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-rw-r--r--auth.c96
1 files changed, 2 insertions, 94 deletions
diff --git a/auth.c b/auth.c
index 086b8ebb1..687c57b42 100644
--- a/auth.c
+++ b/auth.c
@@ -400,7 +400,8 @@ auth_root_allowed(struct ssh *ssh, const char *method)
400 case PERMIT_NO_PASSWD: 400 case PERMIT_NO_PASSWD:
401 if (strcmp(method, "publickey") == 0 || 401 if (strcmp(method, "publickey") == 0 ||
402 strcmp(method, "hostbased") == 0 || 402 strcmp(method, "hostbased") == 0 ||
403 strcmp(method, "gssapi-with-mic") == 0) 403 strcmp(method, "gssapi-with-mic") == 0 ||
404 strcmp(method, "gssapi-keyex") == 0)
404 return 1; 405 return 1;
405 break; 406 break;
406 case PERMIT_FORCED_ONLY: 407 case PERMIT_FORCED_ONLY:
@@ -725,99 +726,6 @@ fakepw(void)
725} 726}
726 727
727/* 728/*
728 * Returns the remote DNS hostname as a string. The returned string must not
729 * be freed. NB. this will usually trigger a DNS query the first time it is
730 * called.
731 * This function does additional checks on the hostname to mitigate some
732 * attacks on legacy rhosts-style authentication.
733 * XXX is RhostsRSAAuthentication vulnerable to these?
734 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
735 */
736
737static char *
738remote_hostname(struct ssh *ssh)
739{
740 struct sockaddr_storage from;
741 socklen_t fromlen;
742 struct addrinfo hints, *ai, *aitop;
743 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
744 const char *ntop = ssh_remote_ipaddr(ssh);
745
746 /* Get IP address of client. */
747 fromlen = sizeof(from);
748 memset(&from, 0, sizeof(from));
749 if (getpeername(ssh_packet_get_connection_in(ssh),
750 (struct sockaddr *)&from, &fromlen) == -1) {
751 debug("getpeername failed: %.100s", strerror(errno));
752 return xstrdup(ntop);
753 }
754
755 ipv64_normalise_mapped(&from, &fromlen);
756 if (from.ss_family == AF_INET6)
757 fromlen = sizeof(struct sockaddr_in6);
758
759 debug3("Trying to reverse map address %.100s.", ntop);
760 /* Map the IP address to a host name. */
761 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
762 NULL, 0, NI_NAMEREQD) != 0) {
763 /* Host name not found. Use ip address. */
764 return xstrdup(ntop);
765 }
766
767 /*
768 * if reverse lookup result looks like a numeric hostname,
769 * someone is trying to trick us by PTR record like following:
770 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
771 */
772 memset(&hints, 0, sizeof(hints));
773 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
774 hints.ai_flags = AI_NUMERICHOST;
775 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
776 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
777 name, ntop);
778 freeaddrinfo(ai);
779 return xstrdup(ntop);
780 }
781
782 /* Names are stored in lowercase. */
783 lowercase(name);
784
785 /*
786 * Map it back to an IP address and check that the given
787 * address actually is an address of this host. This is
788 * necessary because anyone with access to a name server can
789 * define arbitrary names for an IP address. Mapping from
790 * name to IP address can be trusted better (but can still be
791 * fooled if the intruder has access to the name server of
792 * the domain).
793 */
794 memset(&hints, 0, sizeof(hints));
795 hints.ai_family = from.ss_family;
796 hints.ai_socktype = SOCK_STREAM;
797 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
798 logit("reverse mapping checking getaddrinfo for %.700s "
799 "[%s] failed.", name, ntop);
800 return xstrdup(ntop);
801 }
802 /* Look for the address from the list of addresses. */
803 for (ai = aitop; ai; ai = ai->ai_next) {
804 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
805 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
806 (strcmp(ntop, ntop2) == 0))
807 break;
808 }
809 freeaddrinfo(aitop);
810 /* If we reached the end of the list, the address was not there. */
811 if (ai == NULL) {
812 /* Address not found for the host name. */
813 logit("Address %.100s maps to %.600s, but this does not "
814 "map back to the address.", ntop, name);
815 return xstrdup(ntop);
816 }
817 return xstrdup(name);
818}
819
820/*
821 * Return the canonical name of the host in the other side of the current 729 * Return the canonical name of the host in the other side of the current
822 * connection. The host name is cached, so it is efficient to call this 730 * connection. The host name is cached, so it is efficient to call this
823 * several times. 731 * several times.