diff --git a/changes/ticket14710 b/changes/ticket14710 new file mode 100644 index 0000000000..2b6cb2060f --- /dev/null +++ b/changes/ticket14710 @@ -0,0 +1,10 @@ + o Code simplification and refactoring: + - Move the hacky fallback code out of get_interface_address6() + into separate function and get it covered with unit-tests. Resolves + ticket 14710. + + o Minor bugfixes: + - When attempting to use fallback technique for network interface + lookup, disregard loopback and multicast addresses since they are + unsuitable for public communications. + diff --git a/src/common/address.c b/src/common/address.c index 42a116a91e..6bd107889a 100644 --- a/src/common/address.c +++ b/src/common/address.c @@ -1504,6 +1504,80 @@ tor_addr_is_multicast(const tor_addr_t *a) return 0; } +/** Attempt to retrieve IP address of current host by utilizing some + * UDP socket trickery. Only look for address of given family. + * Set result to *addr. Return 0 on success, -1 on failure. + */ +STATIC int +get_interface_address6_via_udp_socket_hack(int severity, + sa_family_t family, + tor_addr_t *addr) +{ + struct sockaddr_storage my_addr, target_addr; + int sock=-1, r=-1; + socklen_t addr_len; + + memset(addr, 0, sizeof(tor_addr_t)); + memset(&target_addr, 0, sizeof(target_addr)); + + /* Don't worry: no packets are sent. We just need to use a real address + * on the actual Internet. */ + if (family == AF_INET6) { + struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&target_addr; + /* Use the "discard" service port */ + sin6->sin6_port = htons(9); + sock = tor_open_socket(PF_INET6,SOCK_DGRAM,IPPROTO_UDP); + addr_len = (socklen_t)sizeof(struct sockaddr_in6); + sin6->sin6_family = AF_INET6; + S6_ADDR16(sin6->sin6_addr)[0] = htons(0x2002); /* 2002:: */ + } else if (family == AF_INET) { + struct sockaddr_in *sin = (struct sockaddr_in*)&target_addr; + /* Use the "discard" service port */ + sin->sin_port = htons(9); + sock = tor_open_socket(PF_INET,SOCK_DGRAM,IPPROTO_UDP); + addr_len = (socklen_t)sizeof(struct sockaddr_in); + sin->sin_family = AF_INET; + sin->sin_addr.s_addr = htonl(0x12000001); /* 18.0.0.1 */ + } else { + return -1; + } + + if (sock < 0) { + int e = tor_socket_errno(-1); + log_fn(severity, LD_NET, "unable to create socket: %s", + tor_socket_strerror(e)); + goto err; + } + + if (tor_connect_socket(sock,(struct sockaddr *)&target_addr, + addr_len) < 0) { + int e = tor_socket_errno(sock); + log_fn(severity, LD_NET, "connect() failed: %s", tor_socket_strerror(e)); + goto err; + } + + if (tor_getsockname(sock,(struct sockaddr*)&my_addr, &addr_len)) { + int e = tor_socket_errno(sock); + log_fn(severity, LD_NET, "getsockname() to determine interface failed: %s", + tor_socket_strerror(e)); + goto err; + } + + if (tor_addr_from_sockaddr(addr, (struct sockaddr*)&my_addr, NULL) == 0) { + if (tor_addr_is_loopback(addr) || tor_addr_is_multicast(addr)) { + log_fn(severity, LD_NET, "Address that we determined via UDP socket" + " magic is unsuitable for public comms."); + } else { + r=0; + } + } + + err: + if (sock >= 0) + tor_close_socket(sock); + return r; +} + /** Set *addr to the IP address (if any) of whatever interface * connects to the Internet. This address should only be used in checking * whether our address has changed. Return 0 on success, -1 on failure. @@ -1513,9 +1587,6 @@ get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr)) { /* XXX really, this function should yield a smartlist of addresses. */ smartlist_t *addrs; - int sock=-1, r=-1; - struct sockaddr_storage my_addr, target_addr; - socklen_t addr_len; tor_assert(addr); /* Try to do this the smart way if possible. */ @@ -1543,55 +1614,7 @@ get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr)) } /* Okay, the smart way is out. */ - memset(addr, 0, sizeof(tor_addr_t)); - memset(&target_addr, 0, sizeof(target_addr)); - /* Don't worry: no packets are sent. We just need to use a real address - * on the actual Internet. */ - if (family == AF_INET6) { - struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&target_addr; - /* Use the "discard" service port */ - sin6->sin6_port = htons(9); - sock = tor_open_socket(PF_INET6,SOCK_DGRAM,IPPROTO_UDP); - addr_len = (socklen_t)sizeof(struct sockaddr_in6); - sin6->sin6_family = AF_INET6; - S6_ADDR16(sin6->sin6_addr)[0] = htons(0x2002); /* 2002:: */ - } else if (family == AF_INET) { - struct sockaddr_in *sin = (struct sockaddr_in*)&target_addr; - /* Use the "discard" service port */ - sin->sin_port = htons(9); - sock = tor_open_socket(PF_INET,SOCK_DGRAM,IPPROTO_UDP); - addr_len = (socklen_t)sizeof(struct sockaddr_in); - sin->sin_family = AF_INET; - sin->sin_addr.s_addr = htonl(0x12000001); /* 18.0.0.1 */ - } else { - return -1; - } - if (sock < 0) { - int e = tor_socket_errno(-1); - log_fn(severity, LD_NET, "unable to create socket: %s", - tor_socket_strerror(e)); - goto err; - } - - if (connect(sock,(struct sockaddr *)&target_addr, addr_len) < 0) { - int e = tor_socket_errno(sock); - log_fn(severity, LD_NET, "connect() failed: %s", tor_socket_strerror(e)); - goto err; - } - - if (getsockname(sock,(struct sockaddr*)&my_addr, &addr_len)) { - int e = tor_socket_errno(sock); - log_fn(severity, LD_NET, "getsockname() to determine interface failed: %s", - tor_socket_strerror(e)); - goto err; - } - - tor_addr_from_sockaddr(addr, (struct sockaddr*)&my_addr, NULL); - r=0; - err: - if (sock >= 0) - tor_close_socket(sock); - return r; + return get_interface_address6_via_udp_socket_hack(severity,family,addr); } /* ====== diff --git a/src/common/address.h b/src/common/address.h index df835e917a..cd80615f93 100644 --- a/src/common/address.h +++ b/src/common/address.h @@ -274,6 +274,9 @@ tor_addr_port_t *tor_addr_port_new(const tor_addr_t *addr, uint16_t port); #ifdef ADDRESS_PRIVATE STATIC smartlist_t *get_interface_addresses_raw(int severity); +STATIC int get_interface_address6_via_udp_socket_hack(int severity, + sa_family_t family, + tor_addr_t *addr); #ifdef HAVE_IFADDRS_TO_SMARTLIST STATIC smartlist_t *ifaddrs_to_smartlist(const struct ifaddrs *ifa); diff --git a/src/common/compat.c b/src/common/compat.c index 1788e32ee3..8da7ef3f69 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -1156,12 +1156,20 @@ mark_socket_open(tor_socket_t s) /** @} */ /** As socket(), but counts the number of open sockets. */ -tor_socket_t -tor_open_socket(int domain, int type, int protocol) +MOCK_IMPL(tor_socket_t, +tor_open_socket,(int domain, int type, int protocol)) { return tor_open_socket_with_extensions(domain, type, protocol, 1, 0); } +/** Mockable wrapper for connect(). */ +MOCK_IMPL(tor_socket_t, +tor_connect_socket,(tor_socket_t socket,const struct sockaddr *address, + socklen_t address_len)) +{ + return connect(socket,address,address_len); +} + /** As socket(), but creates a nonblocking socket and * counts the number of open sockets. */ tor_socket_t @@ -1308,6 +1316,14 @@ get_n_open_sockets(void) return n; } +/** Mockable wrapper for getsockname(). */ +MOCK_IMPL(int, +tor_getsockname,(tor_socket_t socket, struct sockaddr *address, + socklen_t *address_len)) +{ + return getsockname(socket, address, address_len); +} + /** Turn socket into a nonblocking socket. Return 0 on success, -1 * on failure. */ diff --git a/src/common/compat.h b/src/common/compat.h index 11b41cded9..5189b7e056 100644 --- a/src/common/compat.h +++ b/src/common/compat.h @@ -463,7 +463,8 @@ int tor_close_socket(tor_socket_t s); tor_socket_t tor_open_socket_with_extensions( int domain, int type, int protocol, int cloexec, int nonblock); -tor_socket_t tor_open_socket(int domain, int type, int protocol); +MOCK_DECL(tor_socket_t, +tor_open_socket,(int domain, int type, int protocol)); tor_socket_t tor_open_socket_nonblocking(int domain, int type, int protocol); tor_socket_t tor_accept_socket(tor_socket_t sockfd, struct sockaddr *addr, socklen_t *len); @@ -474,8 +475,15 @@ tor_socket_t tor_accept_socket_with_extensions(tor_socket_t sockfd, struct sockaddr *addr, socklen_t *len, int cloexec, int nonblock); +MOCK_DECL(tor_socket_t, +tor_connect_socket,(tor_socket_t socket,const struct sockaddr *address, + socklen_t address_len)); int get_n_open_sockets(void); +MOCK_DECL(int, +tor_getsockname,(tor_socket_t socket, struct sockaddr *address, + socklen_t *address_len)); + #define tor_socket_send(s, buf, len, flags) send(s, buf, len, flags) #define tor_socket_recv(s, buf, len, flags) recv(s, buf, len, flags) diff --git a/src/test/test_address.c b/src/test/test_address.c index 424a6352b0..317b370912 100644 --- a/src/test/test_address.c +++ b/src/test/test_address.c @@ -130,8 +130,8 @@ test_address_ifaddrs_to_smartlist(void *arg) ipv6_sockaddr = tor_malloc(sizeof(struct sockaddr_in6)); ipv6_sockaddr->sin6_family = AF_INET6; ipv6_sockaddr->sin6_port = 0; - inet_pton(AF_INET6, "2001:db8:8714:3a90::12", - &(ipv6_sockaddr->sin6_addr)); + tor_inet_pton(AF_INET6, "2001:db8:8714:3a90::12", + &(ipv6_sockaddr->sin6_addr)); ifa = tor_malloc(sizeof(struct ifaddrs)); ifa_ipv4 = tor_malloc(sizeof(struct ifaddrs)); @@ -452,10 +452,181 @@ test_address_get_if_addrs_ioctl(void *arg) #endif +#define FAKE_SOCKET_FD (42) + +tor_socket_t +fake_open_socket(int domain, int type, int protocol) +{ + (void)domain; + (void)type; + (void)protocol; + + return FAKE_SOCKET_FD; +} + +static int last_connected_socket_fd = 0; + +static int connect_retval = 0; + +tor_socket_t +pretend_to_connect(tor_socket_t socket, const struct sockaddr *address, + socklen_t address_len) +{ + (void)address; + (void)address_len; + + last_connected_socket_fd = socket; + + return connect_retval; +} + +static struct sockaddr *mock_addr = NULL; + +int +fake_getsockname(tor_socket_t socket, struct sockaddr *address, + socklen_t *address_len) +{ + socklen_t bytes_to_copy = 0; + + if (!mock_addr) + return -1; + + if (mock_addr->sa_family == AF_INET) { + bytes_to_copy = sizeof(struct sockaddr_in); + } else if (mock_addr->sa_family == AF_INET6) { + bytes_to_copy = sizeof(struct sockaddr_in6); + } else { + return -1; + } + + if (*address_len < bytes_to_copy) { + return -1; + } + + memcpy(address,mock_addr,bytes_to_copy); + *address_len = bytes_to_copy; + + return 0; +} + +static void +test_address_udp_socket_trick_whitebox(void *arg) +{ + int hack_retval; + tor_addr_t *addr_from_hack = tor_malloc_zero(sizeof(tor_addr_t)); + struct sockaddr_in6 *mock_addr6; + struct sockaddr_in6 *ipv6_to_check = + tor_malloc_zero(sizeof(struct sockaddr_in6)); + + (void)arg; + + MOCK(tor_open_socket,fake_open_socket); + MOCK(tor_connect_socket,pretend_to_connect); + MOCK(tor_getsockname,fake_getsockname); + + mock_addr = tor_malloc_zero(sizeof(struct sockaddr_storage)); + sockaddr_in_from_string("23.32.246.118",(struct sockaddr_in *)mock_addr); + + hack_retval = + get_interface_address6_via_udp_socket_hack(LOG_DEBUG, + AF_INET, addr_from_hack); + + tt_int_op(hack_retval,==,0); + tt_assert(tor_addr_eq_ipv4h(addr_from_hack, 0x1720f676)); + + /* Now, lets do an IPv6 case. */ + memset(mock_addr,0,sizeof(struct sockaddr_storage)); + + mock_addr6 = (struct sockaddr_in6 *)mock_addr; + mock_addr6->sin6_family = AF_INET6; + mock_addr6->sin6_port = 0; + tor_inet_pton(AF_INET6,"2001:cdba::3257:9652",&(mock_addr6->sin6_addr)); + + hack_retval = + get_interface_address6_via_udp_socket_hack(LOG_DEBUG, + AF_INET6, addr_from_hack); + + tt_int_op(hack_retval,==,0); + + tor_addr_to_sockaddr(addr_from_hack,0,(struct sockaddr *)ipv6_to_check, + sizeof(struct sockaddr_in6)); + + tt_assert(sockaddr_in6_are_equal(mock_addr6,ipv6_to_check)); + + UNMOCK(tor_open_socket); + UNMOCK(tor_connect_socket); + UNMOCK(tor_getsockname); + + done: + tor_free(ipv6_to_check); + tor_free(mock_addr); + tor_free(addr_from_hack); + return; +} + +static void +test_address_udp_socket_trick_blackbox(void *arg) +{ + /* We want get_interface_address6_via_udp_socket_hack() to yield + * the same valid address that get_interface_address6() returns. + * If the latter is unable to find a valid address, we want + * _hack() to fail and return-1. + * + * Furthermore, we want _hack() never to crash, even if + * get_interface_addresses_raw() is returning NULL. + */ + + tor_addr_t addr4; + tor_addr_t addr4_to_check; + tor_addr_t addr6; + tor_addr_t addr6_to_check; + int retval, retval_reference; + + (void)arg; + + retval_reference = get_interface_address6(LOG_DEBUG,AF_INET,&addr4); + retval = get_interface_address6_via_udp_socket_hack(LOG_DEBUG, + AF_INET, + &addr4_to_check); + + tt_int_op(retval,==,retval_reference); + tt_assert( (retval == -1 && retval_reference == -1) || + (tor_addr_compare(&addr4,&addr4_to_check,CMP_EXACT) == 0) ); + + //[XXX: Skipping the AF_INET6 case because bug #12377 makes it fail.] + (void)addr6_to_check; + (void)addr6; +#if 0 + retval_reference = get_interface_address6(LOG_DEBUG,AF_INET6,&addr6); + retval = get_interface_address6_via_udp_socket_hack(LOG_DEBUG, + AF_INET6, + &addr6_to_check); + + tt_int_op(retval,==,retval_reference); + tt_assert( (retval == -1 && retval_reference == -1) || + (tor_addr_compare(&addr6,&addr6_to_check,CMP_EXACT) == 0) ); + +#endif + + /* When family is neither AF_INET nor AF_INET6, we want _hack to + * fail and return -1. + */ + + retval = get_interface_address6_via_udp_socket_hack(LOG_DEBUG, + AF_CCITT,&addr4); + + tt_assert(retval == -1); + + done: + return; +} + #define ADDRESS_TEST(name, flags) \ { #name, test_address_ ## name, flags, NULL, NULL } struct testcase_t address_tests[] = { + ADDRESS_TEST(udp_socket_trick_whitebox, TT_FORK), + ADDRESS_TEST(udp_socket_trick_blackbox, TT_FORK), #ifdef HAVE_IFADDRS_TO_SMARTLIST ADDRESS_TEST(get_if_addrs_ifaddrs, TT_FORK), ADDRESS_TEST(ifaddrs_to_smartlist, 0),