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Handle locally-routed DNS Queries (#904940)

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Signed-off-by: Tomas Hozza <thozza@redhat.com>
This commit is contained in:
Tomas Hozza 2013-01-31 11:23:34 +01:00
parent f6006969c4
commit 261955a53f
2 changed files with 185 additions and 1 deletions
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178
dnsmasq-2.65-Handle-wrong-interface-for-locally-routed-packets.patch Normal file
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@ -0,0 +1,178 @@
diff -up dnsmasq-2.65/src/dnsmasq.c.local_queries dnsmasq-2.65/src/dnsmasq.c
--- dnsmasq-2.65/src/dnsmasq.c.local_queries 2013-01-31 09:07:45.603092125 +0100
+++ dnsmasq-2.65/src/dnsmasq.c 2013-01-31 09:07:45.606092127 +0100
@@ -1401,20 +1401,29 @@ static void check_dns_listeners(fd_set *
else
{
int if_index;
-
+ char intr_name[IF_NAMESIZE];
+
/* In full wildcard mode, need to refresh interface list.
This happens automagically in CLEVERBIND */
- if (!option_bool(OPT_CLEVERBIND))
- enumerate_interfaces();
-
- /* if we can find the arrival interface, check it's one that's allowed */
- if ((if_index = tcp_interface(confd, tcp_addr.sa.sa_family)) != 0)
+ if (!option_bool(OPT_CLEVERBIND))
+ enumerate_interfaces();
+
+ /* if we can find the arrival interface, check it's one that's allowed */
+ if ((if_index = tcp_interface(confd, tcp_addr.sa.sa_family)) != 0 &&
+ indextoname(listener->tcpfd, if_index, intr_name))
{
+ struct all_addr addr;
+ addr.addr.addr4 = tcp_addr.in.sin_addr;
+#ifdef HAVE_IPV6
+ if (tcp_addr.sa.sa_family == AF_INET6)
+ addr.addr.addr6 = tcp_addr.in6.sin6_addr;
+#endif
+
for (iface = daemon->interfaces; iface; iface = iface->next)
if (iface->index == if_index)
break;
- if (!iface)
+ if (!iface && !loopback_exception(listener->tcpfd, tcp_addr.sa.sa_family, &addr, intr_name))
client_ok = 0;
}
@@ -1422,10 +1431,10 @@ static void check_dns_listeners(fd_set *
iface = listener->iface; /* May be NULL */
else
{
- /* Check for allowed interfaces when binding the wildcard address:
- we do this by looking for an interface with the same address as
- the local address of the TCP connection, then looking to see if that's
- an allowed interface. As a side effect, we get the netmask of the
+ /* Check for allowed interfaces when binding the wildcard address:
+ we do this by looking for an interface with the same address as
+ the local address of the TCP connection, then looking to see if that's
+ an allowed interface. As a side effect, we get the netmask of the
interface too, for localisation. */
for (iface = daemon->interfaces; iface; iface = iface->next)
diff -up dnsmasq-2.65/src/dnsmasq.h.local_queries dnsmasq-2.65/src/dnsmasq.h
--- dnsmasq-2.65/src/dnsmasq.h.local_queries 2013-01-31 09:07:45.000000000 +0100
+++ dnsmasq-2.65/src/dnsmasq.h 2013-01-31 09:10:36.091202196 +0100
@@ -954,6 +954,7 @@ void create_wildcard_listeners(void);
void create_bound_listeners(int die);
int is_dad_listeners(void);
int iface_check(int family, struct all_addr *addr, char *name);
+int loopback_exception(int fd, int family, struct all_addr *addr, char *name);
int fix_fd(int fd);
int tcp_interface(int fd, int af);
struct in_addr get_ifaddr(char *intr);
diff -up dnsmasq-2.65/src/forward.c.local_queries dnsmasq-2.65/src/forward.c
--- dnsmasq-2.65/src/forward.c.local_queries 2012-12-14 12:48:26.000000000 +0100
+++ dnsmasq-2.65/src/forward.c 2013-01-31 09:19:58.087573008 +0100
@@ -759,10 +759,17 @@ void receive_query(struct listener *list
/* enforce available interface configuration */
- if (!indextoname(listen->fd, if_index, ifr.ifr_name) ||
- !iface_check(listen->family, &dst_addr, ifr.ifr_name))
+ if (!indextoname(listen->fd, if_index, ifr.ifr_name))
return;
+ if (!iface_check(listen->family, &dst_addr, ifr.ifr_name))
+ {
+ if (!option_bool(OPT_CLEVERBIND))
+ enumerate_interfaces();
+ if (!loopback_exception(listen->fd, listen->family, &dst_addr, ifr.ifr_name))
+ return;
+ }
+
if (listen->family == AF_INET && option_bool(OPT_LOCALISE))
{
struct irec *iface;
@@ -776,7 +783,7 @@ void receive_query(struct listener *list
break;
/* interface may be new */
- if (!iface)
+ if (!iface && !option_bool(OPT_CLEVERBIND))
enumerate_interfaces();
for (iface = daemon->interfaces; iface; iface = iface->next)
diff -up dnsmasq-2.65/src/network.c.local_queries dnsmasq-2.65/src/network.c
--- dnsmasq-2.65/src/network.c.local_queries 2013-01-31 09:07:45.000000000 +0100
+++ dnsmasq-2.65/src/network.c 2013-01-31 09:25:28.669822969 +0100
@@ -144,7 +144,39 @@ int iface_check(int family, struct all_a
return ret;
}
-
+
+/* Fix for problem that the kernel sometimes reports the loopback inerface as the
+ arrival interface when a packet originates locally, even when sent to address of
+ an interface other than the loopback. Accept packet if it arrived via a loopback
+ interface, even when we're not accepting packets that way, as long as the destination
+ address is one we're believing. Interface list must be up-to-date before calling. */
+int loopback_exception(int fd, int family, struct all_addr *addr, char *name)
+{
+ struct ifreq ifr;
+ struct irec *iface;
+
+ strncpy(ifr.ifr_name, name, IF_NAMESIZE);
+ if (ioctl(fd, SIOCGIFFLAGS, &ifr) != -1 &&
+ ifr.ifr_flags & IFF_LOOPBACK)
+ {
+ for (iface = daemon->interfaces; iface; iface = iface->next)
+ if (iface->addr.sa.sa_family == family)
+ {
+ if (family == AF_INET)
+ {
+ if (iface->addr.in.sin_addr.s_addr == addr->addr.addr4.s_addr)
+ return 1;
+ }
+#ifdef HAVE_IPV6
+ else if (IN6_ARE_ADDR_EQUAL(&iface->addr.in6.sin6_addr, &addr->addr.addr6))
+ return 1;
+#endif
+
+ }
+ }
+ return 0;
+}
+
static int iface_allowed(struct irec **irecp, int if_index,
union mysockaddr *addr, struct in_addr netmask, int dad)
{
diff -up dnsmasq-2.65/src/tftp.c.local_queries dnsmasq-2.65/src/tftp.c
--- dnsmasq-2.65/src/tftp.c.local_queries 2012-12-14 12:48:26.000000000 +0100
+++ dnsmasq-2.65/src/tftp.c 2013-01-31 09:49:44.478008214 +0100
@@ -61,6 +61,7 @@ void tftp_request(struct listener *liste
char *name = NULL;
char *prefix = daemon->tftp_prefix;
struct tftp_prefix *pref;
+ struct all_addr addra;
union {
struct cmsghdr align; /* this ensures alignment */
@@ -190,16 +191,19 @@ void tftp_request(struct listener *liste
name = namebuff;
+ addra.addr.addr4 = addr.in.sin_addr;
+
#ifdef HAVE_IPV6
if (listen->family == AF_INET6)
+ addra.addr.addr6 = addr.in6.sin6_addr;
+#endif
+ if (!iface_check(listen->family, &addra, name))
{
- if (!iface_check(AF_INET6, (struct all_addr *)&addr.in6.sin6_addr, name))
+ if (!option_bool(OPT_CLEVERBIND))
+ enumerate_interfaces();
+ if (!loopback_exception(listen->tftpfd, listen->family, &addra, name))
return;
}
- else
-#endif
- if (!iface_check(AF_INET, (struct all_addr *)&addr.in.sin_addr, name))
- return;
#ifdef HAVE_DHCP
/* allowed interfaces are the same as for DHCP */

8
dnsmasq.spec
View File

@ -11,7 +11,7 @@
Name: dnsmasq Name: dnsmasq
Version: 2.65 Version: 2.65
Release: 3%{?extraversion}%{?dist} Release: 4%{?extraversion}%{?dist}
Summary: A lightweight DHCP/caching DNS server Summary: A lightweight DHCP/caching DNS server
Group: System Environment/Daemons Group: System Environment/Daemons
@ -22,6 +22,8 @@ Source1: %{name}.service
# http://www.thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=22ce550e5346947a12a781ed0959a7b1165d0dc6 # http://www.thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=22ce550e5346947a12a781ed0959a7b1165d0dc6
Patch0: %{name}-2.65-Correct-behaviour-for-TCP-queries-to-allowed-address.patch Patch0: %{name}-2.65-Correct-behaviour-for-TCP-queries-to-allowed-address.patch
# http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=e25db1f273920d58c5d2e7569cd087e5bd73dd73
Patch1: %{name}-2.65-Handle-wrong-interface-for-locally-routed-packets.patch
BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n) BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@ -57,6 +59,7 @@ query/remove a DHCP server's leases.
%setup -q -n %{name}-%{version}%{?extraversion} %setup -q -n %{name}-%{version}%{?extraversion}
%patch0 -p1 -b .CVE-2013-0198 %patch0 -p1 -b .CVE-2013-0198
%patch1 -p1 -b .local_queries
# use /var/lib/dnsmasq instead of /var/lib/misc # use /var/lib/dnsmasq instead of /var/lib/misc
for file in dnsmasq.conf.example man/dnsmasq.8 man/es/dnsmasq.8 src/config.h; do for file in dnsmasq.conf.example man/dnsmasq.8 man/es/dnsmasq.8 src/config.h; do
@ -134,6 +137,9 @@ rm -rf $RPM_BUILD_ROOT
%{_mandir}/man1/dhcp_* %{_mandir}/man1/dhcp_*
%changelog %changelog
* Thu Jan 31 2013 Tomas Hozza <thozza@redhat.com> - 2.65-4
- Handle locally-routed DNS Queries (#904940)
* Thu Jan 24 2013 Tomas Hozza <thozza@redhat.com> - 2.65-3 * Thu Jan 24 2013 Tomas Hozza <thozza@redhat.com> - 2.65-3
- build dnsmasq with $RPM_OPT_FLAGS, $RPM_LD_FLAGS explicitly (#903362) - build dnsmasq with $RPM_OPT_FLAGS, $RPM_LD_FLAGS explicitly (#903362)