X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/a57568d7167cb54b9b0802aeabf5a424749fbd65..0f9555207a9549a0340d8de49abe9a9438be7018:/socket.c diff --git a/socket.c b/socket.c index b97e2378..eb1ab3f5 100644 --- a/socket.c +++ b/socket.c @@ -1,7 +1,9 @@ /* -*- c-file-style: "linux" -*- + rsync -- fast file replication program + Copyright (C) 1992-2001 by Andrew Tridgell - Copyright (C) 2001 by Martin Pool + Copyright (C) 2001, 2002 by Martin Pool This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -22,13 +24,26 @@ * @file socket.c * * Socket functions used in rsync. + * + * This file is now converted to use the new-style getaddrinfo() + * interface, which supports IPv6 but is also supported on recent + * IPv4-only machines. On systems that don't have that interface, we + * emulate it using the KAME implementation. **/ #include "rsync.h" -#ifndef HAVE_GETADDRINFO -#include "lib/addrinfo.h" -#endif +static const char default_name[] = "UNKNOWN"; + +static int lookup_name(const struct sockaddr_storage *ss, + socklen_t ss_len, + char *name_buf, size_t name_buf_len, + char *port_buf, size_t port_buf_len); + +static int check_name(const struct sockaddr_storage *ss, + socklen_t ss_len, + char *name_buf, + const char *port_buf); /* Establish a proxy connection on an open socket to a web roxy by * using the CONNECT method. */ @@ -94,6 +109,39 @@ static int establish_proxy_connection(int fd, char *host, int port) } +/** + * Try to set the local address for a newly-created socket. Return -1 + * if this fails. + **/ +int try_bind_local(int s, + int ai_family, int ai_socktype, + const char *bind_address) +{ + int error; + struct addrinfo bhints, *bres_all, *r; + + memset(&bhints, 0, sizeof(bhints)); + bhints.ai_family = ai_family; + bhints.ai_socktype = ai_socktype; + bhints.ai_flags = AI_PASSIVE; + if ((error = getaddrinfo(bind_address, NULL, &bhints, &bres_all))) { + rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n", + bind_address, gai_strerror(error)); + return -1; + } + + for (r = bres_all; r; r = r->ai_next) { + if (bind(s, r->ai_addr, r->ai_addrlen) == -1) + continue; + return s; + } + + /* no error message; there might be some problem that allows + * creation of the socket but not binding, perhaps if the + * machine has no ipv6 address of this name. */ + return -1; +} + /** * Open a socket to a tcp remote host with the specified port . @@ -121,7 +169,6 @@ int open_socket_out(char *host, int port, const char *bind_address, int type = SOCK_STREAM; int error; int s; - int result; struct addrinfo hints, *res0, *res; char portbuf[10]; char *h; @@ -162,32 +209,22 @@ int open_socket_out(char *host, int port, const char *bind_address, } s = -1; + /* Try to connect to all addresses for this machine until we get + * through. It might e.g. be multi-homed, or have both IPv4 and IPv6 + * addresses. We need to create a socket for each record, since the + * address record tells us what protocol to use to try to connect. */ for (res = res0; res; res = res->ai_next) { s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (s < 0) continue; - if (bind_address) { - struct addrinfo bhints, *bres; - - memset(&bhints, 0, sizeof(bhints)); - bhints.ai_family = res->ai_family; - bhints.ai_socktype = type; - bhints.ai_flags = AI_PASSIVE; - error = getaddrinfo(bind_address, NULL, &bhints, &bres); - if (error) { - rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s : %s\n", - bind_address, gai_strerror(error)); - continue; - } - if (bres->ai_next) { - rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s resolved to multiple hosts\n", - bind_address); - freeaddrinfo(bres); + if (bind_address) + if (try_bind_local(s, res->ai_family, type, + bind_address) == -1) { + close(s); + s = -1; continue; } - bind(s, bres->ai_addr, bres->ai_addrlen); - } if (connect(s, res->ai_addr, res->ai_addrlen) < 0) { close(s); @@ -263,7 +300,7 @@ static int open_socket_in(int type, int port, const char *bind_address, { int one=1; int s; - struct addrinfo hints, *res, *resp; + struct addrinfo hints, *all_ai, *resp; char portbuf[10]; int error; @@ -272,53 +309,43 @@ static int open_socket_in(int type, int port, const char *bind_address, hints.ai_socktype = type; hints.ai_flags = AI_PASSIVE; snprintf(portbuf, sizeof(portbuf), "%d", port); - error = getaddrinfo(bind_address, portbuf, &hints, &res); + error = getaddrinfo(bind_address, portbuf, &hints, &all_ai); if (error) { rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n", bind_address, gai_strerror(error)); return -1; } - /* XXX: Do we need to care about getting multiple results - * back? I think probably not; if the user passed - * bind_address == NULL and we set AI_PASSIVE then we ought to - * get a wildcard result. */ - resp = res; - while (1) { - s = socket(resp->ai_family, resp->ai_socktype, resp->ai_protocol); - - if (s >= 0) { - break; /* got a socket */ - } else if ((resp = resp->ai_next)) { - switch (errno) { - case EPROTONOSUPPORT: - case EAFNOSUPPORT: - case EPFNOSUPPORT: - /* See if there's another address that will work... */ - continue; - } + /* We may not be able to create the socket, if for example the + * machine knows about IPv6 in the C library, but not in the + * kernel. */ + for (resp = all_ai; resp; resp = resp->ai_next) { + s = socket(resp->ai_family, resp->ai_socktype, + resp->ai_protocol); + + if (s == -1) + /* See if there's another address that will work... */ + continue; + + setsockopt(s, SOL_SOCKET, SO_REUSEADDR, + (char *)&one, sizeof one); + + /* now we've got a socket - we need to bind it */ + if (bind(s, all_ai->ai_addr, all_ai->ai_addrlen) < 0) { + /* Nope, try another */ + close(s); + continue; } - rprintf(FERROR, RSYNC_NAME ": open inbound socket" - "(dom=%d, type=%d, proto=%d) failed: %s\n", - resp->ai_family, resp->ai_socktype, resp->ai_protocol, - strerror(errno)); - goto fail; - } - - setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one)); - - /* now we've got a socket - we need to bind it */ - if (bind(s, res->ai_addr, res->ai_addrlen) < 0) { - rprintf(FERROR, RSYNC_NAME ": bind failed on port %d\n", port); - close(s); - goto fail; + return s; } - return s; + rprintf(FERROR, RSYNC_NAME ": open inbound socket on port %d failed: " + "%s\n", + port, + strerror(errno)); -fail: - freeaddrinfo(res); + freeaddrinfo(all_ai); return -1; } @@ -353,10 +380,10 @@ void start_accept_loop(int port, int (*fn)(int )) { int s; extern char *bind_address; + extern int default_af_hint; /* open an incoming socket */ - s = open_socket_in(SOCK_STREAM, port, bind_address, - global_opts.af_hint); + s = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint); if (s == -1) exit_cleanup(RERR_SOCKETIO); @@ -372,8 +399,8 @@ void start_accept_loop(int port, int (*fn)(int )) while (1) { fd_set fds; int fd; - struct sockaddr addr; - int in_addrlen = sizeof(addr); + struct sockaddr_storage addr; + socklen_t addrlen = sizeof addr; /* close log file before the potentially very long select so file can be trimmed by another process instead of growing @@ -389,7 +416,7 @@ void start_accept_loop(int port, int (*fn)(int )) if(!FD_ISSET(s, &fds)) continue; - fd = accept(s,(struct sockaddr *)&addr,&in_addrlen); + fd = accept(s,(struct sockaddr *)&addr,&addrlen); if (fd == -1) continue; @@ -555,8 +582,8 @@ void become_daemon(void) **/ char *client_addr(int fd) { - struct sockaddr ss; - int length = sizeof(ss); + struct sockaddr_storage ss; + socklen_t length = sizeof ss; static char addr_buf[100]; static int initialised; @@ -564,107 +591,162 @@ char *client_addr(int fd) initialised = 1; - if (getpeername(fd, &ss, &length)) { + if (getpeername(fd, (struct sockaddr *)&ss, &length)) { exit_cleanup(RERR_SOCKETIO); } - getnameinfo(&ss, length, + getnameinfo((struct sockaddr *)&ss, length, addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST); return addr_buf; } +static int get_sockaddr_family(const struct sockaddr_storage *ss) +{ + return ((struct sockaddr *) ss)->sa_family; +} + + /** - * Return the DNS name of the client + * Return the DNS name of the client. + * + * The name is statically cached so that repeated lookups are quick, + * so there is a limit of one lookup per customer. + * + * If anything goes wrong, including the name->addr->name check, then + * we just use "UNKNOWN", so you can use that value in hosts allow + * lines. **/ char *client_name(int fd) { - struct sockaddr ss; - int length = sizeof(ss); + struct sockaddr_storage ss; + socklen_t ss_len = sizeof ss; static char name_buf[100]; static char port_buf[100]; - char *def = "UNKNOWN"; static int initialised; - struct addrinfo hints, *res, *res0; - int error; if (initialised) return name_buf; + strcpy(name_buf, default_name); initialised = 1; - strcpy(name_buf,def); - - if (getpeername(fd, (struct sockaddr *)&ss, &length)) { + if (getpeername(fd, (struct sockaddr *)&ss, &ss_len)) { /* FIXME: Can we really not continue? */ rprintf(FERROR, RSYNC_NAME ": getpeername on fd%d failed: %s\n", - strerror(errno)); + fd, strerror(errno)); exit_cleanup(RERR_SOCKETIO); } + if (!lookup_name(&ss, ss_len, name_buf, sizeof name_buf, port_buf, sizeof port_buf)) + check_name(&ss, ss_len, name_buf, port_buf); + + return name_buf; +} + + +/** + * Look up a name from @p ss into @p name_buf. + **/ +static int lookup_name(const struct sockaddr_storage *ss, + socklen_t ss_len, + char *name_buf, size_t name_buf_len, + char *port_buf, size_t port_buf_len) +{ + int name_err; + #ifdef INET6 - if (ss.ss_family == AF_INET6 && - IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&ss)->sin6_addr)) { + if (get_sockaddr_family(ss) == AF_INET6 && + IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) { + /* OK, so ss is in the IPv6 family, but it is really + * an IPv4 address: something like + * "::ffff:10.130.1.2". If we use it as-is, then the + * reverse lookup might fail or perhaps something else + * bad might happen. So instead we convert it to an + * equivalent address in the IPv4 address family. */ struct sockaddr_in6 sin6; struct sockaddr_in *sin; - memcpy(&sin6, &ss, sizeof(sin6)); - sin = (struct sockaddr_in *)&ss; + memcpy(&sin6, ss, sizeof(sin6)); + sin = (struct sockaddr_in *)ss; memset(sin, 0, sizeof(*sin)); sin->sin_family = AF_INET; - length = sizeof(struct sockaddr_in); + ss_len = sizeof(struct sockaddr_in); #ifdef HAVE_SOCKADDR_LEN - sin->sin_len = length; + sin->sin_len = ss_len; #endif sin->sin_port = sin6.sin6_port; + /* FIXME: Isn't there a macro we can use here rather + * than grovelling through the struct? It might be + * wrong on some systems. */ memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], sizeof(sin->sin_addr)); } #endif /* reverse lookup */ - if (getnameinfo((struct sockaddr *)&ss, length, - name_buf, sizeof(name_buf), port_buf, sizeof(port_buf), - NI_NAMEREQD | NI_NUMERICSERV) != 0) { - strcpy(name_buf, def); - rprintf(FERROR, "reverse name lookup failed\n"); + name_err = getnameinfo((struct sockaddr *) ss, ss_len, + name_buf, name_buf_len, + port_buf, port_buf_len, + NI_NAMEREQD | NI_NUMERICSERV); + if (name_err != 0) { + strcpy(name_buf, default_name); + rprintf(FERROR, RSYNC_NAME ": name lookup failed: %s\n", + gai_strerror(name_err)); + return name_err; } - /* forward lookup */ + return 0; +} + + + +/* Do a forward lookup on name_buf and make sure it corresponds to ss + * -- otherwise we may be being spoofed. If we suspect we are, then + * we don't abort the connection but just emit a warning. */ +static int check_name(const struct sockaddr_storage *ss, + socklen_t ss_len, + char *name_buf, + const char *port_buf) +{ + struct addrinfo hints, *res, *res0; + int error; + memset(&hints, 0, sizeof(hints)); hints.ai_family = PF_UNSPEC; hints.ai_flags = AI_CANONNAME; hints.ai_socktype = SOCK_STREAM; error = getaddrinfo(name_buf, port_buf, &hints, &res0); if (error) { - strcpy(name_buf, def); + strcpy(name_buf, default_name); rprintf(FERROR, - RSYNC_NAME ": forward name lookup for %s failed: %s\n", - port_buf, + RSYNC_NAME ": forward name lookup for %s:%s failed: %s\n", + name_buf, port_buf, gai_strerror(error)); - return name_buf; + return error; } - /* XXX sin6_flowinfo and other fields */ + + /* We expect that one of the results will be the same as ss. */ for (res = res0; res; res = res->ai_next) { - if (res->ai_family != ss.sa_family) + if (res->ai_family != get_sockaddr_family(ss)) continue; - if (res->ai_addrlen != length) + if (res->ai_addrlen != ss_len) continue; - if (memcmp(res->ai_addr, &ss, res->ai_addrlen) == 0) + if (memcmp(res->ai_addr, ss, res->ai_addrlen) == 0) break; } - /* TODO: Do a forward lookup as well to prevent spoofing */ - if (res == NULL) { - strcpy(name_buf, def); - rprintf(FERROR, RSYNC_NAME ": " - "reverse name lookup mismatch on fd%d - spoofed address?\n", - fd); + strcpy(name_buf, default_name); + /* We hit the end of the list without finding an + * address that was the same as ss. */ + rprintf(FERROR, RSYNC_NAME + ": no address record for \"%s\" corresponds to peer name: spoofed address?\n", + name_buf); } freeaddrinfo(res0); - return name_buf; + return 0; }