X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/2c06c99bdf88232ed9b4bdd395241e526a65f00a..HEAD:/openssh/auth2-gss.c diff --git a/openssh/auth2-gss.c b/openssh/auth2-gss.c index 95844a0..c8f28ac 100644 --- a/openssh/auth2-gss.c +++ b/openssh/auth2-gss.c @@ -1,7 +1,7 @@ -/* $OpenBSD: auth2-gss.c,v 1.12 2005/10/13 22:24:31 stevesk Exp $ */ +/* $OpenBSD: auth2-gss.c,v 1.16 2007/10/29 00:52:45 dtucker Exp $ */ /* - * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. + * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -28,24 +28,79 @@ #ifdef GSSAPI +#include + +#include + +#include "xmalloc.h" +#include "key.h" +#include "hostfile.h" #include "auth.h" #include "ssh2.h" -#include "xmalloc.h" #include "log.h" #include "dispatch.h" +#include "buffer.h" #include "servconf.h" #include "packet.h" -#include "monitor_wrap.h" - #include "ssh-gss.h" +#include "monitor_wrap.h" extern ServerOptions options; +static void ssh_gssapi_userauth_error(Gssctxt *ctxt); static void input_gssapi_token(int type, u_int32_t plen, void *ctxt); static void input_gssapi_mic(int type, u_int32_t plen, void *ctxt); static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt); static void input_gssapi_errtok(int, u_int32_t, void *); +/* + * The 'gssapi_keyex' userauth mechanism. + */ +static int +userauth_gsskeyex(Authctxt *authctxt) +{ + int authenticated = 0; + Buffer b, b2; + gss_buffer_desc mic, gssbuf, gssbuf2; + u_int len; + + mic.value = packet_get_string(&len); + mic.length = len; + + packet_check_eom(); + + ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service, + "gssapi-keyex"); + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + /* client may have used empty username to determine target + name from GSSAPI context */ + ssh_gssapi_buildmic(&b2, "", authctxt->service, "gssapi-keyex"); + + gssbuf2.value = buffer_ptr(&b2); + gssbuf2.length = buffer_len(&b2); + + /* gss_kex_context is NULL with privsep, so we can't check it here */ + if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, + &gssbuf, &mic))) || + !GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, + &gssbuf2, &mic)))) { + if (authctxt->valid && authctxt->user && authctxt->user[0]) { + authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user, + authctxt->pw, + 1 /* gssapi-keyex */)); + } + } + + buffer_free(&b); + buffer_free(&b2); + xfree(mic.value); + + return (authenticated); +} + /* * We only support those mechanisms that we know about (ie ones that we know * how to check local user kuserok and the like) @@ -62,7 +117,10 @@ userauth_gssapi(Authctxt *authctxt) u_int len; u_char *doid = NULL; - if (!authctxt->valid || authctxt->user == NULL) + /* authctxt->valid may be 0 if we haven't yet determined + username from gssapi context. */ + + if (authctxt->user == NULL) return (0); mechs = packet_get_int(); @@ -96,11 +154,15 @@ userauth_gssapi(Authctxt *authctxt) if (!present) { xfree(doid); + authctxt->server_caused_failure = 1; return (0); } if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) { + if (ctxt != NULL) + ssh_gssapi_delete_ctx(&ctxt); xfree(doid); + authctxt->server_caused_failure = 1; return (0); } @@ -128,7 +190,7 @@ input_gssapi_token(int type, u_int32_t plen, void *ctxt) Gssctxt *gssctxt; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; - OM_uint32 maj_status, min_status, flags; + OM_uint32 maj_status, min_status, flags=0; u_int len; if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) @@ -146,6 +208,7 @@ input_gssapi_token(int type, u_int32_t plen, void *ctxt) xfree(recv_tok.value); if (GSS_ERROR(maj_status)) { + ssh_gssapi_userauth_error(gssctxt); if (send_tok.length != 0) { packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); packet_put_string(send_tok.value, send_tok.length); @@ -209,6 +272,32 @@ input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) gss_release_buffer(&maj_status, &send_tok); } +static void +gssapi_set_username(Authctxt *authctxt) +{ + char *lname = NULL; + + if ((authctxt->user == NULL) || (authctxt->user[0] == '\0')) { + PRIVSEP(ssh_gssapi_localname(&lname)); + if (lname && lname[0] != '\0') { + if (authctxt->user) xfree(authctxt->user); + authctxt->user = lname; + debug("set username to %s from gssapi context", lname); + authctxt->pw = PRIVSEP(getpwnamallow(authctxt->user)); + if (authctxt->pw) { + authctxt->valid = 1; +#ifdef USE_PAM + if (options.use_pam) + PRIVSEP(start_pam(authctxt)); +#endif + } + } else { + debug("failed to set username from gssapi context"); + packet_send_debug("failed to set username from gssapi context"); + } + } +} + /* * This is called when the client thinks we've completed authentication. * It should only be enabled in the dispatch handler by the function above, @@ -225,6 +314,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt) if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) fatal("No authentication or GSSAPI context"); + gssapi_set_username(authctxt); + gssctxt = authctxt->methoddata; /* @@ -234,7 +325,13 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt) packet_check_eom(); - authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user)); + /* user should be set if valid but we double-check here */ + if (authctxt->valid && authctxt->user && authctxt->user[0]) { + authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user, + authctxt->pw, 0 /* !gssapi-keyex */)); + } else { + authenticated = 0; + } authctxt->postponed = 0; dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); @@ -268,8 +365,16 @@ input_gssapi_mic(int type, u_int32_t plen, void *ctxt) gssbuf.value = buffer_ptr(&b); gssbuf.length = buffer_len(&b); + gssapi_set_username(authctxt); + if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic)))) - authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user)); + if (authctxt->valid && authctxt->user && authctxt->user[0]) { + authenticated = + PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw, + 0 /* !gssapi-keyex */)); + } else { + authenticated = 0; + } else logit("GSSAPI MIC check failed"); @@ -284,6 +389,29 @@ input_gssapi_mic(int type, u_int32_t plen, void *ctxt) userauth_finish(authctxt, authenticated, "gssapi-with-mic"); } +static void ssh_gssapi_userauth_error(Gssctxt *ctxt) { + char *errstr; + OM_uint32 maj,min; + + errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min)); + if (errstr) { + packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR); + packet_put_int(maj); + packet_put_int(min); + packet_put_cstring(errstr); + packet_put_cstring(""); + packet_send(); + packet_write_wait(); + xfree(errstr); + } +} + +Authmethod method_gsskeyex = { + "gssapi-keyex", + userauth_gsskeyex, + &options.gss_authentication +}; + Authmethod method_gssapi = { "gssapi-with-mic", userauth_gssapi,