src/usr.bin/ssh/sshconnect1.c - diff

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Diff for /src/usr.bin/ssh/Attic/sshconnect1.c between version 1.3.2.4 and 1.4

version 1.3.2.4, 2001/03/21 18:53:15

version 1.4, 2000/07/16 08:27:22

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* Author: Tatu Ylonen <ylo@cs.hut.fi>

* Created: Sat Mar 18 22:15:47 1995 ylo

* Code to connect to a remote host, and to perform the client side of the

* login (authentication) dialog.

* As far as I am concerned, the code I have written for this software

* can be used freely for any purpose. Any derived versions of this

* software must be clearly marked as such, and if the derived work is

* incompatible with the protocol description in the RFC file, it must be

* called by a name other than "ssh" or "Secure Shell".

#include "includes.h"

RCSID("$OpenBSD$");

#include <openssl/bn.h>

#include <openssl/dsa.h>

#include <openssl/rsa.h>

#include <openssl/evp.h>

#ifdef KRB4

#include <krb.h>

#endif

#ifdef AFS

#include <kafs.h>

#include "radix.h"

#endif

#include "ssh.h"

#include "ssh1.h"

#include "xmalloc.h"

#include "rsa.h"

#include "ssh.h"

#include "buffer.h"

#include "packet.h"

#include "cipher.h"

#include "mpaux.h"

#include "uidswap.h"

#include "log.h"

#include "readconf.h"

#include "key.h"

#include "authfd.h"

#include "sshconnect.h"

#include "authfile.h"

#include "readpass.h"

#include "cipher.h"

#include "canohost.h"

/* Session id for the current session. */

u_char session_id[16];

unsigned char session_id[16];

u_int supported_authentications = 0;

unsigned int supported_authentications = 0;

extern Options options;

extern char *__progname;

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* authenticate using the agent.

int

try_agent_authentication(void)

try_agent_authentication()

{

int type;

int status, type;

char *comment;

AuthenticationConnection *auth;

u_char response[16];

unsigned char response[16];

u_int i;

unsigned int i;

int plen, clen;

BIGNUM *e, *n, *challenge;

Key *key;

BIGNUM *challenge;

/* Get connection to the agent. */

auth = ssh_get_authentication_connection();

if (!auth)

return 0;

e = BN_new();

n = BN_new();

challenge = BN_new();

/* Loop through identities served by the agent. */

for (key = ssh_get_first_identity(auth, &comment, 1);

for (status = ssh_get_first_identity(auth, e, n, &comment);

key != NULL;

status;

key = ssh_get_next_identity(auth, &comment, 1)) {

status = ssh_get_next_identity(auth, e, n, &comment)) {

int plen, clen;

/* Try this identity. */

debug("Trying RSA authentication via agent with '%.100s'", comment);

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/* 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_put_bignum(n);

packet_send();

packet_write_wait();

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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. */

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debug("Received RSA challenge from server.");

/* Ask the agent to decrypt the challenge. */

if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) {

if (!ssh_decrypt_challenge(auth, e, n, challenge,

session_id, 1, response)) {

* The agent failed to authenticate this identifier

/* The agent failed to authenticate this identifier although it

* although it advertised it supports this. Just

advertised it supports this. Just return a wrong value. */

* return a wrong value.

log("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. */

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/* 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.");

BN_clear_free(e);

BN_clear_free(n);

BN_clear_free(challenge);

return 1;

}

/* Otherwise it should return failure. */

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packet_disconnect("Protocol error waiting RSA auth response: %d",

type);

}

ssh_close_authentication_connection(auth);

BN_clear_free(e);

BN_clear_free(n);

BN_clear_free(challenge);

debug("RSA authentication using agent refused.");

return 0;

}

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void

respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv)

{

u_char buf[32], response[16];

unsigned char buf[32], response[16];

MD5_CTX md;

int i, len;

/* Decrypt the challenge using the private key. */

/* XXX think about Bleichenbacher, too */

rsa_private_decrypt(challenge, challenge, prv);

if (rsa_private_decrypt(challenge, challenge, prv) <= 0)

packet_disconnect(

"respond_to_rsa_challenge: rsa_private_decrypt failed");

/* Compute the response. */

/* The response is MD5 of decrypted challenge plus session id. */

len = BN_num_bytes(challenge);

if (len <= 0 || len > sizeof(buf))

packet_disconnect(

packet_disconnect("respond_to_rsa_challenge: bad challenge length %d",

"respond_to_rsa_challenge: bad challenge length %d", len);

len);

memset(buf, 0, sizeof(buf));

BN_bn2bin(challenge, buf + sizeof(buf) - len);

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int plen, clen;

/* Try to load identification for the authentication key. */

public = key_new(KEY_RSA1);

public = key_new(KEY_RSA);

if (!load_public_key(authfile, public, &comment)) {

key_free(public);

/* Could not load it. Fail. */

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debug("Received RSA challenge from server.");

private = key_new(KEY_RSA1);

private = key_new(KEY_RSA);

* Load the private key. Try first with empty passphrase; if it

* fails, ask for a passphrase.

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/* Expect the server to reject it... */

packet_read_expect(&plen, SSH_SMSG_FAILURE);

xfree(comment);

key_free(private);

BN_clear_free(challenge);

return 0;

}

/* Destroy the passphrase. */

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#ifdef KRB4

int

try_kerberos_authentication(void)

try_kerberos_authentication()

{

KTEXT_ST auth; /* Kerberos data */

char *reply;

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if (stat(tkt_string(), &st) < 0)

return 0;

strncpy(inst, (char *) krb_get_phost(get_canonical_hostname(1)), INST_SZ);

strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ);

realm = (char *) krb_realmofhost(get_canonical_hostname(1));

realm = (char *) krb_realmofhost(get_canonical_hostname());

if (!realm) {

debug("Kerberos V4: no realm for %s", get_canonical_hostname(1));

debug("Kerberos V4: no realm for %s", get_canonical_hostname());

return 0;

}

/* This can really be anything. */

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debug("Kerberos V4 authentication accepted.");

/* Get server's response. */

reply = packet_get_string((u_int *) &auth.length);

reply = packet_get_string((unsigned int *) &auth.length);

memcpy(auth.dat, reply, auth.length);

xfree(reply);

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#ifdef AFS

int

send_kerberos_tgt(void)

send_kerberos_tgt()

{

CREDENTIALS *creds;

char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];

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debug("Kerberos V4 ticket expired: %s", TKT_FILE);

return 0;

}

creds_to_radix(creds, (u_char *)buffer, sizeof buffer);

creds_to_radix(creds, (unsigned char *)buffer, sizeof buffer);

xfree(creds);

packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);

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p = buf;

/* Get secret token. */

memcpy(&creds.ticket_st.length, p, sizeof(u_int));

memcpy(&creds.ticket_st.length, p, sizeof(unsigned int));

if (creds.ticket_st.length > MAX_KTXT_LEN)

break;

p += sizeof(u_int);

p += sizeof(unsigned int);

memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);

p += creds.ticket_st.length;

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creds.pinst[0] = '\0';

/* Encode token, ship it off. */

if (creds_to_radix(&creds, (u_char *) buffer, sizeof buffer) <= 0)

if (creds_to_radix(&creds, (unsigned char*) buffer, sizeof buffer) <= 0)

break;

packet_start(SSH_CMSG_HAVE_AFS_TOKEN);

packet_put_string(buffer, strlen(buffer));

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* Note that the client code is not tied to s/key or TIS.

int

try_challenge_reponse_authentication(void)

try_skey_authentication()

{

int type, i;

int payload_len;

u_int clen;

unsigned int clen;

char prompt[1024];

char *challenge, *response;

debug("Doing challenge reponse authentication.");

debug("Doing skey authentication.");

for (i = 0; i < options.number_of_password_prompts; i++) {

/* request a challenge */

packet_start(SSH_CMSG_AUTH_TIS);

packet_send();

packet_write_wait();

type = packet_read(&payload_len);

if (type != SSH_SMSG_FAILURE &&

type != SSH_SMSG_AUTH_TIS_CHALLENGE) {

packet_disconnect("Protocol error: got %d in response "

"to SSH_CMSG_AUTH_TIS", type);

"to skey-auth", type);

}

if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) {

debug("No challenge.");

debug("No challenge for skey authentication.");

return 0;

}

challenge = packet_get_string(&clen);

packet_integrity_check(payload_len, (4 + clen), type);

snprintf(prompt, sizeof prompt, "%s%s", challenge,

if (options.cipher == SSH_CIPHER_NONE)

strchr(challenge, '\n') ? "" : "\nResponse: ");

log("WARNING: Encryption is disabled! "

xfree(challenge);

"Reponse will be transmitted in clear text.");

fprintf(stderr, "%s\n", challenge);

xfree(challenge);

fflush(stderr);

for (i = 0; i < options.number_of_password_prompts; i++) {

if (i != 0)

error("Permission denied, please try again.");

if (options.cipher == SSH_CIPHER_NONE)

response = read_passphrase("Response: ", 0);

log("WARNING: Encryption is disabled! "

"Reponse will be transmitted in clear text.");

response = read_passphrase(prompt, 0);

if (strcmp(response, "") == 0) {

xfree(response);

break;

}

packet_start(SSH_CMSG_AUTH_TIS_RESPONSE);

ssh_put_password(response);

packet_put_string(response, strlen(response));

memset(response, 0, strlen(response));

xfree(response);

packet_send();

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return 1;

if (type != SSH_SMSG_FAILURE)

packet_disconnect("Protocol error: got %d in response "

"to SSH_CMSG_AUTH_TIS_RESPONSE", type);

"to skey-auth-reponse", type);

}

/* failure */

return 0;

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error("Permission denied, please try again.");

password = read_passphrase(prompt, 0);

packet_start(SSH_CMSG_AUTH_PASSWORD);

ssh_put_password(password);

packet_put_string(password, strlen(password));

memset(password, 0, strlen(password));

xfree(password);

packet_send();

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Key k;

int bits, rbits;

int ssh_cipher_default = SSH_CIPHER_3DES;

u_char session_key[SSH_SESSION_KEY_LENGTH];

unsigned char session_key[SSH_SESSION_KEY_LENGTH];

u_char cookie[8];

unsigned char cookie[8];

u_int supported_ciphers;

unsigned int supported_ciphers;

u_int server_flags, client_flags;

unsigned int server_flags, client_flags;

int payload_len, clen, sum_len = 0;

u_int32_t rand = 0;

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packet_integrity_check(payload_len,

8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4,

SSH_SMSG_PUBLIC_KEY);

k.type = KEY_RSA1;

k.type = KEY_RSA;

k.rsa = host_key;

check_host_key(host, hostaddr, &k,

options.user_hostfile, options.system_hostfile);

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RSA_free(public_key);

RSA_free(host_key);

if (options.cipher == SSH_CIPHER_NOT_SET) {

if (options.cipher == SSH_CIPHER_ILLEGAL) {

if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default))

options.cipher = ssh_cipher_default;

} else if (options.cipher == SSH_CIPHER_ILLEGAL ||

!(cipher_mask_ssh1(1) & (1 << options.cipher))) {

log("No valid SSH1 cipher, using %.100s instead.",

cipher_name(ssh_cipher_default));

cipher_name(SSH_FALLBACK_CIPHER));

options.cipher = ssh_cipher_default;

options.cipher = SSH_FALLBACK_CIPHER;

} else if (options.cipher == SSH_CIPHER_NOT_SET) {

if (cipher_mask1() & supported_ciphers & (1 << ssh_cipher_default))

options.cipher = ssh_cipher_default;

else {

debug("Cipher %s not supported, using %.100s instead.",

cipher_name(ssh_cipher_default),

cipher_name(SSH_FALLBACK_CIPHER));

options.cipher = SSH_FALLBACK_CIPHER;

}

/* Check that the selected cipher is supported. */

if (!(supported_ciphers & (1 << options.cipher)))

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void

ssh_userauth(

const char *local_user,

const char* local_user,

const char *server_user,

const char* server_user,

char *host,

int host_key_valid, RSA *own_host_key)

{

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/* Try RSA authentication for each identity. */

for (i = 0; i < options.num_identity_files; i++)

if (options.identity_keys[i] != NULL &&

if (try_rsa_authentication(options.identity_files[i]))

options.identity_keys[i]->type == KEY_RSA1 &&

try_rsa_authentication(options.identity_files[i]))

return;

}

/* Try challenge response authentication if the server supports it. */

/* Try skey authentication if the server supports it. */

if ((supported_authentications & (1 << SSH_AUTH_TIS)) &&

options.challenge_reponse_authentication && !options.batch_mode) {

options.skey_authentication && !options.batch_mode) {

if (try_challenge_reponse_authentication())

if (try_skey_authentication())

return;

}

/* Try password authentication if the server supports it. */

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options.password_authentication && !options.batch_mode) {

char prompt[80];

snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",

snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",

server_user, host);

if (try_password_authentication(prompt))

return;