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

Return to sshconnect1.c CVS log

Up to [local] / src / usr.bin / ssh

Diff for /src/usr.bin/ssh/Attic/sshconnect1.c between version 1.8.2.7 and 1.9

version 1.8.2.7, 2002/03/08 17:04:43

version 1.9, 2000/11/12 19:50:38

Line 16

RCSID("$OpenBSD$");

#include <openssl/bn.h>

#include <openssl/md5.h>

#include <openssl/dsa.h>

#include <openssl/rsa.h>

#include <openssl/evp.h>

#ifdef KRB4

#include <krb.h>

#endif

#ifdef KRB5

#include <krb5.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 "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"

#include "auth.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;

Line 59

Line 44

* Checks if the user has an authentication agent, and if so, tries to

* authenticate using the agent.

static int

int

try_agent_authentication(void)

try_agent_authentication()

{

int type;

char *comment;

AuthenticationConnection *auth;

u_char response[16];

unsigned char response[16];

u_int i;

unsigned int i;

int plen, clen;

Key *key;

BIGNUM *challenge;

Line 75

Line 61

if (!auth)

return 0;

if ((challenge = BN_new()) == NULL)

challenge = BN_new();

fatal("try_agent_authentication: BN_new failed");

key = key_new(KEY_RSA1);

/* 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);

Line 93

Line 80

packet_write_wait();

/* Wait for server's response. */

type = packet_read();

type = packet_read(&plen);

/* The server sends failure if it doesn\'t like our key or

does not support RSA authentication. */

Line 107

Line 94

packet_disconnect("Protocol error during RSA authentication: %d",

type);

packet_get_bignum(challenge);

packet_get_bignum(challenge, &clen);

packet_check_eom();

packet_integrity_check(plen, clen, type);

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

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

Line 133

Line 121

packet_write_wait();

/* Wait for response from the server. */

type = packet_read();

type = packet_read(&plen);

/* 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;

Line 147

Line 134

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;

Line 157

Line 143

* Computes the proper response to a RSA challenge, and sends the response to

* the server.

static void

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);

Line 202

Line 185

* Checks if the user has authentication file, and if so, tries to authenticate

* the user using it.

static int

int

try_rsa_authentication(int idx)

try_rsa_authentication(const char *authfile)

{

BIGNUM *challenge;

Key *public, *private;

Key *public;

char buf[300], *passphrase, *comment, *authfile;

Key *private;

int i, type, quit;

char *passphrase, *comment;

int type, i;

int plen, clen;

public = options.identity_keys[idx];

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

authfile = options.identity_files[idx];

public = key_new(KEY_RSA1);

comment = xstrdup(authfile);

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

key_free(public);

/* Could not load it. Fail. */

return 0;

}

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

/* Tell the server that we are willing to authenticate using this key. */

Line 222

Line 210

packet_send();

packet_write_wait();

/* We no longer need the public key. */

key_free(public);

/* Wait for server's response. */

type = packet_read();

type = packet_read(&plen);

* The server responds with failure if it doesn\'t like our key or

Line 239

Line 230

packet_disconnect("Protocol error during RSA authentication: %d", type);

/* Get the challenge from the packet. */

if ((challenge = BN_new()) == NULL)

challenge = BN_new();

fatal("try_rsa_authentication: BN_new failed");

packet_get_bignum(challenge, &clen);

packet_get_bignum(challenge);

packet_check_eom();

packet_integrity_check(plen, clen, type);

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

private = key_new(KEY_RSA1);

* If the key is not stored in external hardware, we have to

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

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

* fails, ask for a passphrase.

if (public->flags && KEY_FLAG_EXT)

if (!load_private_key(authfile, "", private, NULL)) {

private = public;

char buf[300];

else

snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ",

private = key_load_private_type(KEY_RSA1, authfile, "", NULL);

comment);

if (private == NULL && !options.batch_mode) {

if (!options.batch_mode)

snprintf(buf, sizeof(buf),

"Enter passphrase for RSA key '%.100s': ", comment);

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

passphrase = read_passphrase(buf, 0);

if (strcmp(passphrase, "") != 0) {

else {

private = key_load_private_type(KEY_RSA1,

debug("Will not query passphrase for %.100s in batch mode.",

authfile, passphrase, NULL);

comment);

quit = 0;

passphrase = xstrdup("");

} else {

}

debug2("no passphrase given, try next key");

quit = 1;

/* Load the authentication file using the pasphrase. */

}

if (!load_private_key(authfile, passphrase, private, NULL)) {

memset(passphrase, 0, strlen(passphrase));

xfree(passphrase);

if (private != NULL || quit)

error("Bad passphrase.");

break;

debug2("bad passphrase given, try again...");

/* Send a dummy response packet to avoid protocol error. */

packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);

for (i = 0; i < 16; i++)

packet_put_char(0);

packet_send();

packet_write_wait();

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

packet_read_expect(&plen, SSH_SMSG_FAILURE);

xfree(comment);

return 0;

}

/* Destroy the passphrase. */

memset(passphrase, 0, strlen(passphrase));

xfree(passphrase);

}

/* We no longer need the comment. */

xfree(comment);

if (private == NULL) {

if (!options.batch_mode)

error("Bad passphrase.");

/* Send a dummy response packet to avoid protocol error. */

packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);

for (i = 0; i < 16; i++)

packet_put_char(0);

packet_send();

packet_write_wait();

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

packet_read_expect(SSH_SMSG_FAILURE);

BN_clear_free(challenge);

return 0;

}

/* Compute and send a response to the challenge. */

respond_to_rsa_challenge(challenge, private->rsa);

/* Destroy the private key unless it in external hardware. */

/* Destroy the private key. */

if (!(private->flags & KEY_FLAG_EXT))

key_free(private);

/* We no longer need the challenge. */

BN_clear_free(challenge);

/* Wait for response from the server. */

type = packet_read();

type = packet_read(&plen);

if (type == SSH_SMSG_SUCCESS) {

debug("RSA authentication accepted by server.");

return 1;

Line 321

Line 304

* Tries to authenticate the user using combined rhosts or /etc/hosts.equiv

* authentication and RSA host authentication.

static int

int

try_rhosts_rsa_authentication(const char *local_user, Key * host_key)

try_rhosts_rsa_authentication(const char *local_user, RSA * host_key)

{

int type;

BIGNUM *challenge;

int plen, clen;

debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication.");

/* Tell the server that we are willing to authenticate using this key. */

packet_start(SSH_CMSG_AUTH_RHOSTS_RSA);

packet_put_cstring(local_user);

packet_put_string(local_user, strlen(local_user));

packet_put_int(BN_num_bits(host_key->rsa->n));

packet_put_int(BN_num_bits(host_key->n));

packet_put_bignum(host_key->rsa->e);

packet_put_bignum(host_key->e);

packet_put_bignum(host_key->rsa->n);

packet_put_bignum(host_key->n);

packet_send();

packet_write_wait();

/* Wait for server's response. */

type = packet_read();

type = packet_read(&plen);

/* The server responds with failure if it doesn't admit our

.rhosts authentication or doesn't know our host key. */

Line 352

Line 336

packet_disconnect("Protocol error during RSA authentication: %d", type);

/* Get the challenge from the packet. */

if ((challenge = BN_new()) == NULL)

challenge = BN_new();

fatal("try_rhosts_rsa_authentication: BN_new failed");

packet_get_bignum(challenge, &clen);

packet_get_bignum(challenge);

packet_check_eom();

packet_integrity_check(plen, clen, type);

debug("Received RSA challenge for host key from server.");

/* Compute a response to the challenge. */

respond_to_rsa_challenge(challenge, host_key->rsa);

respond_to_rsa_challenge(challenge, host_key);

/* We no longer need the challenge. */

BN_clear_free(challenge);

/* Wait for response from the server. */

type = packet_read();

type = packet_read(&plen);

if (type == SSH_SMSG_SUCCESS) {

debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server.");

return 1;

Line 378

Line 362

}

#ifdef KRB4

static int

int

try_krb4_authentication(void)

try_kerberos_authentication()

{

KTEXT_ST auth; /* Kerberos data */

char *reply;

char inst[INST_SZ];

char *realm;

CREDENTIALS cred;

int r, type;

int r, type, plen;

socklen_t slen;

Key_schedule schedule;

u_long checksum, cksum;

Line 398

Line 382

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

return 0;

strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)),

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

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. */

checksum = (u_long)getpid();

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]);

debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]);

return 0;

}

/* Get session key to decrypt the server's reply with. */

Line 434

Line 417

slen = sizeof(local);

memset(&local, 0, sizeof(local));

if (getsockname(packet_get_connection_in(),

(struct sockaddr *)&local, &slen) < 0)

(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) {

(struct sockaddr *) & foreign, &slen) < 0) {

debug("getpeername failed: %s", strerror(errno));

fatal_cleanup();

}

/* Get server reply. */

type = packet_read();

type = packet_read(&plen);

switch (type) {

case SSH_SMSG_FAILURE:

/* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */

debug("Kerberos v4 authentication failed.");

debug("Kerberos V4 authentication failed.");

return 0;

break;

case SSH_SMSG_AUTH_KERBEROS_RESPONSE:

/* SSH_SMSG_AUTH_KERBEROS_SUCCESS */

debug("Kerberos v4 authentication accepted.");

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);

packet_check_eom();

packet_integrity_check(plen, 4 + auth.length, type);

* If his response isn't properly encrypted with the session

Line 470

Line 453

* bogus. Bail out.

r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,

&foreign, &local, &msg_data);

if (r != KSUCCESS) {

debug("Kerberos v4 krb_rd_priv failed: %s",

debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]);

krb_err_txt[r]);

packet_disconnect("Kerberos V4 challenge failed!");

packet_disconnect("Kerberos v4 challenge failed!");

}

/* Fetch the (incremented) checksum that we supplied in the request. */

memcpy((char *)&cksum, (char *)msg_data.app_data,

(void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum));

sizeof(cksum));

cksum = ntohl(cksum);

/* If it matches, we're golden. */

if (cksum == checksum + 1) {

debug("Kerberos v4 challenge successful.");

debug("Kerberos V4 challenge successful.");

return 1;

} else

packet_disconnect("Kerberos v4 challenge failed!");

packet_disconnect("Kerberos V4 challenge failed!");

break;

default:

packet_disconnect("Protocol error on Kerberos v4 response: %d", type);

packet_disconnect("Protocol error on Kerberos V4 response: %d", type);

}

return 0;

}

#endif /* KRB4 */

#ifdef KRB5

static int

try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context)

{

krb5_error_code problem;

const char *tkfile;

struct stat buf;

krb5_ccache ccache = NULL;

const char *remotehost;

krb5_data ap;

int type;

krb5_ap_rep_enc_part *reply = NULL;

int ret;

memset(&ap, 0, sizeof(ap));

problem = krb5_init_context(context);

if (problem) {

debug("Kerberos v5: krb5_init_context failed");

ret = 0;

goto out;

}

tkfile = krb5_cc_default_name(*context);

if (strncmp(tkfile, "FILE:", 5) == 0)

tkfile += 5;

if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {

debug("Kerberos v5: could not get default ccache (permission denied).");

ret = 0;

goto out;

}

problem = krb5_cc_default(*context, &ccache);

if (problem) {

debug("Kerberos v5: krb5_cc_default failed: %s",

krb5_get_err_text(*context, problem));

ret = 0;

goto out;

}

remotehost = get_canonical_hostname(1);

problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED,

"host", remotehost, NULL, ccache, &ap);

if (problem) {

debug("Kerberos v5: krb5_mk_req failed: %s",

krb5_get_err_text(*context, problem));

ret = 0;

goto out;

}

packet_start(SSH_CMSG_AUTH_KERBEROS);

packet_put_string((char *) ap.data, ap.length);

packet_send();

packet_write_wait();

xfree(ap.data);

ap.length = 0;

type = packet_read();

switch (type) {

case SSH_SMSG_FAILURE:

/* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */

debug("Kerberos v5 authentication failed.");

ret = 0;

break;

case SSH_SMSG_AUTH_KERBEROS_RESPONSE:

/* SSH_SMSG_AUTH_KERBEROS_SUCCESS */

debug("Kerberos v5 authentication accepted.");

/* Get server's response. */

ap.data = packet_get_string((unsigned int *) &ap.length);

packet_check_eom();

/* XXX je to dobre? */

problem = krb5_rd_rep(*context, *auth_context, &ap, &reply);

if (problem) {

ret = 0;

}

ret = 1;

break;

default:

packet_disconnect("Protocol error on Kerberos v5 response: %d",

type);

ret = 0;

break;

}

out:

if (ccache != NULL)

krb5_cc_close(*context, ccache);

if (reply != NULL)

krb5_free_ap_rep_enc_part(*context, reply);

if (ap.length > 0)

krb5_data_free(&ap);

return (ret);

}

static void

send_krb5_tgt(krb5_context context, krb5_auth_context auth_context)

{

int fd, type;

krb5_error_code problem;

krb5_data outbuf;

krb5_ccache ccache = NULL;

krb5_creds creds;

krb5_kdc_flags flags;

const char *remotehost;

memset(&creds, 0, sizeof(creds));

memset(&outbuf, 0, sizeof(outbuf));

fd = packet_get_connection_in();

problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd);

if (problem)

goto out;

problem = krb5_cc_default(context, &ccache);

if (problem)

goto out;

problem = krb5_cc_get_principal(context, ccache, &creds.client);

if (problem)

goto out;

problem = krb5_build_principal(context, &creds.server,

strlen(creds.client->realm), creds.client->realm,

"krbtgt", creds.client->realm, NULL);

if (problem)

goto out;

creds.times.endtime = 0;

flags.i = 0;

flags.b.forwarded = 1;

flags.b.forwardable = krb5_config_get_bool(context, NULL,

"libdefaults", "forwardable", NULL);

remotehost = get_canonical_hostname(1);

problem = krb5_get_forwarded_creds(context, auth_context,

ccache, flags.i, remotehost, &creds, &outbuf);

if (problem)

goto out;

packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);

packet_put_string((char *)outbuf.data, outbuf.length);

packet_send();

packet_write_wait();

type = packet_read();

if (type == SSH_SMSG_SUCCESS) {

char *pname;

krb5_unparse_name(context, creds.client, &pname);

debug("Kerberos v5 TGT forwarded (%s).", pname);

xfree(pname);

} else

debug("Kerberos v5 TGT forwarding failed.");

return;

out:

if (problem)

debug("Kerberos v5 TGT forwarding failed: %s",

krb5_get_err_text(context, problem));

if (creds.client)

krb5_free_principal(context, creds.client);

if (creds.server)

krb5_free_principal(context, creds.server);

if (ccache)

krb5_cc_close(context, ccache);

if (outbuf.data)

xfree(outbuf.data);

}

#endif /* KRB5 */

#ifdef AFS

static void

int

send_krb4_tgt(void)

send_kerberos_tgt()

{

CREDENTIALS *creds;

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

int r, type, plen;

char buffer[8192];

struct stat st;

char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];

int problem, type;

/* Don't do anything if we don't have any tickets. */

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

return;

return 0;

creds = xmalloc(sizeof(*creds));

problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm);

if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) {

if (problem)

debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]);

goto out;

return 0;

}

problem = krb_get_cred("krbtgt", prealm, prealm, creds);

if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) {

if (problem)

debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]);

goto out;

return 0;

}

if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {

problem = RD_AP_EXP;

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

goto out;

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);

packet_put_cstring(buffer);

packet_put_string(buffer, strlen(buffer));

packet_send();

packet_write_wait();

type = packet_read();

type = packet_read(&plen);

if (type == SSH_SMSG_SUCCESS)

if (type == SSH_SMSG_FAILURE)

debug("Kerberos v4 TGT forwarded (%s%s%s@%s).",

debug("Kerberos TGT for realm %s rejected.", prealm);

creds->pname, creds->pinst[0] ? "." : "",

else if (type != SSH_SMSG_SUCCESS)

creds->pinst, creds->realm);

packet_disconnect("Protocol error on Kerberos TGT response: %d", type);

else

debug("Kerberos v4 TGT rejected.");

xfree(creds);

return 1;

return;

out:

debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]);

xfree(creds);

}

static void

void

send_afs_tokens(void)

{

CREDENTIALS creds;

struct ViceIoctl parms;

struct ClearToken ct;

int i, type, len;

int i, type, len, plen;

char buf[2048], *p, *server_cell;

char buffer[8192];

Line 753

Line 545

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;

Line 771

Line 563

server_cell = p;

/* Flesh out our credentials. */

strlcpy(creds.service, "afs", sizeof(creds.service));

strlcpy(creds.service, "afs", sizeof creds.service);

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

strlcpy(creds.realm, server_cell, REALM_SZ);

memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);

creds.issue_date = ct.BeginTimestamp;

creds.lifetime = krb_time_to_life(creds.issue_date,

creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp);

ct.EndTimestamp);

creds.kvno = ct.AuthHandle;

snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId);

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

/* Encode token, ship it off. */

if (creds_to_radix(&creds, (u_char *)buffer,

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

sizeof(buffer)) <= 0)

break;

packet_start(SSH_CMSG_HAVE_AFS_TOKEN);

packet_put_cstring(buffer);

packet_put_string(buffer, strlen(buffer));

packet_send();

packet_write_wait();

/* Roger, Roger. Clearance, Clarence. What's your vector,

Victor? */

type = packet_read();

type = packet_read(&plen);

if (type == SSH_SMSG_FAILURE)

debug("AFS token for cell %s rejected.", server_cell);

Line 808

Line 598

* Tries to authenticate with any string-based challenge/response system.

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

static int

int

try_challenge_response_authentication(void)

try_skey_authentication()

{

int type, i;

u_int clen;

int payload_len;

char prompt[1024];

unsigned int clen;

char *challenge, *response;

debug("Doing challenge response 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();

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_check_eom();

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();

packet_write_wait();

type = packet_read();

type = packet_read(&payload_len);

if (type == SSH_SMSG_SUCCESS)

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;

Line 869

Line 655

* Tries to authenticate with plain passwd authentication.

static int

int

try_password_authentication(char *prompt)

{

int type, i;

int type, i, payload_len;

char *password;

debug("Doing password authentication.");

Line 883

Line 669

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();

packet_write_wait();

type = packet_read();

type = packet_read(&payload_len);

if (type == SSH_SMSG_SUCCESS)

return 1;

if (type != SSH_SMSG_FAILURE)

Line 907

Line 693

{

int i;

BIGNUM *key;

Key *host_key, *server_key;

RSA *host_key;

RSA *public_key;

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;

debug("Waiting for server public key.");

/* Wait for a public key packet from the server. */

packet_read_expect(SSH_SMSG_PUBLIC_KEY);

packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY);

/* Get cookie from the packet. */

for (i = 0; i < 8; i++)

cookie[i] = packet_get_char();

/* Get the public key. */

server_key = key_new(KEY_RSA1);

public_key = RSA_new();

bits = packet_get_int();

bits = packet_get_int();/* bits */

packet_get_bignum(server_key->rsa->e);

public_key->e = BN_new();

packet_get_bignum(server_key->rsa->n);

packet_get_bignum(public_key->e, &clen);

sum_len += clen;

public_key->n = BN_new();

packet_get_bignum(public_key->n, &clen);

sum_len += clen;

rbits = BN_num_bits(server_key->rsa->n);

rbits = BN_num_bits(public_key->n);

if (bits != rbits) {

log("Warning: Server lies about size of server public key: "

"actual size is %d bits vs. announced %d.", rbits, bits);

log("Warning: This may be due to an old implementation of ssh.");

}

/* Get the host key. */

host_key = key_new(KEY_RSA1);

host_key = RSA_new();

bits = packet_get_int();

bits = packet_get_int();/* bits */

packet_get_bignum(host_key->rsa->e);

host_key->e = BN_new();

packet_get_bignum(host_key->rsa->n);

packet_get_bignum(host_key->e, &clen);

sum_len += clen;

host_key->n = BN_new();

packet_get_bignum(host_key->n, &clen);

sum_len += clen;

rbits = BN_num_bits(host_key->rsa->n);

rbits = BN_num_bits(host_key->n);

if (bits != rbits) {

log("Warning: Server lies about size of server host key: "

"actual size is %d bits vs. announced %d.", rbits, bits);

Line 956

Line 753

supported_ciphers = packet_get_int();

supported_authentications = packet_get_int();

packet_check_eom();

debug("Received server public key (%d bits) and host key (%d bits).",

BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n));

BN_num_bits(public_key->n), BN_num_bits(host_key->n));

if (verify_host_key(host, hostaddr, host_key) == -1)

packet_integrity_check(payload_len,

fatal("Host key verification failed.");

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

SSH_SMSG_PUBLIC_KEY);

k.type = KEY_RSA1;

k.rsa = host_key;

check_host_key(host, hostaddr, &k,

options.user_hostfile, options.system_hostfile);

client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;

compute_session_id(session_id, cookie, host_key->rsa->n, server_key->rsa->n);

compute_session_id(session_id, cookie, host_key->n, public_key->n);

/* Generate a session key. */

arc4random_stir();

Line 988

Line 789

* is the highest byte of the integer. The session key is xored with

* the first 16 bytes of the session id.

if ((key = BN_new()) == NULL)

key = BN_new();

fatal("respond_to_rsa_challenge: BN_new failed");

BN_set_word(key, 0);

for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {

BN_lshift(key, key, 8);

Line 1003

Line 803

* Encrypt the integer using the public key and host key of the

* server (key with smaller modulus first).

if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) {

if (BN_cmp(public_key->n, host_key->n) < 0) {

/* Public key has smaller modulus. */

if (BN_num_bits(host_key->rsa->n) <

if (BN_num_bits(host_key->n) <

BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {

BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) {

fatal("respond_to_rsa_challenge: host_key %d < server_key %d + "

fatal("respond_to_rsa_challenge: host_key %d < public_key %d + "

"SSH_KEY_BITS_RESERVED %d",

BN_num_bits(host_key->rsa->n),

BN_num_bits(host_key->n),

BN_num_bits(server_key->rsa->n),

BN_num_bits(public_key->n),

SSH_KEY_BITS_RESERVED);

}

rsa_public_encrypt(key, key, server_key->rsa);

rsa_public_encrypt(key, key, public_key);

rsa_public_encrypt(key, key, host_key->rsa);

rsa_public_encrypt(key, key, host_key);

} else {

/* Host key has smaller modulus (or they are equal). */

if (BN_num_bits(server_key->rsa->n) <

if (BN_num_bits(public_key->n) <

BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {

BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) {

fatal("respond_to_rsa_challenge: server_key %d < host_key %d + "

fatal("respond_to_rsa_challenge: public_key %d < host_key %d + "

"SSH_KEY_BITS_RESERVED %d",

BN_num_bits(server_key->rsa->n),

BN_num_bits(public_key->n),

BN_num_bits(host_key->rsa->n),

BN_num_bits(host_key->n),

SSH_KEY_BITS_RESERVED);

}

rsa_public_encrypt(key, key, host_key->rsa);

rsa_public_encrypt(key, key, host_key);

rsa_public_encrypt(key, key, server_key->rsa);

rsa_public_encrypt(key, key, public_key);

}

/* Destroy the public keys since we no longer need them. */

key_free(server_key);

RSA_free(public_key);

key_free(host_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));

options.cipher = ssh_cipher_default;

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

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

options.cipher = ssh_cipher_default;

}

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

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

fatal("Selected cipher type %.100s not supported by server.",

cipher_name(options.cipher));

debug("Encryption type: %.100s", cipher_name(options.cipher));

Line 1080

Line 879

* Expect a success message from the server. Note that this message

* will be received in encrypted form.

packet_read_expect(SSH_SMSG_SUCCESS);

packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);

debug("Received encrypted confirmation.");

}

Line 1089

Line 888

* Authenticate user

void

ssh_userauth1(const char *local_user, const char *server_user, char *host,

ssh_userauth(

Key **keys, int nkeys)

const char* local_user,

const char* server_user,

char *host,

int host_key_valid, RSA *own_host_key)

{

#ifdef KRB5

krb5_context context = NULL;

krb5_auth_context auth_context = NULL;

#endif

int i, type;

int payload_len;

if (supported_authentications == 0)

fatal("ssh_userauth1: server supports no auth methods");

fatal("ssh_userauth: server supports no auth methods");

/* Send the name of the user to log in as on the server. */

packet_start(SSH_CMSG_USER);

packet_put_cstring(server_user);

packet_put_string(server_user, strlen(server_user));

packet_send();

packet_write_wait();

Line 1112

Line 911

* needed (the user has no password). Otherwise the server responds

* with failure.

type = packet_read();

type = packet_read(&payload_len);

/* check whether the connection was accepted without authentication. */

if (type == SSH_SMSG_SUCCESS)

goto success;

return;

if (type != SSH_SMSG_FAILURE)

packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type);

packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER",

type);

#ifdef KRB5

#ifdef AFS

if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&

/* Try Kerberos tgt passing if the server supports it. */

options.kerberos_authentication) {

if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&

debug("Trying Kerberos v5 authentication.");

options.kerberos_tgt_passing) {

if (options.cipher == SSH_CIPHER_NONE)

if (try_krb5_authentication(&context, &auth_context)) {

log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");

type = packet_read();

(void) send_kerberos_tgt();

if (type == SSH_SMSG_SUCCESS)

goto success;

if (type != SSH_SMSG_FAILURE)

packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type);

}

#endif /* KRB5 */

/* Try AFS token passing if the server supports it. */

if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&

options.afs_token_passing && k_hasafs()) {

if (options.cipher == SSH_CIPHER_NONE)

log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");

send_afs_tokens();

}

#endif /* AFS */

#ifdef KRB4

if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&

options.kerberos_authentication) {

debug("Trying Kerberos v4 authentication.");

debug("Trying Kerberos authentication.");

if (try_kerberos_authentication()) {

if (try_krb4_authentication()) {

/* The server should respond with success or failure. */

type = packet_read();

type = packet_read(&payload_len);

if (type == SSH_SMSG_SUCCESS)

goto success;

return;

if (type != SSH_SMSG_FAILURE)

packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type);

packet_disconnect("Protocol error: got %d in response to Kerberos auth", type);

}

#endif /* KRB4 */

Line 1158

Line 960

options.rhosts_authentication) {

debug("Trying rhosts authentication.");

packet_start(SSH_CMSG_AUTH_RHOSTS);

packet_put_cstring(local_user);

packet_put_string(local_user, strlen(local_user));

packet_send();

packet_write_wait();

/* The server should respond with success or failure. */

type = packet_read();

type = packet_read(&payload_len);

if (type == SSH_SMSG_SUCCESS)

goto success;

return;

if (type != SSH_SMSG_FAILURE)

packet_disconnect("Protocol error: got %d in response to rhosts auth",

type);

Line 1175

Line 977

* authentication.

if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&

options.rhosts_rsa_authentication) {

options.rhosts_rsa_authentication && host_key_valid) {

for (i = 0; i < nkeys; i++) {

if (try_rhosts_rsa_authentication(local_user, own_host_key))

if (keys[i] != NULL && keys[i]->type == KEY_RSA1 &&

return;

try_rhosts_rsa_authentication(local_user, keys[i]))

goto success;

}

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

if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&

Line 1191

Line 990

* it, whereas identity files may require passphrases.

if (try_agent_authentication())

goto success;

return;

/* Try RSA authentication for each identity. */

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

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

if (options.identity_files_type[i] == KEY_RSA1 &&

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

try_rsa_authentication(options.identity_files[i]))

try_rsa_authentication(i))

return;

goto success;

}

/* 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_response_authentication && !options.batch_mode) {

options.skey_authentication && !options.batch_mode) {

if (try_challenge_response_authentication())

if (try_skey_authentication())

goto success;

return;

}

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

if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&

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))

goto success;

return;

}

/* All authentication methods have failed. Exit with an error message. */

fatal("Permission denied.");

/* NOTREACHED */

success:

#ifdef KRB5

/* Try Kerberos v5 TGT passing. */

if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&

options.kerberos_tgt_passing && context && auth_context) {

if (options.cipher == SSH_CIPHER_NONE)

log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");

send_krb5_tgt(context, auth_context);

}

if (auth_context)

krb5_auth_con_free(context, auth_context);

if (context)

krb5_free_context(context);

#endif

#ifdef AFS

/* Try Kerberos v4 TGT passing if the server supports it. */

if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&

options.kerberos_tgt_passing) {

if (options.cipher == SSH_CIPHER_NONE)

log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");

send_krb4_tgt();

}

/* Try AFS token passing if the server supports it. */

if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&

options.afs_token_passing && k_hasafs()) {

if (options.cipher == SSH_CIPHER_NONE)

log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");

send_afs_tokens();

}

#endif /* AFS */

return; /* need statement after label */

}