* If anything goes wrong, including the name->addr->name check, then
* we just use "UNKNOWN", so you can use that value in hosts allow
* lines.
+ *
+ * After translation from sockaddr to name we do a forward lookup to
+ * make sure nobody is spoofing PTR records.
**/
char *client_name(int fd)
{
client_sockaddr(fd, &ss, &ss_len);
- if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, port_buf, sizeof port_buf))
- check_name(fd, &ss, ss_len, name_buf, port_buf);
+ if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
+ port_buf, sizeof port_buf))
+ check_name(fd, &ss, name_buf);
return name_buf;
}
/**
- * Get the sockaddr for the client.
+ * Get the sockaddr for the client.
+ *
+ * If it comes in as an ipv4 address mapped into IPv6 format then we
+ * convert it back to a regular IPv4.
**/
void client_sockaddr(int fd,
struct sockaddr_storage *ss,
/**
* Look up a name from @p ss into @p name_buf.
+ *
+ * @param fd file descriptor for client socket.
**/
int lookup_name(int fd, const struct sockaddr_storage *ss,
socklen_t ss_len,
-/* 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. */
+/**
+ * Compare an addrinfo from the resolver to a sockinfo.
+ *
+ * Like strcmp, returns 0 for identical.
+ **/
+int compare_addrinfo_sockaddr(const struct addrinfo *ai,
+ const struct sockaddr_storage *ss)
+{
+ int ss_family = get_sockaddr_family(ss);
+ const char fn[] = "compare_addrinfo_sockaddr";
+
+ if (ai->ai_family != ss_family) {
+ rprintf(FERROR,
+ "%s: response family %d != %d\n",
+ fn, ai->ai_family, ss_family);
+ return 1;
+ }
+
+ /* The comparison method depends on the particular AF. */
+ if (ss_family == AF_INET) {
+ const struct sockaddr_in *sin1, *sin2;
+
+ sin1 = (const struct sockaddr_in *) ss;
+ sin2 = (const struct sockaddr_in *) ai->ai_addr;
+
+ return memcmp(&sin1->sin_addr, &sin2->sin_addr,
+ sizeof sin1->sin_addr);
+ }
+#ifdef INET6
+ else if (ss_family == AF_INET6) {
+ const struct sockaddr_in6 *sin1, *sin2;
+
+ sin1 = (const struct sockaddr_in6 *) ss;
+ sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
+
+ return memcmp(&sin1->sin6_addr, &sin2->sin6_addr,
+ sizeof sin1->sin6_addr);
+ }
+#endif /* INET6 */
+ else {
+ /* don't know */
+ return 1;
+ }
+}
+
+
+/**
+ * Do a forward lookup on @p name_buf and make sure it corresponds to
+ * @p ss -- otherwise we may be being spoofed. If we suspect we are,
+ * then we don't abort the connection but just emit a warning, and
+ * change @p name_buf to be "UNKNOWN".
+ *
+ * We don't do anything with the service when checking the name,
+ * because it doesn't seem that it could be spoofed in any way, and
+ * getaddrinfo on random service names seems to cause problems on AIX.
+ **/
int check_name(int fd,
const struct sockaddr_storage *ss,
- socklen_t ss_len,
- char *name_buf,
- const char *port_buf)
+ char *name_buf)
{
struct addrinfo hints, *res, *res0;
int error;
int ss_family = get_sockaddr_family(ss);
memset(&hints, 0, sizeof(hints));
- hints.ai_family = PF_UNSPEC;
- hints.ai_flags = ss_family;
+ hints.ai_family = ss_family;
+ hints.ai_flags = AI_CANONNAME;
hints.ai_socktype = SOCK_STREAM;
- error = getaddrinfo(name_buf, port_buf, &hints, &res0);
+ error = getaddrinfo(name_buf, NULL, &hints, &res0);
if (error) {
rprintf(FERROR,
- RSYNC_NAME ": forward name lookup for %s:%s failed: %s\n",
- name_buf, port_buf,
- gai_strerror(error));
+ RSYNC_NAME ": forward name lookup for %s failed: %s\n",
+ name_buf, gai_strerror(error));
strcpy(name_buf, default_name);
return error;
}
- /* We expect that one of the results will be the same as ss. */
+ /* Given all these results, we expect that one of them will be
+ * the same as ss. The comparison is a bit complicated. */
for (res = res0; res; res = res->ai_next) {
- if (res->ai_family != ss_family) {
- rprintf(FERROR,
- "check_name: response family %d != %d\n",
- res->ai_family, ss_family);
- continue;
- }
- if (res->ai_addrlen != ss_len) {
- rprintf(FERROR,
- "check_name: addrlen %d != %d\n",
- res->ai_addrlen, ss_len);
- continue;
- }
- if (memcmp(res->ai_addr, ss, res->ai_addrlen) == 0) {
- rprintf(FERROR,
- "check_name: %d bytes of address identical\n",
- res->ai_addrlen);
- break;
- } else{
- rprintf(FERROR,
- "check_name: %d bytes of address NOT identical\n",
- res->ai_addrlen);
- }
+ if (!compare_addrinfo_sockaddr(res, ss))
+ break; /* OK, identical */
}
if (!res0) {
"spoofed address?\n",
name_buf);
strcpy(name_buf, default_name);
- }
- if (res == NULL) {
+ } else if (res == NULL) {
/* We hit the end of the list without finding an
* address that was the same as ss. */
rprintf(FERROR, RSYNC_NAME
Matt McCutchen's Web Site / rsync / rsync.git / blobdiff