busybox/libbb/xconnect.c
Denys Vlasenko 7ab9cd2398 libbb: make bb_lookup_port() abort on bad port names
Also, no need to preserve errno

function                                             old     new   delta
.rodata                                           104247  104241      -6
bb_lookup_port                                        97      83     -14
nc_main                                             1039    1018     -21
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-41)             Total: -41 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-09-09 22:00:44 +02:00

542 lines
14 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Connect to host at port using address resolution from getaddrinfo
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include <sys/types.h>
#include <sys/socket.h> /* netinet/in.h needs it */
#include <netinet/in.h>
#include <net/if.h>
#include <sys/un.h>
#if ENABLE_IFPLUGD || ENABLE_FEATURE_MDEV_DAEMON || ENABLE_UEVENT
# include <linux/netlink.h>
#endif
#include "libbb.h"
int FAST_FUNC setsockopt_int(int fd, int level, int optname, int optval)
{
return setsockopt(fd, level, optname, &optval, sizeof(int));
}
int FAST_FUNC setsockopt_1(int fd, int level, int optname)
{
return setsockopt_int(fd, level, optname, 1);
}
int FAST_FUNC setsockopt_SOL_SOCKET_int(int fd, int optname, int optval)
{
return setsockopt_int(fd, SOL_SOCKET, optname, optval);
}
int FAST_FUNC setsockopt_SOL_SOCKET_1(int fd, int optname)
{
return setsockopt_SOL_SOCKET_int(fd, optname, 1);
}
void FAST_FUNC setsockopt_reuseaddr(int fd)
{
setsockopt_SOL_SOCKET_1(fd, SO_REUSEADDR);
}
int FAST_FUNC setsockopt_broadcast(int fd)
{
return setsockopt_SOL_SOCKET_1(fd, SO_BROADCAST);
}
int FAST_FUNC setsockopt_keepalive(int fd)
{
return setsockopt_SOL_SOCKET_1(fd, SO_KEEPALIVE);
}
#ifdef SO_BINDTODEVICE
int FAST_FUNC setsockopt_bindtodevice(int fd, const char *iface)
{
int r;
struct ifreq ifr;
strncpy_IFNAMSIZ(ifr.ifr_name, iface);
/* NB: passing (iface, strlen(iface) + 1) does not work!
* (maybe it works on _some_ kernels, but not on 2.6.26)
* Actually, ifr_name is at offset 0, and in practice
* just giving char[IFNAMSIZ] instead of struct ifreq works too.
* But just in case it's not true on some obscure arch... */
r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
if (r)
bb_perror_msg("can't bind to interface %s", iface);
return r;
}
#else
int FAST_FUNC setsockopt_bindtodevice(int fd UNUSED_PARAM,
const char *iface UNUSED_PARAM)
{
bb_simple_error_msg("SO_BINDTODEVICE is not supported on this system");
return -1;
}
#endif
static len_and_sockaddr* get_lsa(int fd, int (*get_name)(int fd, struct sockaddr *addr, socklen_t *addrlen))
{
len_and_sockaddr lsa;
len_and_sockaddr *lsa_ptr;
lsa.len = LSA_SIZEOF_SA;
if (get_name(fd, &lsa.u.sa, &lsa.len) != 0)
return NULL;
lsa_ptr = xzalloc(LSA_LEN_SIZE + lsa.len);
if (lsa.len > LSA_SIZEOF_SA) { /* rarely (if ever) happens */
lsa_ptr->len = lsa.len;
get_name(fd, &lsa_ptr->u.sa, &lsa_ptr->len);
} else {
memcpy(lsa_ptr, &lsa, LSA_LEN_SIZE + lsa.len);
}
return lsa_ptr;
}
len_and_sockaddr* FAST_FUNC get_sock_lsa(int fd)
{
return get_lsa(fd, getsockname);
}
len_and_sockaddr* FAST_FUNC get_peer_lsa(int fd)
{
return get_lsa(fd, getpeername);
}
void FAST_FUNC xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
{
if (connect(s, s_addr, addrlen) < 0) {
if (ENABLE_FEATURE_CLEAN_UP)
close(s);
if (s_addr->sa_family == AF_INET)
bb_perror_msg_and_die("%s (%s)",
"can't connect to remote host",
inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
bb_simple_perror_msg_and_die("can't connect to remote host");
}
}
/* Return port number for a service.
* If "port" is a number use it as the port.
* If "port" is a name it is looked up in /etc/services.
* if NULL, return default_port
*/
unsigned FAST_FUNC bb_lookup_port(const char *port, const char *protocol, unsigned port_nr)
{
if (port) {
port_nr = bb_strtou(port, NULL, 10);
if (errno || port_nr > 65535) {
struct servent *tserv = getservbyname(port, protocol);
if (!tserv)
bb_error_msg_and_die("bad port '%s'", port);
port_nr = ntohs(tserv->s_port);
}
}
return (uint16_t)port_nr;
}
/* "New" networking API */
int FAST_FUNC get_nport(const struct sockaddr *sa)
{
#if ENABLE_FEATURE_IPV6
if (sa->sa_family == AF_INET6) {
return ((struct sockaddr_in6*)sa)->sin6_port;
}
#endif
if (sa->sa_family == AF_INET) {
return ((struct sockaddr_in*)sa)->sin_port;
}
/* What? UNIX socket? IPX?? :) */
return -1;
}
void FAST_FUNC set_nport(struct sockaddr *sa, unsigned port)
{
#if ENABLE_FEATURE_IPV6
if (sa->sa_family == AF_INET6) {
struct sockaddr_in6 *sin6 = (void*) sa;
sin6->sin6_port = port;
return;
}
#endif
if (sa->sa_family == AF_INET) {
struct sockaddr_in *sin = (void*) sa;
sin->sin_port = port;
return;
}
/* What? UNIX socket? IPX?? :) */
}
/* We hijack this constant to mean something else */
/* It doesn't hurt because we will remove this bit anyway */
#define DIE_ON_ERROR AI_CANONNAME
/* host: "1.2.3.4[:port]", "www.google.com[:port]"
* port: if neither of above specifies port # */
static len_and_sockaddr* str2sockaddr(
const char *host, int port,
IF_FEATURE_IPV6(sa_family_t af,)
int ai_flags)
{
IF_NOT_FEATURE_IPV6(sa_family_t af = AF_INET;)
int rc;
len_and_sockaddr *r;
struct addrinfo *result = NULL;
struct addrinfo *used_res;
const char *org_host = host; /* only for error msg */
const char *cp;
struct addrinfo hint;
if (ENABLE_FEATURE_UNIX_LOCAL && is_prefixed_with(host, "local:")) {
struct sockaddr_un *sun;
r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_un));
r->len = sizeof(struct sockaddr_un);
r->u.sa.sa_family = AF_UNIX;
sun = (struct sockaddr_un *)&r->u.sa;
safe_strncpy(sun->sun_path, host + 6, sizeof(sun->sun_path));
return r;
}
r = NULL;
/* Ugly parsing of host:addr */
if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
/* Even uglier parsing of [xx]:nn */
host++;
cp = strchr(host, ']');
if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
/* Malformed: must be [xx]:nn or [xx] */
bb_error_msg("bad address '%s'", org_host);
if (ai_flags & DIE_ON_ERROR)
xfunc_die();
return NULL;
}
} else {
cp = strrchr(host, ':');
if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
/* There is more than one ':' (e.g. "::1") */
cp = NULL; /* it's not a port spec */
}
}
if (cp) { /* points to ":" or "]:" */
int sz = cp - host + 1;
host = safe_strncpy(alloca(sz), host, sz);
if (ENABLE_FEATURE_IPV6 && *cp != ':') {
cp++; /* skip ']' */
if (*cp == '\0') /* [xx] without port */
goto skip;
}
cp++; /* skip ':' */
port = bb_strtou(cp, NULL, 10);
if (errno || (unsigned)port > 0xffff) {
bb_error_msg("bad port spec '%s'", org_host);
if (ai_flags & DIE_ON_ERROR)
xfunc_die();
return NULL;
}
skip: ;
}
/* Next two if blocks allow to skip getaddrinfo()
* in case host name is a numeric IP(v6) address.
* getaddrinfo() initializes DNS resolution machinery,
* scans network config and such - tens of syscalls.
*/
/* If we were not asked specifically for IPv6,
* check whether this is a numeric IPv4 */
IF_FEATURE_IPV6(if(af != AF_INET6)) {
struct in_addr in4;
if (inet_aton(host, &in4) != 0) {
r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in));
r->len = sizeof(struct sockaddr_in);
r->u.sa.sa_family = AF_INET;
r->u.sin.sin_addr = in4;
goto set_port;
}
}
#if ENABLE_FEATURE_IPV6
/* If we were not asked specifically for IPv4,
* check whether this is a numeric IPv6 */
if (af != AF_INET) {
struct in6_addr in6;
if (inet_pton(AF_INET6, host, &in6) > 0) {
r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in6));
r->len = sizeof(struct sockaddr_in6);
r->u.sa.sa_family = AF_INET6;
r->u.sin6.sin6_addr = in6;
goto set_port;
}
}
#endif
memset(&hint, 0 , sizeof(hint));
hint.ai_family = af;
/* Need SOCK_STREAM, or else we get each address thrice (or more)
* for each possible socket type (tcp,udp,raw...): */
hint.ai_socktype = SOCK_STREAM;
hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
rc = getaddrinfo(host, NULL, &hint, &result);
if (rc || !result) {
bb_error_msg("bad address '%s'", org_host);
if (ai_flags & DIE_ON_ERROR)
xfunc_die();
goto ret;
}
used_res = result;
#if ENABLE_FEATURE_PREFER_IPV4_ADDRESS
while (1) {
if (used_res->ai_family == AF_INET)
break;
used_res = used_res->ai_next;
if (!used_res) {
used_res = result;
break;
}
}
#endif
r = xmalloc(LSA_LEN_SIZE + used_res->ai_addrlen);
r->len = used_res->ai_addrlen;
memcpy(&r->u.sa, used_res->ai_addr, used_res->ai_addrlen);
set_port:
set_nport(&r->u.sa, htons(port));
ret:
if (result)
freeaddrinfo(result);
return r;
}
#if !ENABLE_FEATURE_IPV6
#define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
#endif
#if ENABLE_FEATURE_IPV6
len_and_sockaddr* FAST_FUNC host_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
return str2sockaddr(host, port, af, 0);
}
len_and_sockaddr* FAST_FUNC xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
return str2sockaddr(host, port, af, DIE_ON_ERROR);
}
#endif
len_and_sockaddr* FAST_FUNC host2sockaddr(const char *host, int port)
{
return str2sockaddr(host, port, AF_UNSPEC, 0);
}
len_and_sockaddr* FAST_FUNC xhost2sockaddr(const char *host, int port)
{
return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
}
len_and_sockaddr* FAST_FUNC xdotted2sockaddr(const char *host, int port)
{
return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
}
int FAST_FUNC xsocket_type(len_and_sockaddr **lsap, int family, int sock_type)
{
len_and_sockaddr *lsa;
int fd;
int len;
if (family == AF_UNSPEC) {
#if ENABLE_FEATURE_IPV6
fd = socket(AF_INET6, sock_type, 0);
if (fd >= 0) {
family = AF_INET6;
goto done;
}
#endif
family = AF_INET;
}
fd = xsocket(family, sock_type, 0);
len = sizeof(struct sockaddr_in);
if (family == AF_UNIX)
len = sizeof(struct sockaddr_un);
#if ENABLE_FEATURE_IPV6
if (family == AF_INET6) {
done:
len = sizeof(struct sockaddr_in6);
}
#endif
lsa = xzalloc(LSA_LEN_SIZE + len);
lsa->len = len;
lsa->u.sa.sa_family = family;
*lsap = lsa;
return fd;
}
int FAST_FUNC xsocket_stream(len_and_sockaddr **lsap)
{
return xsocket_type(lsap, AF_UNSPEC, SOCK_STREAM);
}
static int create_and_bind_or_die(const char *bindaddr, int port, int sock_type)
{
int fd;
len_and_sockaddr *lsa;
if (bindaddr && bindaddr[0]) {
lsa = xdotted2sockaddr(bindaddr, port);
/* user specified bind addr dictates family */
fd = xsocket(lsa->u.sa.sa_family, sock_type, 0);
} else {
fd = xsocket_type(&lsa, AF_UNSPEC, sock_type);
set_nport(&lsa->u.sa, htons(port));
}
setsockopt_reuseaddr(fd);
xbind(fd, &lsa->u.sa, lsa->len);
free(lsa);
return fd;
}
int FAST_FUNC create_and_bind_stream_or_die(const char *bindaddr, int port)
{
return create_and_bind_or_die(bindaddr, port, SOCK_STREAM);
}
int FAST_FUNC create_and_bind_dgram_or_die(const char *bindaddr, int port)
{
return create_and_bind_or_die(bindaddr, port, SOCK_DGRAM);
}
#if ENABLE_IFPLUGD || ENABLE_FEATURE_MDEV_DAEMON || ENABLE_UEVENT
int FAST_FUNC create_and_bind_to_netlink(int proto, int grp, unsigned rcvbuf)
{
struct sockaddr_nl sa;
int fd;
fd = xsocket(AF_NETLINK, SOCK_DGRAM, proto);
/* Set receive buffer size before binding the socket
* We want to have enough space before we start receiving messages.
*/
if (rcvbuf != 0) {
setsockopt_SOL_SOCKET_int(fd, SO_RCVBUF, rcvbuf);
/* SO_RCVBUFFORCE (root only) can go above net.core.rmem_max */
setsockopt_SOL_SOCKET_int(fd, SO_RCVBUFFORCE, rcvbuf);
# if 0
{
int z;
socklen_t zl = sizeof(z);
getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &z, &zl);
bb_error_msg("SO_RCVBUF:%d", z);
}
# endif
}
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
sa.nl_pid = getpid();
sa.nl_groups = grp;
xbind(fd, (struct sockaddr *) &sa, sizeof(sa));
close_on_exec_on(fd);
return fd;
}
#endif
int FAST_FUNC create_and_connect_stream_or_die(const char *peer, int port)
{
int fd;
len_and_sockaddr *lsa;
lsa = xhost2sockaddr(peer, port);
fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
setsockopt_reuseaddr(fd);
xconnect(fd, &lsa->u.sa, lsa->len);
free(lsa);
return fd;
}
int FAST_FUNC xconnect_stream(const len_and_sockaddr *lsa)
{
int fd = xsocket(lsa->u.sa.sa_family, SOCK_STREAM, 0);
xconnect(fd, &lsa->u.sa, lsa->len);
return fd;
}
/* We hijack this constant to mean something else */
/* It doesn't hurt because we will add this bit anyway */
#define IGNORE_PORT NI_NUMERICSERV
static char* FAST_FUNC sockaddr2str(const struct sockaddr *sa, int flags)
{
char host[128];
char serv[16];
int rc;
socklen_t salen;
if (ENABLE_FEATURE_UNIX_LOCAL && sa->sa_family == AF_UNIX) {
struct sockaddr_un *sun = (struct sockaddr_un *)sa;
return xasprintf("local:%.*s",
(int) sizeof(sun->sun_path),
sun->sun_path);
}
salen = LSA_SIZEOF_SA;
#if ENABLE_FEATURE_IPV6
if (sa->sa_family == AF_INET)
salen = sizeof(struct sockaddr_in);
if (sa->sa_family == AF_INET6)
salen = sizeof(struct sockaddr_in6);
#endif
rc = getnameinfo(sa, salen,
host, sizeof(host),
/* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
serv, sizeof(serv),
/* do not resolve port# into service _name_ */
flags | NI_NUMERICSERV
);
if (rc)
return NULL;
if (flags & IGNORE_PORT)
return xstrdup(host);
#if ENABLE_FEATURE_IPV6
if (sa->sa_family == AF_INET6) {
if (strchr(host, ':')) /* heh, it's not a resolved hostname */
return xasprintf("[%s]:%s", host, serv);
/*return xasprintf("%s:%s", host, serv);*/
/* - fall through instead */
}
#endif
/* For now we don't support anything else, so it has to be INET */
/*if (sa->sa_family == AF_INET)*/
return xasprintf("%s:%s", host, serv);
/*return xstrdup(host);*/
}
char* FAST_FUNC xmalloc_sockaddr2host(const struct sockaddr *sa)
{
return sockaddr2str(sa, 0);
}
char* FAST_FUNC xmalloc_sockaddr2host_noport(const struct sockaddr *sa)
{
return sockaddr2str(sa, IGNORE_PORT);
}
char* FAST_FUNC xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa)
{
return sockaddr2str(sa, NI_NAMEREQD | IGNORE_PORT);
}
#ifndef NI_NUMERICSCOPE
# define NI_NUMERICSCOPE 0
#endif
char* FAST_FUNC xmalloc_sockaddr2dotted(const struct sockaddr *sa)
{
return sockaddr2str(sa, NI_NUMERICHOST | NI_NUMERICSCOPE);
}
char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
{
return sockaddr2str(sa, NI_NUMERICHOST | NI_NUMERICSCOPE | IGNORE_PORT);
}