diff options
| -rw-r--r-- | debian/copyright | 2 | ||||
| -rw-r--r-- | irc.c | 14 | ||||
| -rw-r--r-- | lib/misc.c | 101 | ||||
| -rw-r--r-- | lib/misc.h | 4 |
4 files changed, 109 insertions, 12 deletions
diff --git a/debian/copyright b/debian/copyright index c5ca4e16..f1c7f7f4 100644 --- a/debian/copyright +++ b/debian/copyright @@ -16,6 +16,8 @@ Bits of third party code, also (L)GPLed: Other license (but GPL-compatible): * lib/json.[ch] is from <https://github.com/udp/json-parser> and licensed under the modified BSD license. +* reverse_lookup() from lib/misc.c is from OpenSSH and licenced under + the BSD-3-clause licence. BitlBee License: @@ -67,21 +67,11 @@ irc_t *irc_new(int fd) if (global.conf->hostname) { myhost = g_strdup(global.conf->hostname); } else if (getsockname(irc->fd, (struct sockaddr*) &sock, &socklen) == 0) { - char buf[NI_MAXHOST + 1]; - - if (getnameinfo((struct sockaddr *) &sock, socklen, buf, - NI_MAXHOST, NULL, 0, 0) == 0) { - myhost = g_strdup(ipv6_unwrap(buf)); - } + myhost = reverse_lookup((struct sockaddr*) &sock, socklen); } if (getpeername(irc->fd, (struct sockaddr*) &sock, &socklen) == 0) { - char buf[NI_MAXHOST + 1]; - - if (getnameinfo((struct sockaddr *) &sock, socklen, buf, - NI_MAXHOST, NULL, 0, 0) == 0) { - host = g_strdup(ipv6_unwrap(buf)); - } + host = reverse_lookup((struct sockaddr*) &sock, socklen); } if (host == NULL) { @@ -548,6 +548,107 @@ void srv_free(struct ns_srv_reply **srv) g_free(srv); } +/* From OpenSSH 7.4p1 canohost.c" */ +char *reverse_lookup(const struct sockaddr *from_, const socklen_t fromlen_) +{ + struct sockaddr_storage from; + socklen_t fromlen; + struct addrinfo hints, *ai, *aitop; + char name[NI_MAXHOST], ntop2[NI_MAXHOST]; + char ntop[INET6_ADDRSTRLEN]; + + fromlen = sizeof(from); + memset(&from, 0, sizeof(from)); + memcpy(&from, from_, fromlen_); + ipv64_normalise_mapped(&from, &fromlen); + if (from.ss_family == AF_INET6) { + fromlen = sizeof(struct sockaddr_in6); + } + + if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop), + NULL, 0, NI_NUMERICHOST) != 0) { + return NULL; + } + + /* Map the IP address to a host name. */ + if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), + NULL, 0, NI_NAMEREQD) != 0) { + /* Host name not found. Use ip address. */ + return g_strdup(ntop); + } + + /* + * if reverse lookup result looks like a numeric hostname, + * someone is trying to trick us by PTR record like following: + * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_socktype = SOCK_DGRAM; /*dummy*/ + hints.ai_flags = AI_NUMERICHOST; + if (getaddrinfo(name, NULL, &hints, &ai) == 0) { + freeaddrinfo(ai); + return g_strdup(ntop); + } + + /* Names are stored in lowercase. */ + char *tolower = g_utf8_strdown(name, -1); + g_snprintf(name, sizeof(name), "%s", tolower); + g_free(tolower); + + /* + * Map it back to an IP address and check that the given + * address actually is an address of this host. This is + * necessary because anyone with access to a name server can + * define arbitrary names for an IP address. Mapping from + * name to IP address can be trusted better (but can still be + * fooled if the intruder has access to the name server of + * the domain). + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_family = from.ss_family; + hints.ai_socktype = SOCK_STREAM; + if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { + return g_strdup(ntop); + } + /* Look for the address from the list of addresses. */ + for (ai = aitop; ai; ai = ai->ai_next) { + if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, + sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && + (strcmp(ntop, ntop2) == 0)) + break; + } + freeaddrinfo(aitop); + /* If we reached the end of the list, the address was not there. */ + if (ai == NULL) { + /* Address not found for the host name. */ + return g_strdup(ntop); + } + return g_strdup(name); +} + +void +ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len) +{ + struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr; + struct sockaddr_in *a4 = (struct sockaddr_in *)addr; + struct in_addr inaddr; + u_int16_t port; + + if (addr->ss_family != AF_INET6 || + !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr)) + return; + + memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr)); + port = a6->sin6_port; + + memset(a4, 0, sizeof(*a4)); + + a4->sin_family = AF_INET; + *len = sizeof(*a4); + memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr)); + a4->sin_port = port; +} + char *word_wrap(const char *msg, int line_len) { GString *ret = g_string_sized_new(strlen(msg) + 16); @@ -28,6 +28,7 @@ #include <gmodule.h> #include <time.h> +#include <sys/socket.h> struct ns_srv_reply { int prio; @@ -142,6 +143,9 @@ G_MODULE_EXPORT int bool2int(char *value); G_MODULE_EXPORT struct ns_srv_reply **srv_lookup(char *service, char *protocol, char *domain); G_MODULE_EXPORT void srv_free(struct ns_srv_reply **srv); +G_MODULE_EXPORT char *reverse_lookup(const struct sockaddr *from_, const socklen_t fromlen_); +G_MODULE_EXPORT void ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len); + G_MODULE_EXPORT char *word_wrap(const char *msg, int line_len); G_MODULE_EXPORT gboolean ssl_sockerr_again(void *ssl); G_MODULE_EXPORT int md5_verify_password(char *password, char *hash); |