From 9a5a86734fdebb816d81b3276a82b8befc65a740 Mon Sep 17 00:00:00 2001 From: Martin Pool Date: Thu, 24 Jan 2002 03:28:20 +0000 Subject: [PATCH] Refactor client_name() into smaller functions. Better messages for DNS failure. If we can get a reverse name for an IP address, but not confirm that it is correct using a forward lookup then we still proceed to use the name, but also emit a warning. --- socket.c | 106 +++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 75 insertions(+), 31 deletions(-) diff --git a/socket.c b/socket.c index 8a54911f..137d4800 100644 --- a/socket.c +++ b/socket.c @@ -33,6 +33,16 @@ #include "rsync.h" +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, + const char *name_buf, + const char *port_buf); + /* Establish a proxy connection on an open socket to a web roxy by * using the CONNECT method. */ static int establish_proxy_connection(int fd, char *host, int port) @@ -604,30 +614,43 @@ static int get_sockaddr_family(const struct sockaddr_storage *ss) char *client_name(int fd) { struct sockaddr_storage ss; - socklen_t length = sizeof 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; 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", 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; + const char *def = "UNKNOWN"; + #ifdef INET6 - if (get_sockaddr_family(&ss) == 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 @@ -637,13 +660,13 @@ char *client_name(int fd) 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 @@ -655,47 +678,68 @@ char *client_name(int fd) #endif /* reverse lookup */ - if (getnameinfo((struct sockaddr *)&ss, length, - name_buf, sizeof(name_buf), port_buf, sizeof(port_buf), - NI_NAMEREQD | NI_NUMERICSERV) != 0) { + if (!(name_err = getnameinfo((struct sockaddr *) ss, ss_len, + name_buf, name_buf_len, + port_buf, port_buf_len, + NI_NAMEREQD | NI_NUMERICSERV))) { strcpy(name_buf, def); - rprintf(FERROR, "reverse name lookup failed\n"); + rprintf(FERROR, RSYNC_NAME ": reverse 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, + const 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); + /* We still use the name found by the reverse lookup, + * but emit a warning. */ 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 != get_sockaddr_family(&ss)) + 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; } if (res == NULL) { - strcpy(name_buf, def); - rprintf(FERROR, RSYNC_NAME ": " - "reverse name lookup for \"%s\" failed on fd%d - spoofed address? \n", - name_buf, fd); + /* 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; } -- 2.34.1