin(session->out_buffer),
ssh_buffer_get_len(session->out_buffer));
#endif
rc=ssh_socket_write(session->socket, ssh_buffer_get_begin(session->out_buffer),
ssh_buffer_get_len(session->out_buffer));
if(rc== SSH_ERROR) {
goto error;
}
session->send_seq++;
if (buffer_reinit(session->out_buffer) < 0) {
rc = SSH_ERROR;
}
error:
return rc; /* SSH_OK, AGAIN or ERROR */
}
/* channel_select base main loop, with a standard select(2)
*/
static void select_loop(ssh_session session,ssh_channel channel){
fd_set fds;
struct timeval timeout;
char buffer[4096];
ssh_buffer readbuf=ssh_buffer_new();
ssh_channel channels[2];
int lus;
int eof=0;
int maxfd;
int ret;
while(channel){
/* when a signal is caught, ssh_select will return
* with SSH_EINTR, which means it should be started
* again. It lets you handle the signal the faster you
* can, like in this window changed example. Of course, if
* your signal handler doesn't call libssh at all, you're
* free to handle signals directly in sighandler.
*/
do{
FD_ZERO(&fds);
if(!eof)
FD_SET(0,&fds);
timeout.tv_sec=30;
timeout.tv_usec=0;
FD_SET(ssh_get_fd(session),&fds);
maxfd=ssh_get_fd(session)+1;
ret=select(maxfd,&fds,NULL,NULL,&timeout);
if(ret==EINTR)
continue;
if(FD_ISSET(0,&fds)){
lus=read(0,buffer,sizeof(buffer));
if(lus)
ssh_channel_write(channel,buffer,lus);
else {
eof=1;
ssh_channel_send_eof(channel);
}
}
if(FD_ISSET(ssh_get_fd(session),&fds)){
ssh_set_fd_toread(session);
}
channels[0]=channel; // set the first channel we want to read from
channels[1]=NULL;
ret=ssh_channel_select(channels,NULL,NULL,NULL); // no specific timeout - just poll
if(signal_delayed)
sizechanged();
} while (ret==EINTR || ret==SSH_EINTR);
// we already looked for input from stdin. Now, we are looking for input from the channel
if(channel && ssh_channel_is_closed(channel)){
ssh_channel_free(channel);
channel=NULL;
channels[0]=NULL;
}
if(channels[0]){
while(channel && ssh_channel_is_open(channel) && ssh_channel_poll(channel,0)>0){
lus=channel_read_buffer(channel,readbuf,0,0);
if(lus==-1){
fprintf(stderr, "Error reading channel: %s\n",
ssh_get_error(session));
return;
}
if(lus==0){
ssh_channel_free(channel);
channel=channels[0]=NULL;
} else
if (write(1,ssh_buffer_get_begin(readbuf),lus) < 0) {
fprintf(stderr, "Error writing to buffer\n");
return;
}
}
while(channel && ssh_channel_is_open(channel) && ssh_channel_poll(channel,1)>0){ /* stderr */
lus=channel_read_buffer(channel,readbuf,0,1);
if(lus==-1){
fprintf(stderr, "Error reading channel: %s\n",
ssh_get_error(session));
return;
}
if(lus==0){
ssh_channel_free(channel);
channel=channels[0]=NULL;
} else
if (write(2,ssh_buffer_get_begin(readbuf),lus) < 0) {
fprintf(stderr, "Error writing to buffer\n");
return;
}
}
}
if(channel && ssh_channel_is_closed(channel)){
ssh_channel_free(channel);
channel=NULL;
}
}
ssh_buffer_free(readbuf);
}
ssh_string ssh_pki_openssh_privkey_export(const ssh_key privkey,
const char *passphrase,
ssh_auth_callback auth_fn,
void *auth_data)
{
ssh_buffer buffer;
ssh_string str = NULL;
ssh_string pubkey_s=NULL;
ssh_buffer privkey_buffer = NULL;
uint32_t rnd;
uint32_t rounds = 16;
ssh_string salt=NULL;
ssh_string kdf_options=NULL;
int to_encrypt=0;
unsigned char *b64;
uint32_t str_len, len;
int rc;
if (privkey == NULL) {
return NULL;
}
if (privkey->type != SSH_KEYTYPE_ED25519){
ssh_pki_log("Unsupported key type %s", privkey->type_c);
return NULL;
}
if (passphrase != NULL || auth_fn != NULL){
ssh_pki_log("Enabling encryption for private key export");
to_encrypt = 1;
}
buffer = ssh_buffer_new();
pubkey_s = pki_publickey_to_blob(privkey);
if(buffer == NULL || pubkey_s == NULL){
goto error;
}
ssh_get_random(&rnd, sizeof(rnd), 0);
privkey_buffer = ssh_buffer_new();
if (privkey_buffer == NULL) {
goto error;
}
/* checkint1 & 2 */
rc = ssh_buffer_pack(privkey_buffer,
"dd",
rnd,
rnd);
if (rc == SSH_ERROR){
goto error;
}
rc = pki_openssh_export_privkey_blob(privkey, privkey_buffer);
if (rc == SSH_ERROR){
goto error;
}
/* comment */
rc = ssh_buffer_pack(privkey_buffer, "s", "" /* comment */);
if (rc == SSH_ERROR){
goto error;
}
if (to_encrypt){
ssh_buffer kdf_buf;
kdf_buf = ssh_buffer_new();
if (kdf_buf == NULL) {
goto error;
}
salt = ssh_string_new(16);
if (salt == NULL){
ssh_buffer_free(kdf_buf);
goto error;
}
ssh_get_random(ssh_string_data(salt),16, 0);
ssh_buffer_pack(kdf_buf, "Sd", salt, rounds);
kdf_options = ssh_string_new(ssh_buffer_get_len(kdf_buf));
if (kdf_options == NULL){
ssh_buffer_free(kdf_buf);
goto error;
}
memcpy(ssh_string_data(kdf_options),
ssh_buffer_get_begin(kdf_buf),
ssh_buffer_get_len(kdf_buf));
ssh_buffer_free(kdf_buf);
rc = pki_private_key_encrypt(privkey_buffer,
passphrase,
"aes128-cbc",
"bcrypt",
auth_fn,
auth_data,
rounds,
salt);
if (rc != SSH_OK){
goto error;
}
} else {
kdf_options = ssh_string_new(0);
}
rc = ssh_buffer_pack(buffer,
"PssSdSdP",
(size_t)strlen(OPENSSH_AUTH_MAGIC) + 1, OPENSSH_AUTH_MAGIC,
to_encrypt ? "aes128-cbc" : "none", /* ciphername */
to_encrypt ? "bcrypt" : "none", /* kdfname */
kdf_options, /* kdfoptions */
(uint32_t) 1, /* nkeys */
pubkey_s,
(uint32_t)ssh_buffer_get_len(privkey_buffer),
/* rest of buffer is a string */
(size_t)ssh_buffer_get_len(privkey_buffer), ssh_buffer_get_begin(privkey_buffer));
if (rc != SSH_OK) {
goto error;
}
b64 = bin_to_base64(ssh_buffer_get_begin(buffer),
ssh_buffer_get_len(buffer));
if (b64 == NULL){
goto error;
}
/* we can reuse the buffer */
ssh_buffer_reinit(buffer);
rc = ssh_buffer_pack(buffer,
"tttttt",
OPENSSH_HEADER_BEGIN,
"\n",
b64,
"\n",
OPENSSH_HEADER_END,
"\n");
BURN_BUFFER(b64, strlen((char *)b64));
SAFE_FREE(b64);
if (rc != SSH_OK){
goto error;
}
str = ssh_string_new(ssh_buffer_get_len(buffer));
if (str == NULL){
goto error;
}
str_len = ssh_buffer_get_len(buffer);
len = buffer_get_data(buffer, ssh_string_data(str), str_len);
if (str_len != len) {
ssh_string_free(str);
str = NULL;
}
error:
if (privkey_buffer != NULL) {
void *bufptr = ssh_buffer_get_begin(privkey_buffer);
BURN_BUFFER(bufptr, ssh_buffer_get_len(privkey_buffer));
ssh_buffer_free(privkey_buffer);
}
SAFE_FREE(pubkey_s);
SAFE_FREE(kdf_options);
SAFE_FREE(salt);
if (buffer != NULL) {
ssh_buffer_free(buffer);
}
return str;
}
/** @internal
* @brief encrypts an ed25519 private key blob
*
*/
static int pki_private_key_encrypt(ssh_buffer privkey_buffer,
const char* passphrase,
const char *ciphername,
const char *kdfname,
ssh_auth_callback auth_fn,
void *auth_data,
uint32_t rounds,
ssh_string salt)
{
struct ssh_cipher_struct *ciphers = ssh_get_ciphertab();
struct ssh_cipher_struct cipher;
uint8_t key_material[128];
size_t key_material_len;
char passphrase_buffer[128];
int rc;
int i;
uint8_t padding = 1;
int cmp;
cmp = strcmp(ciphername, "none");
if (cmp == 0){
/* no encryption required */
return SSH_OK;
}
for (i = 0; ciphers[i].name != NULL; i++) {
cmp = strcmp(ciphername, ciphers[i].name);
if (cmp == 0){
memcpy(&cipher, &ciphers[i], sizeof(cipher));
break;
}
}
if (ciphers[i].name == NULL){
SSH_LOG(SSH_LOG_WARN, "Unsupported cipher %s", ciphername);
return SSH_ERROR;
}
cmp = strcmp(kdfname, "bcrypt");
if (cmp != 0){
SSH_LOG(SSH_LOG_WARN, "Unsupported KDF %s", kdfname);
return SSH_ERROR;
}
while (ssh_buffer_get_len(privkey_buffer) % cipher.blocksize != 0) {
rc = buffer_add_u8(privkey_buffer, padding);
if (rc < 0) {
return SSH_ERROR;
}
padding++;
}
/* We need material for key (keysize bits / 8) and IV (blocksize) */
key_material_len = cipher.keysize/8 + cipher.blocksize;
if (key_material_len > sizeof(key_material)){
ssh_pki_log("Key material too big");
return SSH_ERROR;
}
ssh_pki_log("Encryption: %d key, %d IV, %d rounds, %zu bytes salt",
cipher.keysize/8,
cipher.blocksize, rounds, ssh_string_len(salt));
if (passphrase == NULL){
if (auth_fn == NULL){
ssh_pki_log("No passphrase provided");
return SSH_ERROR;
}
rc = auth_fn("Passphrase",
passphrase_buffer,
sizeof(passphrase_buffer),
0,
0,
auth_data);
if (rc != SSH_OK){
return SSH_ERROR;
}
passphrase = passphrase_buffer;
}
rc = bcrypt_pbkdf(passphrase,
strlen(passphrase),
ssh_string_data(salt),
ssh_string_len(salt),
key_material,
key_material_len,
rounds);
if (rc < 0){
return SSH_ERROR;
}
cipher.set_encrypt_key(&cipher,
key_material,
key_material + cipher.keysize/8);
cipher.encrypt(&cipher,
ssh_buffer_get_begin(privkey_buffer),
ssh_buffer_get_begin(privkey_buffer),
ssh_buffer_get_len(privkey_buffer));
ssh_cipher_clear(&cipher);
BURN_BUFFER(passphrase_buffer, sizeof(passphrase_buffer));
return SSH_OK;
}
void *buffer_get(ssh_buffer buffer){
return ssh_buffer_get_begin(buffer);
}
