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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 63366768a..76d586e31 100644
--- a/auth.c
+++ b/auth.c
@@ -396,7 +396,8 @@ auth_root_allowed(struct ssh *ssh, const char *method)
396 case PERMIT_NO_PASSWD: 396 case PERMIT_NO_PASSWD:
397 if (strcmp(method, "publickey") == 0 || 397 if (strcmp(method, "publickey") == 0 ||
398 strcmp(method, "hostbased") == 0 || 398 strcmp(method, "hostbased") == 0 ||
399 strcmp(method, "gssapi-with-mic") == 0) 399 strcmp(method, "gssapi-with-mic") == 0 ||
400 strcmp(method, "gssapi-keyex") == 0)
400 return 1; 401 return 1;
401 break; 402 break;
402 case PERMIT_FORCED_ONLY: 403 case PERMIT_FORCED_ONLY:
@@ -729,99 +730,6 @@ fakepw(void)
729} 730}
730 731
731/* 732/*
732 * Returns the remote DNS hostname as a string. The returned string must not
733 * be freed. NB. this will usually trigger a DNS query the first time it is
734 * called.
735 * This function does additional checks on the hostname to mitigate some
736 * attacks on legacy rhosts-style authentication.
737 * XXX is RhostsRSAAuthentication vulnerable to these?
738 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
739 */
740
741static char *
742remote_hostname(struct ssh *ssh)
743{
744 struct sockaddr_storage from;
745 socklen_t fromlen;
746 struct addrinfo hints, *ai, *aitop;
747 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
748 const char *ntop = ssh_remote_ipaddr(ssh);
749
750 /* Get IP address of client. */
751 fromlen = sizeof(from);
752 memset(&from, 0, sizeof(from));
753 if (getpeername(ssh_packet_get_connection_in(ssh),
754 (struct sockaddr *)&from, &fromlen) < 0) {
755 debug("getpeername failed: %.100s", strerror(errno));
756 return strdup(ntop);
757 }
758
759 ipv64_normalise_mapped(&from, &fromlen);
760 if (from.ss_family == AF_INET6)
761 fromlen = sizeof(struct sockaddr_in6);
762
763 debug3("Trying to reverse map address %.100s.", ntop);
764 /* Map the IP address to a host name. */
765 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
766 NULL, 0, NI_NAMEREQD) != 0) {
767 /* Host name not found. Use ip address. */
768 return strdup(ntop);
769 }
770
771 /*
772 * if reverse lookup result looks like a numeric hostname,
773 * someone is trying to trick us by PTR record like following:
774 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
775 */
776 memset(&hints, 0, sizeof(hints));
777 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
778 hints.ai_flags = AI_NUMERICHOST;
779 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
780 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
781 name, ntop);
782 freeaddrinfo(ai);
783 return strdup(ntop);
784 }
785
786 /* Names are stored in lowercase. */
787 lowercase(name);
788
789 /*
790 * Map it back to an IP address and check that the given
791 * address actually is an address of this host. This is
792 * necessary because anyone with access to a name server can
793 * define arbitrary names for an IP address. Mapping from
794 * name to IP address can be trusted better (but can still be
795 * fooled if the intruder has access to the name server of
796 * the domain).
797 */
798 memset(&hints, 0, sizeof(hints));
799 hints.ai_family = from.ss_family;
800 hints.ai_socktype = SOCK_STREAM;
801 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
802 logit("reverse mapping checking getaddrinfo for %.700s "
803 "[%s] failed.", name, ntop);
804 return strdup(ntop);
805 }
806 /* Look for the address from the list of addresses. */
807 for (ai = aitop; ai; ai = ai->ai_next) {
808 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
809 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
810 (strcmp(ntop, ntop2) == 0))
811 break;
812 }
813 freeaddrinfo(aitop);
814 /* If we reached the end of the list, the address was not there. */
815 if (ai == NULL) {
816 /* Address not found for the host name. */
817 logit("Address %.100s maps to %.600s, but this does not "
818 "map back to the address.", ntop, name);
819 return strdup(ntop);
820 }
821 return strdup(name);
822}
823
824/*
825 * Return the canonical name of the host in the other side of the current 733 * Return the canonical name of the host in the other side of the current
826 * connection. The host name is cached, so it is efficient to call this 734 * connection. The host name is cached, so it is efficient to call this
827 * several times. 735 * several times.