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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 9a3bc96f1..80eb78c48 100644
--- a/auth.c
+++ b/auth.c
@@ -395,7 +395,8 @@ auth_root_allowed(struct ssh *ssh, 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:
@@ -734,99 +735,6 @@ fakepw(void)
734} 735}
735 736
736/* 737/*
737 * Returns the remote DNS hostname as a string. The returned string must not
738 * be freed. NB. this will usually trigger a DNS query the first time it is
739 * called.
740 * This function does additional checks on the hostname to mitigate some
741 * attacks on legacy rhosts-style authentication.
742 * XXX is RhostsRSAAuthentication vulnerable to these?
743 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
744 */
745
746static char *
747remote_hostname(struct ssh *ssh)
748{
749 struct sockaddr_storage from;
750 socklen_t fromlen;
751 struct addrinfo hints, *ai, *aitop;
752 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
753 const char *ntop = ssh_remote_ipaddr(ssh);
754
755 /* Get IP address of client. */
756 fromlen = sizeof(from);
757 memset(&from, 0, sizeof(from));
758 if (getpeername(ssh_packet_get_connection_in(ssh),
759 (struct sockaddr *)&from, &fromlen) < 0) {
760 debug("getpeername failed: %.100s", strerror(errno));
761 return strdup(ntop);
762 }
763
764 ipv64_normalise_mapped(&from, &fromlen);
765 if (from.ss_family == AF_INET6)
766 fromlen = sizeof(struct sockaddr_in6);
767
768 debug3("Trying to reverse map address %.100s.", ntop);
769 /* Map the IP address to a host name. */
770 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
771 NULL, 0, NI_NAMEREQD) != 0) {
772 /* Host name not found. Use ip address. */
773 return strdup(ntop);
774 }
775
776 /*
777 * if reverse lookup result looks like a numeric hostname,
778 * someone is trying to trick us by PTR record like following:
779 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
780 */
781 memset(&hints, 0, sizeof(hints));
782 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
783 hints.ai_flags = AI_NUMERICHOST;
784 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
785 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
786 name, ntop);
787 freeaddrinfo(ai);
788 return strdup(ntop);
789 }
790
791 /* Names are stored in lowercase. */
792 lowercase(name);
793
794 /*
795 * Map it back to an IP address and check that the given
796 * address actually is an address of this host. This is
797 * necessary because anyone with access to a name server can
798 * define arbitrary names for an IP address. Mapping from
799 * name to IP address can be trusted better (but can still be
800 * fooled if the intruder has access to the name server of
801 * the domain).
802 */
803 memset(&hints, 0, sizeof(hints));
804 hints.ai_family = from.ss_family;
805 hints.ai_socktype = SOCK_STREAM;
806 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
807 logit("reverse mapping checking getaddrinfo for %.700s "
808 "[%s] failed.", name, ntop);
809 return strdup(ntop);
810 }
811 /* Look for the address from the list of addresses. */
812 for (ai = aitop; ai; ai = ai->ai_next) {
813 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
814 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
815 (strcmp(ntop, ntop2) == 0))
816 break;
817 }
818 freeaddrinfo(aitop);
819 /* If we reached the end of the list, the address was not there. */
820 if (ai == NULL) {
821 /* Address not found for the host name. */
822 logit("Address %.100s maps to %.600s, but this does not "
823 "map back to the address.", ntop, name);
824 return strdup(ntop);
825 }
826 return strdup(name);
827}
828
829/*
830 * Return the canonical name of the host in the other side of the current 738 * Return the canonical name of the host in the other side of the current
831 * connection. The host name is cached, so it is efficient to call this 739 * connection. The host name is cached, so it is efficient to call this
832 * several times. 740 * several times.