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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 a44906174..6aec36052 100644
--- a/auth.c
+++ b/auth.c
@@ -395,7 +395,8 @@ auth_root_allowed(const char *method)
395 case PERMIT_NO_PASSWD: 395 case PERMIT_NO_PASSWD:
396 if (strcmp(method, "publickey") == 0 || 396 if (strcmp(method, "publickey") == 0 ||
397 strcmp(method, "hostbased") == 0 || 397 strcmp(method, "hostbased") == 0 ||
398 strcmp(method, "gssapi-with-mic") == 0) 398 strcmp(method, "gssapi-with-mic") == 0 ||
399 strcmp(method, "gssapi-keyex") == 0)
399 return 1; 400 return 1;
400 break; 401 break;
401 case PERMIT_FORCED_ONLY: 402 case PERMIT_FORCED_ONLY:
@@ -728,99 +729,6 @@ fakepw(void)
728} 729}
729 730
730/* 731/*
731 * Returns the remote DNS hostname as a string. The returned string must not
732 * be freed. NB. this will usually trigger a DNS query the first time it is
733 * called.
734 * This function does additional checks on the hostname to mitigate some
735 * attacks on legacy rhosts-style authentication.
736 * XXX is RhostsRSAAuthentication vulnerable to these?
737 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
738 */
739
740static char *
741remote_hostname(struct ssh *ssh)
742{
743 struct sockaddr_storage from;
744 socklen_t fromlen;
745 struct addrinfo hints, *ai, *aitop;
746 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
747 const char *ntop = ssh_remote_ipaddr(ssh);
748
749 /* Get IP address of client. */
750 fromlen = sizeof(from);
751 memset(&from, 0, sizeof(from));
752 if (getpeername(ssh_packet_get_connection_in(ssh),
753 (struct sockaddr *)&from, &fromlen) < 0) {
754 debug("getpeername failed: %.100s", strerror(errno));
755 return strdup(ntop);
756 }
757
758 ipv64_normalise_mapped(&from, &fromlen);
759 if (from.ss_family == AF_INET6)
760 fromlen = sizeof(struct sockaddr_in6);
761
762 debug3("Trying to reverse map address %.100s.", ntop);
763 /* Map the IP address to a host name. */
764 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
765 NULL, 0, NI_NAMEREQD) != 0) {
766 /* Host name not found. Use ip address. */
767 return strdup(ntop);
768 }
769
770 /*
771 * if reverse lookup result looks like a numeric hostname,
772 * someone is trying to trick us by PTR record like following:
773 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
774 */
775 memset(&hints, 0, sizeof(hints));
776 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
777 hints.ai_flags = AI_NUMERICHOST;
778 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
779 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
780 name, ntop);
781 freeaddrinfo(ai);
782 return strdup(ntop);
783 }
784
785 /* Names are stored in lowercase. */
786 lowercase(name);
787
788 /*
789 * Map it back to an IP address and check that the given
790 * address actually is an address of this host. This is
791 * necessary because anyone with access to a name server can
792 * define arbitrary names for an IP address. Mapping from
793 * name to IP address can be trusted better (but can still be
794 * fooled if the intruder has access to the name server of
795 * the domain).
796 */
797 memset(&hints, 0, sizeof(hints));
798 hints.ai_family = from.ss_family;
799 hints.ai_socktype = SOCK_STREAM;
800 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
801 logit("reverse mapping checking getaddrinfo for %.700s "
802 "[%s] failed.", name, ntop);
803 return strdup(ntop);
804 }
805 /* Look for the address from the list of addresses. */
806 for (ai = aitop; ai; ai = ai->ai_next) {
807 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
808 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
809 (strcmp(ntop, ntop2) == 0))
810 break;
811 }
812 freeaddrinfo(aitop);
813 /* If we reached the end of the list, the address was not there. */
814 if (ai == NULL) {
815 /* Address not found for the host name. */
816 logit("Address %.100s maps to %.600s, but this does not "
817 "map back to the address.", ntop, name);
818 return strdup(ntop);
819 }
820 return strdup(name);
821}
822
823/*
824 * Return the canonical name of the host in the other side of the current 732 * Return the canonical name of the host in the other side of the current
825 * connection. The host name is cached, so it is efficient to call this 733 * connection. The host name is cached, so it is efficient to call this
826 * several times. 734 * several times.