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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 6ee6116df..c63906873 100644
--- a/auth.c
+++ b/auth.c
@@ -372,7 +372,8 @@ auth_root_allowed(const char *method)
372 case PERMIT_NO_PASSWD: 372 case PERMIT_NO_PASSWD:
373 if (strcmp(method, "publickey") == 0 || 373 if (strcmp(method, "publickey") == 0 ||
374 strcmp(method, "hostbased") == 0 || 374 strcmp(method, "hostbased") == 0 ||
375 strcmp(method, "gssapi-with-mic") == 0) 375 strcmp(method, "gssapi-with-mic") == 0 ||
376 strcmp(method, "gssapi-keyex") == 0)
376 return 1; 377 return 1;
377 break; 378 break;
378 case PERMIT_FORCED_ONLY: 379 case PERMIT_FORCED_ONLY:
@@ -795,99 +796,6 @@ fakepw(void)
795} 796}
796 797
797/* 798/*
798 * Returns the remote DNS hostname as a string. The returned string must not
799 * be freed. NB. this will usually trigger a DNS query the first time it is
800 * called.
801 * This function does additional checks on the hostname to mitigate some
802 * attacks on legacy rhosts-style authentication.
803 * XXX is RhostsRSAAuthentication vulnerable to these?
804 * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
805 */
806
807static char *
808remote_hostname(struct ssh *ssh)
809{
810 struct sockaddr_storage from;
811 socklen_t fromlen;
812 struct addrinfo hints, *ai, *aitop;
813 char name[NI_MAXHOST], ntop2[NI_MAXHOST];
814 const char *ntop = ssh_remote_ipaddr(ssh);
815
816 /* Get IP address of client. */
817 fromlen = sizeof(from);
818 memset(&from, 0, sizeof(from));
819 if (getpeername(ssh_packet_get_connection_in(ssh),
820 (struct sockaddr *)&from, &fromlen) < 0) {
821 debug("getpeername failed: %.100s", strerror(errno));
822 return strdup(ntop);
823 }
824
825 ipv64_normalise_mapped(&from, &fromlen);
826 if (from.ss_family == AF_INET6)
827 fromlen = sizeof(struct sockaddr_in6);
828
829 debug3("Trying to reverse map address %.100s.", ntop);
830 /* Map the IP address to a host name. */
831 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
832 NULL, 0, NI_NAMEREQD) != 0) {
833 /* Host name not found. Use ip address. */
834 return strdup(ntop);
835 }
836
837 /*
838 * if reverse lookup result looks like a numeric hostname,
839 * someone is trying to trick us by PTR record like following:
840 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
841 */
842 memset(&hints, 0, sizeof(hints));
843 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
844 hints.ai_flags = AI_NUMERICHOST;
845 if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
846 logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
847 name, ntop);
848 freeaddrinfo(ai);
849 return strdup(ntop);
850 }
851
852 /* Names are stored in lowercase. */
853 lowercase(name);
854
855 /*
856 * Map it back to an IP address and check that the given
857 * address actually is an address of this host. This is
858 * necessary because anyone with access to a name server can
859 * define arbitrary names for an IP address. Mapping from
860 * name to IP address can be trusted better (but can still be
861 * fooled if the intruder has access to the name server of
862 * the domain).
863 */
864 memset(&hints, 0, sizeof(hints));
865 hints.ai_family = from.ss_family;
866 hints.ai_socktype = SOCK_STREAM;
867 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
868 logit("reverse mapping checking getaddrinfo for %.700s "
869 "[%s] failed.", name, ntop);
870 return strdup(ntop);
871 }
872 /* Look for the address from the list of addresses. */
873 for (ai = aitop; ai; ai = ai->ai_next) {
874 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
875 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
876 (strcmp(ntop, ntop2) == 0))
877 break;
878 }
879 freeaddrinfo(aitop);
880 /* If we reached the end of the list, the address was not there. */
881 if (ai == NULL) {
882 /* Address not found for the host name. */
883 logit("Address %.100s maps to %.600s, but this does not "
884 "map back to the address.", ntop, name);
885 return strdup(ntop);
886 }
887 return strdup(name);
888}
889
890/*
891 * Return the canonical name of the host in the other side of the current 799 * Return the canonical name of the host in the other side of the current
892 * connection. The host name is cached, so it is efficient to call this 800 * connection. The host name is cached, so it is efficient to call this
893 * several times. 801 * several times.