/* imgssapi.c * This is the implementation of the GSSAPI input module. * * Note: the root gssapi code was contributed by varmojfekoj and is most often * maintened by him. I am just doing the plumbing around it (I event don't have a * test lab for gssapi yet... ). I am very grateful for this useful code * contribution -- rgerhards, 2008-03-05 * * NOTE: read comments in module-template.h to understand how this file * works! * * Copyright 2007 Rainer Gerhards and Adiscon GmbH. * * This file is part of rsyslog. * * Rsyslog is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Rsyslog is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Rsyslog. If not, see . * * A copy of the GPL can be found in the file "COPYING" in this distribution. */ #include "config.h" #include #include #include #include #include #include #include #include #include #include #include #if HAVE_FCNTL_H #include #endif #include #include "rsyslog.h" #include "syslogd.h" #include "cfsysline.h" #include "module-template.h" #include "net.h" #include "srUtils.h" #include "gss-misc.h" #include "tcpsrv.h" #include "tcps_sess.h" #include "errmsg.h" MODULE_TYPE_INPUT /* defines */ #define ALLOWEDMETHOD_GSS 2 #define ALLOWEDMETHOD_TCP 1 /* some forward definitions - they may go away when we no longer include imtcp.c */ static rsRetVal addGSSListener(void __attribute__((unused)) *pVal, uchar *pNewVal); static int TCPSessGSSInit(void); static void TCPSessGSSClose(tcps_sess_t* pSess); static int TCPSessGSSRecv(tcps_sess_t *pSess, void *buf, size_t buf_len); static rsRetVal onSessAccept(tcpsrv_t *pThis, tcps_sess_t **ppSess, int fd); static rsRetVal OnSessAcceptGSS(tcpsrv_t *pThis, tcps_sess_t **ppSess, int fd); /* static data */ DEF_IMOD_STATIC_DATA DEFobjCurrIf(tcpsrv) DEFobjCurrIf(tcps_sess) DEFobjCurrIf(gssutil) DEFobjCurrIf(errmsg) DEFobjCurrIf(net) static tcpsrv_t *pOurTcpsrv = NULL; /* our TCP server(listener) TODO: change for multiple instances */ static gss_cred_id_t gss_server_creds = GSS_C_NO_CREDENTIAL; /* our usr structure for the tcpsrv object */ typedef struct gsssrv_s { char allowedMethods; } gsssrv_t; /* our usr structure for the session object */ typedef struct gss_sess_s { OM_uint32 gss_flags; gss_ctx_id_t gss_context; char allowedMethods; } gss_sess_t; /* config variables */ static int iTCPSessMax = 200; /* max number of sessions */ static char *gss_listen_service_name = NULL; static int bPermitPlainTcp = 0; /* plain tcp syslog allowed on GSSAPI port? */ /* methods */ /* callbacks */ static rsRetVal OnSessConstructFinalize(void *ppUsr) { DEFiRet; gss_sess_t **ppGSess = (gss_sess_t**) ppUsr; gss_sess_t *pGSess; assert(ppGSess != NULL); if((pGSess = calloc(1, sizeof(gss_sess_t))) == NULL) ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY); pGSess->gss_flags = 0; pGSess->gss_context = GSS_C_NO_CONTEXT; pGSess->allowedMethods = 0; *ppGSess = pGSess; finalize_it: RETiRet; } /* Destruct the user session pointer for a GSSAPI session. Please note * that it *is* valid to receive a NULL user pointer. In this case, the * sessions is to be torn down before it was fully initialized. This * happens in error cases, e.g. when the host ACL did not match. * rgerhards, 2008-03-03 */ static rsRetVal OnSessDestruct(void *ppUsr) { DEFiRet; gss_sess_t **ppGSess = (gss_sess_t**) ppUsr; assert(ppGSess != NULL); if(*ppGSess == NULL) FINALIZE; if((*ppGSess)->allowedMethods & ALLOWEDMETHOD_GSS) { OM_uint32 maj_stat, min_stat; maj_stat = gss_delete_sec_context(&min_stat, &(*ppGSess)->gss_context, GSS_C_NO_BUFFER); if (maj_stat != GSS_S_COMPLETE) gssutil.display_status("deleting context", maj_stat, min_stat); } free(*ppGSess); *ppGSess = NULL; finalize_it: RETiRet; } /* Check if the host is permitted to send us messages. * Note: the pUsrSess may be zero if the server is running in tcp-only mode! */ static int isPermittedHost(struct sockaddr *addr, char *fromHostFQDN, void *pUsrSrv, void*pUsrSess) { gsssrv_t *pGSrv; gss_sess_t *pGSess; char allowedMethods = 0; BEGINfunc assert(pUsrSrv != NULL); pGSrv = (gsssrv_t*) pUsrSrv; pGSess = (gss_sess_t*) pUsrSess; if((pGSrv->allowedMethods & ALLOWEDMETHOD_TCP) && net.isAllowedSender(net.pAllowedSenders_TCP, addr, (char*)fromHostFQDN)) allowedMethods |= ALLOWEDMETHOD_TCP; if((pGSrv->allowedMethods & ALLOWEDMETHOD_GSS) && net.isAllowedSender(net.pAllowedSenders_GSS, addr, (char*)fromHostFQDN)) allowedMethods |= ALLOWEDMETHOD_GSS; if(allowedMethods && pGSess != NULL) pGSess->allowedMethods = allowedMethods; ENDfunc return allowedMethods; } static rsRetVal onSessAccept(tcpsrv_t *pThis, tcps_sess_t **ppSess, int fd) { DEFiRet; gsssrv_t *pGSrv; pGSrv = (gsssrv_t*) pThis->pUsr; if(pGSrv->allowedMethods & ALLOWEDMETHOD_GSS) { iRet = OnSessAcceptGSS(pThis, ppSess, fd); } else { iRet = tcpsrv.SessAccept(pThis, ppSess, fd); } RETiRet; } static rsRetVal onRegularClose(tcps_sess_t *pSess) { DEFiRet; gss_sess_t *pGSess; assert(pSess != NULL); assert(pSess->pUsr != NULL); pGSess = (gss_sess_t*) pSess->pUsr; if(pGSess->allowedMethods & ALLOWEDMETHOD_GSS) TCPSessGSSClose(pSess); else { /* process any incomplete frames left over */ tcps_sess.PrepareClose(pSess); /* Session closed */ tcps_sess.Close(pSess); } RETiRet; } static rsRetVal onErrClose(tcps_sess_t *pSess) { DEFiRet; gss_sess_t *pGSess; assert(pSess != NULL); assert(pSess->pUsr != NULL); pGSess = (gss_sess_t*) pSess->pUsr; if(pGSess->allowedMethods & ALLOWEDMETHOD_GSS) TCPSessGSSClose(pSess); else tcps_sess.Close(pSess); RETiRet; } /* open the listen sockets */ static int* doOpenLstnSocks(tcpsrv_t *pSrv) { int *pRet; gsssrv_t *pGSrv; ISOBJ_TYPE_assert(pSrv, tcpsrv); pGSrv = pSrv->pUsr; assert(pGSrv != NULL); /* first apply some config settings */ if(pGSrv->allowedMethods) { if(pGSrv->allowedMethods & ALLOWEDMETHOD_GSS) { if(TCPSessGSSInit()) { errmsg.LogError(NO_ERRCODE, "GSS-API initialization failed\n"); pGSrv->allowedMethods &= ~(ALLOWEDMETHOD_GSS); } } if(pGSrv->allowedMethods) { /* fallback to plain TCP */ if((pRet = tcpsrv.create_tcp_socket(pSrv)) != NULL) { dbgprintf("Opened %d syslog TCP port(s).\n", *pRet); } } } return pRet; } static int doRcvData(tcps_sess_t *pSess, char *buf, size_t lenBuf) { int state; int allowedMethods; gss_sess_t *pGSess; assert(pSess != NULL); assert(pSess->pUsr != NULL); pGSess = (gss_sess_t*) pSess->pUsr; allowedMethods = pGSess->allowedMethods; if(allowedMethods & ALLOWEDMETHOD_GSS) state = TCPSessGSSRecv(pSess, buf, lenBuf); else state = recv(pSess->sock, buf, lenBuf, 0); return state; } /* end callbacks */ static rsRetVal addGSSListener(void __attribute__((unused)) *pVal, uchar *pNewVal) { DEFiRet; gsssrv_t *pGSrv; if(pOurTcpsrv == NULL) { /* first create/init the gsssrv "object" */ if((pGSrv = calloc(1, sizeof(gsssrv_t))) == NULL) ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY); pGSrv->allowedMethods = ALLOWEDMETHOD_GSS; if(bPermitPlainTcp) pGSrv->allowedMethods |= ALLOWEDMETHOD_TCP; /* gsssrv initialized */ CHKiRet(tcpsrv.Construct(&pOurTcpsrv)); CHKiRet(tcpsrv.SetUsrP(pOurTcpsrv, pGSrv)); CHKiRet(tcpsrv.SetCBOnSessConstructFinalize(pOurTcpsrv, OnSessConstructFinalize)); CHKiRet(tcpsrv.SetCBOnSessDestruct(pOurTcpsrv, OnSessDestruct)); CHKiRet(tcpsrv.SetCBIsPermittedHost(pOurTcpsrv, isPermittedHost)); CHKiRet(tcpsrv.SetCBRcvData(pOurTcpsrv, doRcvData)); CHKiRet(tcpsrv.SetCBOpenLstnSocks(pOurTcpsrv, doOpenLstnSocks)); CHKiRet(tcpsrv.SetCBOnSessAccept(pOurTcpsrv, onSessAccept)); CHKiRet(tcpsrv.SetCBOnRegularClose(pOurTcpsrv, onRegularClose)); CHKiRet(tcpsrv.SetCBOnErrClose(pOurTcpsrv, onErrClose)); tcpsrv.configureTCPListen(pOurTcpsrv, (char *) pNewVal); CHKiRet(tcpsrv.ConstructFinalize(pOurTcpsrv)); } finalize_it: RETiRet; } /* returns 0 if all went OK, -1 if it failed */ static int TCPSessGSSInit(void) { gss_buffer_desc name_buf; gss_name_t server_name; OM_uint32 maj_stat, min_stat; if (gss_server_creds != GSS_C_NO_CREDENTIAL) return 0; name_buf.value = (gss_listen_service_name == NULL) ? "host" : gss_listen_service_name; name_buf.length = strlen(name_buf.value) + 1; maj_stat = gss_import_name(&min_stat, &name_buf, GSS_C_NT_HOSTBASED_SERVICE, &server_name); if (maj_stat != GSS_S_COMPLETE) { gssutil.display_status("importing name", maj_stat, min_stat); return -1; } maj_stat = gss_acquire_cred(&min_stat, server_name, 0, GSS_C_NULL_OID_SET, GSS_C_ACCEPT, &gss_server_creds, NULL, NULL); if (maj_stat != GSS_S_COMPLETE) { gssutil.display_status("acquiring credentials", maj_stat, min_stat); return -1; } gss_release_name(&min_stat, &server_name); dbgprintf("GSS-API initialized\n"); return 0; } /* returns 0 if all went OK, -1 if it failed * Calls tcpsrv's SessAccept() and then tries to guess if the connection uses * gssapi. */ static rsRetVal OnSessAcceptGSS(tcpsrv_t *pThis, tcps_sess_t **ppSess, int fd) { DEFiRet; gss_buffer_desc send_tok, recv_tok; gss_name_t client; OM_uint32 maj_stat, min_stat, acc_sec_min_stat; gss_ctx_id_t *context; OM_uint32 *sess_flags; int fdSess; char allowedMethods; gsssrv_t *pGSrv; tcps_sess_t *pSess; gss_sess_t *pGSess; assert(ppSess != NULL); /* first do the usual coding */ CHKiRet(tcpsrv.SessAccept(pThis, &pSess, fd)); pGSrv = (gsssrv_t*) pThis->pUsr; pGSess = (gss_sess_t*) pSess->pUsr; allowedMethods = pGSrv->allowedMethods; if(allowedMethods & ALLOWEDMETHOD_GSS) { /* Buffer to store raw message in case that * gss authentication fails halfway through. */ char buf[MAXLINE]; int ret = 0; dbgprintf("GSS-API Trying to accept TCP session %p\n", pSess); fdSess = pSess->sock; // TODO: method access! if (allowedMethods & ALLOWEDMETHOD_TCP) { int len; fd_set fds; struct timeval tv; do { FD_ZERO(&fds); FD_SET(fdSess, &fds); tv.tv_sec = 1; tv.tv_usec = 0; ret = select(fdSess + 1, &fds, NULL, NULL, &tv); } while (ret < 0 && errno == EINTR); if (ret < 0) { errmsg.LogError(NO_ERRCODE, "TCP session %p will be closed, error ignored\n", pSess); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } else if (ret == 0) { dbgprintf("GSS-API Reverting to plain TCP\n"); pGSess->allowedMethods = ALLOWEDMETHOD_TCP; ABORT_FINALIZE(RS_RET_OK); // TODO: define good error codes } do { ret = recv(fdSess, buf, sizeof (buf), MSG_PEEK); } while (ret < 0 && errno == EINTR); if (ret <= 0) { if (ret == 0) dbgprintf("GSS-API Connection closed by peer\n"); else errmsg.LogError(NO_ERRCODE, "TCP(GSS) session %p will be closed, error ignored\n", pSess); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } if (ret < 4) { dbgprintf("GSS-API Reverting to plain TCP\n"); pGSess->allowedMethods = ALLOWEDMETHOD_TCP; ABORT_FINALIZE(RS_RET_OK); // TODO: define good error codes } else if (ret == 4) { /* The client might has been interupted after sending * the data length (4B), give him another chance. */ srSleep(1, 0); do { ret = recv(fdSess, buf, sizeof (buf), MSG_PEEK); } while (ret < 0 && errno == EINTR); if (ret <= 0) { if (ret == 0) dbgprintf("GSS-API Connection closed by peer\n"); else errmsg.LogError(NO_ERRCODE, "TCP session %p will be closed, error ignored\n", pSess); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } } /* TODO: how does this work together with IPv6? Does it? */ len = ntohl((buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]); if ((ret - 4) < len || len == 0) { dbgprintf("GSS-API Reverting to plain TCP\n"); pGSess->allowedMethods = ALLOWEDMETHOD_TCP; ABORT_FINALIZE(RS_RET_OK); // TODO: define good error codes } } context = &pGSess->gss_context; *context = GSS_C_NO_CONTEXT; sess_flags = &pGSess->gss_flags; do { if (gssutil.recv_token(fdSess, &recv_tok) <= 0) { errmsg.LogError(NO_ERRCODE, "TCP session %p will be closed, error ignored\n", pSess); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } maj_stat = gss_accept_sec_context(&acc_sec_min_stat, context, gss_server_creds, &recv_tok, GSS_C_NO_CHANNEL_BINDINGS, &client, NULL, &send_tok, sess_flags, NULL, NULL); if (recv_tok.value) { free(recv_tok.value); recv_tok.value = NULL; } if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED) { gss_release_buffer(&min_stat, &send_tok); if (*context != GSS_C_NO_CONTEXT) gss_delete_sec_context(&min_stat, context, GSS_C_NO_BUFFER); if ((allowedMethods & ALLOWEDMETHOD_TCP) && (GSS_ROUTINE_ERROR(maj_stat) == GSS_S_DEFECTIVE_TOKEN)) { dbgprintf("GSS-API Reverting to plain TCP\n"); dbgprintf("tcp session socket with new data: #%d\n", fdSess); if(tcps_sess.DataRcvd(pSess, buf, ret) == 0) { errmsg.LogError(NO_ERRCODE, "Tearing down TCP Session %p - see " "previous messages for reason(s)\n", pSess); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } pGSess->allowedMethods = ALLOWEDMETHOD_TCP; ABORT_FINALIZE(RS_RET_OK); // TODO: define good error codes } gssutil.display_status("accepting context", maj_stat, acc_sec_min_stat); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } if (send_tok.length != 0) { if(gssutil.send_token(fdSess, &send_tok) < 0) { gss_release_buffer(&min_stat, &send_tok); errmsg.LogError(NO_ERRCODE, "TCP session %p will be closed, error ignored\n", pSess); if (*context != GSS_C_NO_CONTEXT) gss_delete_sec_context(&min_stat, context, GSS_C_NO_BUFFER); tcps_sess.Close(pSess); ABORT_FINALIZE(RS_RET_ERR); // TODO: define good error codes } gss_release_buffer(&min_stat, &send_tok); } } while (maj_stat == GSS_S_CONTINUE_NEEDED); maj_stat = gss_display_name(&min_stat, client, &recv_tok, NULL); if (maj_stat != GSS_S_COMPLETE) gssutil.display_status("displaying name", maj_stat, min_stat); else dbgprintf("GSS-API Accepted connection from: %s\n", (char*) recv_tok.value); gss_release_name(&min_stat, &client); gss_release_buffer(&min_stat, &recv_tok); dbgprintf("GSS-API Provided context flags:\n"); gssutil.display_ctx_flags(*sess_flags); pGSess->allowedMethods = ALLOWEDMETHOD_GSS; } *ppSess = pSess; finalize_it: RETiRet; } /* returns: number of bytes read or -1 on error * Replaces recv() for gssapi connections. */ int TCPSessGSSRecv(tcps_sess_t *pSess, void *buf, size_t buf_len) { gss_buffer_desc xmit_buf, msg_buf; gss_ctx_id_t *context; OM_uint32 maj_stat, min_stat; int fdSess; int conf_state; int state, len; gss_sess_t *pGSess; assert(pSess->pUsr != NULL); pGSess = (gss_sess_t*) pSess->pUsr; fdSess = pSess->sock; if ((state = gssutil.recv_token(fdSess, &xmit_buf)) <= 0) return state; context = &pGSess->gss_context; maj_stat = gss_unwrap(&min_stat, *context, &xmit_buf, &msg_buf, &conf_state, (gss_qop_t *) NULL); if(maj_stat != GSS_S_COMPLETE) { gssutil.display_status("unsealing message", maj_stat, min_stat); if(xmit_buf.value) { free(xmit_buf.value); xmit_buf.value = 0; } return (-1); } if (xmit_buf.value) { free(xmit_buf.value); xmit_buf.value = 0; } len = msg_buf.length < buf_len ? msg_buf.length : buf_len; memcpy(buf, msg_buf.value, len); gss_release_buffer(&min_stat, &msg_buf); return len; } /* Takes care of cleaning up gssapi stuff and then calls * TCPSessClose(). */ void TCPSessGSSClose(tcps_sess_t* pSess) { OM_uint32 maj_stat, min_stat; gss_ctx_id_t *context; gss_sess_t *pGSess; assert(pSess->pUsr != NULL); pGSess = (gss_sess_t*) pSess->pUsr; context = &pGSess->gss_context; maj_stat = gss_delete_sec_context(&min_stat, context, GSS_C_NO_BUFFER); if (maj_stat != GSS_S_COMPLETE) gssutil.display_status("deleting context", maj_stat, min_stat); *context = GSS_C_NO_CONTEXT; pGSess->gss_flags = 0; pGSess->allowedMethods = 0; tcps_sess.Close(pSess); } /* Counterpart of TCPSessGSSInit(). This is called to exit the GSS system * at all. It is a server-based session exit. */ static rsRetVal TCPSessGSSDeinit(void) { DEFiRet; OM_uint32 maj_stat, min_stat; if (gss_server_creds != GSS_C_NO_CREDENTIAL) { maj_stat = gss_release_cred(&min_stat, &gss_server_creds); if (maj_stat != GSS_S_COMPLETE) gssutil.display_status("releasing credentials", maj_stat, min_stat); } RETiRet; } /* This function is called to gather input. */ BEGINrunInput CODESTARTrunInput iRet = tcpsrv.Run(pOurTcpsrv); ENDrunInput /* initialize and return if will run or not */ BEGINwillRun CODESTARTwillRun if(pOurTcpsrv == NULL) ABORT_FINALIZE(RS_RET_NO_RUN); net.PrintAllowedSenders(2); /* TCP */ net.PrintAllowedSenders(3); /* GSS */ finalize_it: ENDwillRun BEGINmodExit CODESTARTmodExit if(pOurTcpsrv != NULL) iRet = tcpsrv.Destruct(&pOurTcpsrv); TCPSessGSSDeinit(); /* release objects we used */ objRelease(tcps_sess, LM_TCPSRV_FILENAME); objRelease(tcpsrv, LM_TCPSRV_FILENAME); objRelease(gssutil, LM_GSSUTIL_FILENAME); objRelease(errmsg, CORE_COMPONENT); objRelease(net, LM_NET_FILENAME); ENDmodExit BEGINafterRun CODESTARTafterRun /* do cleanup here */ if (net.pAllowedSenders_TCP != NULL) { net.clearAllowedSenders (net.pAllowedSenders_TCP); net.pAllowedSenders_TCP = NULL; } if (net.pAllowedSenders_GSS != NULL) { net.clearAllowedSenders (net.pAllowedSenders_GSS); net.pAllowedSenders_GSS = NULL; } ENDafterRun BEGINqueryEtryPt CODESTARTqueryEtryPt CODEqueryEtryPt_STD_IMOD_QUERIES ENDqueryEtryPt static rsRetVal resetConfigVariables(uchar __attribute__((unused)) *pp, void __attribute__((unused)) *pVal) { if (gss_listen_service_name != NULL) { free(gss_listen_service_name); gss_listen_service_name = NULL; } bPermitPlainTcp = 0; iTCPSessMax = 200; return RS_RET_OK; } BEGINmodInit() CODESTARTmodInit *ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current definition */ CODEmodInit_QueryRegCFSLineHdlr pOurTcpsrv = NULL; /* request objects we use */ CHKiRet(objUse(tcps_sess, LM_TCPSRV_FILENAME)); CHKiRet(objUse(tcpsrv, LM_TCPSRV_FILENAME)); CHKiRet(objUse(gssutil, LM_GSSUTIL_FILENAME)); CHKiRet(objUse(errmsg, CORE_COMPONENT)); CHKiRet(objUse(net, LM_NET_FILENAME)); /* register config file handlers */ CHKiRet(omsdRegCFSLineHdlr((uchar *)"inputgssserverpermitplaintcp", 0, eCmdHdlrBinary, NULL, &bPermitPlainTcp, STD_LOADABLE_MODULE_ID)); CHKiRet(omsdRegCFSLineHdlr((uchar *)"inputgssserverrun", 0, eCmdHdlrGetWord, addGSSListener, NULL, STD_LOADABLE_MODULE_ID)); CHKiRet(omsdRegCFSLineHdlr((uchar *)"inputgssserverservicename", 0, eCmdHdlrGetWord, NULL, &gss_listen_service_name, STD_LOADABLE_MODULE_ID)); CHKiRet(omsdRegCFSLineHdlr((uchar *)"inputgssservermaxsessions", 0, eCmdHdlrInt, NULL, &iTCPSessMax, STD_LOADABLE_MODULE_ID)); CHKiRet(omsdRegCFSLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler, resetConfigVariables, NULL, STD_LOADABLE_MODULE_ID)); ENDmodInit /* vim:set ai: */