/*
* Processes input from the client and the program. Input data is stored
* in buffers and processed later.
*/
static void
process_input(fd_set * readset)
{
int len;
char buf[16384];
/* Read and buffer any input data from the client. */
if (FD_ISSET(connection_in, readset)) {
len = read(connection_in, buf, sizeof(buf));
if (len == 0) {
verbose("Connection closed by %.100s",
get_remote_ipaddr());
connection_closed = 1;
if (compat20)
return;
fatal_cleanup();
} else if (len < 0) {
if (errno != EINTR && errno != EAGAIN) {
verbose("Read error from remote host "
"%.100s: %.100s",
get_remote_ipaddr(), strerror(errno));
fatal_cleanup();
}
} else {
/* Buffer any received data. */
packet_process_incoming(buf, len);
}
}
if (compat20)
return;
/* Read and buffer any available stdout data from the program. */
if (!fdout_eof && FD_ISSET(fdout, readset)) {
len = read(fdout, buf, sizeof(buf));
if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
/* do nothing */
} else if (len <= 0) {
fdout_eof = 1;
} else {
buffer_append(&stdout_buffer, buf, len);
fdout_bytes += len;
}
}
/* Read and buffer any available stderr data from the program. */
if (!fderr_eof && FD_ISSET(fderr, readset)) {
len = read(fderr, buf, sizeof(buf));
if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
/* do nothing */
} else if (len <= 0) {
fderr_eof = 1;
} else {
buffer_append(&stderr_buffer, buf, len);
}
}
}
static int
get_sock_port(int sock, int local)
{
struct sockaddr_storage from;
socklen_t fromlen;
char strport[NI_MAXSERV];
/* Get IP address of client. */
fromlen = sizeof(from);
memset(&from, 0, sizeof(from));
if (local) {
if (getsockname(sock, (struct sockaddr *)&from, &fromlen) < 0) {
error("getsockname failed: %.100s", strerror(errno));
return 0;
}
} else {
if (getpeername(sock, (struct sockaddr *) & from, &fromlen) < 0) {
debug("getpeername failed: %.100s", strerror(errno));
fatal_cleanup();
}
}
/* Return port number. */
if (getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
strport, sizeof(strport), NI_NUMERICSERV) != 0)
fatal("get_sock_port: getnameinfo NI_NUMERICSERV failed");
return atoi(strport);
}
void
fatal(const char *fmt,...)
{
va_list args;
va_start(args, fmt);
do_log(SYSLOG_LEVEL_FATAL, fmt, args);
va_end(args);
fatal_cleanup();
}
ok_t
_log_fatal(char *file, int line, char *msg)
{
extern void fatal_cleanup();
_log(file, line, "FATAL", msg );
fatal_cleanup();
return NG;
}
static void ATTR_NORETURN
cleanup(int signum)
{
FATAL(SYSTEM, "receive signal %d\n", signum);
switch (signum) {
case SIGPIPE:
sigpipe_arised = TRUE;
break;
default:
break;
}
fatal_cleanup();
}
const char *
get_remote_ipaddr(void)
{
static char *canonical_host_ip = NULL;
/* Check whether we have cached the ipaddr. */
if (canonical_host_ip == NULL) {
if (packet_connection_is_on_socket()) {
canonical_host_ip =
get_peer_ipaddr(packet_get_connection_in());
if (canonical_host_ip == NULL)
fatal_cleanup();
} else {
/* If not on socket, return UNKNOWN. */
canonical_host_ip = xstrdup("UNKNOWN");
}
}
return canonical_host_ip;
}
static void
mm_record_login(Session *s, struct passwd *pw)
{
socklen_t fromlen;
struct sockaddr_storage from;
/*
* Get IP address of client. If the connection is not a socket, let
* the address be 0.0.0.0.
*/
memset(&from, 0, sizeof(from));
fromlen = sizeof(from);
if (packet_connection_is_on_socket()) {
if (getpeername(packet_get_connection_in(),
(struct sockaddr *) & from, &fromlen) < 0) {
debug("getpeername: %.100s", strerror(errno));
fatal_cleanup();
}
}
/* Record that there was a login on that tty from the remote host. */
record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
(struct sockaddr *)&from, fromlen);
}
void
mm_request_receive(int socket, Buffer *m)
{
u_char buf[4];
u_int msg_len;
ssize_t res;
debug3("%s entering", __func__);
res = atomicio(read, socket, buf, sizeof(buf));
if (res != sizeof(buf)) {
if (res == 0)
fatal_cleanup();
fatal("%s: read: %ld", __func__, (long)res);
}
msg_len = GET_32BIT(buf);
if (msg_len > 256 * 1024)
fatal("%s: read: bad msg_len %d", __func__, msg_len);
buffer_clear(m);
buffer_append_space(m, msg_len);
res = atomicio(read, socket, buffer_ptr(m), msg_len);
if (res != msg_len)
fatal("%s: read: %ld != msg_len", __func__, (long)res);
}
int
auth_krb4(Authctxt *authctxt, KTEXT auth, char **client, KTEXT reply)
{
AUTH_DAT adat = {0};
Key_schedule schedule;
struct sockaddr_in local, foreign;
char instance[INST_SZ];
socklen_t slen;
u_int cksum;
int r, s;
s = packet_get_connection_in();
slen = sizeof(local);
memset(&local, 0, sizeof(local));
if (getsockname(s, (struct sockaddr *) & local, &slen) < 0)
debug("getsockname failed: %.100s", strerror(errno));
slen = sizeof(foreign);
memset(&foreign, 0, sizeof(foreign));
if (getpeername(s, (struct sockaddr *) & foreign, &slen) < 0) {
debug("getpeername failed: %.100s", strerror(errno));
fatal_cleanup();
}
instance[0] = '*';
instance[1] = 0;
/* Get the encrypted request, challenge, and session key. */
if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance,
0, &adat, ""))) {
debug("Kerberos v4 krb_rd_req: %.100s", krb_err_txt[r]);
return (0);
}
des_key_sched((des_cblock *) adat.session, schedule);
*client = xmalloc(MAX_K_NAME_SZ);
(void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
*adat.pinst ? "." : "", adat.pinst, adat.prealm);
/* Check ~/.klogin authorization now. */
if (kuserok(&adat, authctxt->user) != KSUCCESS) {
log("Kerberos v4 .klogin authorization failed for %s to "
"account %s", *client, authctxt->user);
xfree(*client);
*client = NULL;
return (0);
}
/* Increment the checksum, and return it encrypted with the
session key. */
cksum = adat.checksum + 1;
cksum = htonl(cksum);
/* If we can't successfully encrypt the checksum, we send back an
empty message, admitting our failure. */
if ((r = krb_mk_priv((u_char *) & cksum, reply->dat, sizeof(cksum) + 1,
schedule, &adat.session, &local, &foreign)) < 0) {
debug("Kerberos v4 mk_priv: (%d) %s", r, krb_err_txt[r]);
reply->dat[0] = 0;
reply->length = 0;
} else
reply->length = r;
/* Clear session key. */
memset(&adat.session, 0, sizeof(&adat.session));
return (1);
}
static char *
get_remote_hostname(int socket, int verify_reverse_mapping)
{
struct sockaddr_storage from;
int i, res;
socklen_t fromlen;
struct addrinfo hints, *ai, *aitop;
char name[NI_MAXHOST], ntop[NI_MAXHOST], ntop2[NI_MAXHOST];
/* Get IP address of client. */
fromlen = sizeof(from);
memset(&from, 0, sizeof(from));
if (getpeername(socket, (struct sockaddr *) &from, &fromlen) < 0) {
debug("getpeername failed: %.100s", strerror(errno));
fatal_cleanup();
}
if ((res = getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
NULL, 0, NI_NUMERICHOST)) != 0)
fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed: %d", res);
#ifdef IPV4_IN_IPV6
if (from.ss_family == AF_INET6) {
struct sockaddr_in6 *from6 = (struct sockaddr_in6 *)&from;
(void) inet_ntop_native(from.ss_family,
from6->sin6_addr.s6_addr,
ntop, sizeof(ntop));
}
#endif /* IPV4_IN_IPV6 */
if (!verify_reverse_mapping)
return xstrdup(ntop);
debug3("Trying to reverse map address %.100s.", ntop);
/* Map the IP address to a host name. */
if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
NULL, 0, NI_NAMEREQD) != 0) {
/* Host name not found. Use ip address. */
return xstrdup(ntop);
}
/* Got host name. */
name[sizeof(name) - 1] = '\0';
/*
* Convert it to all lowercase (which is expected by the rest
* of this software).
*/
for (i = 0; name[i]; i++)
if (isupper(name[i]))
name[i] = tolower(name[i]);
/*
* Map it back to an IP address and check that the given
* address actually is an address of this host. This is
* necessary because anyone with access to a name server can
* define arbitrary names for an IP address. Mapping from
* name to IP address can be trusted better (but can still be
* fooled if the intruder has access to the name server of
* the domain).
*/
memset(&hints, 0, sizeof(hints));
hints.ai_family = from.ss_family;
hints.ai_socktype = SOCK_STREAM;
if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
log("reverse mapping checking getaddrinfo for %.700s "
"failed - POSSIBLE BREAKIN ATTEMPT!", name);
return xstrdup(ntop);
}
/* Look for the address from the list of addresses. */
for (ai = aitop; ai; ai = ai->ai_next) {
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
(strcmp(ntop, ntop2) == 0))
break;
}
freeaddrinfo(aitop);
/* If we reached the end of the list, the address was not there. */
if (!ai) {
/* Address not found for the host name. */
log("Address %.100s maps to %.600s, but this does not "
"map back to the address - POSSIBLE BREAKIN ATTEMPT!",
ntop, name);
return xstrdup(ntop);
}
return xstrdup(name);
}
static void
sshd_exchange_identification(int sock_in, int sock_out)
{
int i, mismatch;
int remote_major, remote_minor;
int major, minor;
char *s;
char buf[256]; /* Must not be larger than remote_version. */
char remote_version[256]; /* Must be at least as big as buf. */
if ((options.protocol & SSH_PROTO_1) &&
(options.protocol & SSH_PROTO_2)) {
major = PROTOCOL_MAJOR_1;
minor = 99;
} else if (options.protocol & SSH_PROTO_2) {
major = PROTOCOL_MAJOR_2;
minor = PROTOCOL_MINOR_2;
} else {
major = PROTOCOL_MAJOR_1;
minor = PROTOCOL_MINOR_1;
}
snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
server_version_string = xstrdup(buf);
if (client_version_string == NULL) {
/* Send our protocol version identification. */
if (atomicio(write, sock_out, server_version_string,
strlen(server_version_string))
!= strlen(server_version_string)) {
log("Could not write ident string to %s", get_remote_ipaddr());
fatal_cleanup();
}
/* Read other sides version identification. */
memset(buf, 0, sizeof(buf));
for (i = 0; i < sizeof(buf) - 1; i++) {
if (atomicio(read, sock_in, &buf[i], 1) != 1) {
log("Did not receive identification string from %s",
get_remote_ipaddr());
fatal_cleanup();
}
if (buf[i] == '\r') {
buf[i] = 0;
/* Kludge for F-Secure Macintosh < 1.0.2 */
if (i == 12 &&
strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
break;
continue;
}
if (buf[i] == '\n') {
buf[i] = 0;
break;
}
}
buf[sizeof(buf) - 1] = 0;
client_version_string = xstrdup(buf);
}
/*
* Check that the versions match. In future this might accept
* several versions and set appropriate flags to handle them.
*/
if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
&remote_major, &remote_minor, remote_version) != 3) {
s = "Protocol mismatch.\n";
(void) atomicio(write, sock_out, s, strlen(s));
close(sock_in);
close(sock_out);
log("Bad protocol version identification '%.100s' from %s",
client_version_string, get_remote_ipaddr());
fatal_cleanup();
}
debug("Client protocol version %d.%d; client software version %.100s",
remote_major, remote_minor, remote_version);
compat_datafellows(remote_version);
if (datafellows & SSH_BUG_SCANNER) {
log("scanned from %s with %s. Don't panic.",
get_remote_ipaddr(), client_version_string);
fatal_cleanup();
}
mismatch = 0;
switch (remote_major) {
case 1:
if (remote_minor == 99) {
if (options.protocol & SSH_PROTO_2)
enable_compat20();
else
mismatch = 1;
break;
}
if (!(options.protocol & SSH_PROTO_1)) {
mismatch = 1;
break;
}
if (remote_minor < 3) {
packet_disconnect("Your ssh version is too old and "
"is no longer supported. Please install a newer version.");
} else if (remote_minor == 3) {
/* note that this disables agent-forwarding */
enable_compat13();
}
break;
case 2:
if (options.protocol & SSH_PROTO_2) {
enable_compat20();
break;
}
/* FALLTHROUGH */
default:
mismatch = 1;
break;
}
chop(server_version_string);
debug("Local version string %.200s", server_version_string);
if (mismatch) {
s = "Protocol major versions differ.\n";
(void) atomicio(write, sock_out, s, strlen(s));
close(sock_in);
close(sock_out);
log("Protocol major versions differ for %s: %.200s vs. %.200s",
get_remote_ipaddr(),
server_version_string, client_version_string);
fatal_cleanup();
}
}
