* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by Markus Friedl.
- * 4. The name of the author may not be used to endorse or promote products
- * derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
*/
#include "includes.h"
-RCSID("$OpenBSD: sshconnect2.c,v 1.10 2000/05/08 17:42:25 markus Exp $");
+RCSID("$OpenBSD: sshconnect2.c,v 1.81 2001/07/23 09:06:28 markus Exp $");
#include <openssl/bn.h>
-#include <openssl/rsa.h>
-#include <openssl/dsa.h>
#include <openssl/md5.h>
#include <openssl/dh.h>
#include <openssl/hmac.h>
#include "ssh.h"
+#include "ssh2.h"
#include "xmalloc.h"
#include "rsa.h"
#include "buffer.h"
#include "packet.h"
-#include "cipher.h"
#include "uidswap.h"
#include "compat.h"
-#include "readconf.h"
#include "bufaux.h"
-#include "ssh2.h"
+#include "cipher.h"
#include "kex.h"
#include "myproposal.h"
#include "key.h"
-#include "dsa.h"
#include "sshconnect.h"
#include "authfile.h"
+#include "dh.h"
+#include "authfd.h"
+#include "log.h"
+#include "readconf.h"
+#include "readpass.h"
+#include "match.h"
+#include "dispatch.h"
+#include "canohost.h"
/* import */
extern char *client_version_string;
* SSH2 key exchange
*/
-unsigned char *session_id2 = NULL;
+u_char *session_id2 = NULL;
int session_id2_len = 0;
+char *xxx_host;
+struct sockaddr *xxx_hostaddr;
+
+Kex *xxx_kex = NULL;
+
+static int
+verify_host_key_callback(Key *hostkey)
+{
+ if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
+ fatal("verify_host_key failed");
+ return 0;
+}
+
void
ssh_kex2(char *host, struct sockaddr *hostaddr)
{
Kex *kex;
- char *cprop[PROPOSAL_MAX];
- char *sprop[PROPOSAL_MAX];
- Buffer *client_kexinit;
- Buffer *server_kexinit;
- int payload_len, dlen;
- unsigned int klen, kout;
- char *ptr;
- char *signature = NULL;
- unsigned int slen;
- char *server_host_key_blob = NULL;
- Key *server_host_key;
- unsigned int sbloblen;
- DH *dh;
- BIGNUM *dh_server_pub = 0;
- BIGNUM *shared_secret = 0;
- int i;
- unsigned char *kbuf;
- unsigned char *hash;
-
-/* KEXINIT */
-
- debug("Sending KEX init.");
+
+ xxx_host = host;
+ xxx_hostaddr = hostaddr;
+
+ if (options.ciphers == (char *)-1) {
+ log("No valid ciphers for protocol version 2 given, using defaults.");
+ options.ciphers = NULL;
+ }
if (options.ciphers != NULL) {
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
- } else if (options.cipher == SSH_CIPHER_3DES) {
- myproposal[PROPOSAL_ENC_ALGS_CTOS] =
- myproposal[PROPOSAL_ENC_ALGS_STOC] =
- cipher_name(SSH_CIPHER_3DES_CBC);
- } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
- myproposal[PROPOSAL_ENC_ALGS_CTOS] =
- myproposal[PROPOSAL_ENC_ALGS_STOC] =
- cipher_name(SSH_CIPHER_BLOWFISH_CBC);
}
+ myproposal[PROPOSAL_ENC_ALGS_CTOS] =
+ compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
+ myproposal[PROPOSAL_ENC_ALGS_STOC] =
+ compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
if (options.compression) {
- myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib";
+ myproposal[PROPOSAL_COMP_ALGS_CTOS] =
myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
} else {
- myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none";
+ myproposal[PROPOSAL_COMP_ALGS_CTOS] =
myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
}
- for (i = 0; i < PROPOSAL_MAX; i++)
- cprop[i] = xstrdup(myproposal[i]);
-
- client_kexinit = kex_init(cprop);
- packet_start(SSH2_MSG_KEXINIT);
- packet_put_raw(buffer_ptr(client_kexinit), buffer_len(client_kexinit));
- packet_send();
- packet_write_wait();
-
- debug("done");
-
- packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
-
- /* save payload for session_id */
- server_kexinit = xmalloc(sizeof(*server_kexinit));
- buffer_init(server_kexinit);
- ptr = packet_get_raw(&payload_len);
- buffer_append(server_kexinit, ptr, payload_len);
-
- /* skip cookie */
- for (i = 0; i < 16; i++)
- (void) packet_get_char();
- /* kex init proposal strings */
- for (i = 0; i < PROPOSAL_MAX; i++) {
- sprop[i] = packet_get_string(NULL);
- debug("got kexinit string: %s", sprop[i]);
+ if (options.macs != NULL) {
+ myproposal[PROPOSAL_MAC_ALGS_CTOS] =
+ myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
}
- i = (int) packet_get_char();
- debug("first kex follow == %d", i);
- i = packet_get_int();
- debug("reserved == %d", i);
- packet_done();
+ if (options.hostkeyalgorithms != NULL)
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
+ options.hostkeyalgorithms;
- debug("done read kexinit");
- kex = kex_choose_conf(cprop, sprop, 0);
+ /* start key exchange */
+ kex = kex_setup(myproposal);
+ kex->client_version_string=client_version_string;
+ kex->server_version_string=server_version_string;
+ kex->verify_host_key=&verify_host_key_callback;
-/* KEXDH */
+ xxx_kex = kex;
- debug("Sending SSH2_MSG_KEXDH_INIT.");
+ dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
- /* generate and send 'e', client DH public key */
- dh = dh_new_group1();
- packet_start(SSH2_MSG_KEXDH_INIT);
- packet_put_bignum2(dh->pub_key);
- packet_send();
- packet_write_wait();
+ session_id2 = kex->session_id;
+ session_id2_len = kex->session_id_len;
#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");
- DHparams_print_fp(stderr, dh);
+ /* send 1st encrypted/maced/compressed message */
+ packet_start(SSH2_MSG_IGNORE);
+ packet_put_cstring("markus");
+ packet_send();
+ packet_write_wait();
#endif
+ debug("done: ssh_kex2.");
+}
- debug("Wait SSH2_MSG_KEXDH_REPLY.");
+/*
+ * Authenticate user
+ */
- packet_read_expect(&payload_len, SSH2_MSG_KEXDH_REPLY);
+typedef struct Authctxt Authctxt;
+typedef struct Authmethod Authmethod;
+
+typedef int sign_cb_fn(
+ Authctxt *authctxt, Key *key,
+ u_char **sigp, int *lenp, u_char *data, int datalen);
+
+struct Authctxt {
+ const char *server_user;
+ const char *local_user;
+ const char *host;
+ const char *service;
+ Authmethod *method;
+ int success;
+ char *authlist;
+ /* pubkey */
+ Key *last_key;
+ sign_cb_fn *last_key_sign;
+ int last_key_hint;
+ AuthenticationConnection *agent;
+ /* hostbased */
+ Key **keys;
+ int nkeys;
+};
+struct Authmethod {
+ char *name; /* string to compare against server's list */
+ int (*userauth)(Authctxt *authctxt);
+ int *enabled; /* flag in option struct that enables method */
+ int *batch_flag; /* flag in option struct that disables method */
+};
+
+void input_userauth_success(int type, int plen, void *ctxt);
+void input_userauth_failure(int type, int plen, void *ctxt);
+void input_userauth_banner(int type, int plen, void *ctxt);
+void input_userauth_error(int type, int plen, void *ctxt);
+void input_userauth_info_req(int type, int plen, void *ctxt);
+void input_userauth_pk_ok(int type, int plen, void *ctxt);
+
+int userauth_none(Authctxt *authctxt);
+int userauth_pubkey(Authctxt *authctxt);
+int userauth_passwd(Authctxt *authctxt);
+int userauth_kbdint(Authctxt *authctxt);
+int userauth_hostbased(Authctxt *authctxt);
+
+void userauth(Authctxt *authctxt, char *authlist);
+
+static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
+static void clear_auth_state(Authctxt *);
+
+static Authmethod *authmethod_get(char *authlist);
+static Authmethod *authmethod_lookup(const char *name);
+static char *authmethods_get(void);
+
+Authmethod authmethods[] = {
+ {"hostbased",
+ userauth_hostbased,
+ &options.hostbased_authentication,
+ NULL},
+ {"publickey",
+ userauth_pubkey,
+ &options.pubkey_authentication,
+ NULL},
+ {"keyboard-interactive",
+ userauth_kbdint,
+ &options.kbd_interactive_authentication,
+ &options.batch_mode},
+ {"password",
+ userauth_passwd,
+ &options.password_authentication,
+ &options.batch_mode},
+ {"none",
+ userauth_none,
+ NULL,
+ NULL},
+ {NULL, NULL, NULL, NULL}
+};
- debug("Got SSH2_MSG_KEXDH_REPLY.");
+void
+ssh_userauth2(const char *local_user, const char *server_user, char *host,
+ Key **keys, int nkeys)
+{
+ Authctxt authctxt;
+ int type;
+ int plen;
- /* key, cert */
- server_host_key_blob = packet_get_string(&sbloblen);
- server_host_key = dsa_key_from_blob(server_host_key_blob, sbloblen);
- if (server_host_key == NULL)
- fatal("cannot decode server_host_key_blob");
+ if (options.challenge_response_authentication)
+ options.kbd_interactive_authentication = 1;
- check_host_key(host, hostaddr, server_host_key,
- options.user_hostfile2, options.system_hostfile2);
+ debug("send SSH2_MSG_SERVICE_REQUEST");
+ packet_start(SSH2_MSG_SERVICE_REQUEST);
+ packet_put_cstring("ssh-userauth");
+ packet_send();
+ packet_write_wait();
+ type = packet_read(&plen);
+ if (type != SSH2_MSG_SERVICE_ACCEPT) {
+ fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
+ }
+ if (packet_remaining() > 0) {
+ char *reply = packet_get_string(&plen);
+ debug("service_accept: %s", reply);
+ xfree(reply);
+ } else {
+ debug("buggy server: service_accept w/o service");
+ }
+ packet_done();
+ debug("got SSH2_MSG_SERVICE_ACCEPT");
- /* DH paramter f, server public DH key */
- dh_server_pub = BN_new();
- if (dh_server_pub == NULL)
- fatal("dh_server_pub == NULL");
- packet_get_bignum2(dh_server_pub, &dlen);
+ if (options.preferred_authentications == NULL)
+ options.preferred_authentications = authmethods_get();
+
+ /* setup authentication context */
+ authctxt.agent = ssh_get_authentication_connection();
+ authctxt.server_user = server_user;
+ authctxt.local_user = local_user;
+ authctxt.host = host;
+ authctxt.service = "ssh-connection"; /* service name */
+ authctxt.success = 0;
+ authctxt.method = authmethod_lookup("none");
+ authctxt.authlist = NULL;
+ authctxt.keys = keys;
+ authctxt.nkeys = nkeys;
+ if (authctxt.method == NULL)
+ fatal("ssh_userauth2: internal error: cannot send userauth none request");
+
+ /* initial userauth request */
+ userauth_none(&authctxt);
+
+ dispatch_init(&input_userauth_error);
+ dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
+ dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
+ dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
+ dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
+
+ if (authctxt.agent != NULL)
+ ssh_close_authentication_connection(authctxt.agent);
+
+ debug("ssh-userauth2 successful: method %s", authctxt.method->name);
+}
+void
+userauth(Authctxt *authctxt, char *authlist)
+{
+ if (authlist == NULL) {
+ authlist = authctxt->authlist;
+ } else {
+ if (authctxt->authlist)
+ xfree(authctxt->authlist);
+ authctxt->authlist = authlist;
+ }
+ for (;;) {
+ Authmethod *method = authmethod_get(authlist);
+ if (method == NULL)
+ fatal("Permission denied (%s).", authlist);
+ authctxt->method = method;
+ if (method->userauth(authctxt) != 0) {
+ debug2("we sent a %s packet, wait for reply", method->name);
+ break;
+ } else {
+ debug2("we did not send a packet, disable method");
+ method->enabled = NULL;
+ }
+ }
+}
+void
+input_userauth_error(int type, int plen, void *ctxt)
+{
+ fatal("input_userauth_error: bad message during authentication: "
+ "type %d", type);
+}
+void
+input_userauth_banner(int type, int plen, void *ctxt)
+{
+ char *msg, *lang;
+ debug3("input_userauth_banner");
+ msg = packet_get_string(NULL);
+ lang = packet_get_string(NULL);
+ fprintf(stderr, "%s", msg);
+ xfree(msg);
+ xfree(lang);
+}
+void
+input_userauth_success(int type, int plen, void *ctxt)
+{
+ Authctxt *authctxt = ctxt;
+ if (authctxt == NULL)
+ fatal("input_userauth_success: no authentication context");
+ if (authctxt->authlist)
+ xfree(authctxt->authlist);
+ clear_auth_state(authctxt);
+ authctxt->success = 1; /* break out */
+}
+void
+input_userauth_failure(int type, int plen, void *ctxt)
+{
+ Authctxt *authctxt = ctxt;
+ char *authlist = NULL;
+ int partial;
-#ifdef DEBUG_KEXDH
- fprintf(stderr, "\ndh_server_pub= ");
- bignum_print(dh_server_pub);
- fprintf(stderr, "\n");
- debug("bits %d", BN_num_bits(dh_server_pub));
-#endif
+ if (authctxt == NULL)
+ fatal("input_userauth_failure: no authentication context");
- /* signed H */
- signature = packet_get_string(&slen);
+ authlist = packet_get_string(NULL);
+ partial = packet_get_char();
packet_done();
- if (!dh_pub_is_valid(dh, dh_server_pub))
- packet_disconnect("bad server public DH value");
+ if (partial != 0)
+ log("Authenticated with partial success.");
+ debug("authentications that can continue: %s", authlist);
- klen = DH_size(dh);
- kbuf = xmalloc(klen);
- kout = DH_compute_key(kbuf, dh_server_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);
-
- /* calc and verify H */
- 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),
- server_host_key_blob, sbloblen,
- dh->pub_key,
- dh_server_pub,
- shared_secret
- );
- xfree(server_host_key_blob);
- 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
- if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1)
- fatal("dsa_verify failed for server_host_key");
- key_free(server_host_key);
+ clear_auth_state(authctxt);
+ userauth(authctxt, authlist);
+}
+void
+input_userauth_pk_ok(int type, int plen, void *ctxt)
+{
+ Authctxt *authctxt = ctxt;
+ Key *key = NULL;
+ Buffer b;
+ int alen, blen, sent = 0;
+ char *pkalg, *pkblob, *fp;
+
+ if (authctxt == NULL)
+ fatal("input_userauth_pk_ok: no authentication context");
+ if (datafellows & SSH_BUG_PKOK) {
+ /* this is similar to SSH_BUG_PKAUTH */
+ debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
+ pkblob = packet_get_string(&blen);
+ buffer_init(&b);
+ buffer_append(&b, pkblob, blen);
+ pkalg = buffer_get_string(&b, &alen);
+ buffer_free(&b);
+ } else {
+ pkalg = packet_get_string(&alen);
+ pkblob = packet_get_string(&blen);
+ }
+ packet_done();
- kex_derive_keys(kex, hash, shared_secret);
- packet_set_kex(kex);
+ debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
+ pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
- /* have keys, free DH */
- DH_free(dh);
+ do {
+ if (authctxt->last_key == NULL ||
+ authctxt->last_key_sign == NULL) {
+ debug("no last key or no sign cb");
+ break;
+ }
+ if (key_type_from_name(pkalg) == KEY_UNSPEC) {
+ debug("unknown pkalg %s", pkalg);
+ break;
+ }
+ if ((key = key_from_blob(pkblob, blen)) == NULL) {
+ debug("no key from blob. pkalg %s", pkalg);
+ break;
+ }
+ fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
+ debug2("input_userauth_pk_ok: fp %s", fp);
+ xfree(fp);
+ if (!key_equal(key, authctxt->last_key)) {
+ debug("key != last_key");
+ break;
+ }
+ sent = sign_and_send_pubkey(authctxt, key,
+ authctxt->last_key_sign);
+ } while(0);
- /* save session id */
- session_id2_len = 20;
- session_id2 = xmalloc(session_id2_len);
- memcpy(session_id2, hash, session_id2_len);
+ if (key != NULL)
+ key_free(key);
+ xfree(pkalg);
+ xfree(pkblob);
- debug("Wait SSH2_MSG_NEWKEYS.");
- packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
- packet_done();
- debug("GOT SSH2_MSG_NEWKEYS.");
+ /* unregister */
+ clear_auth_state(authctxt);
+ dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
- debug("send SSH2_MSG_NEWKEYS.");
- packet_start(SSH2_MSG_NEWKEYS);
- packet_send();
- packet_write_wait();
- debug("done: send SSH2_MSG_NEWKEYS.");
+ /* try another method if we did not send a packet*/
+ if (sent == 0)
+ userauth(authctxt, NULL);
-#ifdef DEBUG_KEXDH
- /* send 1st encrypted/maced/compressed message */
- packet_start(SSH2_MSG_IGNORE);
- packet_put_cstring("markus");
+}
+
+int
+userauth_none(Authctxt *authctxt)
+{
+ /* initial userauth request */
+ packet_start(SSH2_MSG_USERAUTH_REQUEST);
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
packet_send();
- packet_write_wait();
-#endif
- debug("done: KEX2.");
+ return 1;
}
-/*
- * Authenticate user
- */
+
int
-ssh2_try_passwd(const char *server_user, const char *host, const char *service)
+userauth_passwd(Authctxt *authctxt)
{
static int attempt = 0;
char prompt[80];
char *password;
- if (attempt++ > options.number_of_password_prompts)
+ if (attempt++ >= options.number_of_password_prompts)
return 0;
- snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",
- server_user, host);
+ if(attempt != 1)
+ error("Permission denied, please try again.");
+
+ snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
+ authctxt->server_user, authctxt->host);
password = read_passphrase(prompt, 0);
packet_start(SSH2_MSG_USERAUTH_REQUEST);
- packet_put_cstring(server_user);
- packet_put_cstring(service);
- packet_put_cstring("password");
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
packet_put_char(0);
packet_put_cstring(password);
memset(password, 0, strlen(password));
xfree(password);
+ packet_inject_ignore(64);
packet_send();
- packet_write_wait();
return 1;
}
-int
-ssh2_try_pubkey(char *filename,
- const char *server_user, const char *host, const char *service)
+static void
+clear_auth_state(Authctxt *authctxt)
+{
+ /* XXX clear authentication state */
+ if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
+ debug3("clear_auth_state: key_free %p", authctxt->last_key);
+ key_free(authctxt->last_key);
+ }
+ authctxt->last_key = NULL;
+ authctxt->last_key_hint = -2;
+ authctxt->last_key_sign = NULL;
+}
+
+static int
+sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
{
Buffer b;
- Key *k;
- unsigned char *blob, *signature;
+ u_char *blob, *signature;
int bloblen, slen;
- struct stat st;
+ int skip = 0;
+ int ret = -1;
+ int have_sig = 1;
- if (stat(filename, &st) != 0) {
- debug("key does not exist: %s", filename);
- return 0;
- }
- debug("try pubkey: %s", filename);
+ debug3("sign_and_send_pubkey");
- k = key_new(KEY_DSA);
- if (!load_private_key(filename, "", k, NULL)) {
- int success = 0;
- char *passphrase;
- char prompt[300];
- snprintf(prompt, sizeof prompt,
- "Enter passphrase for DSA key '%.100s': ",
- filename);
- passphrase = read_passphrase(prompt, 0);
- success = load_private_key(filename, passphrase, k, NULL);
- memset(passphrase, 0, strlen(passphrase));
- xfree(passphrase);
- if (!success)
- return 0;
+ if (key_to_blob(k, &blob, &bloblen) == 0) {
+ /* we cannot handle this key */
+ debug3("sign_and_send_pubkey: cannot handle key");
+ return 0;
}
- dsa_make_key_blob(k, &blob, &bloblen);
-
/* data to be signed */
buffer_init(&b);
- buffer_append(&b, session_id2, session_id2_len);
+ if (datafellows & SSH_OLD_SESSIONID) {
+ buffer_append(&b, session_id2, session_id2_len);
+ skip = session_id2_len;
+ } else {
+ buffer_put_string(&b, session_id2, session_id2_len);
+ skip = buffer_len(&b);
+ }
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
- buffer_put_cstring(&b, server_user);
+ buffer_put_cstring(&b, authctxt->server_user);
buffer_put_cstring(&b,
- datafellows & SSH_BUG_PUBKEYAUTH ?
+ datafellows & SSH_BUG_PKSERVICE ?
"ssh-userauth" :
- service);
- buffer_put_cstring(&b, "publickey");
- buffer_put_char(&b, 1);
- buffer_put_cstring(&b, KEX_DSS);
+ authctxt->service);
+ if (datafellows & SSH_BUG_PKAUTH) {
+ buffer_put_char(&b, have_sig);
+ } else {
+ buffer_put_cstring(&b, authctxt->method->name);
+ buffer_put_char(&b, have_sig);
+ buffer_put_cstring(&b, key_ssh_name(k));
+ }
buffer_put_string(&b, blob, bloblen);
/* generate signature */
- dsa_sign(k, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
- key_free(k);
-#ifdef DEBUG_DSS
+ ret = (*sign_callback)(authctxt, k, &signature, &slen,
+ buffer_ptr(&b), buffer_len(&b));
+ if (ret == -1) {
+ xfree(blob);
+ buffer_free(&b);
+ return 0;
+ }
+#ifdef DEBUG_PK
buffer_dump(&b);
#endif
- if (datafellows & SSH_BUG_PUBKEYAUTH) {
- /* e.g. ssh-2.0.13: data-to-be-signed != data-on-the-wire */
+ if (datafellows & SSH_BUG_PKSERVICE) {
buffer_clear(&b);
buffer_append(&b, session_id2, session_id2_len);
+ skip = session_id2_len;
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
- buffer_put_cstring(&b, server_user);
- buffer_put_cstring(&b, service);
- buffer_put_cstring(&b, "publickey");
- buffer_put_char(&b, 1);
- buffer_put_cstring(&b, KEX_DSS);
+ buffer_put_cstring(&b, authctxt->server_user);
+ buffer_put_cstring(&b, authctxt->service);
+ buffer_put_cstring(&b, authctxt->method->name);
+ buffer_put_char(&b, have_sig);
+ if (!(datafellows & SSH_BUG_PKAUTH))
+ buffer_put_cstring(&b, key_ssh_name(k));
buffer_put_string(&b, blob, bloblen);
}
xfree(blob);
+
/* append signature */
buffer_put_string(&b, signature, slen);
xfree(signature);
/* skip session id and packet type */
- if (buffer_len(&b) < session_id2_len + 1)
- fatal("ssh2_try_pubkey: internal error");
- buffer_consume(&b, session_id2_len + 1);
+ if (buffer_len(&b) < skip + 1)
+ fatal("userauth_pubkey: internal error");
+ buffer_consume(&b, skip + 1);
/* put remaining data from buffer into packet */
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_raw(buffer_ptr(&b), buffer_len(&b));
buffer_free(&b);
-
- /* send */
packet_send();
- packet_write_wait();
+
return 1;
}
-void
-ssh_userauth2(const char *server_user, char *host)
+static int
+send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
+ int hint)
{
- int type;
- int plen;
- int sent;
- unsigned int dlen;
- int partial;
- int i = 0;
- char *auths;
- char *service = "ssh-connection"; /* service name */
+ u_char *blob;
+ int bloblen, have_sig = 0;
- debug("send SSH2_MSG_SERVICE_REQUEST");
- packet_start(SSH2_MSG_SERVICE_REQUEST);
- packet_put_cstring("ssh-userauth");
+ debug3("send_pubkey_test");
+
+ if (key_to_blob(k, &blob, &bloblen) == 0) {
+ /* we cannot handle this key */
+ debug3("send_pubkey_test: cannot handle key");
+ return 0;
+ }
+ /* register callback for USERAUTH_PK_OK message */
+ authctxt->last_key_sign = sign_callback;
+ authctxt->last_key_hint = hint;
+ authctxt->last_key = k;
+ dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
+
+ packet_start(SSH2_MSG_USERAUTH_REQUEST);
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
+ packet_put_char(have_sig);
+ if (!(datafellows & SSH_BUG_PKAUTH))
+ packet_put_cstring(key_ssh_name(k));
+ packet_put_string(blob, bloblen);
+ xfree(blob);
packet_send();
- packet_write_wait();
+ return 1;
+}
- type = packet_read(&plen);
- if (type != SSH2_MSG_SERVICE_ACCEPT) {
- fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
+static Key *
+load_identity_file(char *filename)
+{
+ Key *private;
+ char prompt[300], *passphrase;
+ int quit, i;
+ struct stat st;
+
+ if (stat(filename, &st) < 0) {
+ debug3("no such identity: %s", filename);
+ return NULL;
}
- if (packet_remaining() > 0) {
- char *reply = packet_get_string(&plen);
- debug("service_accept: %s", reply);
- xfree(reply);
+ private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
+ if (private == NULL) {
+ if (options.batch_mode)
+ return NULL;
+ snprintf(prompt, sizeof prompt,
+ "Enter passphrase for key '%.100s': ", filename);
+ for (i = 0; i < options.number_of_password_prompts; i++) {
+ passphrase = read_passphrase(prompt, 0);
+ if (strcmp(passphrase, "") != 0) {
+ private = key_load_private_type(KEY_UNSPEC, filename,
+ passphrase, NULL);
+ quit = 0;
+ } else {
+ debug2("no passphrase given, try next key");
+ quit = 1;
+ }
+ memset(passphrase, 0, strlen(passphrase));
+ xfree(passphrase);
+ if (private != NULL || quit)
+ break;
+ debug2("bad passphrase given, try again...");
+ }
+ }
+ return private;
+}
+
+static int
+identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
+ u_char *data, int datalen)
+{
+ Key *private;
+ int idx, ret;
+
+ idx = authctxt->last_key_hint;
+ if (idx < 0)
+ return -1;
+
+ /* private key is stored in external hardware */
+ if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
+ return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
+
+ private = load_identity_file(options.identity_files[idx]);
+ if (private == NULL)
+ return -1;
+ ret = key_sign(private, sigp, lenp, data, datalen);
+ key_free(private);
+ return ret;
+}
+
+static int
+agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
+ u_char *data, int datalen)
+{
+ return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
+}
+
+static int
+key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
+ u_char *data, int datalen)
+{
+ return key_sign(key, sigp, lenp, data, datalen);
+}
+
+static int
+userauth_pubkey_agent(Authctxt *authctxt)
+{
+ static int called = 0;
+ int ret = 0;
+ char *comment;
+ Key *k;
+
+ if (called == 0) {
+ if (ssh_get_num_identities(authctxt->agent, 2) == 0)
+ debug2("userauth_pubkey_agent: no keys at all");
+ called = 1;
+ }
+ k = ssh_get_next_identity(authctxt->agent, &comment, 2);
+ if (k == NULL) {
+ debug2("userauth_pubkey_agent: no more keys");
} else {
- /* payload empty for ssh-2.0.13 ?? */
- debug("buggy server: service_accept w/o service");
+ debug("userauth_pubkey_agent: testing agent key %s", comment);
+ xfree(comment);
+ ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
+ if (ret == 0)
+ key_free(k);
}
- packet_done();
- debug("got SSH2_MSG_SERVICE_ACCEPT");
+ if (ret == 0)
+ debug2("userauth_pubkey_agent: no message sent");
+ return ret;
+}
- /* INITIAL request for auth */
+int
+userauth_pubkey(Authctxt *authctxt)
+{
+ static int idx = 0;
+ int sent = 0;
+ Key *key;
+ char *filename;
+
+ if (authctxt->agent != NULL) {
+ do {
+ sent = userauth_pubkey_agent(authctxt);
+ } while(!sent && authctxt->agent->howmany > 0);
+ }
+ while (!sent && idx < options.num_identity_files) {
+ key = options.identity_keys[idx];
+ filename = options.identity_files[idx];
+ if (key == NULL) {
+ debug("try privkey: %s", filename);
+ key = load_identity_file(filename);
+ if (key != NULL) {
+ sent = sign_and_send_pubkey(authctxt, key,
+ key_sign_cb);
+ key_free(key);
+ }
+ } else if (key->type != KEY_RSA1) {
+ debug("try pubkey: %s", filename);
+ sent = send_pubkey_test(authctxt, key,
+ identity_sign_cb, idx);
+ }
+ idx++;
+ }
+ return sent;
+}
+
+/*
+ * Send userauth request message specifying keyboard-interactive method.
+ */
+int
+userauth_kbdint(Authctxt *authctxt)
+{
+ static int attempt = 0;
+
+ if (attempt++ >= options.number_of_password_prompts)
+ return 0;
+
+ debug2("userauth_kbdint");
packet_start(SSH2_MSG_USERAUTH_REQUEST);
- packet_put_cstring(server_user);
- packet_put_cstring(service);
- packet_put_cstring("none");
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
+ packet_put_cstring(""); /* lang */
+ packet_put_cstring(options.kbd_interactive_devices ?
+ options.kbd_interactive_devices : "");
packet_send();
- packet_write_wait();
- for (;;) {
- sent = 0;
- type = packet_read(&plen);
- if (type == SSH2_MSG_USERAUTH_SUCCESS)
+ dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
+ return 1;
+}
+
+/*
+ * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
+ */
+void
+input_userauth_info_req(int type, int plen, void *ctxt)
+{
+ Authctxt *authctxt = ctxt;
+ char *name, *inst, *lang, *prompt, *response;
+ u_int num_prompts, i;
+ int echo = 0;
+
+ debug2("input_userauth_info_req");
+
+ if (authctxt == NULL)
+ fatal("input_userauth_info_req: no authentication context");
+
+ name = packet_get_string(NULL);
+ inst = packet_get_string(NULL);
+ lang = packet_get_string(NULL);
+ if (strlen(name) > 0)
+ log("%s", name);
+ if (strlen(inst) > 0)
+ log("%s", inst);
+ xfree(name);
+ xfree(inst);
+ xfree(lang);
+
+ num_prompts = packet_get_int();
+ /*
+ * Begin to build info response packet based on prompts requested.
+ * We commit to providing the correct number of responses, so if
+ * further on we run into a problem that prevents this, we have to
+ * be sure and clean this up and send a correct error response.
+ */
+ packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
+ packet_put_int(num_prompts);
+
+ debug2("input_userauth_info_req: num_prompts %d", num_prompts);
+ for (i = 0; i < num_prompts; i++) {
+ prompt = packet_get_string(NULL);
+ echo = packet_get_char();
+
+ response = read_passphrase(prompt, echo ? RP_ECHO : 0);
+
+ packet_put_cstring(response);
+ memset(response, 0, strlen(response));
+ xfree(response);
+ xfree(prompt);
+ }
+ packet_done(); /* done with parsing incoming message. */
+
+ packet_inject_ignore(64);
+ packet_send();
+}
+
+/*
+ * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign
+ * will be setuid-root and the sbit can be removed from /usr/bin/ssh.
+ */
+int
+userauth_hostbased(Authctxt *authctxt)
+{
+ Key *private = NULL;
+ Buffer b;
+ u_char *signature, *blob;
+ char *chost, *pkalg, *p;
+ const char *service;
+ u_int blen, slen;
+ int ok, i, len, found = 0;
+
+ p = get_local_name(packet_get_connection_in());
+ if (p == NULL) {
+ error("userauth_hostbased: cannot get local ipaddr/name");
+ return 0;
+ }
+ len = strlen(p) + 2;
+ chost = xmalloc(len);
+ strlcpy(chost, p, len);
+ strlcat(chost, ".", len);
+ debug2("userauth_hostbased: chost %s", chost);
+ /* check for a useful key */
+ for (i = 0; i < authctxt->nkeys; i++) {
+ private = authctxt->keys[i];
+ if (private && private->type != KEY_RSA1) {
+ found = 1;
+ /* we take and free the key */
+ authctxt->keys[i] = NULL;
break;
- if (type != SSH2_MSG_USERAUTH_FAILURE)
- fatal("access denied: %d", type);
- /* SSH2_MSG_USERAUTH_FAILURE means: try again */
- auths = packet_get_string(&dlen);
- debug("authentications that can continue: %s", auths);
- partial = packet_get_char();
- packet_done();
- if (partial)
- debug("partial success");
- if (options.dsa_authentication &&
- strstr(auths, "publickey") != NULL) {
- while (i < options.num_identity_files2) {
- sent = ssh2_try_pubkey(
- options.identity_files2[i++],
- server_user, host, service);
- if (sent)
- break;
- }
}
- if (!sent) {
- if (options.password_authentication &&
- !options.batch_mode &&
- strstr(auths, "password") != NULL) {
- sent = ssh2_try_passwd(server_user, host, service);
- }
+ }
+ if (!found) {
+ xfree(chost);
+ return 0;
+ }
+ if (key_to_blob(private, &blob, &blen) == 0) {
+ key_free(private);
+ xfree(chost);
+ return 0;
+ }
+ service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
+ authctxt->service;
+ pkalg = xstrdup(key_ssh_name(private));
+ buffer_init(&b);
+ /* construct data */
+ buffer_put_string(&b, session_id2, session_id2_len);
+ buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
+ buffer_put_cstring(&b, authctxt->server_user);
+ buffer_put_cstring(&b, service);
+ buffer_put_cstring(&b, authctxt->method->name);
+ buffer_put_cstring(&b, pkalg);
+ buffer_put_string(&b, blob, blen);
+ buffer_put_cstring(&b, chost);
+ buffer_put_cstring(&b, authctxt->local_user);
+#ifdef DEBUG_PK
+ buffer_dump(&b);
+#endif
+ debug2("xxx: chost %s", chost);
+ ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
+ key_free(private);
+ buffer_free(&b);
+ if (ok != 0) {
+ error("key_sign failed");
+ xfree(chost);
+ xfree(pkalg);
+ return 0;
+ }
+ packet_start(SSH2_MSG_USERAUTH_REQUEST);
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
+ packet_put_cstring(pkalg);
+ packet_put_string(blob, blen);
+ packet_put_cstring(chost);
+ packet_put_cstring(authctxt->local_user);
+ packet_put_string(signature, slen);
+ memset(signature, 's', slen);
+ xfree(signature);
+ xfree(chost);
+ xfree(pkalg);
+
+ packet_send();
+ return 1;
+}
+
+/* find auth method */
+
+/*
+ * given auth method name, if configurable options permit this method fill
+ * in auth_ident field and return true, otherwise return false.
+ */
+static int
+authmethod_is_enabled(Authmethod *method)
+{
+ if (method == NULL)
+ return 0;
+ /* return false if options indicate this method is disabled */
+ if (method->enabled == NULL || *method->enabled == 0)
+ return 0;
+ /* return false if batch mode is enabled but method needs interactive mode */
+ if (method->batch_flag != NULL && *method->batch_flag != 0)
+ return 0;
+ return 1;
+}
+
+static Authmethod *
+authmethod_lookup(const char *name)
+{
+ Authmethod *method = NULL;
+ if (name != NULL)
+ for (method = authmethods; method->name != NULL; method++)
+ if (strcmp(name, method->name) == 0)
+ return method;
+ debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
+ return NULL;
+}
+
+/* XXX internal state */
+static Authmethod *current = NULL;
+static char *supported = NULL;
+static char *preferred = NULL;
+/*
+ * Given the authentication method list sent by the server, return the
+ * next method we should try. If the server initially sends a nil list,
+ * use a built-in default list.
+ */
+static Authmethod *
+authmethod_get(char *authlist)
+{
+
+ char *name = NULL;
+ int next;
+
+ /* Use a suitable default if we're passed a nil list. */
+ if (authlist == NULL || strlen(authlist) == 0)
+ authlist = options.preferred_authentications;
+
+ if (supported == NULL || strcmp(authlist, supported) != 0) {
+ debug3("start over, passed a different list %s", authlist);
+ if (supported != NULL)
+ xfree(supported);
+ supported = xstrdup(authlist);
+ preferred = options.preferred_authentications;
+ debug3("preferred %s", preferred);
+ current = NULL;
+ } else if (current != NULL && authmethod_is_enabled(current))
+ return current;
+
+ for (;;) {
+ if ((name = match_list(preferred, supported, &next)) == NULL) {
+ debug("no more auth methods to try");
+ current = NULL;
+ return NULL;
+ }
+ preferred += next;
+ debug3("authmethod_lookup %s", name);
+ debug3("remaining preferred: %s", preferred);
+ if ((current = authmethod_lookup(name)) != NULL &&
+ authmethod_is_enabled(current)) {
+ debug3("authmethod_is_enabled %s", name);
+ debug("next auth method to try is %s", name);
+ return current;
}
- if (!sent)
- fatal("Permission denied (%s).", auths);
- xfree(auths);
}
- packet_done();
- debug("ssh-userauth2 successfull");
+}
+
+
+#define DELIM ","
+
+static char *
+authmethods_get(void)
+{
+ Authmethod *method = NULL;
+ char buf[1024];
+
+ buf[0] = '\0';
+ for (method = authmethods; method->name != NULL; method++) {
+ if (authmethod_is_enabled(method)) {
+ if (buf[0] != '\0')
+ strlcat(buf, DELIM, sizeof buf);
+ strlcat(buf, method->name, sizeof buf);
+ }
+ }
+ return xstrdup(buf);
}
andersk / openssh.git / blobdiff