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, buffer_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 (ssh_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(SSH_LOG_PACKET, "Reading a %d bytes packet", len);
session->in_packet.len = len;
session->packet_state = PACKET_STATE_SIZEREAD;
/* FALL THROUGH */
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 (ssh_buffer_add_data(session->in_buffer,packet,to_be_read) < 0) {
goto error;
}
processed += to_be_read;
#ifdef DEBUG_CRYPTO
ssh_print_hexa("read packet:", ssh_buffer_get(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
*/
buffer_len = ssh_buffer_get_len(session->in_buffer);
if (buffer_len > 0) {
int rc;
rc = ssh_packet_decrypt(session,
ssh_buffer_get(session->in_buffer),
buffer_len);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL, "Packet decrypt error");
goto error;
}
}
}
#ifdef DEBUG_CRYPTO
ssh_print_hexa("read packet decrypted:", ssh_buffer_get(session->in_buffer),
ssh_buffer_get_len(session->in_buffer));
#endif
SSH_LOG(SSH_LOG_PACKET, "%d bytes padding", padding);
if(((len + padding) != ssh_buffer_get_len(session->in_buffer)) ||
((len + padding) < sizeof(uint32_t))) {
SSH_LOG(SSH_LOG_RARE, "no crc32 in packet");
ssh_set_error(session, SSH_FATAL, "no crc32 in packet");
goto error;
}
memcpy(&crc,
(unsigned char *)ssh_buffer_get(session->in_buffer) + (len+padding) - sizeof(uint32_t),
sizeof(uint32_t));
ssh_buffer_pass_bytes_end(session->in_buffer, sizeof(uint32_t));
crc = ntohl(crc);
if (ssh_crc32(ssh_buffer_get(session->in_buffer),
(len + padding) - sizeof(uint32_t)) != crc) {
#ifdef DEBUG_CRYPTO
ssh_print_hexa("crc32 on",ssh_buffer_get(session->in_buffer),
len + padding - sizeof(uint32_t));
#endif
SSH_LOG(SSH_LOG_RARE, "Invalid crc32");
ssh_set_error(session, SSH_FATAL,
"Invalid crc32: expected %.8x, got %.8x",
crc,
ssh_crc32(ssh_buffer_get(session->in_buffer),
len + padding - sizeof(uint32_t)));
goto error;
}
/* pass the padding */
ssh_buffer_pass_bytes(session->in_buffer, padding);
SSH_LOG(SSH_LOG_PACKET, "The packet is valid");
/* TODO FIXME
#ifdef WITH_ZLIB
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(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(SSH_LOG_PACKET, "Nested packet processing. Delaying.");
return 0;
}
error:
session->session_state=SSH_SESSION_STATE_ERROR;
return processed;
}
/** \internal
* \brief starts a nonblocking flush of the output buffer
*
*/
int ssh_socket_nonblocking_flush(ssh_socket s) {
ssh_session session = s->session;
uint32_t len;
int w;
if (!ssh_socket_is_open(s)) {
session->alive = 0;
if(s->callbacks && s->callbacks->exception){
s->callbacks->exception(
SSH_SOCKET_EXCEPTION_ERROR,
s->last_errno,s->callbacks->userdata);
}else{
ssh_set_error(session, SSH_FATAL,
"Writing packet: error on socket (or connection closed): %s",
strerror(s->last_errno));
}
return SSH_ERROR;
}
len = ssh_buffer_get_len(s->out_buffer);
if (!s->write_wontblock && s->poll_out && len > 0) {
/* force the poll system to catch pollout events */
ssh_poll_add_events(s->poll_out, POLLOUT);
return SSH_AGAIN;
}
if (s->write_wontblock && len > 0) {
w = ssh_socket_unbuffered_write(s, ssh_buffer_get(s->out_buffer), len);
if (w < 0) {
session->alive = 0;
ssh_socket_close(s);
if(s->callbacks && s->callbacks->exception){
s->callbacks->exception(
SSH_SOCKET_EXCEPTION_ERROR,
s->last_errno,s->callbacks->userdata);
}else{
ssh_set_error(session, SSH_FATAL,
"Writing packet: error on socket (or connection closed): %s",
strerror(s->last_errno));
}
return SSH_ERROR;
}
ssh_buffer_pass_bytes(s->out_buffer, w);
if (s->session->socket_counter != NULL) {
s->session->socket_counter->out_bytes += w;
}
}
/* Is there some data pending? */
len = ssh_buffer_get_len(s->out_buffer);
if (s->poll_out && len > 0) {
/* force the poll system to catch pollout events */
ssh_poll_add_events(s->poll_out, POLLOUT);
return SSH_AGAIN;
}
/* all data written */
return SSH_OK;
}
/** @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);
unsigned int lenfield_blocksize = (session->current_crypto ?
session->current_crypto->in_cipher->lenfield_blocksize : 8);
size_t current_macsize = 0;
uint8_t *ptr = NULL;
int to_be_read;
int rc;
uint8_t *cleartext_packet = NULL;
uint8_t *packet_second_block = NULL;
uint8_t *mac = NULL;
size_t packet_remaining;
uint32_t packet_len, compsize, payloadsize;
uint8_t padding;
size_t processed = 0; /* number of byte processed from the callback */
if(session->current_crypto != NULL) {
current_macsize = hmac_digest_len(session->current_crypto->in_hmac);
}
if (lenfield_blocksize == 0) {
lenfield_blocksize = blocksize;
}
if (data == NULL) {
goto error;
}
if (session->session_state == SSH_SESSION_STATE_ERROR) {
goto error;
}
#ifdef DEBUG_PACKET
SSH_LOG(SSH_LOG_PACKET,
"rcv packet cb (len=%zu, state=%s)",
receivedlen,
session->packet_state == PACKET_STATE_INIT ?
"INIT" :
session->packet_state == PACKET_STATE_SIZEREAD ?
"SIZE_READ" :
session->packet_state == PACKET_STATE_PROCESSING ?
"PROCESSING" : "unknown");
#endif
switch(session->packet_state) {
case PACKET_STATE_INIT:
if (receivedlen < lenfield_blocksize) {
/*
* We didn't receive enough data to read at least one
* block size, give up
*/
#ifdef DEBUG_PACKET
SSH_LOG(SSH_LOG_PACKET,
"Waiting for more data (%zu < %u)",
receivedlen,
lenfield_blocksize);
#endif
return 0;
}
memset(&session->in_packet, 0, sizeof(PACKET));
if (session->in_buffer) {
rc = ssh_buffer_reinit(session->in_buffer);
if (rc < 0) {
goto error;
}
} else {
session->in_buffer = ssh_buffer_new();
if (session->in_buffer == NULL) {
goto error;
}
}
ptr = ssh_buffer_allocate(session->in_buffer, lenfield_blocksize);
if (ptr == NULL) {
goto error;
}
processed += lenfield_blocksize;
packet_len = ssh_packet_decrypt_len(session, ptr, (uint8_t *)data);
if (packet_len > MAX_PACKET_LEN) {
ssh_set_error(session,
SSH_FATAL,
"read_packet(): Packet len too high(%u %.4x)",
packet_len, packet_len);
goto error;
}
to_be_read = packet_len - lenfield_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;
}
session->in_packet.len = packet_len;
session->packet_state = PACKET_STATE_SIZEREAD;
FALL_THROUGH;
case PACKET_STATE_SIZEREAD:
packet_len = session->in_packet.len;
processed = lenfield_blocksize;
to_be_read = packet_len + sizeof(uint32_t) + current_macsize;
/* if to_be_read is zero, the whole packet was blocksize bytes. */
if (to_be_read != 0) {
if (receivedlen < (unsigned int)to_be_read) {
/* give up, not enough data in buffer */
SSH_LOG(SSH_LOG_PACKET,
"packet: partial packet (read len) "
"[len=%d, receivedlen=%d, to_be_read=%d]",
packet_len,
(int)receivedlen,
to_be_read);
return 0;
}
packet_second_block = (uint8_t*)data + lenfield_blocksize;
processed = to_be_read - current_macsize;
}
/* remaining encrypted bytes from the packet, MAC not included */
packet_remaining =
packet_len - (lenfield_blocksize - sizeof(uint32_t));
cleartext_packet = ssh_buffer_allocate(session->in_buffer,
packet_remaining);
if (session->current_crypto) {
/*
* Decrypt the rest of the packet (lenfield_blocksize bytes already
* have been decrypted)
*/
if (packet_remaining > 0) {
rc = ssh_packet_decrypt(session,
cleartext_packet,
(uint8_t *)data,
lenfield_blocksize,
processed - lenfield_blocksize);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL, "Decryption error");
goto error;
}
}
mac = packet_second_block + packet_remaining;
rc = ssh_packet_hmac_verify(session, session->in_buffer, mac, session->current_crypto->in_hmac);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL, "HMAC error");
goto error;
}
processed += current_macsize;
} else {
memcpy(cleartext_packet, packet_second_block, packet_remaining);
}
/* skip the size field which has been processed before */
ssh_buffer_pass_bytes(session->in_buffer, sizeof(uint32_t));
rc = ssh_buffer_get_u8(session->in_buffer, &padding);
if (rc == 0) {
ssh_set_error(session,
SSH_FATAL,
"Packet too short to read padding");
goto error;
}
if (padding > ssh_buffer_get_len(session->in_buffer)) {
ssh_set_error(session,
SSH_FATAL,
"Invalid padding: %d (%d left)",
padding,
ssh_buffer_get_len(session->in_buffer));
goto error;
}
ssh_buffer_pass_bytes_end(session->in_buffer, padding);
compsize = ssh_buffer_get_len(session->in_buffer);
#ifdef WITH_ZLIB
if (session->current_crypto
&& session->current_crypto->do_compress_in
&& ssh_buffer_get_len(session->in_buffer) > 0) {
rc = decompress_buffer(session, session->in_buffer,MAX_PACKET_LEN);
if (rc < 0) {
goto error;
}
}
#endif /* WITH_ZLIB */
payloadsize = ssh_buffer_get_len(session->in_buffer);
session->recv_seq++;
if (session->raw_counter != NULL) {
session->raw_counter->in_bytes += payloadsize;
session->raw_counter->in_packets++;
}
/*
* 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);
SSH_LOG(SSH_LOG_PACKET,
"packet: read type %hhd [len=%d,padding=%hhd,comp=%d,payload=%d]",
session->in_packet.type, packet_len, padding, compsize, payloadsize);
/* 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(SSH_LOG_PACKET,
"Processing %" PRIdS " bytes left in socket buffer",
receivedlen-processed);
ptr = ((uint8_t*)data) + processed;
rc = ssh_packet_socket_callback(ptr, receivedlen - processed,user);
processed += rc;
}
return processed;
case PACKET_STATE_PROCESSING:
SSH_LOG(SSH_LOG_PACKET, "Nested packet processing. Delaying.");
return 0;
}
ssh_set_error(session,
SSH_FATAL,
"Invalid state into packet_read2(): %d",
session->packet_state);
error:
session->session_state= SSH_SESSION_STATE_ERROR;
SSH_LOG(SSH_LOG_PACKET,"Packet: processed %" PRIdS " bytes", processed);
return processed;
}
/**
* @brief SSH poll callback. This callback will be used when an event
* caught on the socket.
*
* @param p Poll object this callback belongs to.
* @param fd The raw socket.
* @param revents The current poll events on the socket.
* @param userdata Userdata to be passed to the callback function,
* in this case the socket object.
*
* @return 0 on success, < 0 when the poll object has been removed
* from its poll context.
*/
int ssh_socket_pollcallback(struct ssh_poll_handle_struct *p, socket_t fd,
int revents, void *v_s) {
ssh_socket s = (ssh_socket)v_s;
char buffer[MAX_BUF_SIZE];
int r;
int err = 0;
socklen_t errlen = sizeof(err);
/* Do not do anything if this socket was already closed */
if (!ssh_socket_is_open(s)) {
return -1;
}
SSH_LOG(SSH_LOG_TRACE, "Poll callback on socket %d (%s%s%s), out buffer %d",fd,
(revents & POLLIN) ? "POLLIN ":"",
(revents & POLLOUT) ? "POLLOUT ":"",
(revents & POLLERR) ? "POLLERR":"",
ssh_buffer_get_len(s->out_buffer));
if (revents & POLLERR || revents & POLLHUP) {
/* Check if we are in a connecting state */
if (s->state == SSH_SOCKET_CONNECTING) {
s->state = SSH_SOCKET_ERROR;
r = getsockopt(fd, SOL_SOCKET, SO_ERROR, (char *)&err, &errlen);
if (r < 0) {
err = errno;
}
s->last_errno = err;
ssh_socket_close(s);
if (s->callbacks && s->callbacks->connected) {
s->callbacks->connected(SSH_SOCKET_CONNECTED_ERROR, err,
s->callbacks->userdata);
}
return -1;
}
/* Then we are in a more standard kind of error */
/* force a read to get an explanation */
revents |= POLLIN;
}
if ((revents & POLLIN) && s->state == SSH_SOCKET_CONNECTED) {
s->read_wontblock = 1;
r = ssh_socket_unbuffered_read(s, buffer, sizeof(buffer));
if (r < 0) {
if (p != NULL) {
ssh_poll_remove_events(p, POLLIN);
}
if (s->callbacks && s->callbacks->exception) {
s->callbacks->exception(SSH_SOCKET_EXCEPTION_ERROR,
s->last_errno, s->callbacks->userdata);
/* p may have been freed, so don't use it
* anymore in this function */
p = NULL;
return -2;
}
}
if (r == 0) {
if (p != NULL) {
ssh_poll_remove_events(p, POLLIN);
}
if (p != NULL) {
ssh_poll_remove_events(p, POLLIN);
}
if (s->callbacks && s->callbacks->exception) {
s->callbacks->exception(SSH_SOCKET_EXCEPTION_EOF,
0, s->callbacks->userdata);
/* p may have been freed, so don't use it
* anymore in this function */
p = NULL;
return -2;
}
}
if (r > 0) {
if (s->session->socket_counter != NULL) {
s->session->socket_counter->in_bytes += r;
}
/* Bufferize the data and then call the callback */
r = ssh_buffer_add_data(s->in_buffer, buffer, r);
if (r < 0) {
return -1;
}
if (s->callbacks && s->callbacks->data) {
do {
r = s->callbacks->data(ssh_buffer_get(s->in_buffer),
ssh_buffer_get_len(s->in_buffer),
s->callbacks->userdata);
ssh_buffer_pass_bytes(s->in_buffer, r);
} while ((r > 0) && (s->state == SSH_SOCKET_CONNECTED));
/* p may have been freed, so don't use it
* anymore in this function */
p = NULL;
}
}
}
#ifdef _WIN32
if (revents & POLLOUT || revents & POLLWRNORM) {
#else
if (revents & POLLOUT) {
#endif
/* First, POLLOUT is a sign we may be connected */
if (s->state == SSH_SOCKET_CONNECTING) {
SSH_LOG(SSH_LOG_PACKET, "Received POLLOUT in connecting state");
s->state = SSH_SOCKET_CONNECTED;
if (p != NULL) {
ssh_poll_set_events(p, POLLOUT | POLLIN);
}
r = ssh_socket_set_blocking(ssh_socket_get_fd_in(s));
if (r < 0) {
return -1;
}
if (s->callbacks && s->callbacks->connected) {
s->callbacks->connected(SSH_SOCKET_CONNECTED_OK, 0,
s->callbacks->userdata);
}
return 0;
}
/* So, we can write data */
s->write_wontblock=1;
if (p != NULL) {
ssh_poll_remove_events(p, POLLOUT);
}
/* If buffered data is pending, write it */
if (ssh_buffer_get_len(s->out_buffer) > 0) {
ssh_socket_nonblocking_flush(s);
} else if (s->callbacks && s->callbacks->controlflow) {
/* Otherwise advertise the upper level that write can be done */
SSH_LOG(SSH_LOG_TRACE,"sending control flow event");
s->callbacks->controlflow(SSH_SOCKET_FLOW_WRITEWONTBLOCK,
s->callbacks->userdata);
}
/* TODO: Find a way to put back POLLOUT when buffering occurs */
}
/* Return -1 if one of the poll handlers disappeared */
return (s->poll_in == NULL || s->poll_out == NULL) ? -1 : 0;
}
/** @internal
* @brief returns the input poll handle corresponding to the socket,
* creates it if it does not exist.
* @returns allocated and initialized ssh_poll_handle object
*/
ssh_poll_handle ssh_socket_get_poll_handle_in(ssh_socket s){
if(s->poll_in)
return s->poll_in;
s->poll_in=ssh_poll_new(s->fd_in,0,ssh_socket_pollcallback,s);
if(s->fd_in == s->fd_out && s->poll_out == NULL)
s->poll_out=s->poll_in;
return s->poll_in;
}
/** @internal
* @brief returns the output poll handle corresponding to the socket,
* creates it if it does not exist.
* @returns allocated and initialized ssh_poll_handle object
*/
ssh_poll_handle ssh_socket_get_poll_handle_out(ssh_socket s){
if(s->poll_out)
return s->poll_out;
s->poll_out=ssh_poll_new(s->fd_out,0,ssh_socket_pollcallback,s);
if(s->fd_in == s->fd_out && s->poll_in == NULL)
s->poll_in=s->poll_out;
return s->poll_out;
}
/** \internal
* \brief Deletes a socket object
*/
void ssh_socket_free(ssh_socket s){
if (s == NULL) {
return;
}
ssh_socket_close(s);
ssh_buffer_free(s->in_buffer);
ssh_buffer_free(s->out_buffer);
SAFE_FREE(s);
}
#ifndef _WIN32
int ssh_socket_unix(ssh_socket s, const char *path) {
struct sockaddr_un sunaddr;
socket_t fd;
sunaddr.sun_family = AF_UNIX;
snprintf(sunaddr.sun_path, sizeof(sunaddr.sun_path), "%s", path);
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd == SSH_INVALID_SOCKET) {
ssh_set_error(s->session, SSH_FATAL,
"Error from socket(AF_UNIX, SOCK_STREAM, 0): %s",
strerror(errno));
return -1;
}
if (fcntl(fd, F_SETFD, 1) == -1) {
ssh_set_error(s->session, SSH_FATAL,
"Error from fcntl(fd, F_SETFD, 1): %s",
strerror(errno));
close(fd);
return -1;
}
if (connect(fd, (struct sockaddr *) &sunaddr,
sizeof(sunaddr)) < 0) {
ssh_set_error(s->session, SSH_FATAL, "Error from connect(): %s",
strerror(errno));
close(fd);
return -1;
}
ssh_socket_set_fd(s,fd);
return 0;
}
#endif
/** \internal
* \brief closes a socket
*/
void ssh_socket_close(ssh_socket s){
if (ssh_socket_is_open(s)) {
#ifdef _WIN32
CLOSE_SOCKET(s->fd_in);
/* fd_in = fd_out under win32 */
s->last_errno = WSAGetLastError();
#else
if (s->fd_out != s->fd_in && s->fd_out != -1) {
CLOSE_SOCKET(s->fd_out);
}
CLOSE_SOCKET(s->fd_in);
s->last_errno = errno;
#endif
}
if(s->poll_in != NULL){
if(s->poll_out == s->poll_in)
s->poll_out = NULL;
ssh_poll_free(s->poll_in);
s->poll_in=NULL;
}
if(s->poll_out != NULL){
ssh_poll_free(s->poll_out);
s->poll_out=NULL;
}
s->state = SSH_SOCKET_CLOSED;
}
/**
* @internal
* @brief sets the file descriptor of the socket.
* @param[out] s ssh_socket to update
* @param[in] fd file descriptor to set
* @warning this function updates boths the input and output
* file descriptors
*/
void ssh_socket_set_fd(ssh_socket s, socket_t fd) {
s->fd_in = s->fd_out = fd;
if (s->poll_in) {
ssh_poll_set_fd(s->poll_in,fd);
} else {
s->state = SSH_SOCKET_CONNECTING;
/* POLLOUT is the event to wait for in a nonblocking connect */
ssh_poll_set_events(ssh_socket_get_poll_handle_in(s), POLLOUT);
#ifdef _WIN32
ssh_poll_add_events(ssh_socket_get_poll_handle_in(s), POLLWRNORM);
#endif
}
}
/** @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);
unsigned char mac[DIGEST_MAX_LEN] = {0};
char buffer[16] = {0};
size_t current_macsize = 0;
const uint8_t *packet;
int to_be_read;
int rc;
uint32_t len, compsize, payloadsize;
uint8_t padding;
size_t processed = 0; /* number of byte processed from the callback */
if(session->current_crypto != NULL) {
current_macsize = hmac_digest_len(session->current_crypto->in_hmac);
}
if (data == NULL) {
goto error;
}
if (session->session_state == SSH_SESSION_STATE_ERROR) {
goto error;
}
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
*/
return 0;
}
memset(&session->in_packet, 0, sizeof(PACKET));
if (session->in_buffer) {
rc = ssh_buffer_reinit(session->in_buffer);
if (rc < 0) {
goto error;
}
} else {
session->in_buffer = ssh_buffer_new();
if (session->in_buffer == NULL) {
goto error;
}
}
memcpy(buffer, data, blocksize);
processed += blocksize;
len = ssh_packet_decrypt_len(session, buffer);
rc = ssh_buffer_add_data(session->in_buffer, buffer, blocksize);
if (rc < 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;
/* FALL TROUGH */
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 */
SSH_LOG(SSH_LOG_PACKET,"packet: partial packet (read len) [len=%d]",len);
return processed;
}
packet = ((uint8_t*)data) + processed;
#if 0
ssh_socket_read(session->socket,
packet,
to_be_read - current_macsize);
#endif
rc = ssh_buffer_add_data(session->in_buffer,
packet,
to_be_read - current_macsize);
if (rc < 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)
*/
uint32_t buffer_len = ssh_buffer_get_len(session->in_buffer);
/* The following check avoids decrypting zero bytes */
if (buffer_len > blocksize) {
uint8_t *payload = ((uint8_t*)ssh_buffer_get(session->in_buffer) + blocksize);
uint32_t plen = buffer_len - blocksize;
rc = ssh_packet_decrypt(session, payload, plen);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL, "Decrypt error");
goto error;
}
}
/* copy the last part from the incoming buffer */
packet = ((uint8_t *)data) + processed;
memcpy(mac, packet, current_macsize);
rc = ssh_packet_hmac_verify(session, session->in_buffer, mac, session->current_crypto->in_hmac);
if (rc < 0) {
ssh_set_error(session, SSH_FATAL, "HMAC error");
goto error;
}
processed += current_macsize;
}
/* skip the size field which has been processed before */
ssh_buffer_pass_bytes(session->in_buffer, sizeof(uint32_t));
rc = ssh_buffer_get_u8(session->in_buffer, &padding);
if (rc == 0) {
ssh_set_error(session,
SSH_FATAL,
"Packet too short to read padding");
goto error;
}
if (padding > ssh_buffer_get_len(session->in_buffer)) {
ssh_set_error(session,
SSH_FATAL,
"Invalid padding: %d (%d left)",
padding,
ssh_buffer_get_len(session->in_buffer));
goto error;
}
ssh_buffer_pass_bytes_end(session->in_buffer, padding);
compsize = ssh_buffer_get_len(session->in_buffer);
#ifdef WITH_ZLIB
if (session->current_crypto
&& session->current_crypto->do_compress_in
&& ssh_buffer_get_len(session->in_buffer) > 0) {
rc = decompress_buffer(session, session->in_buffer,MAX_PACKET_LEN);
if (rc < 0) {
goto error;
}
}
#endif /* WITH_ZLIB */
payloadsize = ssh_buffer_get_len(session->in_buffer);
session->recv_seq++;
if (session->raw_counter != NULL) {
session->raw_counter->in_bytes += payloadsize;
session->raw_counter->in_packets++;
}
/*
* 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);
SSH_LOG(SSH_LOG_PACKET,
"packet: read type %hhd [len=%d,padding=%hhd,comp=%d,payload=%d]",
session->in_packet.type, len, padding, compsize, payloadsize);
/* 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(SSH_LOG_PACKET,
"Processing %" PRIdS " bytes left in socket buffer",
receivedlen-processed);
packet = ((uint8_t*)data) + processed;
rc = ssh_packet_socket_callback(packet, receivedlen - processed,user);
processed += rc;
}
return processed;
case PACKET_STATE_PROCESSING:
SSH_LOG(SSH_LOG_PACKET, "Nested packet processing. Delaying.");
return 0;
}
ssh_set_error(session,
SSH_FATAL,
"Invalid state into packet_read2(): %d",
session->packet_state);
error:
session->session_state= SSH_SESSION_STATE_ERROR;
return processed;
}