X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/51b9ca7540d0faddc5c630f0b4d126b29fbd50fb..fa7499cc6ff64268191a9f17bb35c28908ea4a40:/openssh/sshconnect2.c diff --git a/openssh/sshconnect2.c b/openssh/sshconnect2.c index 4da1990..42aadb1 100644 --- a/openssh/sshconnect2.c +++ b/openssh/sshconnect2.c @@ -1,3 +1,4 @@ +/* $OpenBSD: sshconnect2.c,v 1.164 2007/05/17 23:53:41 jolan Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -23,18 +24,31 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshconnect2.c,v 1.134 2004/01/19 21:25:15 markus Exp $"); + +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include #include "openbsd-compat/sys-queue.h" +#include "xmalloc.h" #include "ssh.h" #include "ssh2.h" -#include "xmalloc.h" #include "buffer.h" #include "packet.h" #include "compat.h" -#include "bufaux.h" #include "cipher.h" +#include "key.h" #include "kex.h" #include "myproposal.h" #include "sshconnect.h" @@ -43,12 +57,13 @@ RCSID("$OpenBSD: sshconnect2.c,v 1.134 2004/01/19 21:25:15 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" @@ -59,6 +74,11 @@ extern char *client_version_string; extern char *server_version_string; extern Options options; +/* tty_flag is set in ssh.c. use this in ssh_userauth2 */ +/* if it is set then prevent the switch to the null cipher */ + +extern int tty_flag; + /* * SSH2 key exchange */ @@ -83,9 +103,10 @@ void ssh_kex2(char *host, struct sockaddr *hostaddr) { Kex *kex; + #ifdef GSSAPI - char *orig, *gss; - int len; + char *orig = NULL, *gss = NULL; + char *gss_host = NULL; #endif xxx_host = host; @@ -93,15 +114,21 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) #ifdef GSSAPI if (options.gss_keyex) { - /* Add the GSSAPI mechanisms currently supported on this client to - * the key exchange algorithm proposal */ - orig = myproposal[PROPOSAL_KEX_ALGS]; - gss = ssh_gssapi_client_mechanisms((char *)get_canonical_hostname(1)); - if (gss) { - len = strlen(orig)+strlen(gss)+2; - myproposal[PROPOSAL_KEX_ALGS]=xmalloc(len); - snprintf(myproposal[PROPOSAL_KEX_ALGS],len,"%s,%s",gss,orig); - } + /* Add the GSSAPI mechanisms currently supported on this + * client to the key exchange algorithm proposal */ + orig = myproposal[PROPOSAL_KEX_ALGS]; + + if (options.gss_trust_dns) + gss_host = (char *)get_canonical_hostname(1); + else + gss_host = host; + + gss = ssh_gssapi_client_mechanisms(gss_host); + if (gss) { + debug("Offering GSSAPI proposal: %s", gss); + xasprintf(&myproposal[PROPOSAL_KEX_ALGS], + "%s,%s", gss, orig); + } } #endif @@ -119,10 +146,10 @@ 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] = @@ -133,13 +160,12 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) options.hostkeyalgorithms; #ifdef GSSAPI - /* If we've got GSSAPI algorithms, then we also support the - * 'null' hostkey, as a last resort */ + /* If we've got GSSAPI algorithms, then we also support the + * 'null' hostkey, as a last resort */ if (options.gss_keyex && gss) { - orig=myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; - len = strlen(orig)+sizeof(",null"); - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]=xmalloc(len); - snprintf(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],len,"%s,null",orig); + orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; + xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], + "%s,null", orig); } #endif @@ -149,15 +175,22 @@ ssh_kex2(char *host, struct sockaddr *hostaddr) /* 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; #ifdef GSSAPI kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; + kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; + kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; #endif kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->verify_host_key=&verify_host_key_callback; + #ifdef GSSAPI - kex->options.gss_deleg_creds=options.gss_deleg_creds; + kex->gss_deleg_creds = options.gss_deleg_creds; + kex->gss_trust_dns = options.gss_trust_dns; + kex->gss_host = gss_host; #endif xxx_kex = kex; @@ -235,15 +268,6 @@ int userauth_kbdint(Authctxt *); int userauth_hostbased(Authctxt *); int userauth_kerberos(Authctxt *); -#ifdef GSSAPI -int userauth_gssapi(Authctxt *authctxt); -void input_gssapi_response(int type, u_int32_t, void *); -void input_gssapi_token(int type, u_int32_t, void *); -void input_gssapi_hash(int type, u_int32_t, void *); -void input_gssapi_error(int, u_int32_t, void *); -void input_gssapi_errtok(int, u_int32_t, void *); -#endif - #ifdef GSSAPI int userauth_external(Authctxt *authctxt); int userauth_gssapi(Authctxt *authctxt); @@ -254,6 +278,7 @@ void input_gssapi_token(int type, u_int32_t, void *); void input_gssapi_hash(int type, u_int32_t, void *); void input_gssapi_error(int, u_int32_t, void *); void input_gssapi_errtok(int, u_int32_t, void *); +int userauth_gsskeyex(Authctxt *authctxt); #endif void userauth(Authctxt *, char *); @@ -269,6 +294,10 @@ static char *authmethods_get(void); Authmethod authmethods[] = { #ifdef GSSAPI + {"gssapi-keyex", + userauth_gsskeyex, + &options.gss_authentication, + NULL}, {"external-keyx", userauth_external, &options.gss_authentication, @@ -364,6 +393,28 @@ ssh_userauth2(const char *local_user, const char *server_user, char *host, pubkey_cleanup(&authctxt); dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); + /* if the user wants to use the none cipher do it */ + /* post authentication and only if the right conditions are met */ + /* both of the NONE commands must be true and there must be no */ + /* tty allocated */ + if ((options.none_switch == 1) && (options.none_enabled == 1)) + { + if (!tty_flag) /* no null on tty sessions */ + { + debug("Requesting none rekeying..."); + myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; + myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; + kex_prop2buf(&xxx_kex->my,myproposal); + packet_request_rekeying(); + fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n"); + } + else + { + /* requested NONE cipher when in a tty */ + debug("Cannot switch to NONE cipher with tty allocated"); + fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n"); + } + } debug("Authentication succeeded (%s).", authctxt.method->name); } @@ -406,7 +457,7 @@ 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 @@ -417,7 +468,7 @@ input_userauth_banner(int type, u_int32_t seq, void *ctxt) debug3("input_userauth_banner"); msg = packet_get_string(NULL); lang = packet_get_string(NULL); - if (options.log_level > SYSLOG_LEVEL_QUIET) + if (options.log_level >= SYSLOG_LEVEL_INFO) fprintf(stderr, "%s", msg); xfree(msg); xfree(lang); @@ -513,7 +564,7 @@ input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) * moved to the end of the queue. this also avoids confusion by * duplicate keys */ - TAILQ_FOREACH_REVERSE(id, &authctxt->keys, next, idlist) { + TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { if (key_equal(key, id->key)) { sent = sign_and_send_pubkey(authctxt, id); break; @@ -536,15 +587,21 @@ userauth_gssapi(Authctxt *authctxt) { Gssctxt *gssctxt = NULL; static gss_OID_set gss_supported = NULL; - static int mech = 0; + static u_int mech = 0; OM_uint32 min; int ok = 0; + char *gss_host = NULL; if (!options.gss_authentication) { verbose("GSSAPI authentication disabled."); return 0; } + if (options.gss_trust_dns) + gss_host = (char *)get_canonical_hostname(1); + else + gss_host = (char *)authctxt->host; + /* Try one GSSAPI method at a time, rather than sending them all at * once. */ @@ -553,22 +610,18 @@ userauth_gssapi(Authctxt *authctxt) /* Check to see if the mechanism is usable before we offer it */ while (mech < gss_supported->count && !ok) { - if (gssctxt) - ssh_gssapi_delete_ctx(&gssctxt); - ssh_gssapi_build_ctx(&gssctxt); - ssh_gssapi_set_oid(gssctxt, &gss_supported->elements[mech]); - /* My DER encoding requires length<128 */ if (gss_supported->elements[mech].length < 128 && - !GSS_ERROR(ssh_gssapi_import_name(gssctxt, - authctxt->host))) { + ssh_gssapi_check_mechanism(&gssctxt, + &gss_supported->elements[mech], gss_host)) { ok = 1; /* Mechanism works */ } else { mech++; } } - if (!ok) return 0; + if (!ok) + return 0; authctxt->methoddata=(void *)gssctxt; @@ -579,17 +632,11 @@ 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(gss_supported->elements[mech].elements, - gss_supported->elements[mech].length); - } else { - 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_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(); @@ -609,7 +656,8 @@ 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 gssbuf, mic; + gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; + gss_buffer_desc gssbuf; OM_uint32 status, ms, flags; Buffer b; @@ -662,8 +710,8 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; - int oidlen; - char *oidv; + u_int oidlen; + u_char *oidv; if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); @@ -672,20 +720,18 @@ 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); @@ -746,7 +792,7 @@ input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) /* 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); @@ -768,11 +814,20 @@ 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); } +#ifdef GSI +extern +const gss_OID_desc * const gss_mech_globus_gssapi_openssl; +#define is_gsi_oid(oid) \ + (oid->length == gss_mech_globus_gssapi_openssl->length && \ + (memcmp(oid->elements, gss_mech_globus_gssapi_openssl->elements, \ + oid->length) == 0)) +#endif + int userauth_external(Authctxt *authctxt) { @@ -784,7 +839,7 @@ userauth_external(Authctxt *authctxt) /* The client MUST NOT try this method if initial key exchange was not performed using a GSSAPI-based key exchange method. */ - if (xxx_kex->kex_type != KEX_GSS_GRP1_SHA1) { + if (gss_kex_context == NULL) { debug2("gsskex not performed, skipping external-keyx"); return 0; } @@ -792,11 +847,11 @@ userauth_external(Authctxt *authctxt) debug2("userauth_external"); packet_start(SSH2_MSG_USERAUTH_REQUEST); #ifdef GSI - if(options.implicit && !(datafellows & SSH_BUG_GSS_EMPTYUSER)) { - packet_put_cstring(""); + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + packet_put_cstring(""); } else { #endif - packet_put_cstring(authctxt->server_user); + packet_put_cstring(authctxt->server_user); #ifdef GSI } #endif @@ -806,6 +861,63 @@ userauth_external(Authctxt *authctxt) packet_write_wait(); return 1; } +int +userauth_gsskeyex(Authctxt *authctxt) +{ + Buffer b; + gss_buffer_desc gssbuf; + gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; + OM_uint32 ms; + + static int attempt = 0; + if (attempt++ >= 1) + return (0); + + if (gss_kex_context == NULL) { + debug("No valid Key exchange context"); + return (0); + } + +#ifdef GSI + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex"); + } else { +#endif + ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, + "gssapi-keyex"); +#ifdef GSI + } +#endif + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) { + buffer_free(&b); + return (0); + } + + packet_start(SSH2_MSG_USERAUTH_REQUEST); +#ifdef GSI + if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { + packet_put_cstring(""); + } else { +#endif + packet_put_cstring(authctxt->server_user); +#ifdef GSI + } +#endif + packet_put_cstring(authctxt->service); + packet_put_cstring(authctxt->method->name); + packet_put_string(mic.value, mic.length); + packet_send(); + + buffer_free(&b); + gss_release_buffer(&ms, &mic); + + return (1); +} + #endif /* GSSAPI */ int @@ -1063,14 +1175,16 @@ 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; @@ -1079,8 +1193,8 @@ 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"); @@ -1123,8 +1237,7 @@ 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); @@ -1147,9 +1260,8 @@ 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; @@ -1345,8 +1457,7 @@ 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)); @@ -1398,7 +1509,7 @@ 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; @@ -1422,16 +1533,24 @@ 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); @@ -1464,6 +1583,7 @@ userauth_hostbased(Authctxt *authctxt) error("key_sign failed"); xfree(chost); xfree(pkalg); + xfree(blob); return 0; } packet_start(SSH2_MSG_USERAUTH_REQUEST); @@ -1479,6 +1599,7 @@ userauth_hostbased(Authctxt *authctxt) xfree(signature); xfree(chost); xfree(pkalg); + xfree(blob); packet_send(); return 1;