diff options
Diffstat (limited to 'usr.bin/ssh/sshconnect.c')
| -rw-r--r-- | usr.bin/ssh/sshconnect.c | 187 |
1 files changed, 117 insertions, 70 deletions
diff --git a/usr.bin/ssh/sshconnect.c b/usr.bin/ssh/sshconnect.c index 19a8235586f..c3ef1365043 100644 --- a/usr.bin/ssh/sshconnect.c +++ b/usr.bin/ssh/sshconnect.c @@ -8,7 +8,7 @@ */ #include "includes.h" -RCSID("$Id: sshconnect.c,v 1.39 1999/11/24 00:26:03 deraadt Exp $"); +RCSID("$Id: sshconnect.c,v 1.40 1999/11/24 19:53:53 markus Exp $"); #include <ssl/bn.h> #include "xmalloc.h" @@ -136,8 +136,10 @@ ssh_create_socket(uid_t original_real_uid, int privileged) { int sock; - /* If we are running as root and want to connect to a privileged - port, bind our own socket to a privileged port. */ + /* + * If we are running as root and want to connect to a privileged + * port, bind our own socket to a privileged port. + */ if (privileged) { int p = IPPORT_RESERVED - 1; @@ -221,9 +223,11 @@ ssh_connect(const char *host, struct sockaddr_in * hostaddr, !anonymous && geteuid() == 0 && port < IPPORT_RESERVED); - /* Connect to the host. We use the user's uid in - the hope that it will help with the problems of - tcp_wrappers showing the remote uid as root. */ + /* + * Connect to the host. We use the user's uid in the + * hope that it will help with the problems of + * tcp_wrappers showing the remote uid as root. + */ temporarily_use_uid(original_real_uid); if (connect(sock, (struct sockaddr *) hostaddr, sizeof(*hostaddr)) >= 0) { @@ -264,8 +268,12 @@ ssh_connect(const char *host, struct sockaddr_in * hostaddr, !anonymous && geteuid() == 0 && port < IPPORT_RESERVED); - /* Connect to the host. We use the user's uid in the hope that - it will help with tcp_wrappers showing the remote uid as root. */ + /* + * Connect to the host. We use the user's + * uid in the hope that it will help with + * tcp_wrappers showing the remote uid as + * root. + */ temporarily_use_uid(original_real_uid); if (connect(sock, (struct sockaddr *) hostaddr, sizeof(*hostaddr)) >= 0) { @@ -276,8 +284,12 @@ ssh_connect(const char *host, struct sockaddr_in * hostaddr, debug("connect: %.100s", strerror(errno)); restore_uid(); - /* Close the failed socket; there appear to be some problems when - reusing a socket for which connect() has already returned an error. */ + /* + * Close the failed socket; there appear to + * be some problems when reusing a socket for + * which connect() has already returned an + * error. + */ shutdown(sock, SHUT_RDWR); close(sock); } @@ -294,10 +306,11 @@ ssh_connect(const char *host, struct sockaddr_in * hostaddr, debug("Connection established."); - /* Set socket options. We would like the socket to disappear as - soon as it has been closed for whatever reason. */ - /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, - sizeof(on)); */ + /* + * Set socket options. We would like the socket to disappear as soon + * as it has been closed for whatever reason. + */ + /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *) &on, sizeof(on)); linger.l_onoff = 1; linger.l_linger = 5; @@ -487,8 +500,10 @@ try_rsa_authentication(struct passwd * pw, const char *authfile) /* Wait for server's response. */ type = packet_read(&plen); - /* The server responds with failure if it doesn\'t like our key or - doesn\'t support RSA authentication. */ + /* + * 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); @@ -508,8 +523,10 @@ try_rsa_authentication(struct passwd * pw, const char *authfile) debug("Received RSA challenge from server."); private_key = RSA_new(); - /* Load the private key. Try first with empty passphrase; if it - fails, ask for a passphrase. */ + /* + * Load the private key. Try first with empty passphrase; if it + * fails, ask for a passphrase. + */ if (!load_private_key(authfile, "", private_key, NULL)) { char buf[300]; snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", @@ -714,9 +731,11 @@ try_kerberos_authentication() packet_integrity_check(plen, 4 + auth.length, type); - /* If his response isn't properly encrypted with the - session key, and the decrypted checksum fails to match, - he's bogus. Bail out. */ + /* + * 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, schedule, &cred.session, &foreign, &local, &msg_data); if (r != KSUCCESS) { @@ -888,8 +907,10 @@ ssh_exchange_identification() } buf[sizeof(buf) - 1] = 0; - /* Check that the versions match. In future this might accept - several versions and set appropriate flags to handle them. */ + /* + * Check that the versions match. In future this might accept + * several versions and set appropriate flags to handle them. + */ if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, remote_version) != 3) fatal("Bad remote protocol version identification: '%.100s'", buf); @@ -910,9 +931,11 @@ ssh_exchange_identification() } } #if 0 - /* Removed for now, to permit compatibility with latter versions. - The server will reject our version and disconnect if it doesn't - support it. */ + /* + * Removed for now, to permit compatibility with latter versions. The + * server will reject our version and disconnect if it doesn't + * support it. + */ if (remote_major != PROTOCOL_MAJOR) fatal("Protocol major versions differ: %d vs. %d", PROTOCOL_MAJOR, remote_major); @@ -1080,10 +1103,7 @@ ssh_login(int host_key_valid, protocol_flags = packet_get_int(); packet_set_protocol_flags(protocol_flags); - /* Get supported cipher types. */ supported_ciphers = packet_get_int(); - - /* Get supported authentication types. */ supported_authentications = packet_get_int(); debug("Received server public key (%d bits) and host key (%d bits).", @@ -1093,11 +1113,12 @@ ssh_login(int host_key_valid, 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, SSH_SMSG_PUBLIC_KEY); - /* Compute the session id. */ compute_session_id(session_id, check_bytes, host_key->n, public_key->n); - /* Check if the host key is present in the user\'s list of known - hosts or in the systemwide list. */ + /* + * Check if the host key is present in the user\'s list of known + * hosts or in the systemwide list. + */ host_status = check_host_in_hostfile(options.user_hostfile, host, host_key->e, host_key->n, file_key->e, file_key->n); @@ -1105,18 +1126,22 @@ ssh_login(int host_key_valid, host_status = check_host_in_hostfile(options.system_hostfile, host, host_key->e, host_key->n, file_key->e, file_key->n); - /* Force accepting of the host key for localhost and 127.0.0.1. - The problem is that if the home directory is NFS-mounted to - multiple machines, localhost will refer to a different machine - in each of them, and the user will get bogus HOST_CHANGED - warnings. This essentially disables host authentication for - localhost; however, this is probably not a real problem. */ + /* + * Force accepting of the host key for localhost and 127.0.0.1. The + * problem is that if the home directory is NFS-mounted to multiple + * machines, localhost will refer to a different machine in each of + * them, and the user will get bogus HOST_CHANGED warnings. This + * essentially disables host authentication for localhost; however, + * this is probably not a real problem. + */ if (local) { debug("Forcing accepting of host key for localhost."); host_status = HOST_OK; } - /* Also perform check for the ip address, skip the check if we are - localhost or the hostname was an ip address to begin with */ + /* + * Also perform check for the ip address, skip the check if we are + * localhost or the hostname was an ip address to begin with + */ if (options.check_host_ip && !local && strcmp(host, ip)) { RSA *ip_key = RSA_new(); ip_key->n = BN_new(); @@ -1220,13 +1245,18 @@ ssh_login(int host_key_valid, error("Add correct host key in %.100s to get rid of this message.", options.user_hostfile); - /* If strict host key checking is in use, the user will - have to edit the key manually and we can only abort. */ + /* + * If strict host key checking is in use, the user will have + * to edit the key manually and we can only abort. + */ if (options.strict_host_key_checking) fatal("Host key for %.200s has changed and you have requested strict checking.", host); - /* If strict host key checking has not been requested, allow the connection - but without password authentication or agent forwarding. */ + /* + * If strict host key checking has not been requested, allow + * the connection but without password authentication or + * agent forwarding. + */ if (options.password_authentication) { error("Password authentication is disabled to avoid trojan horses."); options.password_authentication = 0; @@ -1235,11 +1265,13 @@ ssh_login(int host_key_valid, error("Agent forwarding is disabled to avoid trojan horses."); options.forward_agent = 0; } - /* XXX Should permit the user to change to use the new id. - This could be done by converting the host key to an - identifying sentence, tell that the host identifies - itself by that sentence, and ask the user if he/she - whishes to accept the authentication. */ + /* + * XXX Should permit the user to change to use the new id. + * This could be done by converting the host key to an + * identifying sentence, tell that the host identifies itself + * by that sentence, and ask the user if he/she whishes to + * accept the authentication. + */ break; } @@ -1249,9 +1281,11 @@ ssh_login(int host_key_valid, /* Generate a session key. */ arc4random_stir(); - /* Generate an encryption key for the session. The key is a 256 - bit random number, interpreted as a 32-byte key, with the least - significant 8 bits being the first byte of the key. */ + /* + * Generate an encryption key for the session. The key is a 256 bit + * random number, interpreted as a 32-byte key, with the least + * significant 8 bits being the first byte of the key. + */ for (i = 0; i < 32; i++) { if (i % 4 == 0) rand = arc4random(); @@ -1259,9 +1293,11 @@ ssh_login(int host_key_valid, rand >>= 8; } - /* According to the protocol spec, the first byte of the session - key is the highest byte of the integer. The session key is - xored with the first 16 bytes of the session id. */ + /* + * According to the protocol spec, the first byte of the session key + * is the highest byte of the integer. The session key is xored with + * the first 16 bytes of the session id. + */ key = BN_new(); BN_set_word(key, 0); for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { @@ -1272,8 +1308,10 @@ ssh_login(int host_key_valid, BN_add_word(key, session_key[i]); } - /* Encrypt the integer using the public key and host key of the - server (key with smaller modulus first). */ + /* + * Encrypt the integer using the public key and host key of the + * server (key with smaller modulus first). + */ if (BN_cmp(public_key->n, host_key->n) < 0) { /* Public key has smaller modulus. */ if (BN_num_bits(host_key->n) < @@ -1348,8 +1386,10 @@ ssh_login(int host_key_valid, /* We will no longer need the session key here. Destroy any extra copies. */ memset(session_key, 0, sizeof(session_key)); - /* Expect a success message from the server. Note that this - message will be received in encrypted form. */ + /* + * Expect a success message from the server. Note that this message + * will be received in encrypted form. + */ packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); debug("Received encrypted confirmation."); @@ -1360,9 +1400,11 @@ ssh_login(int host_key_valid, packet_send(); packet_write_wait(); - /* The server should respond with success if no authentication is - needed (the user has no password). Otherwise the server - responds with failure. */ + /* + * The server should respond with success if no authentication is + * needed (the user has no password). Otherwise the server responds + * with failure. + */ type = packet_read(&payload_len); /* check whether the connection was accepted without authentication. */ @@ -1404,8 +1446,10 @@ ssh_login(int host_key_valid, } #endif /* KRB4 */ - /* Use rhosts authentication if running in privileged socket and - we do not wish to remain anonymous. */ + /* + * Use rhosts authentication if running in privileged socket and we + * do not wish to remain anonymous. + */ if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && options.rhosts_authentication) { debug("Trying rhosts authentication."); @@ -1422,8 +1466,10 @@ ssh_login(int host_key_valid, packet_disconnect("Protocol error: got %d in response to rhosts auth", type); } - /* Try .rhosts or /etc/hosts.equiv authentication with RSA host - authentication. */ + /* + * Try .rhosts or /etc/hosts.equiv authentication with RSA host + * authentication. + */ if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && options.rhosts_rsa_authentication && host_key_valid) { if (try_rhosts_rsa_authentication(local_user, own_host_key)) @@ -1432,10 +1478,11 @@ ssh_login(int host_key_valid, /* Try RSA authentication if the server supports it. */ if ((supported_authentications & (1 << SSH_AUTH_RSA)) && options.rsa_authentication) { - /* Try RSA authentication using the authentication agent. - The agent is tried first because no passphrase is - needed for it, whereas identity files may require - passphrases. */ + /* + * Try RSA authentication using the authentication agent. The + * agent is tried first because no passphrase is needed for + * it, whereas identity files may require passphrases. + */ if (try_agent_authentication()) return; |