* information to/from the application to the user client over an encrypted
* connection. This can also handle forwarding of X11, TCP/IP, and authentication
* agent connections.
+ *
+ * SSH2 implementation,
+ * Copyright (c) 2000 Markus Friedl. All rights reserved.
*/
#include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.97 2000/04/04 21:37:27 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.111 2000/04/27 08:01:28 markus Exp $");
#include "xmalloc.h"
#include "rsa.h"
#include "compat.h"
#include "buffer.h"
-#ifdef HAVE_OPENSSL
-# include <openssl/dh.h>
-# include <openssl/bn.h>
-# include <openssl/hmac.h>
-# include <openssl/dsa.h>
-# include <openssl/rsa.h>
-#endif
-#ifdef HAVE_SSL
-# include <ssl/dh.h>
-# include <ssl/bn.h>
-# include <ssl/hmac.h>
-# include <ssl/dsa.h>
-# include <ssl/rsa.h>
-#endif
+#include "ssh2.h"
+#include <openssl/dh.h>
+#include <openssl/bn.h>
+#include <openssl/hmac.h>
+#include "kex.h"
+#include <openssl/dsa.h>
+#include <openssl/rsa.h>
#include "key.h"
+#include "dsa.h"
#include "auth.h"
+#include "myproposal.h"
+#include "authfile.h"
#ifdef LIBWRAP
#include <tcpd.h>
/* Name of the server configuration file. */
char *config_file_name = SERVER_CONFIG_FILE;
-/*
+/*
* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
* Default value is AF_UNSPEC means both IPv4 and IPv6.
*/
* not very useful. Currently, memory locking is not implemented.
*/
struct {
- RSA *private_key; /* Private part of server key. */
+ RSA *private_key; /* Private part of empheral server key. */
RSA *host_key; /* Private part of host key. */
+ Key *dsa_host_key; /* Private DSA host key. */
} sensitive_data;
/*
/* session identifier, used by RSA-auth */
unsigned char session_id[16];
+/* same for ssh2 */
+unsigned char *session_id2 = NULL;
+int session_id2_len = 0;
+
/* Prototypes for various functions defined later in this file. */
void do_ssh1_kex();
+void do_ssh2_kex();
/*
* Close all listening sockets
* the effect is to reread the configuration file (and to regenerate
* the server key).
*/
-void
+void
sighup_handler(int sig)
{
received_sighup = 1;
* Called from the main program after receiving SIGHUP.
* Restarts the server.
*/
-void
+void
sighup_restart()
{
log("Received SIGHUP; restarting.");
* These close the listen socket; not closing it seems to cause "Address
* already in use" problems on some machines, which is inconvenient.
*/
-void
+void
sigterm_handler(int sig)
{
log("Received signal %d; terminating.", sig);
* SIGCHLD handler. This is called whenever a child dies. This will then
* reap any zombies left by exited c.
*/
-void
+void
main_sigchld_handler(int sig)
{
int save_errno = errno;
/*
* Signal handler for the alarm after the login grace period has expired.
*/
-void
+void
grace_alarm_handler(int sig)
{
/* Close the connection. */
* Thus there should be no concurrency control/asynchronous execution
* problems.
*/
-void
+/* XXX do we really want this work to be done in a signal handler ? -m */
+void
key_regeneration_alarm(int sig)
{
int save_errno = errno;
errno = save_errno;
}
+char *
+chop(char *s)
+{
+ char *t = s;
+ while (*t) {
+ if(*t == '\n' || *t == '\r') {
+ *t = '\0';
+ return s;
+ }
+ t++;
+ }
+ return s;
+
+}
+
void
sshd_exchange_identification(int sock_in, int sock_out)
{
- int i;
+ 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. */
- snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
- PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
+ 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) {
buf[i] = '\n';
buf[i + 1] = 0;
continue;
- /*break; XXX eat \r */
}
if (buf[i] == '\n') {
/* buf[i] == '\n' */
*/
if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
&remote_major, &remote_minor, remote_version) != 3) {
- s = "Protocol mismatch.\n";
+ s = "Protocol mismatch.\n";
(void) atomicio(write, sock_out, s, strlen(s));
close(sock_in);
close(sock_out);
debug("Client protocol version %d.%d; client software version %.100s",
remote_major, remote_minor, remote_version);
+ compat_datafellows(remote_version);
+
+ 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.");
enable_compat13();
}
break;
- default:
+ case 2:
+ if (options.protocol & SSH_PROTO_2) {
+ enable_compat20();
+ break;
+ }
+ /* FALLTHROUGH */
+ default:
+ mismatch = 1;
+ break;
+ }
+ chop(server_version_string);
+ chop(client_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: %d vs. %d",
- get_remote_ipaddr(), PROTOCOL_MAJOR, remote_major);
+ log("Protocol major versions differ for %s: %.200s vs. %.200s",
+ get_remote_ipaddr(),
+ server_version_string, client_version_string);
fatal_cleanup();
- break;
}
+ if (compat20)
+ packet_set_ssh2_format();
+}
+
+
+void
+destroy_sensitive_data(void)
+{
+ /* Destroy the private and public keys. They will no longer be needed. */
+ RSA_free(public_key);
+ RSA_free(sensitive_data.private_key);
+ RSA_free(sensitive_data.host_key);
+ if (sensitive_data.dsa_host_key != NULL)
+ key_free(sensitive_data.dsa_host_key);
}
/*
{
extern char *optarg;
extern int optind;
- int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
+ int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, on = 1;
+ pid_t pid;
socklen_t fromlen;
- int silentrsa = 0;
+ int silent = 0;
fd_set *fdset;
struct sockaddr_storage from;
const char *remote_ip;
int remote_port;
- char *comment;
FILE *f;
struct linger linger;
struct addrinfo *ai;
inetd_flag = 1;
break;
case 'Q':
- silentrsa = 1;
+ silent = 1;
break;
case 'q':
options.log_level = SYSLOG_LEVEL_QUIET;
log_init(av0,
options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
- !inetd_flag);
+ !silent && !inetd_flag);
- /* check if RSA support exists */
- if (rsa_alive() == 0) {
- if (silentrsa == 0)
- printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
- log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
- exit(1);
- }
/* Read server configuration options from the configuration file. */
read_server_config(&options, config_file_name);
/* Fill in default values for those options not explicitly set. */
fill_default_server_options(&options);
- /* Check certain values for sanity. */
- if (options.server_key_bits < 512 ||
- options.server_key_bits > 32768) {
- fprintf(stderr, "Bad server key size.\n");
- exit(1);
- }
/* Check that there are no remaining arguments. */
if (optind < ac) {
fprintf(stderr, "Extra argument %s.\n", av[optind]);
debug("sshd version %.100s", SSH_VERSION);
- sensitive_data.host_key = RSA_new();
- errno = 0;
- /* Load the host key. It must have empty passphrase. */
- if (!load_private_key(options.host_key_file, "",
- sensitive_data.host_key, &comment)) {
- error("Could not load host key: %.200s: %.100s",
- options.host_key_file, strerror(errno));
+ sensitive_data.dsa_host_key = NULL;
+ sensitive_data.host_key = NULL;
+
+ /* check if RSA support exists */
+ if ((options.protocol & SSH_PROTO_1) &&
+ rsa_alive() == 0) {
+ log("no RSA support in libssl and libcrypto. See ssl(8)");
+ log("Disabling protocol version 1");
+ options.protocol &= ~SSH_PROTO_1;
+ }
+ /* Load the RSA/DSA host key. It must have empty passphrase. */
+ if (options.protocol & SSH_PROTO_1) {
+ Key k;
+ sensitive_data.host_key = RSA_new();
+ k.type = KEY_RSA;
+ k.rsa = sensitive_data.host_key;
+ errno = 0;
+ if (!load_private_key(options.host_key_file, "", &k, NULL)) {
+ error("Could not load host key: %.200s: %.100s",
+ options.host_key_file, strerror(errno));
+ log("Disabling protocol version 1");
+ options.protocol &= ~SSH_PROTO_1;
+ }
+ k.rsa = NULL;
+ }
+ if (options.protocol & SSH_PROTO_2) {
+ sensitive_data.dsa_host_key = key_new(KEY_DSA);
+ if (!load_private_key(options.dsa_key_file, "", sensitive_data.dsa_host_key, NULL)) {
+ error("Could not load DSA host key: %.200s", options.dsa_key_file);
+ log("Disabling protocol version 2");
+ options.protocol &= ~SSH_PROTO_2;
+ }
+ }
+ if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) {
+ if (silent == 0)
+ fprintf(stderr, "sshd: no hostkeys available -- exiting.\n");
+ log("sshd: no hostkeys available -- exiting.\n");
exit(1);
}
- xfree(comment);
- /* Initialize the log (it is reinitialized below in case we
- forked). */
+ /* Check certain values for sanity. */
+ if (options.protocol & SSH_PROTO_1) {
+ if (options.server_key_bits < 512 ||
+ options.server_key_bits > 32768) {
+ fprintf(stderr, "Bad server key size.\n");
+ exit(1);
+ }
+ /*
+ * Check that server and host key lengths differ sufficiently. This
+ * is necessary to make double encryption work with rsaref. Oh, I
+ * hate software patents. I dont know if this can go? Niels
+ */
+ if (options.server_key_bits >
+ BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
+ options.server_key_bits <
+ BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
+ options.server_key_bits =
+ BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
+ debug("Forcing server key to %d bits to make it differ from host key.",
+ options.server_key_bits);
+ }
+ }
+
+ /* Initialize the log (it is reinitialized below in case we forked). */
if (debug_flag && !inetd_flag)
log_stderr = 1;
log_init(av0, options.log_level, options.log_facility, log_stderr);
- /* If not in debugging mode, and not started from inetd,
- disconnect from the controlling terminal, and fork. The
- original process exits. */
+ /*
+ * If not in debugging mode, and not started from inetd, disconnect
+ * from the controlling terminal, and fork. The original process
+ * exits.
+ */
if (!debug_flag && !inetd_flag) {
#ifdef TIOCNOTTY
int fd;
/* Reinitialize the log (because of the fork above). */
log_init(av0, options.log_level, options.log_facility, log_stderr);
- /* Check that server and host key lengths differ sufficiently.
- This is necessary to make double encryption work with rsaref.
- Oh, I hate software patents. I dont know if this can go? Niels */
- if (options.server_key_bits >
- BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
- options.server_key_bits <
- BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
- options.server_key_bits =
- BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
- debug("Forcing server key to %d bits to make it differ from host key.",
- options.server_key_bits);
- }
/* Do not display messages to stdout in RSA code. */
rsa_set_verbose(0);
s2 = dup(s1);
sock_in = dup(0);
sock_out = dup(1);
- /* We intentionally do not close the descriptors 0, 1, and 2
- as our code for setting the descriptors won\'t work
- if ttyfd happens to be one of those. */
+ /*
+ * We intentionally do not close the descriptors 0, 1, and 2
+ * as our code for setting the descriptors won\'t work if
+ * ttyfd happens to be one of those.
+ */
debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
- public_key = RSA_new();
- sensitive_data.private_key = RSA_new();
-
- log("Generating %d bit RSA key.", options.server_key_bits);
- rsa_generate_key(sensitive_data.private_key, public_key,
- options.server_key_bits);
- arc4random_stir();
- log("RSA key generation complete.");
+ if (options.protocol & SSH_PROTO_1) {
+ public_key = RSA_new();
+ sensitive_data.private_key = RSA_new();
+ log("Generating %d bit RSA key.", options.server_key_bits);
+ rsa_generate_key(sensitive_data.private_key, public_key,
+ options.server_key_bits);
+ arc4random_stir();
+ log("RSA key generation complete.");
+ }
} else {
for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
fclose(f);
}
}
+ if (options.protocol & SSH_PROTO_1) {
+ public_key = RSA_new();
+ sensitive_data.private_key = RSA_new();
- public_key = RSA_new();
- sensitive_data.private_key = RSA_new();
-
- log("Generating %d bit RSA key.", options.server_key_bits);
- rsa_generate_key(sensitive_data.private_key, public_key,
- options.server_key_bits);
- arc4random_stir();
- log("RSA key generation complete.");
+ log("Generating %d bit RSA key.", options.server_key_bits);
+ rsa_generate_key(sensitive_data.private_key, public_key,
+ options.server_key_bits);
+ arc4random_stir();
+ log("RSA key generation complete.");
- /* Schedule server key regeneration alarm. */
- signal(SIGALRM, key_regeneration_alarm);
- alarm(options.key_regeneration_time);
+ /* Schedule server key regeneration alarm. */
+ signal(SIGALRM, key_regeneration_alarm);
+ alarm(options.key_regeneration_time);
+ }
/* Arrange to restart on SIGHUP. The handler needs listen_sock. */
signal(SIGHUP, sighup_handler);
for (i = 0; i < num_listen_socks; i++)
if (listen_socks[i] > maxfd)
maxfd = listen_socks[i];
- fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
- fdset = (fd_set *)xmalloc(fdsetsz);
+ fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
+ fdset = (fd_set *)xmalloc(fdsetsz);
/*
* Stay listening for connections until the system crashes or
packet_set_nonblocking();
/* perform the key exchange */
- do_ssh1_kex();
/* authenticate user and start session */
- do_authentication();
+ if (compat20) {
+ do_ssh2_kex();
+ do_authentication2();
+ } else {
+ do_ssh1_kex();
+ do_authentication();
+ }
#ifdef KRB4
/* Cleanup user's ticket cache file. */
/* Get cipher type and check whether we accept this. */
cipher_type = packet_get_char();
- if (!(cipher_mask() & (1 << cipher_type)))
+ if (!(cipher_mask() & (1 << cipher_type)))
packet_disconnect("Warning: client selects unsupported cipher.");
/* Get check bytes from the packet. These must match those we
sensitive_data.private_key->n);
/* Destroy the private and public keys. They will no longer be needed. */
- RSA_free(public_key);
- RSA_free(sensitive_data.private_key);
- RSA_free(sensitive_data.host_key);
+ destroy_sensitive_data();
/*
* Extract session key from the decrypted integer. The key is in the
packet_send();
packet_write_wait();
}
+
+/*
+ * SSH2 key exchange: diffie-hellman-group1-sha1
+ */
+void
+do_ssh2_kex()
+{
+ Buffer *server_kexinit;
+ Buffer *client_kexinit;
+ int payload_len, dlen;
+ int slen;
+ unsigned int klen, kout;
+ char *ptr;
+ unsigned char *signature = NULL;
+ unsigned char *server_host_key_blob = NULL;
+ unsigned int sbloblen;
+ DH *dh;
+ BIGNUM *dh_client_pub = 0;
+ BIGNUM *shared_secret = 0;
+ int i;
+ unsigned char *kbuf;
+ unsigned char *hash;
+ Kex *kex;
+ char *cprop[PROPOSAL_MAX];
+ char *sprop[PROPOSAL_MAX];
+
+/* KEXINIT */
+
+ if (options.ciphers != NULL) {
+ myproposal[PROPOSAL_ENC_ALGS_CTOS] =
+ myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
+ }
+
+ debug("Sending KEX init.");
+
+ for (i = 0; i < PROPOSAL_MAX; i++)
+ sprop[i] = xstrdup(myproposal[i]);
+ server_kexinit = kex_init(sprop);
+ packet_start(SSH2_MSG_KEXINIT);
+ packet_put_raw(buffer_ptr(server_kexinit), buffer_len(server_kexinit));
+ packet_send();
+ packet_write_wait();
+
+ debug("done");
+
+ packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
+
+ /*
+ * save raw KEXINIT payload in buffer. this is used during
+ * computation of the session_id and the session keys.
+ */
+ client_kexinit = xmalloc(sizeof(*client_kexinit));
+ buffer_init(client_kexinit);
+ ptr = packet_get_raw(&payload_len);
+ buffer_append(client_kexinit, ptr, payload_len);
+
+ /* skip cookie */
+ for (i = 0; i < 16; i++)
+ (void) packet_get_char();
+ /* save kex init proposal strings */
+ for (i = 0; i < PROPOSAL_MAX; i++) {
+ cprop[i] = packet_get_string(NULL);
+ debug("got kexinit string: %s", cprop[i]);
+ }
+
+ i = (int) packet_get_char();
+ debug("first kex follow == %d", i);
+ i = packet_get_int();
+ debug("reserved == %d", i);
+
+ debug("done read kexinit");
+ kex = kex_choose_conf(cprop, sprop, 1);
+
+/* KEXDH */
+
+ debug("Wait SSH2_MSG_KEXDH_INIT.");
+ packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
+
+ /* key, cert */
+ dh_client_pub = BN_new();
+ if (dh_client_pub == NULL)
+ fatal("dh_client_pub == NULL");
+ packet_get_bignum2(dh_client_pub, &dlen);
+
+#ifdef DEBUG_KEXDH
+ fprintf(stderr, "\ndh_client_pub= ");
+ bignum_print(dh_client_pub);
+ fprintf(stderr, "\n");
+ debug("bits %d", BN_num_bits(dh_client_pub));
+#endif
+
+ /* generate DH key */
+ dh = dh_new_group1(); /* XXX depends on 'kex' */
+
+#ifdef DEBUG_KEXDH
+ fprintf(stderr, "\np= ");
+ bignum_print(dh->p);
+ fprintf(stderr, "\ng= ");
+ bignum_print(dh->g);
+ fprintf(stderr, "\npub= ");
+ bignum_print(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);
+ kout = DH_compute_key(kbuf, dh_client_pub, dh);
+
+#ifdef DEBUG_KEXDH
+ debug("shared secret: len %d/%d", klen, kout);
+ fprintf(stderr, "shared secret == ");
+ for (i = 0; i< kout; i++)
+ fprintf(stderr, "%02x", (kbuf[i])&0xff);
+ fprintf(stderr, "\n");
+#endif
+ shared_secret = BN_new();
+
+ BN_bin2bn(kbuf, kout, shared_secret);
+ memset(kbuf, 0, klen);
+ xfree(kbuf);
+
+ /* XXX precompute? */
+ dsa_make_key_blob(sensitive_data.dsa_host_key, &server_host_key_blob, &sbloblen);
+
+ /* calc H */ /* XXX depends on 'kex' */
+ hash = kex_hash(
+ client_version_string,
+ server_version_string,
+ buffer_ptr(client_kexinit), buffer_len(client_kexinit),
+ buffer_ptr(server_kexinit), buffer_len(server_kexinit),
+ (char *)server_host_key_blob, sbloblen,
+ dh_client_pub,
+ dh->pub_key,
+ shared_secret
+ );
+ buffer_free(client_kexinit);
+ buffer_free(server_kexinit);
+ xfree(client_kexinit);
+ xfree(server_kexinit);
+#ifdef DEBUG_KEXDH
+ fprintf(stderr, "hash == ");
+ for (i = 0; i< 20; i++)
+ fprintf(stderr, "%02x", (hash[i])&0xff);
+ fprintf(stderr, "\n");
+#endif
+ /* save session id := H */
+ /* XXX hashlen depends on KEX */
+ session_id2_len = 20;
+ session_id2 = xmalloc(session_id2_len);
+ memcpy(session_id2, hash, session_id2_len);
+
+ /* sign H */
+ /* XXX hashlen depends on KEX */
+ dsa_sign(sensitive_data.dsa_host_key, &signature, &slen, hash, 20);
+
+ destroy_sensitive_data();
+
+ /* send server hostkey, DH pubkey 'f' and singed H */
+ packet_start(SSH2_MSG_KEXDH_REPLY);
+ packet_put_string((char *)server_host_key_blob, sbloblen);
+ packet_put_bignum2(dh->pub_key); // f
+ packet_put_string((char *)signature, slen);
+ packet_send();
+ xfree(signature);
+ xfree(server_host_key_blob);
+ packet_write_wait();
+
+ kex_derive_keys(kex, hash, shared_secret);
+ packet_set_kex(kex);
+
+ /* have keys, free DH */
+ DH_free(dh);
+
+ debug("send SSH2_MSG_NEWKEYS.");
+ packet_start(SSH2_MSG_NEWKEYS);
+ packet_send();
+ packet_write_wait();
+ debug("done: send SSH2_MSG_NEWKEYS.");
+
+ debug("Wait SSH2_MSG_NEWKEYS.");
+ packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
+ debug("GOT SSH2_MSG_NEWKEYS.");
+
+#ifdef DEBUG_KEXDH
+ /* send 1st encrypted/maced/compressed message */
+ packet_start(SSH2_MSG_IGNORE);
+ packet_put_cstring("markus");
+ packet_send();
+ packet_write_wait();
+#endif
+ debug("done: KEX2.");
+}
andersk / openssh.git / blobdiff