X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/7364bd04fc18484f99f74b901c4581795bcf2787..cdfbc8299cfe8754522579b641440aee9cde44cf:/sshconnect2.c?ds=sidebyside diff --git a/sshconnect2.c b/sshconnect2.c index c71ad506..5bb77236 100644 --- a/sshconnect2.c +++ b/sshconnect2.c @@ -1,3 +1,4 @@ +/* $OpenBSD: sshconnect2.c,v 1.165 2008/01/19 23:09:49 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -23,25 +24,31 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshconnect2.c,v 1.121 2003/08/22 10:56:09 markus Exp $"); -#ifdef KRB5 -#include -#ifndef HEIMDAL -#define krb5_get_err_text(context,code) error_message(code) -#endif /* !HEIMDAL */ -#endif +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include #include "openbsd-compat/sys-queue.h" +#include "xmalloc.h" #include "ssh.h" #include "ssh2.h" -#include "xmalloc.h" #include "buffer.h" #include "packet.h" #include "compat.h" -#include "bufaux.h" #include "cipher.h" +#include "key.h" #include "kex.h" #include "myproposal.h" #include "sshconnect.h" @@ -50,12 +57,13 @@ RCSID("$OpenBSD: sshconnect2.c,v 1.121 2003/08/22 10:56:09 markus Exp $"); #include "authfd.h" #include "log.h" #include "readconf.h" -#include "readpass.h" +#include "misc.h" #include "match.h" #include "dispatch.h" #include "canohost.h" #include "msg.h" #include "pathnames.h" +#include "uidswap.h" #ifdef GSSAPI #include "ssh-gss.h" @@ -108,10 +116,10 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); if (options.compression) { myproposal[PROPOSAL_COMP_ALGS_CTOS] = - myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib,none"; + myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; } else { myproposal[PROPOSAL_COMP_ALGS_CTOS] = - myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib"; + myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; } if (options.macs != NULL) { myproposal[PROPOSAL_MAC_ALGS_CTOS] = @@ -122,12 +130,14 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) options.hostkeyalgorithms; if (options.rekey_limit) - packet_set_rekey_limit(options.rekey_limit); + packet_set_rekey_limit((u_int32_t)options.rekey_limit); /* start key exchange */ kex = kex_setup(myproposal); kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; + kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; + kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->verify_host_key=&verify_host_key_callback; @@ -229,7 +239,7 @@ static char *authmethods_get(void); Authmethod authmethods[] = { #ifdef GSSAPI - {"gssapi", + {"gssapi-with-mic", userauth_gssapi, &options.gss_authentication, NULL}, @@ -238,12 +248,6 @@ Authmethod authmethods[] = { userauth_hostbased, &options.hostbased_authentication, NULL}, -#if KRB5 - {"kerberos-2@ssh.com", - userauth_kerberos, - &options.kerberos_authentication, - NULL}, -#endif {"publickey", userauth_pubkey, &options.pubkey_authentication, @@ -364,17 +368,19 @@ void input_userauth_error(int type, u_int32_t seq, void *ctxt) { fatal("input_userauth_error: bad message during authentication: " - "type %d", type); + "type %d", type); } void input_userauth_banner(int type, u_int32_t seq, void *ctxt) { char *msg, *lang; + debug3("input_userauth_banner"); msg = packet_get_string(NULL); lang = packet_get_string(NULL); - fprintf(stderr, "%s", msg); + if (options.log_level >= SYSLOG_LEVEL_INFO) + fprintf(stderr, "%s", msg); xfree(msg); xfree(lang); } @@ -385,10 +391,14 @@ input_userauth_success(int type, u_int32_t seq, void *ctxt) Authctxt *authctxt = ctxt; if (authctxt == NULL) fatal("input_userauth_success: no authentication context"); - if (authctxt->authlist) + if (authctxt->authlist) { xfree(authctxt->authlist); - if (authctxt->methoddata) + authctxt->authlist = NULL; + } + if (authctxt->methoddata) { xfree(authctxt->methoddata); + authctxt->methoddata = NULL; + } authctxt->success = 1; /* break out */ } @@ -460,7 +470,12 @@ input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) debug2("input_userauth_pk_ok: fp %s", fp); xfree(fp); - TAILQ_FOREACH(id, &authctxt->keys, next) { + /* + * search keys in the reverse order, because last candidate has been + * moved to the end of the queue. this also avoids confusion by + * duplicate keys + */ + TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { if (key_equal(key, id->key)) { sent = sign_and_send_pubkey(authctxt, id); break; @@ -478,39 +493,35 @@ done: } #ifdef GSSAPI -int +int userauth_gssapi(Authctxt *authctxt) { Gssctxt *gssctxt = NULL; - static gss_OID_set supported = NULL; - static int mech = 0; + static gss_OID_set gss_supported = NULL; + static u_int mech = 0; OM_uint32 min; int ok = 0; /* Try one GSSAPI method at a time, rather than sending them all at * once. */ - if (supported == NULL) - gss_indicate_mechs(&min, &supported); + if (gss_supported == NULL) + gss_indicate_mechs(&min, &gss_supported); /* Check to see if the mechanism is usable before we offer it */ - while (mechcount && !ok) { - if (gssctxt) - ssh_gssapi_delete_ctx(&gssctxt); - ssh_gssapi_build_ctx(&gssctxt); - ssh_gssapi_set_oid(gssctxt, &supported->elements[mech]); - + while (mech < gss_supported->count && !ok) { /* My DER encoding requires length<128 */ - if (supported->elements[mech].length < 128 && - !GSS_ERROR(ssh_gssapi_import_name(gssctxt, - authctxt->host))) { + if (gss_supported->elements[mech].length < 128 && + ssh_gssapi_check_mechanism(&gssctxt, + &gss_supported->elements[mech], authctxt->host)) { ok = 1; /* Mechanism works */ } else { mech++; } } - if (!ok) return 0; + if (!ok) + return 0; authctxt->methoddata=(void *)gssctxt; @@ -521,17 +532,11 @@ userauth_gssapi(Authctxt *authctxt) packet_put_int(1); - /* Some servers encode the OID incorrectly (as we used to) */ - if (datafellows & SSH_BUG_GSSAPI_BER) { - packet_put_string(supported->elements[mech].elements, - supported->elements[mech].length); - } else { - packet_put_int((supported->elements[mech].length)+2); - packet_put_char(SSH_GSS_OIDTYPE); - packet_put_char(supported->elements[mech].length); - packet_put_raw(supported->elements[mech].elements, - supported->elements[mech].length); - } + packet_put_int((gss_supported->elements[mech].length) + 2); + packet_put_char(SSH_GSS_OIDTYPE); + packet_put_char(gss_supported->elements[mech].length); + packet_put_raw(gss_supported->elements[mech].elements, + gss_supported->elements[mech].length); packet_send(); @@ -545,15 +550,67 @@ userauth_gssapi(Authctxt *authctxt) return 1; } +static OM_uint32 +process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) +{ + Authctxt *authctxt = ctxt; + Gssctxt *gssctxt = authctxt->methoddata; + gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; + gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; + gss_buffer_desc gssbuf; + OM_uint32 status, ms, flags; + Buffer b; + + status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, + recv_tok, &send_tok, &flags); + + if (send_tok.length > 0) { + if (GSS_ERROR(status)) + packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); + else + packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); + + packet_put_string(send_tok.value, send_tok.length); + packet_send(); + gss_release_buffer(&ms, &send_tok); + } + + if (status == GSS_S_COMPLETE) { + /* send either complete or MIC, depending on mechanism */ + if (!(flags & GSS_C_INTEG_FLAG)) { + packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); + packet_send(); + } else { + ssh_gssapi_buildmic(&b, authctxt->server_user, + authctxt->service, "gssapi-with-mic"); + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); + + if (!GSS_ERROR(status)) { + packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); + packet_put_string(mic.value, mic.length); + + packet_send(); + } + + buffer_free(&b); + gss_release_buffer(&ms, &mic); + } + } + + return status; +} + void input_gssapi_response(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; - OM_uint32 status, ms; int oidlen; char *oidv; - gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); @@ -562,94 +619,55 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt) /* Setup our OID */ oidv = packet_get_string(&oidlen); - if (datafellows & SSH_BUG_GSSAPI_BER) { - if (!ssh_gssapi_check_oid(gssctxt, oidv, oidlen)) - fatal("Server returned different OID than expected"); - } else { - if(oidv[0] != SSH_GSS_OIDTYPE || oidv[1] != oidlen-2) { - debug("Badly encoded mechanism OID received"); - userauth(authctxt, NULL); - xfree(oidv); - return; - } - if (!ssh_gssapi_check_oid(gssctxt, oidv+2, oidlen-2)) - fatal("Server returned different OID than expected"); + if (oidlen <= 2 || + oidv[0] != SSH_GSS_OIDTYPE || + oidv[1] != oidlen - 2) { + xfree(oidv); + debug("Badly encoded mechanism OID received"); + userauth(authctxt, NULL); + return; } + if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) + fatal("Server returned different OID than expected"); + packet_check_eom(); xfree(oidv); - status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - GSS_C_NO_BUFFER, &send_tok, NULL); - if (GSS_ERROR(status)) { - if (send_tok.length > 0) { - packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); - packet_put_string(send_tok.value, send_tok.length); - packet_send(); - gss_release_buffer(&ms, &send_tok); - } + if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { /* Start again with next method on list */ debug("Trying to start again"); userauth(authctxt, NULL); return; } - - /* We must have data to send */ - packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); - packet_put_string(send_tok.value, send_tok.length); - packet_send(); - gss_release_buffer(&ms, &send_tok); } void input_gssapi_token(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; - Gssctxt *gssctxt; - gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; - OM_uint32 status, ms; + OM_uint32 status; u_int slen; if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); - gssctxt = authctxt->methoddata; recv_tok.value = packet_get_string(&slen); recv_tok.length = slen; /* safe typecast */ packet_check_eom(); - status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - &recv_tok, &send_tok, NULL); + status = process_gssapi_token(ctxt, &recv_tok); xfree(recv_tok.value); if (GSS_ERROR(status)) { - if (send_tok.length > 0) { - packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); - packet_put_string(send_tok.value, send_tok.length); - packet_send(); - gss_release_buffer(&ms, &send_tok); - } /* Start again with the next method in the list */ userauth(authctxt, NULL); return; } - - if (send_tok.length > 0) { - packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); - packet_put_string(send_tok.value, send_tok.length); - packet_send(); - gss_release_buffer(&ms, &send_tok); - } - - if (status == GSS_S_COMPLETE) { - /* If that succeeded, send a exchange complete message */ - packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); - packet_send(); - } } void @@ -660,18 +678,20 @@ input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; OM_uint32 status, ms; + u_int len; if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); gssctxt = authctxt->methoddata; - recv_tok.value = packet_get_string(&recv_tok.length); + recv_tok.value = packet_get_string(&len); + recv_tok.length = len; packet_check_eom(); /* Stick it into GSSAPI and see what it says */ status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, - &recv_tok, &send_tok, NULL); + &recv_tok, &send_tok, NULL); xfree(recv_tok.value); gss_release_buffer(&ms, &send_tok); @@ -693,7 +713,7 @@ input_gssapi_error(int type, u_int32_t plen, void *ctxt) packet_check_eom(); - debug("Server GSSAPI Error:\n%s\n", msg); + debug("Server GSSAPI Error:\n%s", msg); xfree(msg); xfree(lang); } @@ -954,14 +974,16 @@ load_identity_file(char *filename) { Key *private; char prompt[300], *passphrase; - int quit, i; + int perm_ok, quit, i; struct stat st; if (stat(filename, &st) < 0) { debug3("no such identity: %s", filename); return NULL; } - private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); + private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); + if (!perm_ok) + return NULL; if (private == NULL) { if (options.batch_mode) return NULL; @@ -970,8 +992,8 @@ load_identity_file(char *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); + private = key_load_private_type(KEY_UNSPEC, + filename, passphrase, NULL, NULL); quit = 0; } else { debug2("no passphrase given, try next key"); @@ -1014,8 +1036,7 @@ pubkey_prepare(Authctxt *authctxt) if (key && key->type == KEY_RSA1) continue; options.identity_keys[i] = NULL; - id = xmalloc(sizeof(*id)); - memset(id, 0, sizeof(*id)); + id = xcalloc(1, sizeof(*id)); id->key = key; id->filename = xstrdup(options.identity_files[i]); TAILQ_INSERT_TAIL(&files, id, next); @@ -1027,7 +1048,7 @@ pubkey_prepare(Authctxt *authctxt) key = ssh_get_next_identity(ac, &comment, 2)) { found = 0; TAILQ_FOREACH(id, &files, next) { - /* agent keys from the config file are preferred */ + /* agent keys from the config file are preferred */ if (key_equal(key, id->key)) { key_free(key); xfree(comment); @@ -1038,9 +1059,8 @@ pubkey_prepare(Authctxt *authctxt) break; } } - if (!found) { - id = xmalloc(sizeof(*id)); - memset(id, 0, sizeof(*id)); + if (!found && !options.identities_only) { + id = xcalloc(1, sizeof(*id)); id->key = key; id->filename = comment; id->ac = ac; @@ -1091,6 +1111,7 @@ userauth_pubkey(Authctxt *authctxt) while ((id = TAILQ_FIRST(&authctxt->keys))) { if (id->tried++) return (0); + /* move key to the end of the queue */ TAILQ_REMOVE(&authctxt->keys, id, next); TAILQ_INSERT_TAIL(&authctxt->keys, id, next); /* @@ -1235,8 +1256,7 @@ ssh_keysign(Key *key, u_char **sigp, u_int *lenp, return -1; } if (pid == 0) { - seteuid(getuid()); - setuid(getuid()); + permanently_drop_suid(getuid()); close(from[0]); if (dup2(from[1], STDOUT_FILENO) < 0) fatal("ssh_keysign: dup2: %s", strerror(errno)); @@ -1255,11 +1275,12 @@ ssh_keysign(Key *key, u_char **sigp, u_int *lenp, buffer_init(&b); buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ buffer_put_string(&b, data, datalen); - ssh_msg_send(to[1], version, &b); + if (ssh_msg_send(to[1], version, &b) == -1) + fatal("ssh_keysign: couldn't send request"); if (ssh_msg_recv(from[0], &b) < 0) { error("ssh_keysign: no reply"); - buffer_clear(&b); + buffer_free(&b); return -1; } close(from[0]); @@ -1271,11 +1292,11 @@ ssh_keysign(Key *key, u_char **sigp, u_int *lenp, if (buffer_get_char(&b) != version) { error("ssh_keysign: bad version"); - buffer_clear(&b); + buffer_free(&b); return -1; } *sigp = buffer_get_string(&b, lenp); - buffer_clear(&b); + buffer_free(&b); return 0; } @@ -1287,7 +1308,7 @@ userauth_hostbased(Authctxt *authctxt) Sensitive *sensitive = authctxt->sensitive; Buffer b; u_char *signature, *blob; - char *chost, *pkalg, *p; + char *chost, *pkalg, *p, myname[NI_MAXHOST]; const char *service; u_int blen, slen; int ok, i, len, found = 0; @@ -1311,16 +1332,24 @@ userauth_hostbased(Authctxt *authctxt) return 0; } /* figure out a name for the client host */ - p = get_local_name(packet_get_connection_in()); + p = NULL; + if (packet_connection_is_on_socket()) + p = get_local_name(packet_get_connection_in()); + if (p == NULL) { + if (gethostname(myname, sizeof(myname)) == -1) { + verbose("userauth_hostbased: gethostname: %s", + strerror(errno)); + } else + p = xstrdup(myname); + } if (p == NULL) { error("userauth_hostbased: cannot get local ipaddr/name"); key_free(private); + xfree(blob); return 0; } len = strlen(p) + 2; - chost = xmalloc(len); - strlcpy(chost, p, len); - strlcat(chost, ".", len); + xasprintf(&chost, "%s.", p); debug2("userauth_hostbased: chost %s", chost); xfree(p); @@ -1353,6 +1382,7 @@ userauth_hostbased(Authctxt *authctxt) error("key_sign failed"); xfree(chost); xfree(pkalg); + xfree(blob); return 0; } packet_start(SSH2_MSG_USERAUTH_REQUEST); @@ -1368,106 +1398,12 @@ userauth_hostbased(Authctxt *authctxt) xfree(signature); xfree(chost); xfree(pkalg); + xfree(blob); packet_send(); return 1; } -#if KRB5 -static int -ssh_krb5_helper(krb5_data *ap, krb5_context *context) -{ - krb5_context xcontext = NULL; /* XXX share with ssh1 */ - krb5_auth_context xauth_context = NULL; - krb5_auth_context *auth_context; - krb5_error_code problem; - const char *tkfile; - struct stat buf; - krb5_ccache ccache = NULL; - const char *remotehost; - int ret; - - memset(ap, 0, sizeof(*ap)); - - context = &xcontext; - auth_context = &xauth_context; - - 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; - } - ret = 1; - - out: - if (ccache != NULL) - krb5_cc_close(*context, ccache); - if (*auth_context) - krb5_auth_con_free(*context, *auth_context); - return (ret); -} - -int -userauth_kerberos(Authctxt *authctxt) -{ - krb5_data ap; - krb5_context *context; - int ret = 0; - - if (ssh_krb5_helper(&ap, context) == 0) - goto out; - - 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_string(ap.data, ap.length); - packet_send(); - -#ifdef HEIMDAL - krb5_data_free(&ap); -#else - krb5_free_data_contents(*context, &ap); -#endif - ret = 1; - -out: - if (*context) - krb5_free_context(*context); - return ret; -} -#endif - /* find auth method */ /*