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Diffstat (limited to 'runtime/net.c')
| -rw-r--r-- | runtime/net.c | 1149 |
1 files changed, 1149 insertions, 0 deletions
diff --git a/runtime/net.c b/runtime/net.c new file mode 100644 index 00000000..84c286d2 --- /dev/null +++ b/runtime/net.c @@ -0,0 +1,1149 @@ +/* net.c + * Implementation of network-related stuff. + * + * File begun on 2007-07-20 by RGerhards (extracted from syslogd.c) + * This file is under development and has not yet arrived at being fully + * self-contained and a real object. So far, it is mostly an excerpt + * of the "old" message code without any modifications. However, it + * helps to have things at the right place one we go to the meat of it. + * + * Starting 2007-12-24, I have begun to shuffle more network-related code + * from syslogd.c to over here. I am not sure if it will stay here in the + * long term, but it is good to have it out of syslogd.c. Maybe this here is + * an interim location ;) + * + * Copyright 2007, 2008 Rainer Gerhards and Adiscon GmbH. + * + * rgerhards, 2008-04-16: I changed this code to LGPL today. I carefully analyzed + * that it does not borrow code from the original sysklogd and that I have + * permission to do so from all other contributors. My analysis found that all + * code from sysklogd has been superseeded by our own functionality, so it + * is OK to move this file to LGPL. Some variable sysklogd variable names + * remain, but even this will change as the net object evolves. + * + * This file is part of the rsyslog runtime library. + * + * The rsyslog runtime library is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * The rsyslog runtime library 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 Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the rsyslog runtime library. If not, see <http://www.gnu.org/licenses/>. + * + * A copy of the GPL can be found in the file "COPYING" in this distribution. + * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution. + */ +#include "config.h" + +#include "rsyslog.h" +#include <stdio.h> +#include <stdarg.h> +#include <stdlib.h> +#include <assert.h> +#include <errno.h> +#include <string.h> +#include <signal.h> +#include <ctype.h> +#include <netdb.h> +#include <fnmatch.h> +#include <fcntl.h> +#include <unistd.h> + +#include "syslogd.h" +#include "syslogd-types.h" +#include "module-template.h" +#include "parse.h" +#include "srUtils.h" +#include "obj.h" +#include "errmsg.h" +#include "net.h" + +MODULE_TYPE_LIB + +/* static data */ +DEFobjStaticHelpers +DEFobjCurrIf(errmsg) + +/* support for defining allowed TCP and UDP senders. We use the same + * structure to implement this (a linked list), but we define two different + * list roots, one for UDP and one for TCP. + * rgerhards, 2005-09-26 + */ +/* All of the five below are read-only after startup */ +struct AllowedSenders *pAllowedSenders_UDP = NULL; /* the roots of the allowed sender */ +struct AllowedSenders *pAllowedSenders_TCP = NULL; /* lists. If NULL, all senders are ok! */ +static struct AllowedSenders *pLastAllowedSenders_UDP = NULL; /* and now the pointers to the last */ +static struct AllowedSenders *pLastAllowedSenders_TCP = NULL; /* element in the respective list */ +#ifdef USE_GSSAPI +struct AllowedSenders *pAllowedSenders_GSS = NULL; +static struct AllowedSenders *pLastAllowedSenders_GSS = NULL; +#endif + +int ACLAddHostnameOnFail = 0; /* add hostname to acl when DNS resolving has failed */ +int ACLDontResolve = 0; /* add hostname to acl instead of resolving it to IP(s) */ + +/* Code for handling allowed/disallowed senders + */ +static inline void MaskIP6 (struct in6_addr *addr, uint8_t bits) { + register uint8_t i; + + assert (addr != NULL); + assert (bits <= 128); + + i = bits/32; + if (bits%32) + addr->s6_addr32[i++] &= htonl(0xffffffff << (32 - (bits % 32))); + for (; i < (sizeof addr->s6_addr32)/4; i++) + addr->s6_addr32[i] = 0; +} + +static inline void MaskIP4 (struct in_addr *addr, uint8_t bits) { + + assert (addr != NULL); + assert (bits <=32 ); + + addr->s_addr &= htonl(0xffffffff << (32 - bits)); +} + +#define SIN(sa) ((struct sockaddr_in *)(sa)) +#define SIN6(sa) ((struct sockaddr_in6 *)(sa)) + +/* This function adds an allowed sender entry to the ACL linked list. + * In any case, a single entry is added. If an error occurs, the + * function does its error reporting itself. All validity checks + * must already have been done by the caller. + * This is a helper to AddAllowedSender(). + * rgerhards, 2007-07-17 + */ +static rsRetVal AddAllowedSenderEntry(struct AllowedSenders **ppRoot, struct AllowedSenders **ppLast, + struct NetAddr *iAllow, uint8_t iSignificantBits) +{ + struct AllowedSenders *pEntry = NULL; + + assert(ppRoot != NULL); + assert(ppLast != NULL); + assert(iAllow != NULL); + + if((pEntry = (struct AllowedSenders*) calloc(1, sizeof(struct AllowedSenders))) == NULL) { + glblHadMemShortage = 1; + return RS_RET_OUT_OF_MEMORY; /* no options left :( */ + } + + memcpy(&(pEntry->allowedSender), iAllow, sizeof (struct NetAddr)); + pEntry->pNext = NULL; + pEntry->SignificantBits = iSignificantBits; + + /* enqueue */ + if(*ppRoot == NULL) { + *ppRoot = pEntry; + } else { + (*ppLast)->pNext = pEntry; + } + *ppLast = pEntry; + + return RS_RET_OK; +} + +/* function to clear the allowed sender structure in cases where + * it must be freed (occurs most often when HUPed. + * TODO: reconsider recursive implementation + * I think there is also a memory leak, because only the last entry + * is acutally deleted... -- rgerhards, 2007-12-25 + */ +void clearAllowedSenders (struct AllowedSenders *pAllow) +{ + if (pAllow != NULL) { + if (pAllow->pNext != NULL) + clearAllowedSenders (pAllow->pNext); + else { + if (F_ISSET(pAllow->allowedSender.flags, ADDR_NAME)) + free (pAllow->allowedSender.addr.HostWildcard); + else + free (pAllow->allowedSender.addr.NetAddr); + + free (pAllow); + } + } +} + +/* function to add an allowed sender to the allowed sender list. The + * root of the list is caller-provided, so it can be used for all + * supported lists. The caller must provide a pointer to the root, + * as it eventually needs to be updated. Also, a pointer to the + * pointer to the last element must be provided (to speed up adding + * list elements). + * rgerhards, 2005-09-26 + * If a hostname is given there are possible multiple entries + * added (all addresses from that host). + */ +static rsRetVal AddAllowedSender(struct AllowedSenders **ppRoot, struct AllowedSenders **ppLast, + struct NetAddr *iAllow, uint8_t iSignificantBits) +{ + DEFiRet; + + assert(ppRoot != NULL); + assert(ppLast != NULL); + assert(iAllow != NULL); + + if (!F_ISSET(iAllow->flags, ADDR_NAME)) { + if(iSignificantBits == 0) + /* we handle this seperatly just to provide a better + * error message. + */ + errmsg.LogError(NO_ERRCODE, "You can not specify 0 bits of the netmask, this would " + "match ALL systems. If you really intend to do that, " + "remove all $AllowedSender directives."); + + switch (iAllow->addr.NetAddr->sa_family) { + case AF_INET: + if((iSignificantBits < 1) || (iSignificantBits > 32)) { + errmsg.LogError(NO_ERRCODE, "Invalid number of bits (%d) in IPv4 address - adjusted to 32", + (int)iSignificantBits); + iSignificantBits = 32; + } + + MaskIP4 (&(SIN(iAllow->addr.NetAddr)->sin_addr), iSignificantBits); + break; + case AF_INET6: + if((iSignificantBits < 1) || (iSignificantBits > 128)) { + errmsg.LogError(NO_ERRCODE, "Invalid number of bits (%d) in IPv6 address - adjusted to 128", + iSignificantBits); + iSignificantBits = 128; + } + + MaskIP6 (&(SIN6(iAllow->addr.NetAddr)->sin6_addr), iSignificantBits); + break; + default: + /* rgerhards, 2007-07-16: We have an internal program error in this + * case. However, there is not much we can do against it right now. Of + * course, we could abort, but that would probably cause more harm + * than good. So we continue to run. We simply do not add this line - the + * worst thing that happens is that one host will not be allowed to + * log. + */ + errmsg.LogError(NO_ERRCODE, "Internal error caused AllowedSender to be ignored, AF = %d", + iAllow->addr.NetAddr->sa_family); + ABORT_FINALIZE(RS_RET_ERR); + } + /* OK, entry constructed, now lets add it to the ACL list */ + iRet = AddAllowedSenderEntry(ppRoot, ppLast, iAllow, iSignificantBits); + } else { + /* we need to process a hostname ACL */ + if (DisableDNS) { + errmsg.LogError(NO_ERRCODE, "Ignoring hostname based ACLs because DNS is disabled."); + ABORT_FINALIZE(RS_RET_OK); + } + + if (!strchr (iAllow->addr.HostWildcard, '*') && + !strchr (iAllow->addr.HostWildcard, '?') && + ACLDontResolve == 0) { + /* single host - in this case, we pull its IP addresses from DNS + * and add IP-based ACLs. + */ + struct addrinfo hints, *res, *restmp; + struct NetAddr allowIP; + + memset (&hints, 0, sizeof (struct addrinfo)); + hints.ai_family = AF_UNSPEC; + hints.ai_socktype = SOCK_DGRAM; +# ifdef AI_ADDRCONFIG /* seems not to be present on all systems */ + hints.ai_flags = AI_ADDRCONFIG; +# endif + + if (getaddrinfo (iAllow->addr.HostWildcard, NULL, &hints, &res) != 0) { + errmsg.LogError(NO_ERRCODE, "DNS error: Can't resolve \"%s\"", iAllow->addr.HostWildcard); + + if (ACLAddHostnameOnFail) { + errmsg.LogError(NO_ERRCODE, "Adding hostname \"%s\" to ACL as a wildcard entry.", iAllow->addr.HostWildcard); + iRet = AddAllowedSenderEntry(ppRoot, ppLast, iAllow, iSignificantBits); + FINALIZE; + } else { + errmsg.LogError(NO_ERRCODE, "Hostname \"%s\" WON\'T be added to ACL.", iAllow->addr.HostWildcard); + ABORT_FINALIZE(RS_RET_NOENTRY); + } + } + + for (restmp = res ; res != NULL ; res = res->ai_next) { + switch (res->ai_family) { + case AF_INET: /* add IPv4 */ + iSignificantBits = 32; + allowIP.flags = 0; + if((allowIP.addr.NetAddr = malloc(res->ai_addrlen)) == NULL) { + glblHadMemShortage = 1; + ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY); + } + memcpy(allowIP.addr.NetAddr, res->ai_addr, res->ai_addrlen); + + if((iRet = AddAllowedSenderEntry(ppRoot, ppLast, &allowIP, iSignificantBits)) + != RS_RET_OK) + FINALIZE; + break; + case AF_INET6: /* IPv6 - but need to check if it is a v6-mapped IPv4 */ + if(IN6_IS_ADDR_V4MAPPED (&SIN6(res->ai_addr)->sin6_addr)) { + /* extract & add IPv4 */ + + iSignificantBits = 32; + allowIP.flags = 0; + if((allowIP.addr.NetAddr = malloc(sizeof(struct sockaddr_in))) + == NULL) { + glblHadMemShortage = 1; + ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY); + } + SIN(allowIP.addr.NetAddr)->sin_family = AF_INET; +#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN + SIN(allowIP.addr.NetAddr)->sin_len = sizeof (struct sockaddr_in); +#endif + SIN(allowIP.addr.NetAddr)->sin_port = 0; + memcpy(&(SIN(allowIP.addr.NetAddr)->sin_addr.s_addr), + &(SIN6(res->ai_addr)->sin6_addr.s6_addr32[3]), + sizeof (struct sockaddr_in)); + + if((iRet = AddAllowedSenderEntry(ppRoot, ppLast, &allowIP, + iSignificantBits)) + != RS_RET_OK) + FINALIZE; + } else { + /* finally add IPv6 */ + + iSignificantBits = 128; + allowIP.flags = 0; + if((allowIP.addr.NetAddr = malloc(res->ai_addrlen)) == NULL) { + glblHadMemShortage = 1; + ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY); + } + memcpy(allowIP.addr.NetAddr, res->ai_addr, res->ai_addrlen); + + if((iRet = AddAllowedSenderEntry(ppRoot, ppLast, &allowIP, + iSignificantBits)) + != RS_RET_OK) + FINALIZE; + } + break; + } + } + freeaddrinfo (restmp); + } else { + /* wildcards in hostname - we need to add a text-based ACL. + * For this, we already have everything ready and just need + * to pass it along... + */ + iRet = AddAllowedSenderEntry(ppRoot, ppLast, iAllow, iSignificantBits); + } + } + +finalize_it: + RETiRet; +} + + +/* Print an allowed sender list. The caller must tell us which one. + * iListToPrint = 1 means UDP, 2 means TCP + * rgerhards, 2005-09-27 + */ +void PrintAllowedSenders(int iListToPrint) +{ + struct AllowedSenders *pSender; + uchar szIP[64]; + + assert((iListToPrint == 1) || (iListToPrint == 2) +#ifdef USE_GSSAPI + || (iListToPrint == 3) +#endif + ); + + dbgprintf("Allowed %s Senders:\n", + (iListToPrint == 1) ? "UDP" : +#ifdef USE_GSSAPI + (iListToPrint == 3) ? "GSS" : +#endif + "TCP"); + + pSender = (iListToPrint == 1) ? pAllowedSenders_UDP : +#ifdef USE_GSSAPI + (iListToPrint == 3) ? pAllowedSenders_GSS : +#endif + pAllowedSenders_TCP; + if(pSender == NULL) { + dbgprintf("\tNo restrictions set.\n"); + } else { + while(pSender != NULL) { + if (F_ISSET(pSender->allowedSender.flags, ADDR_NAME)) + dbgprintf ("\t%s\n", pSender->allowedSender.addr.HostWildcard); + else { + if(getnameinfo (pSender->allowedSender.addr.NetAddr, + SALEN(pSender->allowedSender.addr.NetAddr), + (char*)szIP, 64, NULL, 0, NI_NUMERICHOST) == 0) { + dbgprintf ("\t%s/%u\n", szIP, pSender->SignificantBits); + } else { + /* getnameinfo() failed - but as this is only a + * debug function, we simply spit out an error and do + * not care much about it. + */ + dbgprintf("\tERROR in getnameinfo() - something may be wrong " + "- ignored for now\n"); + } + } + pSender = pSender->pNext; + } + } +} + + +/* parse an allowed sender config line and add the allowed senders + * (if the line is correct). + * rgerhards, 2005-09-27 + */ +rsRetVal addAllowedSenderLine(char* pName, uchar** ppRestOfConfLine) +{ + struct AllowedSenders **ppRoot; + struct AllowedSenders **ppLast; + rsParsObj *pPars; + rsRetVal iRet; + struct NetAddr *uIP = NULL; + int iBits; + + assert(pName != NULL); + assert(ppRestOfConfLine != NULL); + assert(*ppRestOfConfLine != NULL); + + if(!strcasecmp(pName, "udp")) { + ppRoot = &pAllowedSenders_UDP; + ppLast = &pLastAllowedSenders_UDP; + } else if(!strcasecmp(pName, "tcp")) { + ppRoot = &pAllowedSenders_TCP; + ppLast = &pLastAllowedSenders_TCP; +#ifdef USE_GSSAPI + } else if(!strcasecmp(pName, "gss")) { + ppRoot = &pAllowedSenders_GSS; + ppLast = &pLastAllowedSenders_GSS; +#endif + } else { + errmsg.LogError(NO_ERRCODE, "Invalid protocol '%s' in allowed sender " + "list, line ignored", pName); + return RS_RET_ERR; + } + + /* OK, we now know the protocol and have valid list pointers. + * So let's process the entries. We are using the parse class + * for this. + */ + /* create parser object starting with line string without leading colon */ + if((iRet = rsParsConstructFromSz(&pPars, (uchar*) *ppRestOfConfLine) != RS_RET_OK)) { + errmsg.LogError(NO_ERRCODE, "Error %d constructing parser object - ignoring allowed sender list", iRet); + return(iRet); + } + + while(!parsIsAtEndOfParseString(pPars)) { + if(parsPeekAtCharAtParsPtr(pPars) == '#') + break; /* a comment-sign stops processing of line */ + /* now parse a single IP address */ + if((iRet = parsAddrWithBits(pPars, &uIP, &iBits)) != RS_RET_OK) { + errmsg.LogError(NO_ERRCODE, "Error %d parsing address in allowed sender" + "list - ignoring.", iRet); + rsParsDestruct(pPars); + return(iRet); + } + if((iRet = AddAllowedSender(ppRoot, ppLast, uIP, iBits)) + != RS_RET_OK) { + if (iRet == RS_RET_NOENTRY) { + errmsg.LogError(NO_ERRCODE, "Error %d adding allowed sender entry " + "- ignoring.", iRet); + } else { + errmsg.LogError(NO_ERRCODE, "Error %d adding allowed sender entry " + "- terminating, nothing more will be added.", iRet); + rsParsDestruct(pPars); + return(iRet); + } + } + free (uIP); /* copy stored in AllowedSenders list */ + } + + /* cleanup */ + *ppRestOfConfLine += parsGetCurrentPosition(pPars); + return rsParsDestruct(pPars); +} + + + +/* compares a host to an allowed sender list entry. Handles all subleties + * including IPv4/v6 as well as domain name wildcards. + * This is a helper to isAllowedSender. As it is only called once, it is + * declared inline. + * Returns 0 if they do not match, something else otherwise. + * contributed 1007-07-16 by mildew@gmail.com + */ +static inline int MaskCmp(struct NetAddr *pAllow, uint8_t bits, struct sockaddr *pFrom, const char *pszFromHost) +{ + assert(pAllow != NULL); + assert(pFrom != NULL); + + if(F_ISSET(pAllow->flags, ADDR_NAME)) { + dbgprintf("MaskCmp: host=\"%s\"; pattern=\"%s\"\n", pszFromHost, pAllow->addr.HostWildcard); + +# if !defined(FNM_CASEFOLD) + /* TODO: I don't know if that then works, seen on HP UX, what I have not in lab... ;) */ + return(fnmatch(pAllow->addr.HostWildcard, pszFromHost, FNM_NOESCAPE) == 0); +# else + return(fnmatch(pAllow->addr.HostWildcard, pszFromHost, FNM_NOESCAPE|FNM_CASEFOLD) == 0); +# endif + } else {/* We need to compare an IP address */ + switch (pFrom->sa_family) { + case AF_INET: + if (AF_INET == pAllow->addr.NetAddr->sa_family) + return(( SIN(pFrom)->sin_addr.s_addr & htonl(0xffffffff << (32 - bits)) ) + == SIN(pAllow->addr.NetAddr)->sin_addr.s_addr); + else + return 0; + break; + case AF_INET6: + switch (pAllow->addr.NetAddr->sa_family) { + case AF_INET6: { + struct in6_addr ip, net; + register uint8_t i; + + memcpy (&ip, &(SIN6(pFrom))->sin6_addr, sizeof (struct in6_addr)); + memcpy (&net, &(SIN6(pAllow->addr.NetAddr))->sin6_addr, sizeof (struct in6_addr)); + + i = bits/32; + if (bits % 32) + ip.s6_addr32[i++] &= htonl(0xffffffff << (32 - (bits % 32))); + for (; i < (sizeof ip.s6_addr32)/4; i++) + ip.s6_addr32[i] = 0; + + return (memcmp (ip.s6_addr, net.s6_addr, sizeof ip.s6_addr) == 0 && + (SIN6(pAllow->addr.NetAddr)->sin6_scope_id != 0 ? + SIN6(pFrom)->sin6_scope_id == SIN6(pAllow->addr.NetAddr)->sin6_scope_id : 1)); + } + case AF_INET: { + struct in6_addr *ip6 = &(SIN6(pFrom))->sin6_addr; + struct in_addr *net = &(SIN(pAllow->addr.NetAddr))->sin_addr; + + if ((ip6->s6_addr32[3] & (u_int32_t) htonl((0xffffffff << (32 - bits)))) == net->s_addr && +#if BYTE_ORDER == LITTLE_ENDIAN + (ip6->s6_addr32[2] == (u_int32_t)0xffff0000) && +#else + (ip6->s6_addr32[2] == (u_int32_t)0x0000ffff) && +#endif + (ip6->s6_addr32[1] == 0) && (ip6->s6_addr32[0] == 0)) + return 1; + else + return 0; + } + default: + /* Unsupported AF */ + return 0; + } + default: + /* Unsupported AF */ + return 0; + } + } +} + + +/* check if a sender is allowed. The root of the the allowed sender. + * list must be proveded by the caller. As such, this function can be + * used to check both UDP and TCP allowed sender lists. + * returns 1, if the sender is allowed, 0 otherwise. + * rgerhards, 2005-09-26 + */ +static int isAllowedSender(struct AllowedSenders *pAllowRoot, struct sockaddr *pFrom, const char *pszFromHost) +{ + struct AllowedSenders *pAllow; + + assert(pFrom != NULL); + + if(pAllowRoot == NULL) + return 1; /* checking disabled, everything is valid! */ + + /* now we loop through the list of allowed senders. As soon as + * we find a match, we return back (indicating allowed). We loop + * until we are out of allowed senders. If so, we fall through the + * loop and the function's terminal return statement will indicate + * that the sender is disallowed. + */ + for(pAllow = pAllowRoot ; pAllow != NULL ; pAllow = pAllow->pNext) { + if (MaskCmp (&(pAllow->allowedSender), pAllow->SignificantBits, pFrom, pszFromHost)) + return 1; + } + return 0; +} + + +/* The following #ifdef sequence is a small compatibility + * layer. It tries to work around the different availality + * levels of SO_BSDCOMPAT on linuxes... + * I borrowed this code from + * http://www.erlang.org/ml-archive/erlang-questions/200307/msg00037.html + * It still needs to be a bit better adapted to rsyslog. + * rgerhards 2005-09-19 + */ +#include <sys/utsname.h> +static int +should_use_so_bsdcompat(void) +{ +#ifndef OS_BSD + static int init_done; + static int so_bsdcompat_is_obsolete; + + if (!init_done) { + struct utsname myutsname; + unsigned int version, patchlevel; + + init_done = 1; + if (uname(&myutsname) < 0) { + char errStr[1024]; + dbgprintf("uname: %s\r\n", rs_strerror_r(errno, errStr, sizeof(errStr))); + return 1; + } + /* Format is <version>.<patchlevel>.<sublevel><extraversion> + where the first three are unsigned integers and the last + is an arbitrary string. We only care about the first two. */ + if (sscanf(myutsname.release, "%u.%u", &version, &patchlevel) != 2) { + dbgprintf("uname: unexpected release '%s'\r\n", + myutsname.release); + return 1; + } + /* SO_BSCOMPAT is deprecated and triggers warnings in 2.5 + kernels. It is a no-op in 2.4 but not in 2.2 kernels. */ + if (version > 2 || (version == 2 && patchlevel >= 5)) + so_bsdcompat_is_obsolete = 1; + } + return !so_bsdcompat_is_obsolete; +#else /* #ifndef OS_BSD */ + return 1; +#endif /* #ifndef OS_BSD */ +} +#ifndef SO_BSDCOMPAT +/* this shall prevent compiler errors due to undfined name */ +#define SO_BSDCOMPAT 0 +#endif + + +/* get the hostname of the message source. This was originally in cvthname() + * but has been moved out of it because of clarity and fuctional separation. + * It must be provided by the socket we received the message on as well as + * a NI_MAXHOST size large character buffer for the FQDN. + * + * Please see http://www.hmug.org/man/3/getnameinfo.php (under Caveats) + * for some explanation of the code found below. We do by default not + * discard message where we detected malicouos DNS PTR records. However, + * there is a user-configurabel option that will tell us if + * we should abort. For this, the return value tells the caller if the + * message should be processed (1) or discarded (0). + */ +static rsRetVal +gethname(struct sockaddr_storage *f, uchar *pszHostFQDN) +{ + DEFiRet; + int error; + sigset_t omask, nmask; + char ip[NI_MAXHOST]; + struct addrinfo hints, *res; + + assert(f != NULL); + assert(pszHostFQDN != NULL); + + error = getnameinfo((struct sockaddr *)f, SALEN((struct sockaddr *)f), + ip, sizeof ip, NULL, 0, NI_NUMERICHOST); + + if (error) { + dbgprintf("Malformed from address %s\n", gai_strerror(error)); + strcpy((char*) pszHostFQDN, "???"); + ABORT_FINALIZE(RS_RET_INVALID_SOURCE); + } + + if (!DisableDNS) { + sigemptyset(&nmask); + sigaddset(&nmask, SIGHUP); + pthread_sigmask(SIG_BLOCK, &nmask, &omask); + + error = getnameinfo((struct sockaddr *)f, SALEN((struct sockaddr *) f), + (char*)pszHostFQDN, NI_MAXHOST, NULL, 0, NI_NAMEREQD); + + if (error == 0) { + memset (&hints, 0, sizeof (struct addrinfo)); + hints.ai_flags = AI_NUMERICHOST; + hints.ai_socktype = SOCK_DGRAM; + + /* we now do a lookup once again. This one should fail, + * because we should not have obtained a non-numeric address. If + * we got a numeric one, someone messed with DNS! + */ + if (getaddrinfo ((char*)pszHostFQDN, NULL, &hints, &res) == 0) { + uchar szErrMsg[1024]; + freeaddrinfo (res); + /* OK, we know we have evil. The question now is what to do about + * it. One the one hand, the message might probably be intended + * to harm us. On the other hand, losing the message may also harm us. + * Thus, the behaviour is controlled by the $DropMsgsWithMaliciousDnsPTRRecords + * option. If it tells us we should discard, we do so, else we proceed, + * but log an error message together with it. + * time being, we simply drop the name we obtained and use the IP - that one + * is OK in any way. We do also log the error message. rgerhards, 2007-07-16 + */ + if(bDropMalPTRMsgs == 1) { + snprintf((char*)szErrMsg, sizeof(szErrMsg) / sizeof(uchar), + "Malicious PTR record, message dropped " + "IP = \"%s\" HOST = \"%s\"", + ip, pszHostFQDN); + errmsg.LogError(NO_ERRCODE, "%s", szErrMsg); + pthread_sigmask(SIG_SETMASK, &omask, NULL); + ABORT_FINALIZE(RS_RET_MALICIOUS_ENTITY); + } + + /* Please note: we deal with a malicous entry. Thus, we have crafted + * the snprintf() below so that all text is in front of the entry - maybe + * it contains characters that make the message unreadable + * (OK, I admit this is more or less impossible, but I am paranoid...) + * rgerhards, 2007-07-16 + */ + snprintf((char*)szErrMsg, sizeof(szErrMsg) / sizeof(uchar), + "Malicious PTR record (message accepted, but used IP " + "instead of PTR name: IP = \"%s\" HOST = \"%s\"", + ip, pszHostFQDN); + errmsg.LogError(NO_ERRCODE, "%s", szErrMsg); + + error = 1; /* that will trigger using IP address below. */ + } + } + pthread_sigmask(SIG_SETMASK, &omask, NULL); + } + + if (error || DisableDNS) { + dbgprintf("Host name for your address (%s) unknown\n", ip); + strcpy((char*) pszHostFQDN, ip); + ABORT_FINALIZE(RS_RET_ADDRESS_UNKNOWN); + } + +finalize_it: + RETiRet; +} + + + +/* print out which socket we are listening on. This is only + * a debug aid. rgerhards, 2007-07-02 + */ +void debugListenInfo(int fd, char *type) +{ + char *szFamily; + int port; + struct sockaddr sa; + struct sockaddr_in *ipv4; + struct sockaddr_in6 *ipv6; + socklen_t saLen = sizeof(sa); + + if(getsockname(fd, &sa, &saLen) == 0) { + switch(sa.sa_family) { + case PF_INET: + szFamily = "IPv4"; + ipv4 = (struct sockaddr_in*) &sa; + port = ntohs(ipv4->sin_port); + break; + case PF_INET6: + szFamily = "IPv6"; + ipv6 = (struct sockaddr_in6*) &sa; + port = ntohs(ipv6->sin6_port); + break; + default: + szFamily = "other"; + port = -1; + break; + } + dbgprintf("Listening on %s syslogd socket %d (%s/port %d).\n", + type, fd, szFamily, port); + return; + } + + /* we can not obtain peer info. We are just providing + * debug info, so this is no reason to break the program + * or do any serious error reporting. + */ + dbgprintf("Listening on syslogd socket %d - could not obtain peer info.\n", fd); +} + + +/* Return a printable representation of a host address. + * Now (2007-07-16) also returns the full host name (if it could be obtained) + * in the second param [thanks to mildew@gmail.com for the patch]. + * The caller must provide buffer space for pszHost and pszHostFQDN. These + * buffers must be of size NI_MAXHOST. This is not checked here, because + * there is no way to check it. We use this way of doing things because it + * frees us from using dynamic memory allocation where it really does not + * pay. + */ +rsRetVal cvthname(struct sockaddr_storage *f, uchar *pszHost, uchar *pszHostFQDN) +{ + DEFiRet; + register uchar *p; + int count; + + assert(f != NULL); + assert(pszHost != NULL); + assert(pszHostFQDN != NULL); + + iRet = gethname(f, pszHostFQDN); + + if(iRet == RS_RET_INVALID_SOURCE || iRet == RS_RET_ADDRESS_UNKNOWN) { + strcpy((char*) pszHost, (char*) pszHostFQDN); /* we use whatever was provided as replacement */ + ABORT_FINALIZE(RS_RET_OK); /* this is handled, we are happy with it */ + } else if(iRet != RS_RET_OK) { + FINALIZE; /* we return whatever error state we have - can not handle it */ + } + + /* if we reach this point, we obtained a non-numeric hostname and can now process it */ + + /* Convert to lower case */ + for(p = pszHostFQDN ; *p ; p++) + if (isupper((int) *p)) + *p = tolower(*p); + + /* OK, the fqdn is now known. Now it is time to extract only the hostname + * part if we were instructed to do so. + */ + /* TODO: quick and dirty right now: we need to optimize that. We simply + * copy over the buffer and then use the old code. In the long term, that should + * be placed in its own function and probably outside of the net module (at least + * if should no longer reley on syslogd.c's global config-setting variables). + * Note that the old code always removes the local domain. We may want to + * make this in option in the long term. (rgerhards, 2007-09-11) + */ + strcpy((char*)pszHost, (char*)pszHostFQDN); + if ((p = (uchar*) strchr((char*)pszHost, '.'))) { /* find start of domain name "machine.example.com" */ + if(strcmp((char*) (p + 1), LocalDomain) == 0) { + *p = '\0'; /* simply terminate the string */ + } else { + /* now check if we belong to any of the domain names that were specified + * in the -s command line option. If so, remove and we are done. + * TODO: this must go away! -- rgerhards, 2008-04-16 + * For proper modularization, this must be done different, e.g. via a + * "to be stripped" property of *this* object itself. + */ + if (StripDomains) { + count=0; + while (StripDomains[count]) { + if (strcmp((char*)(p + 1), StripDomains[count]) == 0) { + *p = '\0'; + FINALIZE; /* we are done */ + } + count++; + } + } + /* if we reach this point, we have not found any domain we should strip. Now + * we try and see if the host itself is listed in the -l command line option + * and so should be stripped also. If so, we do it and return. Please note that + * -l list FQDNs, not just the hostname part. If it did just list the hostname, the + * door would be wide-open for all kinds of mixing up of hosts. Because of this, + * you'll see comparison against the full string (pszHost) below. The termination + * still occurs at *p, which points at the first dot after the hostname. + * TODO: this must also go away - see comment above -- rgerhards, 2008-04-16 + */ + if (LocalHosts) { + count=0; + while (LocalHosts[count]) { + if (!strcmp((char*)pszHost, LocalHosts[count])) { + *p = '\0'; + break; /* we are done */ + } + count++; + } + } + } + } + +finalize_it: + RETiRet; +} + + +/* get the name of the local host. A pointer to a character pointer is passed + * in, which on exit points to the local hostname. This buffer is dynamically + * allocated and must be free()ed by the caller. If the functions returns an + * error, the pointer is NULL. This function is based on GNU/Hurd's localhostname + * function. + * rgerhards, 20080-04-10 + */ +static rsRetVal +getLocalHostname(uchar **ppName) +{ + DEFiRet; + uchar *buf = NULL; + size_t buf_len = 0; + + assert(ppName != NULL); + + do { + if(buf == NULL) { + buf_len = 128; /* Initial guess */ + CHKmalloc(buf = malloc(buf_len)); + } else { + buf_len += buf_len; + CHKmalloc(buf = realloc (buf, buf_len)); + } + } while((gethostname((char*)buf, buf_len) == 0 && !memchr (buf, '\0', buf_len)) || errno == ENAMETOOLONG); + + *ppName = buf; + buf = NULL; + +finalize_it: + if(iRet != RS_RET_OK) { + if(buf != NULL) + free(buf); + } + RETiRet; +} + + +/* closes the UDP listen sockets (if they exist) and frees + * all dynamically assigned memory. + */ +void closeUDPListenSockets(int *pSockArr) +{ + register int i; + + assert(pSockArr != NULL); + if(pSockArr != NULL) { + for (i = 0; i < *pSockArr; i++) + close(pSockArr[i+1]); + free(pSockArr); + } +} + + +/* creates the UDP listen sockets + * hostname and/or pszPort may be NULL, but not both! + * bIsServer indicates if a server socket should be created + * 1 - server, 0 - client + */ +int *create_udp_socket(uchar *hostname, uchar *pszPort, int bIsServer) +{ + struct addrinfo hints, *res, *r; + int error, maxs, *s, *socks, on = 1; + int sockflags; + + assert(!((pszPort == NULL) && (hostname == NULL))); + memset(&hints, 0, sizeof(hints)); + if(bIsServer) + hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV; + else + hints.ai_flags = AI_NUMERICSERV; + hints.ai_family = family; + hints.ai_socktype = SOCK_DGRAM; + error = getaddrinfo((char*) hostname, (char*) pszPort, &hints, &res); + if(error) { + errmsg.LogError(NO_ERRCODE, "%s", gai_strerror(error)); + errmsg.LogError(NO_ERRCODE, "UDP message reception disabled due to error logged in last message.\n"); + return NULL; + } + + /* Count max number of sockets we may open */ + for (maxs = 0, r = res; r != NULL ; r = r->ai_next, maxs++) + /* EMPTY */; + socks = malloc((maxs+1) * sizeof(int)); + if (socks == NULL) { + errmsg.LogError(NO_ERRCODE, "couldn't allocate memory for UDP sockets, suspending UDP message reception"); + freeaddrinfo(res); + return NULL; + } + + *socks = 0; /* num of sockets counter at start of array */ + s = socks + 1; + for (r = res; r != NULL ; r = r->ai_next) { + *s = socket(r->ai_family, r->ai_socktype, r->ai_protocol); + if (*s < 0) { + if(!(r->ai_family == PF_INET6 && errno == EAFNOSUPPORT)) + errmsg.LogError(NO_ERRCODE, "create_udp_socket(), socket"); + /* it is debateble if PF_INET with EAFNOSUPPORT should + * also be ignored... + */ + continue; + } + +# ifdef IPV6_V6ONLY + if (r->ai_family == AF_INET6) { + int ion = 1; + if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY, + (char *)&ion, sizeof (ion)) < 0) { + errmsg.LogError(NO_ERRCODE, "setsockopt"); + close(*s); + *s = -1; + continue; + } + } +# endif + + /* if we have an error, we "just" suspend that socket. Eventually + * other sockets will work. At the end of this function, we check + * if we managed to open at least one socket. If not, we'll write + * a "inet suspended" message and declare failure. Else we use + * what we could obtain. + * rgerhards, 2007-06-22 + */ + if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, + (char *) &on, sizeof(on)) < 0 ) { + errmsg.LogError(NO_ERRCODE, "setsockopt(REUSEADDR)"); + close(*s); + *s = -1; + continue; + } + + /* We need to enable BSD compatibility. Otherwise an attacker + * could flood our log files by sending us tons of ICMP errors. + */ +#if !defined(OS_BSD) && !defined(__hpux) + if (should_use_so_bsdcompat()) { + if (setsockopt(*s, SOL_SOCKET, SO_BSDCOMPAT, + (char *) &on, sizeof(on)) < 0) { + errmsg.LogError(NO_ERRCODE, "setsockopt(BSDCOMPAT)"); + close(*s); + *s = -1; + continue; + } + } +#endif + /* We must not block on the network socket, in case a packet + * gets lost between select and recv, otherwise the process + * will stall until the timeout, and other processes trying to + * log will also stall. + * Patch vom Colin Phipps <cph@cph.demon.co.uk> to the original + * sysklogd source. Applied to rsyslogd on 2005-10-19. + */ + if ((sockflags = fcntl(*s, F_GETFL)) != -1) { + sockflags |= O_NONBLOCK; + /* SETFL could fail too, so get it caught by the subsequent + * error check. + */ + sockflags = fcntl(*s, F_SETFL, sockflags); + } + if (sockflags == -1) { + errmsg.LogError(NO_ERRCODE, "fcntl(O_NONBLOCK)"); + close(*s); + *s = -1; + continue; + } + + if(bIsServer) { + /* rgerhards, 2007-06-22: if we run on a kernel that does not support + * the IPV6_V6ONLY socket option, we need to use a work-around. On such + * systems the IPv6 socket does also accept IPv4 sockets. So an IPv4 + * socket can not listen on the same port as an IPv6 socket. The only + * workaround is to ignore the "socket in use" error. This is what we + * do if we have to. + */ + if( (bind(*s, r->ai_addr, r->ai_addrlen) < 0) + # ifndef IPV6_V6ONLY + && (errno != EADDRINUSE) + # endif + ) { + errmsg.LogError(NO_ERRCODE, "bind"); + close(*s); + *s = -1; + continue; + } + } + + (*socks)++; + s++; + } + + if(res != NULL) + freeaddrinfo(res); + + if(Debug && *socks != maxs) + dbgprintf("We could initialize %d UDP listen sockets out of %d we received " + "- this may or may not be an error indication.\n", *socks, maxs); + + if(*socks == 0) { + errmsg.LogError(NO_ERRCODE, "No UDP listen socket could successfully be initialized, " + "message reception via UDP disabled.\n"); + /* we do NOT need to free any sockets, because there were none... */ + free(socks); + return(NULL); + } + + return(socks); +} + + +/* queryInterface function + * rgerhards, 2008-03-05 + */ +BEGINobjQueryInterface(net) +CODESTARTobjQueryInterface(net) + if(pIf->ifVersion != netCURR_IF_VERSION) { /* check for current version, increment on each change */ + ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED); + } + + /* ok, we have the right interface, so let's fill it + * Please note that we may also do some backwards-compatibility + * work here (if we can support an older interface version - that, + * of course, also affects the "if" above). + */ + pIf->cvthname = cvthname; + /* things to go away after proper modularization */ + pIf->addAllowedSenderLine = addAllowedSenderLine; + pIf->PrintAllowedSenders = PrintAllowedSenders; + pIf->clearAllowedSenders = clearAllowedSenders; + pIf->debugListenInfo = debugListenInfo; + pIf->create_udp_socket = create_udp_socket; + pIf->closeUDPListenSockets = closeUDPListenSockets; + pIf->isAllowedSender = isAllowedSender; + pIf->should_use_so_bsdcompat = should_use_so_bsdcompat; + pIf->getLocalHostname = getLocalHostname; +finalize_it: +ENDobjQueryInterface(net) + + +/* exit our class + * rgerhards, 2008-03-10 + */ +BEGINObjClassExit(net, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */ +CODESTARTObjClassExit(net) + /* release objects we no longer need */ + objRelease(errmsg, CORE_COMPONENT); +ENDObjClassExit(net) + + +/* Initialize the net class. Must be called as the very first method + * before anything else is called inside this class. + * rgerhards, 2008-02-19 + */ +BEGINAbstractObjClassInit(net, 1, OBJ_IS_CORE_MODULE) /* class, version */ + /* request objects we use */ + CHKiRet(objUse(errmsg, CORE_COMPONENT)); + + /* set our own handlers */ +ENDObjClassInit(net) + + +/* --------------- here now comes the plumbing that makes as a library module --------------- */ + + +BEGINmodExit +CODESTARTmodExit + netClassExit(); +ENDmodExit + + +BEGINqueryEtryPt +CODESTARTqueryEtryPt +CODEqueryEtryPt_STD_LIB_QUERIES +ENDqueryEtryPt + + +BEGINmodInit() +CODESTARTmodInit + *ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */ + + /* Initialize all classes that are in our module - this includes ourselfs */ + CHKiRet(netClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */ +ENDmodInit +/* vi:set ai: + */ |