static int post_rpc(struct rpc_state *rpc)
{
struct active_request_slot *slot;
struct curl_slist *headers = http_copy_default_headers();
int use_gzip = rpc->gzip_request;
char *gzip_body = NULL;
size_t gzip_size = 0;
int err, large_request = 0;
int needs_100_continue = 0;
/* Try to load the entire request, if we can fit it into the
* allocated buffer space we can use HTTP/1.0 and avoid the
* chunked encoding mess.
*/
while (1) {
size_t left = rpc->alloc - rpc->len;
char *buf = rpc->buf + rpc->len;
int n;
if (left < LARGE_PACKET_MAX) {
large_request = 1;
use_gzip = 0;
break;
}
n = packet_read(rpc->out, NULL, NULL, buf, left, 0);
if (!n)
break;
rpc->len += n;
}
if (large_request) {
struct slot_results results;
do {
err = probe_rpc(rpc, &results);
if (err == HTTP_REAUTH)
credential_fill(&http_auth);
} while (err == HTTP_REAUTH);
if (err != HTTP_OK)
return -1;
if (results.auth_avail & CURLAUTH_GSSNEGOTIATE)
needs_100_continue = 1;
}
headers = curl_slist_append(headers, rpc->hdr_content_type);
headers = curl_slist_append(headers, rpc->hdr_accept);
headers = curl_slist_append(headers, needs_100_continue ?
"Expect: 100-continue" : "Expect:");
/* Add the extra Git-Protocol header */
if (rpc->protocol_header)
headers = curl_slist_append(headers, rpc->protocol_header);
retry:
slot = get_active_slot();
curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
curl_easy_setopt(slot->curl, CURLOPT_URL, rpc->service_url);
curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "gzip");
if (large_request) {
/* The request body is large and the size cannot be predicted.
* We must use chunked encoding to send it.
*/
headers = curl_slist_append(headers, "Transfer-Encoding: chunked");
rpc->initial_buffer = 1;
curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, rpc_out);
curl_easy_setopt(slot->curl, CURLOPT_INFILE, rpc);
#ifndef NO_CURL_IOCTL
curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, rpc_ioctl);
curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, rpc);
#endif
if (options.verbosity > 1) {
fprintf(stderr, "POST %s (chunked)\n", rpc->service_name);
fflush(stderr);
}
} else if (gzip_body) {
/*
* If we are looping to retry authentication, then the previous
* run will have set up the headers and gzip buffer already,
* and we just need to send it.
*/
curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, gzip_body);
curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE_LARGE, xcurl_off_t(gzip_size));
} else if (use_gzip && 1024 < rpc->len) {
/* The client backend isn't giving us compressed data so
* we can try to deflate it ourselves, this may save on.
* the transfer time.
*/
git_zstream stream;
int ret;
git_deflate_init_gzip(&stream, Z_BEST_COMPRESSION);
gzip_size = git_deflate_bound(&stream, rpc->len);
gzip_body = xmalloc(gzip_size);
stream.next_in = (unsigned char *)rpc->buf;
stream.avail_in = rpc->len;
stream.next_out = (unsigned char *)gzip_body;
stream.avail_out = gzip_size;
ret = git_deflate(&stream, Z_FINISH);
if (ret != Z_STREAM_END)
die("cannot deflate request; zlib deflate error %d", ret);
ret = git_deflate_end_gently(&stream);
if (ret != Z_OK)
die("cannot deflate request; zlib end error %d", ret);
gzip_size = stream.total_out;
headers = curl_slist_append(headers, "Content-Encoding: gzip");
curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, gzip_body);
curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE_LARGE, xcurl_off_t(gzip_size));
if (options.verbosity > 1) {
fprintf(stderr, "POST %s (gzip %lu to %lu bytes)\n",
rpc->service_name,
(unsigned long)rpc->len, (unsigned long)gzip_size);
fflush(stderr);
}
} else {
/* We know the complete request size in advance, use the
* more normal Content-Length approach.
*/
curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, rpc->buf);
curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE_LARGE, xcurl_off_t(rpc->len));
if (options.verbosity > 1) {
fprintf(stderr, "POST %s (%lu bytes)\n",
rpc->service_name, (unsigned long)rpc->len);
fflush(stderr);
}
}
curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, rpc_in);
curl_easy_setopt(slot->curl, CURLOPT_FILE, rpc);
rpc->any_written = 0;
err = run_slot(slot, NULL);
if (err == HTTP_REAUTH && !large_request) {
credential_fill(&http_auth);
goto retry;
}
if (err != HTTP_OK)
err = -1;
if (!rpc->any_written)
err = -1;
curl_slist_free_all(headers);
free(gzip_body);
return err;
}
/*
* Performs the interactive session. This handles data transmission between
* the client and the program. Note that the notion of stdin, stdout, and
* stderr in this function is sort of reversed: this function writes to
* stdin (of the child program), and reads from stdout and stderr (of the
* child program).
*/
void
server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
{
fd_set *readset = NULL, *writeset = NULL;
int max_fd = 0;
u_int nalloc = 0;
int wait_status; /* Status returned by wait(). */
pid_t wait_pid; /* pid returned by wait(). */
int waiting_termination = 0; /* Have displayed waiting close message. */
u_int max_time_milliseconds;
u_int previous_stdout_buffer_bytes;
u_int stdout_buffer_bytes;
int type;
debug("Entering interactive session.");
/* Initialize the SIGCHLD kludge. */
child_terminated = 0;
signal(SIGCHLD, sigchld_handler);
if (!use_privsep) {
signal(SIGTERM, sigterm_handler);
signal(SIGINT, sigterm_handler);
signal(SIGQUIT, sigterm_handler);
}
/* Initialize our global variables. */
fdin = fdin_arg;
fdout = fdout_arg;
fderr = fderr_arg;
/* nonblocking IO */
set_nonblock(fdin);
set_nonblock(fdout);
/* we don't have stderr for interactive terminal sessions, see below */
if (fderr != -1)
set_nonblock(fderr);
if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
fdin_is_tty = 1;
connection_in = packet_get_connection_in();
connection_out = packet_get_connection_out();
notify_setup();
previous_stdout_buffer_bytes = 0;
/* Set approximate I/O buffer size. */
if (packet_is_interactive())
buffer_high = 4096;
else
buffer_high = 64 * 1024;
#if 0
/* Initialize max_fd to the maximum of the known file descriptors. */
max_fd = MAX(connection_in, connection_out);
max_fd = MAX(max_fd, fdin);
max_fd = MAX(max_fd, fdout);
if (fderr != -1)
max_fd = MAX(max_fd, fderr);
#endif
/* Initialize Initialize buffers. */
buffer_init(&stdin_buffer);
buffer_init(&stdout_buffer);
buffer_init(&stderr_buffer);
/*
* If we have no separate fderr (which is the case when we have a pty
* - there we cannot make difference between data sent to stdout and
* stderr), indicate that we have seen an EOF from stderr. This way
* we don't need to check the descriptor everywhere.
*/
if (fderr == -1)
fderr_eof = 1;
server_init_dispatch();
/* Main loop of the server for the interactive session mode. */
for (;;) {
/* Process buffered packets from the client. */
process_buffered_input_packets();
/*
* If we have received eof, and there is no more pending
* input data, cause a real eof by closing fdin.
*/
if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
if (fdin != fdout)
close(fdin);
else
shutdown(fdin, SHUT_WR); /* We will no longer send. */
fdin = -1;
}
/* Make packets from buffered stderr data to send to the client. */
make_packets_from_stderr_data();
/*
* Make packets from buffered stdout data to send to the
* client. If there is very little to send, this arranges to
* not send them now, but to wait a short while to see if we
* are getting more data. This is necessary, as some systems
* wake up readers from a pty after each separate character.
*/
max_time_milliseconds = 0;
stdout_buffer_bytes = buffer_len(&stdout_buffer);
if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
stdout_buffer_bytes != previous_stdout_buffer_bytes) {
/* try again after a while */
max_time_milliseconds = 10;
} else {
/* Send it now. */
make_packets_from_stdout_data();
}
previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
/* Send channel data to the client. */
if (packet_not_very_much_data_to_write())
channel_output_poll();
/*
* Bail out of the loop if the program has closed its output
* descriptors, and we have no more data to send to the
* client, and there is no pending buffered data.
*/
if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
if (!channel_still_open())
break;
if (!waiting_termination) {
const char *s = "Waiting for forwarded connections to terminate...\r\n";
char *cp;
waiting_termination = 1;
buffer_append(&stderr_buffer, s, strlen(s));
/* Display list of open channels. */
cp = channel_open_message();
buffer_append(&stderr_buffer, cp, strlen(cp));
xfree(cp);
}
}
max_fd = MAX(connection_in, connection_out);
max_fd = MAX(max_fd, fdin);
max_fd = MAX(max_fd, fdout);
max_fd = MAX(max_fd, fderr);
max_fd = MAX(max_fd, notify_pipe[0]);
/* Sleep in select() until we can do something. */
wait_until_can_do_something(&readset, &writeset, &max_fd,
&nalloc, max_time_milliseconds);
if (received_sigterm) {
logit("Exiting on signal %d", received_sigterm);
/* Clean up sessions, utmp, etc. */
cleanup_exit(255);
}
/* Process any channel events. */
channel_after_select(readset, writeset);
/* Process input from the client and from program stdout/stderr. */
process_input(readset);
/* Process output to the client and to program stdin. */
process_output(writeset);
}
if (readset)
xfree(readset);
if (writeset)
xfree(writeset);
/* Cleanup and termination code. */
/* Wait until all output has been sent to the client. */
drain_output();
debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
/* Free and clear the buffers. */
buffer_free(&stdin_buffer);
buffer_free(&stdout_buffer);
buffer_free(&stderr_buffer);
/* Close the file descriptors. */
if (fdout != -1)
close(fdout);
fdout = -1;
fdout_eof = 1;
if (fderr != -1)
close(fderr);
fderr = -1;
fderr_eof = 1;
if (fdin != -1)
close(fdin);
fdin = -1;
channel_free_all();
/* We no longer want our SIGCHLD handler to be called. */
signal(SIGCHLD, SIG_DFL);
while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
if (errno != EINTR)
packet_disconnect("wait: %.100s", strerror(errno));
if (wait_pid != pid)
error("Strange, wait returned pid %ld, expected %ld",
(long)wait_pid, (long)pid);
/* Check if it exited normally. */
if (WIFEXITED(wait_status)) {
/* Yes, normal exit. Get exit status and send it to the client. */
debug("Command exited with status %d.", WEXITSTATUS(wait_status));
packet_start(SSH_SMSG_EXITSTATUS);
packet_put_int(WEXITSTATUS(wait_status));
packet_send();
packet_write_wait();
/*
* Wait for exit confirmation. Note that there might be
* other packets coming before it; however, the program has
* already died so we just ignore them. The client is
* supposed to respond with the confirmation when it receives
* the exit status.
*/
do {
type = packet_read();
}
while (type != SSH_CMSG_EXIT_CONFIRMATION);
debug("Received exit confirmation.");
return;
}
/* Check if the program terminated due to a signal. */
if (WIFSIGNALED(wait_status))
packet_disconnect("Command terminated on signal %d.",
WTERMSIG(wait_status));
/* Some weird exit cause. Just exit. */
packet_disconnect("wait returned status %04x.", wait_status);
/* NOTREACHED */
}
/*
* read packets, try to authenticate the user and
* return only if authentication is successful
*/
static void
do_authloop(Authctxt *authctxt)
{
int authenticated = 0;
char info[1024];
int type = 0;
const struct AuthMethod1 *meth;
debug("Attempting authentication for %s%.100s.",
authctxt->valid ? "" : "invalid user ", authctxt->user);
/* If the user has no password, accept authentication immediately. */
if (options.password_authentication &&
#ifdef KRB5
(!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif
PRIVSEP(auth_password(authctxt, ""))) {
auth_log(authctxt, 1, "without authentication", "");
return;
}
/* Indicate that authentication is needed. */
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
for (;;) {
/* default to fail */
authenticated = 0;
info[0] = '\0';
/* Get a packet from the client. */
type = packet_read();
if (authctxt->failures >= options.max_authtries)
goto skip;
if ((meth = lookup_authmethod1(type)) == NULL) {
logit("Unknown message during authentication: "
"type %d", type);
goto skip;
}
if (!*(meth->enabled)) {
verbose("%s authentication disabled.", meth->name);
goto skip;
}
authenticated = meth->method(authctxt, info, sizeof(info));
if (authenticated == -1)
continue; /* "postponed" */
if (authctxt->as) {
auth_close(authctxt->as);
authctxt->as = NULL;
}
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
/* Special handling for root */
if (authenticated && authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(meth->name))
authenticated = 0;
skip:
/* Log before sending the reply */
auth_log(authctxt, authenticated, get_authname(type), info);
if (authenticated)
return;
if (++authctxt->failures >= options.max_authtries)
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
}
}
/*
* read packets, try to authenticate the user and
* return only if authentication is successful
*/
static void
do_authloop(Authctxt *authctxt)
{
int authenticated = 0;
u_int bits;
Key *client_host_key;
BIGNUM *n;
char *client_user, *password;
char info[1024];
u_int dlen;
u_int ulen;
int prev, type = 0;
struct passwd *pw = authctxt->pw;
debug("Attempting authentication for %s%.100s.",
authctxt->valid ? "" : "illegal user ", authctxt->user);
/* If the user has no password, accept authentication immediately. */
if (options.password_authentication &&
#ifdef KRB5
(!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif
PRIVSEP(auth_password(authctxt, ""))) {
auth_log(authctxt, 1, "without authentication", "");
return;
}
/* Indicate that authentication is needed. */
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
client_user = NULL;
for (;;) {
/* default to fail */
authenticated = 0;
info[0] = '\0';
/* Get a packet from the client. */
prev = type;
type = packet_read();
/*
* If we started challenge-response authentication but the
* next packet is not a response to our challenge, release
* the resources allocated by get_challenge() (which would
* normally have been released by verify_response() had we
* received such a response)
*/
if (prev == SSH_CMSG_AUTH_TIS &&
type != SSH_CMSG_AUTH_TIS_RESPONSE)
abandon_challenge_response(authctxt);
/* Process the packet. */
switch (type) {
case SSH_CMSG_AUTH_RHOSTS_RSA:
if (!options.rhosts_rsa_authentication) {
verbose("Rhosts with RSA authentication disabled.");
break;
}
/*
* Get client user name. Note that we just have to
* trust the client; root on the client machine can
* claim to be any user.
*/
client_user = packet_get_string(&ulen);
/* Get the client host key. */
client_host_key = key_new(KEY_RSA1);
bits = packet_get_int();
packet_get_bignum(client_host_key->rsa->e);
packet_get_bignum(client_host_key->rsa->n);
if (bits != BN_num_bits(client_host_key->rsa->n))
verbose("Warning: keysize mismatch for client_host_key: "
"actual %d, announced %d",
BN_num_bits(client_host_key->rsa->n), bits);
packet_check_eom();
authenticated = auth_rhosts_rsa(pw, client_user,
client_host_key);
key_free(client_host_key);
snprintf(info, sizeof info, " ruser %.100s", client_user);
break;
case SSH_CMSG_AUTH_RSA:
if (!options.rsa_authentication) {
verbose("RSA authentication disabled.");
break;
}
/* RSA authentication requested. */
if ((n = BN_new()) == NULL)
fatal("do_authloop: BN_new failed");
packet_get_bignum(n);
packet_check_eom();
authenticated = auth_rsa(pw, n);
BN_clear_free(n);
break;
case SSH_CMSG_AUTH_PASSWORD:
if (!options.password_authentication) {
verbose("Password authentication disabled.");
break;
}
/*
* Read user password. It is in plain text, but was
* transmitted over the encrypted channel so it is
* not visible to an outside observer.
*/
password = packet_get_string(&dlen);
packet_check_eom();
/* Try authentication with the password. */
authenticated = PRIVSEP(auth_password(authctxt, password));
memset(password, 0, strlen(password));
xfree(password);
break;
case SSH_CMSG_AUTH_TIS:
debug("rcvd SSH_CMSG_AUTH_TIS");
if (options.challenge_response_authentication == 1) {
char *challenge = get_challenge(authctxt);
if (challenge != NULL) {
debug("sending challenge '%s'", challenge);
packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
packet_put_cstring(challenge);
xfree(challenge);
packet_send();
packet_write_wait();
continue;
}
}
break;
case SSH_CMSG_AUTH_TIS_RESPONSE:
debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
if (options.challenge_response_authentication == 1) {
char *response = packet_get_string(&dlen);
packet_check_eom();
authenticated = verify_response(authctxt, response);
memset(response, 'r', dlen);
xfree(response);
}
break;
default:
/*
* Any unknown messages will be ignored (and failure
* returned) during authentication.
*/
logit("Unknown message during authentication: type %d", type);
break;
}
#ifdef BSD_AUTH
if (authctxt->as) {
auth_close(authctxt->as);
authctxt->as = NULL;
}
#endif
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
#ifdef _UNICOS
if (authenticated && cray_access_denied(authctxt->user)) {
authenticated = 0;
fatal("Access denied for user %s.",authctxt->user);
}
#endif /* _UNICOS */
#ifdef HAVE_CYGWIN
if (authenticated &&
!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD, pw)) {
packet_disconnect("Authentication rejected for uid %d.",
pw == NULL ? -1 : pw->pw_uid);
authenticated = 0;
}
#else
/* Special handling for root */
if (authenticated && authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(get_authname(type)))
authenticated = 0;
#endif
#ifdef USE_PAM
if (options.use_pam && authenticated &&
!PRIVSEP(do_pam_account()))
authenticated = 0;
#endif
#ifdef SECURITY_COUNTS
access__attempted(!authenticated, authctxt->user);
#endif
/* Log before sending the reply */
auth_log(authctxt, authenticated, get_authname(type), info);
if (client_user != NULL) {
xfree(client_user);
client_user = NULL;
}
if (authenticated)
return;
if (authctxt->failures++ > AUTH_FAIL_MAX)
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
}
}
static int wait_auth_status(ssh_session session, int kbdint) {
char *auth_methods = NULL;
ssh_string auth;
int rc = SSH_AUTH_ERROR;
int cont = 1;
uint8_t partial = 0;
enter_function();
while (cont) {
if (packet_read(session) != SSH_OK) {
break;
}
if (packet_translate(session) != SSH_OK) {
break;
}
switch (session->in_packet.type) {
case SSH2_MSG_USERAUTH_FAILURE:
auth = buffer_get_ssh_string(session->in_buffer);
if (auth == NULL || buffer_get_u8(session->in_buffer, &partial) != 1) {
ssh_set_error(session, SSH_FATAL,
"Invalid SSH_MSG_USERAUTH_FAILURE message");
leave_function();
return SSH_AUTH_ERROR;
}
auth_methods = string_to_char(auth);
if (auth_methods == NULL) {
ssh_set_error(session, SSH_FATAL,
"Not enough space");
string_free(auth);
leave_function();
return SSH_AUTH_ERROR;
}
if (partial) {
rc = SSH_AUTH_PARTIAL;
ssh_set_error(session, SSH_NO_ERROR,
"Partial success. Authentication that can continue: %s",
auth_methods);
} else {
rc = SSH_AUTH_DENIED;
ssh_set_error(session, SSH_REQUEST_DENIED,
"Access denied. Authentication that can continue: %s",
auth_methods);
session->auth_methods = 0;
if (strstr(auth_methods, "password") != NULL) {
session->auth_methods |= SSH_AUTH_METHOD_PASSWORD;
}
if (strstr(auth_methods, "keyboard-interactive") != NULL) {
session->auth_methods |= SSH_AUTH_METHOD_INTERACTIVE;
}
if (strstr(auth_methods, "publickey") != NULL) {
session->auth_methods |= SSH_AUTH_METHOD_PUBLICKEY;
}
if (strstr(auth_methods, "hostbased") != NULL) {
session->auth_methods |= SSH_AUTH_METHOD_HOSTBASED;
}
}
string_free(auth);
SAFE_FREE(auth_methods);
cont = 0;
break;
case SSH2_MSG_USERAUTH_PK_OK:
/* SSH monkeys have defined the same number for both */
/* SSH_MSG_USERAUTH_PK_OK and SSH_MSG_USERAUTH_INFO_REQUEST */
/* which is not really smart; */
/*case SSH2_MSG_USERAUTH_INFO_REQUEST: */
if (kbdint) {
rc = SSH_AUTH_INFO;
cont = 0;
break;
}
/* continue through success */
case SSH2_MSG_USERAUTH_SUCCESS:
rc = SSH_AUTH_SUCCESS;
cont = 0;
break;
case SSH2_MSG_USERAUTH_BANNER:
{
ssh_string banner;
banner = buffer_get_ssh_string(session->in_buffer);
if (banner == NULL) {
ssh_log(session, SSH_LOG_PACKET,
"The banner message was invalid. Continuing though\n");
break;
}
ssh_log(session, SSH_LOG_PACKET,
"Received a message banner\n");
string_free(session->banner); /* erase the older one */
session->banner = banner;
break;
}
default:
packet_parse(session);
break;
}
}
leave_function();
return rc;
}
void do_authenticated(char *pw)
{
int type;
int compression_level = 0, enable_compression_after_reply = 0;
int row, col, xpixel, ypixel;
unsigned long max_size;
char *display = NULL, *proto = NULL, *data = NULL;
/* Cancel the alarm we set to limit the time taken for authentication. */
alarm(0);
/* Inform the channel mechanism that we are the server side and that
the client may request to connect to any port at all. (The user could
do it anyway, and we wouldn\'t know what is permitted except by the
client telling us, so we can equally well trust the client not to request
anything bogus.) */
/* We stay in this loop until the client requests to execute a shell or a
command. */
while (1) {
/* Get a packet from the client. */
type = packet_read();
/* Process the packet. */
switch (type) {
case SSH_CMSG_REQUEST_COMPRESSION:
/* COMMAN: k core said that compression is not useful */
goto fail;
compression_level = packet_get_int();
if (compression_level < 1 || compression_level > 9) {
packet_send_debug("Received illegal compression level %d.", compression_level);
goto fail;
}
/* Enable compression after we have responded with SUCCESS. */
enable_compression_after_reply = 1;
break;
case SSH_CMSG_MAX_PACKET_SIZE:
/* Get maximum size from paket. */
max_size = packet_get_int();
/* Make sure that it is acceptable. */
if (max_size < 4096 || max_size > 256 * 1024) {
packet_send_debug("Received illegal max packet size %lu.", max_size);
goto fail;
}
/* Set the size and return success. */
packet_set_max_size(max_size);
break;
case SSH_CMSG_REQUEST_PTY:
packet_get_string(NULL);
row = packet_get_int();
col = packet_get_int();
xpixel = packet_get_int();
ypixel = packet_get_int();
do_naws(row, col);
packet_get_all();
debug("Allocating a pty not permitted for this authentication.");
break;
case SSH_CMSG_X11_REQUEST_FORWARDING:
packet_get_all();
debug("X11 forwarding disabled in this site.");
packet_send_debug("X11 forwarding disabled in this site.");
goto fail;
case SSH_CMSG_AGENT_REQUEST_FORWARDING:
packet_get_all();
debug("Authentication agent forwarding not permitted for this authentication.");
goto fail;
case SSH_CMSG_PORT_FORWARD_REQUEST:
packet_get_all();
debug("All port forwardings disabled in this site.");
packet_send_debug("All port forwardings disabled in this site.");
goto fail;
case SSH_CMSG_EXEC_SHELL:
/* Set interactive/non-interactive mode. */
packet_set_interactive(1, options.keepalives);
if (forced_command != NULL)
goto do_forced_command;
debug("Forking shell.");
do_exec_no_pty(NULL, pw, display, proto, data);
return;
case SSH_CMSG_EXEC_CMD:
packet_get_all();
debug("command executing disabled in this site.");
packet_send_debug("command executing disabled in this site.");
goto fail;
case SSH_CMSG_WINDOW_SIZE:
debug("Window change received.");
row = packet_get_int();
col = packet_get_int();
xpixel = packet_get_int();
ypixel = packet_get_int();
do_naws(row, col);
break;
default:
/* Any unknown messages in this phase are ignored, and a failure
message is returned. */
packet_get_all();
log_msg("Unknown packet type received after authentication: %d", type);
goto fail;
}
/* The request was successfully processed. */
packet_start(SSH_SMSG_SUCCESS);
packet_send();
packet_write_wait();
/* Enable compression now that we have replied if appropriate. */
if (enable_compression_after_reply) {
enable_compression_after_reply = 0;
packet_start_compression(compression_level);
}
continue;
fail:
/* The request failed. */
packet_get_all();
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
continue;
do_forced_command:
/* There is a forced command specified for this login. Execute it. */
debug("Executing forced command: %.900s", forced_command);
return;
}
}
/*
* Checks if the user has an authentication agent, and if so, tries to
* authenticate using the agent.
*/
static int
try_agent_authentication(void)
{
int type;
char *comment;
AuthenticationConnection *auth;
u_char response[16];
u_int i;
Key *key;
BIGNUM *challenge;
/* Get connection to the agent. */
auth = ssh_get_authentication_connection();
if (!auth)
return 0;
if ((challenge = BN_new()) == NULL)
fatal("try_agent_authentication: BN_new failed");
/* Loop through identities served by the agent. */
for (key = ssh_get_first_identity(auth, &comment, 1);
key != NULL;
key = ssh_get_next_identity(auth, &comment, 1)) {
/* Try this identity. */
debug("Trying RSA authentication via agent with '%.100s'", comment);
xfree(comment);
/* Tell the server that we are willing to authenticate using this key. */
packet_start(SSH_CMSG_AUTH_RSA);
packet_put_bignum(key->rsa->n);
packet_send();
packet_write_wait();
/* Wait for server's response. */
type = packet_read();
/* The server sends failure if it doesn\'t like our key or
does not support RSA authentication. */
if (type == SSH_SMSG_FAILURE) {
debug("Server refused our key.");
key_free(key);
continue;
}
/* Otherwise it should have sent a challenge. */
if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
packet_disconnect("Protocol error during RSA authentication: %d",
type);
packet_get_bignum(challenge);
packet_check_eom();
debug("Received RSA challenge from server.");
/* Ask the agent to decrypt the challenge. */
if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) {
/*
* The agent failed to authenticate this identifier
* although it advertised it supports this. Just
* return a wrong value.
*/
logit("Authentication agent failed to decrypt challenge.");
memset(response, 0, sizeof(response));
}
key_free(key);
debug("Sending response to RSA challenge.");
/* Send the decrypted challenge back to the server. */
packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
for (i = 0; i < 16; i++)
packet_put_char(response[i]);
packet_send();
packet_write_wait();
/* Wait for response from the server. */
type = packet_read();
/* The server returns success if it accepted the authentication. */
if (type == SSH_SMSG_SUCCESS) {
ssh_close_authentication_connection(auth);
BN_clear_free(challenge);
debug("RSA authentication accepted by server.");
return 1;
}
/* Otherwise it should return failure. */
if (type != SSH_SMSG_FAILURE)
packet_disconnect("Protocol error waiting RSA auth response: %d",
type);
}
ssh_close_authentication_connection(auth);
BN_clear_free(challenge);
debug("RSA authentication using agent refused.");
return 0;
}
/*
* read packets, try to authenticate the user and
* return only if authentication is successful
*/
static void
do_authloop(Authctxt *authctxt)
{
int authenticated = 0;
int prev = 0, type = 0;
const struct AuthMethod1 *meth;
debug("Attempting authentication for %s%.100s.",
authctxt->valid ? "" : "invalid user ", authctxt->user);
/* If the user has no password, accept authentication immediately. */
if (options.permit_empty_passwd && options.password_authentication &&
#ifdef KRB5
(!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif
PRIVSEP(auth_password(authctxt, ""))) {
#ifdef USE_PAM
if (options.use_pam && (PRIVSEP(do_pam_account())))
#endif
{
auth_log(authctxt, 1, 0, "without authentication",
NULL);
return;
}
}
/* Indicate that authentication is needed. */
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
for (;;) {
/* default to fail */
authenticated = 0;
/* Get a packet from the client. */
prev = type;
type = packet_read();
/*
* If we started challenge-response authentication but the
* next packet is not a response to our challenge, release
* the resources allocated by get_challenge() (which would
* normally have been released by verify_response() had we
* received such a response)
*/
if (prev == SSH_CMSG_AUTH_TIS &&
type != SSH_CMSG_AUTH_TIS_RESPONSE)
abandon_challenge_response(authctxt);
if (authctxt->failures >= options.max_authtries)
goto skip;
if ((meth = lookup_authmethod1(type)) == NULL) {
logit("Unknown message during authentication: "
"type %d", type);
goto skip;
}
if (!*(meth->enabled)) {
verbose("%s authentication disabled.", meth->name);
goto skip;
}
authenticated = meth->method(authctxt);
if (authenticated == -1)
continue; /* "postponed" */
#ifdef BSD_AUTH
if (authctxt->as) {
auth_close(authctxt->as);
authctxt->as = NULL;
}
#endif
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
#ifdef _UNICOS
if (authenticated && cray_access_denied(authctxt->user)) {
authenticated = 0;
fatal("Access denied for user %s.",authctxt->user);
}
#endif /* _UNICOS */
#ifndef HAVE_CYGWIN
/* Special handling for root */
if (authenticated && authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(meth->name)) {
authenticated = 0;
# ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
# endif
}
#endif
#ifdef USE_PAM
if (options.use_pam && authenticated &&
!PRIVSEP(do_pam_account())) {
char *msg;
size_t len;
error("Access denied for user %s by PAM account "
"configuration", authctxt->user);
len = buffer_len(&loginmsg);
buffer_append(&loginmsg, "\0", 1);
msg = buffer_ptr(&loginmsg);
/* strip trailing newlines */
if (len > 0)
while (len > 0 && msg[--len] == '\n')
msg[len] = '\0';
else
msg = "Access denied.";
packet_disconnect("%s", msg);
}
#endif
skip:
/* Log before sending the reply */
auth_log(authctxt, authenticated, 0, get_authname(type), NULL);
free(client_user);
client_user = NULL;
if (authenticated)
return;
if (++authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
auth_maxtries_exceeded(authctxt);
}
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
}
}
static int
ssh_session(void)
{
int type;
int interactive = 0;
int have_tty = 0;
struct winsize ws;
char *cp;
const char *display;
/* Enable compression if requested. */
if (options.compression) {
debug("Requesting compression at level %d.",
options.compression_level);
if (options.compression_level < 1 ||
options.compression_level > 9)
fatal("Compression level must be from 1 (fast) to "
"9 (slow, best).");
/* Send the request. */
packet_start(SSH_CMSG_REQUEST_COMPRESSION);
packet_put_int(options.compression_level);
packet_send();
packet_write_wait();
type = packet_read();
if (type == SSH_SMSG_SUCCESS)
packet_start_compression(options.compression_level);
else if (type == SSH_SMSG_FAILURE)
logit("Warning: Remote host refused compression.");
else
packet_disconnect("Protocol error waiting for "
"compression response.");
}
/* Allocate a pseudo tty if appropriate. */
if (tty_flag) {
debug("Requesting pty.");
/* Start the packet. */
packet_start(SSH_CMSG_REQUEST_PTY);
/* Store TERM in the packet. There is no limit on the
length of the string. */
cp = getenv("TERM");
if (!cp)
cp = "";
packet_put_cstring(cp);
/* Store window size in the packet. */
if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
memset(&ws, 0, sizeof(ws));
packet_put_int((u_int)ws.ws_row);
packet_put_int((u_int)ws.ws_col);
packet_put_int((u_int)ws.ws_xpixel);
packet_put_int((u_int)ws.ws_ypixel);
/* Store tty modes in the packet. */
tty_make_modes(fileno(stdin), NULL);
/* Send the packet, and wait for it to leave. */
packet_send();
packet_write_wait();
/* Read response from the server. */
type = packet_read();
if (type == SSH_SMSG_SUCCESS) {
interactive = 1;
have_tty = 1;
} else if (type == SSH_SMSG_FAILURE)
logit("Warning: Remote host failed or refused to "
"allocate a pseudo tty.");
else
packet_disconnect("Protocol error waiting for pty "
"request response.");
}
/* Request X11 forwarding if enabled and DISPLAY is set. */
display = getenv("DISPLAY");
if (options.forward_x11 && display != NULL) {
char *proto, *data;
/* Get reasonable local authentication information. */
client_x11_get_proto(display, options.xauth_location,
options.forward_x11_trusted, &proto, &data);
/* Request forwarding with authentication spoofing. */
debug("Requesting X11 forwarding with authentication "
"spoofing.");
x11_request_forwarding_with_spoofing(0, display, proto, data);
/* Read response from the server. */
type = packet_read();
if (type == SSH_SMSG_SUCCESS) {
interactive = 1;
} else if (type == SSH_SMSG_FAILURE) {
logit("Warning: Remote host denied X11 forwarding.");
} else {
packet_disconnect("Protocol error waiting for X11 "
"forwarding");
}
}
/* Tell the packet module whether this is an interactive session. */
packet_set_interactive(interactive);
/* Request authentication agent forwarding if appropriate. */
check_agent_present();
if (options.forward_agent) {
debug("Requesting authentication agent forwarding.");
auth_request_forwarding();
/* Read response from the server. */
type = packet_read();
packet_check_eom();
if (type != SSH_SMSG_SUCCESS)
logit("Warning: Remote host denied authentication agent forwarding.");
}
/* Initiate port forwardings. */
ssh_init_forwarding();
/* Execute a local command */
if (options.local_command != NULL &&
options.permit_local_command)
ssh_local_cmd(options.local_command);
/*
* If requested and we are not interested in replies to remote
* forwarding requests, then let ssh continue in the background.
*/
if (fork_after_authentication_flag &&
(!options.exit_on_forward_failure ||
options.num_remote_forwards == 0)) {
fork_after_authentication_flag = 0;
if (daemon(1, 1) < 0)
fatal("daemon() failed: %.200s", strerror(errno));
}
/*
* If a command was specified on the command line, execute the
* command now. Otherwise request the server to start a shell.
*/
if (buffer_len(&command) > 0) {
int len = buffer_len(&command);
if (len > 900)
len = 900;
debug("Sending command: %.*s", len,
(u_char *)buffer_ptr(&command));
packet_start(SSH_CMSG_EXEC_CMD);
packet_put_string(buffer_ptr(&command), buffer_len(&command));
packet_send();
packet_write_wait();
} else {
debug("Requesting shell.");
packet_start(SSH_CMSG_EXEC_SHELL);
packet_send();
packet_write_wait();
}
/* Enter the interactive session. */
return client_loop(have_tty, tty_flag ?
options.escape_char : SSH_ESCAPECHAR_NONE, 0);
}
static void
kex_choose_conf(Kex *kex)
{
Newkeys *newkeys;
char **my, **peer;
char **cprop, **sprop;
int nenc, nmac, ncomp;
u_int mode, ctos, need, authlen;
int first_kex_follows, type;
#ifdef NONE_CIPHER_ENABLED
int auth_flag;
#endif
my = kex_buf2prop(&kex->my, NULL);
peer = kex_buf2prop(&kex->peer, &first_kex_follows);
if (kex->server) {
cprop=peer;
sprop=my;
} else {
cprop=my;
sprop=peer;
}
/* Check whether server offers roaming */
if (!kex->server) {
char *roaming;
roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL);
if (roaming) {
kex->roaming = 1;
xfree(roaming);
}
}
/* Algorithm Negotiation */
#ifdef NONE_CIPHER_ENABLED
auth_flag = packet_get_authentication_state();
debug ("AUTH STATE is %d", auth_flag);
#endif
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = xcalloc(1, sizeof(*newkeys));
kex->newkeys[mode] = newkeys;
ctos = (!kex->server && mode == MODE_OUT) ||
(kex->server && mode == MODE_IN);
nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
choose_enc(&newkeys->enc, cprop[nenc], sprop[nenc]);
/* ignore mac for authenticated encryption */
authlen = cipher_authlen(newkeys->enc.cipher);
if (authlen == 0)
choose_mac(&newkeys->mac, cprop[nmac], sprop[nmac]);
choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
#ifdef NONE_CIPHER_ENABLED
debug("REQUESTED ENC.NAME is '%s'", newkeys->enc.name);
if (strcmp(newkeys->enc.name, "none") == 0) {
debug("Requesting NONE. Authflag is %d", auth_flag);
if (auth_flag == 1)
debug("None requested post authentication.");
else
fatal("Pre-authentication none cipher requests "
"are not allowed.");
}
#endif
debug("kex: %s %s %s %s",
ctos ? "client->server" : "server->client",
newkeys->enc.name,
authlen == 0 ? newkeys->mac.name : "<implicit>",
newkeys->comp.name);
}
choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
need = 0;
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = kex->newkeys[mode];
if (need < newkeys->enc.key_len)
need = newkeys->enc.key_len;
if (need < newkeys->enc.block_size)
need = newkeys->enc.block_size;
if (need < newkeys->enc.iv_len)
need = newkeys->enc.iv_len;
if (need < newkeys->mac.key_len)
need = newkeys->mac.key_len;
}
/* XXX need runden? */
kex->we_need = need;
/* ignore the next message if the proposals do not match */
if (first_kex_follows && !proposals_match(my, peer) &&
!(datafellows & SSH_BUG_FIRSTKEX)) {
type = packet_read();
debug2("skipping next packet (type %u)", type);
}
kex_prop_free(my);
kex_prop_free(peer);
}
void
kexgex_server(Kex *kex)
{
BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
Key *server_host_public, *server_host_private;
DH *dh;
u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
u_int sbloblen, klen, slen, hashlen;
int omin = -1, min = -1, omax = -1, max = -1, onbits = -1, nbits = -1;
int type, kout;
if (kex->load_host_public_key == NULL ||
kex->load_host_private_key == NULL)
fatal("Cannot load hostkey");
server_host_public = kex->load_host_public_key(kex->hostkey_type);
if (server_host_public == NULL)
fatal("Unsupported hostkey type %d", kex->hostkey_type);
server_host_private = kex->load_host_private_key(kex->hostkey_type);
if (server_host_private == NULL)
fatal("Missing private key for hostkey type %d",
kex->hostkey_type);
type = packet_read();
switch (type) {
case SSH2_MSG_KEX_DH_GEX_REQUEST:
debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
omin = min = packet_get_int();
onbits = nbits = packet_get_int();
omax = max = packet_get_int();
min = MAX(DH_GRP_MIN, min);
max = MIN(DH_GRP_MAX, max);
nbits = MAX(DH_GRP_MIN, nbits);
nbits = MIN(DH_GRP_MAX, nbits);
break;
case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD:
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received");
onbits = nbits = packet_get_int();
/* unused for old GEX */
omin = min = DH_GRP_MIN;
omax = max = DH_GRP_MAX;
break;
default:
fatal("protocol error during kex, no DH_GEX_REQUEST: %d", type);
}
packet_check_eom();
if (omax < omin || onbits < omin || omax < onbits)
fatal("DH_GEX_REQUEST, bad parameters: %d !< %d !< %d",
omin, onbits, omax);
/* Contact privileged parent */
dh = PRIVSEP(choose_dh(min, nbits, max));
if (dh == NULL)
packet_disconnect("Protocol error: no matching DH grp found");
debug("SSH2_MSG_KEX_DH_GEX_GROUP sent");
packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
packet_put_bignum2(dh->p);
packet_put_bignum2(dh->g);
packet_send();
/* flush */
packet_write_wait();
/* Compute our exchange value in parallel with the client */
dh_gen_key(dh, kex->we_need * 8);
debug("expecting SSH2_MSG_KEX_DH_GEX_INIT");
packet_read_expect(SSH2_MSG_KEX_DH_GEX_INIT);
/* key, cert */
if ((dh_client_pub = BN_new()) == NULL)
fatal("dh_client_pub == NULL");
packet_get_bignum2(dh_client_pub);
packet_check_eom();
#ifdef DEBUG_KEXDH
fprintf(stderr, "dh_client_pub= ");
BN_print_fp(stderr, dh_client_pub);
fprintf(stderr, "\n");
debug("bits %d", BN_num_bits(dh_client_pub));
#endif
#ifdef DEBUG_KEXDH
DHparams_print_fp(stderr, dh);
fprintf(stderr, "pub= ");
BN_print_fp(stderr, dh->pub_key);
fprintf(stderr, "\n");
#endif
if (!dh_pub_is_valid(dh, dh_client_pub))
packet_disconnect("bad client public DH value");
klen = DH_size(dh);
kbuf = xmalloc(klen);
if ((kout = DH_compute_key(kbuf, dh_client_pub, dh)) < 0)
fatal("DH_compute_key: failed");
#ifdef DEBUG_KEXDH
dump_digest("shared secret", kbuf, kout);
#endif
if ((shared_secret = BN_new()) == NULL)
fatal("kexgex_server: BN_new failed");
if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
fatal("kexgex_server: BN_bin2bn failed");
memset(kbuf, 0, klen);
xfree(kbuf);
key_to_blob(server_host_public, &server_host_key_blob, &sbloblen);
if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD)
omin = min = omax = max = -1;
/* calc H */
kexgex_hash(
kex->evp_md,
kex->client_version_string,
kex->server_version_string,
buffer_ptr(&kex->peer), buffer_len(&kex->peer),
buffer_ptr(&kex->my), buffer_len(&kex->my),
server_host_key_blob, sbloblen,
omin, onbits, omax,
dh->p, dh->g,
dh_client_pub,
dh->pub_key,
shared_secret,
&hash, &hashlen
);
BN_clear_free(dh_client_pub);
/* save session id := H */
if (kex->session_id == NULL) {
kex->session_id_len = hashlen;
kex->session_id = xmalloc(kex->session_id_len);
memcpy(kex->session_id, hash, kex->session_id_len);
}
/* sign H */
if (PRIVSEP(key_sign(server_host_private, &signature, &slen, hash,
hashlen)) < 0)
fatal("kexgex_server: key_sign failed");
/* destroy_sensitive_data(); */
/* send server hostkey, DH pubkey 'f' and singed H */
debug("SSH2_MSG_KEX_DH_GEX_REPLY sent");
packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
packet_put_string(server_host_key_blob, sbloblen);
packet_put_bignum2(dh->pub_key); /* f */
packet_put_string(signature, slen);
packet_send();
xfree(signature);
xfree(server_host_key_blob);
/* have keys, free DH */
DH_free(dh);
kex_derive_keys(kex, hash, hashlen, shared_secret);
BN_clear_free(shared_secret);
kex_finish(kex);
}
static void
kex_choose_conf(Kex *kex)
{
Newkeys *newkeys;
char **my, **peer;
char **cprop, **sprop;
int nenc, nmac, ncomp;
u_int mode, ctos, need;
int first_kex_follows, type;
my = kex_buf2prop(&kex->my, NULL);
peer = kex_buf2prop(&kex->peer, &first_kex_follows);
if (kex->server) {
cprop=peer;
sprop=my;
} else {
cprop=my;
sprop=peer;
}
/* Check whether server offers roaming */
if (!kex->server) {
char *roaming;
roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL);
if (roaming) {
kex->roaming = 1;
xfree(roaming);
}
}
/* Algorithm Negotiation */
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = xcalloc(1, sizeof(*newkeys));
kex->newkeys[mode] = newkeys;
ctos = (!kex->server && mode == MODE_OUT) ||
(kex->server && mode == MODE_IN);
nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
debug("kex: %s %s %s %s",
ctos ? "client->server" : "server->client",
newkeys->enc.name,
newkeys->mac.name,
newkeys->comp.name);
}
choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
need = 0;
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = kex->newkeys[mode];
if (need < newkeys->enc.key_len)
need = newkeys->enc.key_len;
if (need < newkeys->enc.block_size)
need = newkeys->enc.block_size;
if (need < newkeys->mac.key_len)
need = newkeys->mac.key_len;
}
/* XXX need runden? */
kex->we_need = need;
/* ignore the next message if the proposals do not match */
if (first_kex_follows && !proposals_match(my, peer) &&
!(datafellows & SSH_BUG_FIRSTKEX)) {
type = packet_read();
debug2("skipping next packet (type %u)", type);
}
kex_prop_free(my);
kex_prop_free(peer);
}
/*
* Checks if the user has an authentication agent, and if so, tries to
* authenticate using the agent.
*/
static int
try_agent_authentication(void)
{
int r, type, agent_fd, ret = 0;
u_char response[16];
size_t i;
BIGNUM *challenge;
struct ssh_identitylist *idlist = NULL;
/* Get connection to the agent. */
if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) {
if (r != SSH_ERR_AGENT_NOT_PRESENT)
debug("%s: ssh_get_authentication_socket: %s",
__func__, ssh_err(r));
return 0;
}
if ((challenge = BN_new()) == NULL)
fatal("try_agent_authentication: BN_new failed");
/* Loop through identities served by the agent. */
if ((r = ssh_fetch_identitylist(agent_fd, 1, &idlist)) != 0) {
if (r != SSH_ERR_AGENT_NO_IDENTITIES)
debug("%s: ssh_fetch_identitylist: %s",
__func__, ssh_err(r));
goto out;
}
for (i = 0; i < idlist->nkeys; i++) {
/* Try this identity. */
debug("Trying RSA authentication via agent with '%.100s'",
idlist->comments[i]);
/* Tell the server that we are willing to authenticate using this key. */
packet_start(SSH_CMSG_AUTH_RSA);
packet_put_bignum(idlist->keys[i]->rsa->n);
packet_send();
packet_write_wait();
/* Wait for server's response. */
type = packet_read();
/* The server sends failure if it doesn't like our key or
does not support RSA authentication. */
if (type == SSH_SMSG_FAILURE) {
debug("Server refused our key.");
continue;
}
/* Otherwise it should have sent a challenge. */
if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
packet_disconnect("Protocol error during RSA authentication: %d",
type);
packet_get_bignum(challenge);
packet_check_eom();
debug("Received RSA challenge from server.");
/* Ask the agent to decrypt the challenge. */
if ((r = ssh_decrypt_challenge(agent_fd, idlist->keys[i],
challenge, session_id, response)) != 0) {
/*
* The agent failed to authenticate this identifier
* although it advertised it supports this. Just
* return a wrong value.
*/
logit("Authentication agent failed to decrypt "
"challenge: %s", ssh_err(r));
explicit_bzero(response, sizeof(response));
}
debug("Sending response to RSA challenge.");
/* Send the decrypted challenge back to the server. */
packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
for (i = 0; i < 16; i++)
packet_put_char(response[i]);
packet_send();
packet_write_wait();
/* Wait for response from the server. */
type = packet_read();
/*
* The server returns success if it accepted the
* authentication.
*/
if (type == SSH_SMSG_SUCCESS) {
debug("RSA authentication accepted by server.");
ret = 1;
break;
} else if (type != SSH_SMSG_FAILURE)
packet_disconnect("Protocol error waiting RSA auth "
"response: %d", type);
}
if (ret != 1)
debug("RSA authentication using agent refused.");
out:
ssh_free_identitylist(idlist);
ssh_close_authentication_socket(agent_fd);
BN_clear_free(challenge);
return ret;
}
static int
try_krb4_authentication(void)
{
KTEXT_ST auth; /* Kerberos data */
char *reply;
char inst[INST_SZ];
char *realm;
CREDENTIALS cred;
int r, type;
socklen_t slen;
Key_schedule schedule;
u_long checksum, cksum;
MSG_DAT msg_data;
struct sockaddr_in local, foreign;
struct stat st;
/* Don't do anything if we don't have any tickets. */
if (stat(tkt_string(), &st) < 0)
return 0;
strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)),
INST_SZ);
realm = (char *)krb_realmofhost(get_canonical_hostname(1));
if (!realm) {
debug("Kerberos v4: no realm for %s", get_canonical_hostname(1));
return 0;
}
/* This can really be anything. */
checksum = (u_long)getpid();
r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum);
if (r != KSUCCESS) {
debug("Kerberos v4 krb_mk_req failed: %s", krb_err_txt[r]);
return 0;
}
/* Get session key to decrypt the server's reply with. */
r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred);
if (r != KSUCCESS) {
debug("get_cred failed: %s", krb_err_txt[r]);
return 0;
}
des_key_sched((des_cblock *) cred.session, schedule);
/* Send authentication info to server. */
packet_start(SSH_CMSG_AUTH_KERBEROS);
packet_put_string((char *) auth.dat, auth.length);
packet_send();
packet_write_wait();
/* Zero the buffer. */
(void) memset(auth.dat, 0, MAX_KTXT_LEN);
slen = sizeof(local);
memset(&local, 0, sizeof(local));
if (getsockname(packet_get_connection_in(),
(struct sockaddr *)&local, &slen) < 0)
debug("getsockname failed: %s", strerror(errno));
slen = sizeof(foreign);
memset(&foreign, 0, sizeof(foreign));
if (getpeername(packet_get_connection_in(),
(struct sockaddr *)&foreign, &slen) < 0) {
debug("getpeername failed: %s", strerror(errno));
cleanup_exit(255);
}
/* Get server reply. */
type = packet_read();
switch (type) {
case SSH_SMSG_FAILURE:
/* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
debug("Kerberos v4 authentication failed.");
return 0;
break;
case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
/* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
debug("Kerberos v4 authentication accepted.");
/* Get server's response. */
reply = packet_get_string((u_int *) &auth.length);
if (auth.length >= MAX_KTXT_LEN)
fatal("Kerberos v4: Malformed response from server");
memcpy(auth.dat, reply, auth.length);
free(reply);
packet_check_eom();
/*
* If his response isn't properly encrypted with the session
* key, and the decrypted checksum fails to match, he's
* bogus. Bail out.
*/
r = krb_rd_priv(auth.dat, auth.length, (void *)schedule,
&cred.session, &foreign, &local, &msg_data);
if (r != KSUCCESS) {
debug("Kerberos v4 krb_rd_priv failed: %s",
krb_err_txt[r]);
packet_disconnect("Kerberos v4 challenge failed!");
}
/* Fetch the (incremented) checksum that we supplied in the request. */
memcpy((char *)&cksum, (char *)msg_data.app_data,
sizeof(cksum));
cksum = ntohl(cksum);
/* If it matches, we're golden. */
if (cksum == checksum + 1) {
debug("Kerberos v4 challenge successful.");
return 1;
} else
packet_disconnect("Kerberos v4 challenge failed!");
break;
default:
packet_disconnect("Protocol error on Kerberos v4 response: %d", type);
}
return 0;
}
static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
{
const char *svc = rpc->service_name;
struct strbuf buf = STRBUF_INIT;
struct strbuf *preamble = rpc->stdin_preamble;
struct child_process client = CHILD_PROCESS_INIT;
int err = 0;
client.in = -1;
client.out = -1;
client.git_cmd = 1;
client.argv = rpc->argv;
if (start_command(&client))
exit(1);
if (preamble)
write_or_die(client.in, preamble->buf, preamble->len);
if (heads)
write_or_die(client.in, heads->buf, heads->len);
rpc->alloc = http_post_buffer;
rpc->buf = xmalloc(rpc->alloc);
rpc->in = client.in;
rpc->out = client.out;
strbuf_init(&rpc->result, 0);
strbuf_addf(&buf, "%s%s", url.buf, svc);
rpc->service_url = strbuf_detach(&buf, NULL);
strbuf_addf(&buf, "Content-Type: application/x-%s-request", svc);
rpc->hdr_content_type = strbuf_detach(&buf, NULL);
strbuf_addf(&buf, "Accept: application/x-%s-result", svc);
rpc->hdr_accept = strbuf_detach(&buf, NULL);
if (get_protocol_http_header(heads->version, &buf))
rpc->protocol_header = strbuf_detach(&buf, NULL);
else
rpc->protocol_header = NULL;
while (!err) {
int n = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
if (!n)
break;
rpc->pos = 0;
rpc->len = n;
err |= post_rpc(rpc);
}
close(client.in);
client.in = -1;
if (!err) {
strbuf_read(&rpc->result, client.out, 0);
} else {
char buf[4096];
for (;;)
if (xread(client.out, buf, sizeof(buf)) <= 0)
break;
}
close(client.out);
client.out = -1;
err |= finish_command(&client);
free(rpc->service_url);
free(rpc->hdr_content_type);
free(rpc->hdr_accept);
free(rpc->protocol_header);
free(rpc->buf);
strbuf_release(&buf);
return err;
}
int i, type, quit;
public = client_options.identity_keys[idx];
authfile = client_options.identity_files[idx];
comment = xstrdup(authfile);
debug("Trying RSA authentication with key '%.100s'", comment);
/* Tell the server that we are willing to authenticate using this key. */
packet_start(SSH_CMSG_AUTH_RSA);
packet_put_bignum(public->rsa->n);
packet_send();
packet_write_wait();
/* Wait for server's response. */
type = packet_read();
/*
* The server responds with failure if it doesn\'t like our key or
* doesn\'t support RSA authentication.
*/
if (type == SSH_SMSG_FAILURE) {
debug("Server refused our key.");
xfree(comment);
return 0;
}
/* Otherwise, the server should respond with a challenge. */
if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
packet_disconnect("Protocol error during RSA authentication: %d", type);
/* Get the challenge from the packet. */
static int
roaming_resume(void)
{
u_int64_t recv_bytes;
char *str = NULL, *kexlist = NULL, *c;
int i, type;
int timeout_ms = options.connection_timeout * 1000;
u_int len;
u_int32_t rnd = 0;
resume_in_progress = 1;
/* Exchange banners */
ssh_exchange_identification(timeout_ms);
packet_set_nonblocking();
/* Send a kexinit message with [email protected] as only kex algo */
packet_start(SSH2_MSG_KEXINIT);
for (i = 0; i < KEX_COOKIE_LEN; i++) {
if (i % 4 == 0)
rnd = arc4random();
packet_put_char(rnd & 0xff);
rnd >>= 8;
}
packet_put_cstring(KEX_RESUME);
for (i = 1; i < PROPOSAL_MAX; i++) {
/* kex algorithm added so start with i=1 and not 0 */
packet_put_cstring(""); /* Not used when we resume */
}
packet_put_char(1); /* first kex_packet follows */
packet_put_int(0); /* reserved */
packet_send();
/* Assume that [email protected] will be accepted */
packet_start(SSH2_MSG_KEX_ROAMING_RESUME);
packet_put_int(roaming_id);
packet_send();
/* Read the server's kexinit and check for [email protected] */
if ((type = packet_read()) != SSH2_MSG_KEXINIT) {
debug("expected kexinit on resume, got %d", type);
goto fail;
}
for (i = 0; i < KEX_COOKIE_LEN; i++)
(void)packet_get_char();
kexlist = packet_get_string(&len);
if (!kexlist
|| (str = match_list(KEX_RESUME, kexlist, NULL)) == NULL) {
debug("server doesn't allow resume");
goto fail;
}
free(str);
for (i = 1; i < PROPOSAL_MAX; i++) {
/* kex algorithm taken care of so start with i=1 and not 0 */
free(packet_get_string(&len));
}
i = packet_get_char(); /* first_kex_packet_follows */
if (i && (c = strchr(kexlist, ',')))
*c = 0;
if (i && strcmp(kexlist, KEX_RESUME)) {
debug("server's kex guess (%s) was wrong, skipping", kexlist);
(void)packet_read(); /* Wrong guess - discard packet */
}
/*
* Read the ROAMING_AUTH_REQUIRED challenge from the server and
* send ROAMING_AUTH
*/
if ((type = packet_read()) != SSH2_MSG_KEX_ROAMING_AUTH_REQUIRED) {
debug("expected roaming_auth_required, got %d", type);
goto fail;
}
roaming_auth_required();
/* Read ROAMING_AUTH_OK from the server */
if ((type = packet_read()) != SSH2_MSG_KEX_ROAMING_AUTH_OK) {
debug("expected roaming_auth_ok, got %d", type);
goto fail;
}
recv_bytes = packet_get_int64() ^ oldkey2;
#ifdef WIN32_FIXME
debug("Peer received %I64u bytes", (unsigned long long)recv_bytes);
#else
debug("Peer received %llu bytes", (unsigned long long)recv_bytes);
#endif
resend_bytes(packet_get_connection_out(), &recv_bytes);
resume_in_progress = 0;
session_resumed = 1; /* Tell clientloop */
return 0;
fail:
free(kexlist);
if (packet_get_connection_in() == packet_get_connection_out())
close(packet_get_connection_in());
else {
close(packet_get_connection_in());
close(packet_get_connection_out());
}
return 1;
}
void do_authentication(char *user, int privileged_port, int cipher_type)
{
int type;
int authenticated = 0;
int authentication_type = 0;
char *password;
int row, col, xpixel, ypixel;
int password_attempts = 0;
if (strlen(user) > 255)
do_authentication_fail_loop();
/* Verify that the user is a valid user. We disallow usernames starting
with any characters that are commonly used to start NIS entries. */
if (user[0] == '-' || user[0] == '+' || user[0] == '@')
do_authentication_fail_loop();
debug("Attempting authentication for %.100s.", user);
/* If the user has no password, accept authentication immediately. */
if (auth_password(user, "")) {
/* Authentication with empty password succeeded. */
authentication_type = SSH_AUTH_PASSWORD;
authenticated = 1;
/* Success packet will be sent after loop below. */
} else {
/* Indicate that authentication is needed. */
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
}
/* Loop until the user has been authenticated or the connection is closed. */
while (!authenticated) {
/* Get a packet from the client. */
type = packet_read();
/* Process the packet. */
switch (type) {
case SSH_CMSG_AUTH_RHOSTS:
packet_get_all();
log_msg("Rhosts authentication disabled.");
break;
case SSH_CMSG_AUTH_RHOSTS_RSA:
packet_get_all();
log_msg("Rhosts with RSA authentication disabled.");
break;
case SSH_CMSG_AUTH_RSA:
packet_get_all();
log_msg("RSA authentication disabled.");
break;
case SSH_CMSG_AUTH_PASSWORD:
if (cipher_type == SSH_CIPHER_NONE) {
packet_get_all();
log_msg("Password authentication not available for unencrypted session.");
break;
}
/* Password authentication requested. */
/* Read user password. It is in plain text, but was transmitted
over the encrypted channel so it is not visible to an outside
observer. */
password = packet_get_string(NULL);
if (password_attempts >= 5) { /* Too many password authentication attempts. */
packet_disconnect("Too many password authentication attempts from %.100s for user %.100s.", get_canonical_hostname(), user);
/*NOTREACHED*/}
/* Count password authentication attempts, and log if appropriate. */
if (password_attempts > 0) {
/* Log failures if attempted more than once. */
debug("Password authentication failed for user %.100s from %.100s.", user, get_canonical_hostname());
}
password_attempts++;
/* Try authentication with the password. */
if (auth_password(user, password)) {
/* Successful authentication. */
/* Clear the password from memory. */
memset(password, 0, strlen(password));
xfree(password);
log_msg("Password authentication for %.100s accepted.", user);
authentication_type = SSH_AUTH_PASSWORD;
authenticated = 1;
break;
}
debug("Password authentication for %.100s failed.", user);
memset(password, 0, strlen(password));
xfree(password);
break;
case SSH_CMSG_WINDOW_SIZE:
debug("Window change received.");
row = packet_get_int();
col = packet_get_int();
xpixel = packet_get_int();
ypixel = packet_get_int();
do_naws(row, col);
break;
default:
/* Any unknown messages will be ignored (and failure returned)
during authentication. */
packet_get_all();
log_msg("Unknown message during authentication: type %d", type);
break; /* Respond with a failure message. */
}
/* If successfully authenticated, break out of loop. */
if (authenticated)
break;
/* Send a message indicating that the authentication attempt failed. */
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
}
/* The user has been authenticated and accepted. */
packet_start(SSH_SMSG_SUCCESS);
packet_send();
packet_write_wait();
/* Perform session preparation. */
do_authenticated(NULL);
}
