From ecaaf4456e5aeacae1acdb1775bb5aadd3b19e13 Mon Sep 17 00:00:00 2001
From: Iker Pedrosa <ipedrosa@redhat.com>
Date: 2024年10月16日 12:41:09 +0200
Subject: [PATCH] pam_access: always match local address

* modules/pam_access/pam_access.c: match the local address regardless of
 the IP version in use.

In some circumstances the `localhost` may be translated to IPv4 or IPv6,
but the configuration file only indicated the address for one of the two
versions. Since the originating value is set in `PAM_RHOST` and PAM has
no control over it, let's match the local addresses regardless of the IP
version in use.

Resolves: https://issues.redhat.com/browse/RHEL-23018
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
---
 modules/pam_access/pam_access.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/modules/pam_access/pam_access.c b/modules/pam_access/pam_access.c
index bfbc6d574..48e7c7e97 100644
--- a/modules/pam_access/pam_access.c
+++ b/modules/pam_access/pam_access.c
@@ -306,6 +306,23 @@ isipaddr (const char *string, int *addr_type,
 return is_ip;
 }
 
+/* is_local_addr - checks if the IP address is local */
+static int
+is_local_addr (const char *string, int addr_type)
+{
+ if (addr_type == AF_INET) {
+ if (strcmp(string, "127.0.0.1") == 0) {
+ return YES;
+ }
+ } else if (addr_type == AF_INET6) {
+ if (strcmp(string, "::1") == 0) {
+ return YES;
+ }
+ }
+
+ return NO;
+}
+
 
 /* are_addresses_equal - translate IP address strings to real IP
 * addresses and compare them to find out if they are equal.
@@ -327,9 +344,18 @@ are_addresses_equal (const char *ipaddr0, const char *ipaddr1,
 if (isipaddr (ipaddr1, &addr_type1, &addr1) == NO)
 return NO;
 
- if (addr_type0 != addr_type1)
- /* different address types */
+ if (addr_type0 != addr_type1) {
+ /* different address types, but there is still a possibility that they are
+ * both local addresses
+ */
+ int local1 = is_local_addr(ipaddr0, addr_type0);
+ int local2 = is_local_addr(ipaddr1, addr_type1);
+
+ if (local1 == YES && local2 == YES)
+ return YES;
+
 return NO;
+ }
 
 if (netmask != NULL) {
 /* Got a netmask, so normalize addresses? */