From 2aeb201c9751d4ee82978c623310e14b9e831b94 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Tue, 17 Apr 2018 12:43:54 +0200 Subject: [PATCH] libbb: new option FEATURE_ETC_SERVICES: if off, /etc/services reads often avoided In practice, "wget http://host.com/" always uses port 80. People explicitly set non-standard ports via options or parameters ("telnet 1.2.3.4 567" or "telnet 1.2.3.4 ftp") instead of modifying /etc/services. function old new delta telnet_main 1466 1464 -2 rdate_main 215 198 -17 fakeidentd_main 269 252 -17 parse_url 459 392 -67 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-103) Total: -103 bytes Signed-off-by: Denys Vlasenko --- include/libbb.h | 5 +++++ libbb/Config.src | 12 ++++++++++++ networking/isrv_identd.c | 2 +- networking/telnet.c | 3 ++- networking/wget.c | 8 ++++---- util-linux/rdate.c | 2 +- 6 files changed, 25 insertions(+), 7 deletions(-) diff --git a/include/libbb.h b/include/libbb.h index 646c58bf2..a605c7f03 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -640,6 +640,11 @@ int setsockopt_bindtodevice(int fd, const char *iface) FAST_FUNC; int bb_getsockname(int sockfd, void *addr, socklen_t addrlen) FAST_FUNC; /* NB: returns port in host byte order */ unsigned bb_lookup_port(const char *port, const char *protocol, unsigned default_port) FAST_FUNC; +#if ENABLE_FEATURE_ETC_SERVICES +# define bb_lookup_std_port(portstr, protocol, portnum) bb_lookup_port(portstr, protocol, portnum) +#else +# define bb_lookup_std_port(portstr, protocol, portnum) (portnum) +#endif typedef struct len_and_sockaddr { socklen_t len; union { diff --git a/libbb/Config.src b/libbb/Config.src index fdf8bbb28..16e16480b 100644 --- a/libbb/Config.src +++ b/libbb/Config.src @@ -76,6 +76,18 @@ config FEATURE_ETC_NETWORKS a rarely used feature which allows you to use names instead of IP/mask pairs in route command. +config FEATURE_ETC_SERVICES + bool "Consult /etc/services even for well-known ports" + default n + help + Look up e.g. "telnet" and "http" in /etc/services file + instead of assuming ports 23 and 80. + This is almost never necessary (everybody uses standard ports), + and it makes sense to avoid reading this file. + If you disable this option, in the cases where port is explicitly + specified as a service name (e.g. "telnet HOST PORTNAME"), + it will still be looked up in /etc/services. + config FEATURE_EDITING bool "Command line editing" default y diff --git a/networking/isrv_identd.c b/networking/isrv_identd.c index 133d62a65..0c33dde4f 100644 --- a/networking/isrv_identd.c +++ b/networking/isrv_identd.c @@ -159,7 +159,7 @@ int fakeidentd_main(int argc UNUSED_PARAM, char **argv) fd = 0; if (!(opt & OPT_inetdwait)) { fd = create_and_bind_stream_or_die(bind_address, - bb_lookup_port("identd", "tcp", 113)); + bb_lookup_std_port("identd", "tcp", 113)); xlisten(fd, 5); } diff --git a/networking/telnet.c b/networking/telnet.c index 15d6a08d8..1e6be85bd 100644 --- a/networking/telnet.c +++ b/networking/telnet.c @@ -643,7 +643,8 @@ int telnet_main(int argc UNUSED_PARAM, char **argv) if (!*argv) bb_show_usage(); host = *argv++; - port = bb_lookup_port(*argv ? *argv++ : "telnet", "tcp", 23); + port = *argv ? bb_lookup_port(*argv++, "tcp", 23) + : bb_lookup_std_port("telnet", "tcp", 23); if (*argv) /* extra params?? */ bb_show_usage(); diff --git a/networking/wget.c b/networking/wget.c index 2650b5384..b6c76e9dc 100644 --- a/networking/wget.c +++ b/networking/wget.c @@ -505,23 +505,23 @@ static void parse_url(const char *src_url, struct host_info *h) *p = '\0'; h->host = p + 3; if (strcmp(url, P_FTP) == 0) { - h->port = bb_lookup_port(P_FTP, "tcp", 21); + h->port = bb_lookup_std_port(P_FTP, "tcp", 21); } else #if SSL_SUPPORTED # if ENABLE_FEATURE_WGET_HTTPS if (strcmp(url, P_FTPS) == 0) { - h->port = bb_lookup_port(P_FTPS, "tcp", 990); + h->port = bb_lookup_std_port(P_FTPS, "tcp", 990); h->protocol = P_FTPS; } else # endif if (strcmp(url, P_HTTPS) == 0) { - h->port = bb_lookup_port(P_HTTPS, "tcp", 443); + h->port = bb_lookup_std_port(P_HTTPS, "tcp", 443); h->protocol = P_HTTPS; } else #endif if (strcmp(url, P_HTTP) == 0) { http: - h->port = bb_lookup_port(P_HTTP, "tcp", 80); + h->port = bb_lookup_std_port(P_HTTP, "tcp", 80); h->protocol = P_HTTP; } else { *p = ':'; diff --git a/util-linux/rdate.c b/util-linux/rdate.c index f27294e25..5ec795208 100644 --- a/util-linux/rdate.c +++ b/util-linux/rdate.c @@ -45,7 +45,7 @@ static time_t askremotedate(const char *host) alarm(10); signal(SIGALRM, socket_timeout); - fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37)); + fd = create_and_connect_stream_or_die(host, bb_lookup_std_port("time", "tcp", 37)); if (safe_read(fd, &nett, 4) != 4) /* read time from server */ bb_error_msg_and_die("%s: %s", host, "short read"); -- 2.25.1