[dnsmasq/f18] Fix for CVE-2013-0198 (checking of TCP connection interfaces)

[Tomas Hozza]

commit 837eefae26c209cb0204f376ed23f5b339e63424
Author: Tomas Hozza <thozza(a)redhat.com&gt;
Date:   Tue Jan 22 17:40:49 2013 +0100

    Fix for CVE-2013-0198 (checking of TCP connection interfaces)
    
    Resolves: rhbz#901555
    Signed-off-by: Tomas Hozza <thozza(a)redhat.com&gt;

 ...aviour-for-TCP-queries-to-allowed-address.patch |  189 ++++++++++++++++++++
 dnsmasq.spec                                       |   10 +-
 2 files changed, 198 insertions(+), 1 deletions(-)
---
diff --git a/dnsmasq-2.65-Correct-behaviour-for-TCP-queries-to-allowed-address.patch
b/dnsmasq-2.65-Correct-behaviour-for-TCP-queries-to-allowed-address.patch
new file mode 100644
index 0000000..4b08fdc
--- /dev/null
+++ b/dnsmasq-2.65-Correct-behaviour-for-TCP-queries-to-allowed-address.patch
@@ -0,0 +1,189 @@
+diff -up dnsmasq-2.65/src/dnsmasq.c.CVE-2013-0198 dnsmasq-2.65/src/dnsmasq.c
+--- dnsmasq-2.65/src/dnsmasq.c.CVE-2013-0198	2012-12-14 12:48:26.000000000 +0100
++++ dnsmasq-2.65/src/dnsmasq.c	2013-01-22 16:32:30.387640907 +0100
+@@ -1384,7 +1384,7 @@ static void check_dns_listeners(fd_set *
+ 
+       if (listener->tcpfd != -1 && FD_ISSET(listener->tcpfd, set))
+ 	{
+-	  int confd;
++	  int confd, client_ok = 1;
+ 	  struct irec *iface = NULL;
+ 	  pid_t p;
+ 	  union mysockaddr tcp_addr;
+@@ -1395,25 +1395,49 @@ static void check_dns_listeners(fd_set *
+ 	  if (confd == -1 ||
+ 	      getsockname(confd, (struct sockaddr *)&tcp_addr, &tcp_len) == -1)
+ 	    continue;
+-	  
+-	  if (option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND))
++
++	   if (option_bool(OPT_NOWILD))
+ 	    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
+-		 interface too, for localisation. */
+-	      
+-	      /* interface may be new since startup */
+-	      if (enumerate_interfaces())
+-		for (iface = daemon->interfaces; iface; iface = iface->next)
+-		  if (sockaddr_isequal(&iface->addr, &tcp_addr))
+-		    break;
+-	    }
+-	  
+-	  if (!iface && !(option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND)))
++	   else 
++	     {
++	       int if_index;
++
++	       /* 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)
++		 {
++		   for (iface = daemon->interfaces; iface; iface = iface->next)
++		     if (iface->index == if_index)
++		       break;
++		   
++		   if (!iface)
++		     client_ok = 0;
++		 }
++	       
++	       if (option_bool(OPT_CLEVERBIND))
++		 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
++		      interface too, for localisation. */
++		   
++		   for (iface = daemon->interfaces; iface; iface = iface->next)
++		     if (sockaddr_isequal(&iface->addr, &tcp_addr))
++		       break;
++		   
++		   if (!iface)
++		     client_ok = 0;
++		 }
++	     }
++	  	  
++	  if (!client_ok)
+ 	    {
+ 	      shutdown(confd, SHUT_RDWR);
+ 	      close(confd);
+diff -up dnsmasq-2.65/src/dnsmasq.h.CVE-2013-0198 dnsmasq-2.65/src/dnsmasq.h
+--- dnsmasq-2.65/src/dnsmasq.h.CVE-2013-0198	2012-12-14 12:48:26.000000000 +0100
++++ dnsmasq-2.65/src/dnsmasq.h	2013-01-22 16:32:30.387640907 +0100
+@@ -412,7 +412,7 @@ struct server {
+ struct irec {
+   union mysockaddr addr;
+   struct in_addr netmask; /* only valid for IPv4 */
+-  int tftp_ok, dhcp_ok, mtu, done, dad;
++  int tftp_ok, dhcp_ok, mtu, done, dad, index;
+   char *name;
+   struct irec *next;
+ };
+@@ -955,6 +955,7 @@ void create_bound_listeners(int die);
+ int is_dad_listeners(void);
+ int iface_check(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);
+ #ifdef HAVE_IPV6
+ int set_ipv6pktinfo(int fd);
+diff -up dnsmasq-2.65/src/network.c.CVE-2013-0198 dnsmasq-2.65/src/network.c
+--- dnsmasq-2.65/src/network.c.CVE-2013-0198	2012-12-14 12:48:26.000000000 +0100
++++ dnsmasq-2.65/src/network.c	2013-01-22 17:33:00.349128334 +0100
+@@ -239,6 +239,7 @@ static int iface_allowed(struct irec **i
+       iface->mtu = mtu;
+       iface->dad = dad;
+       iface->done = 0;
++      iface->index = if_index;
+       if ((iface->name = whine_malloc(strlen(ifr.ifr_name)+1)))
+ 	{
+ 	  strcpy(iface->name, ifr.ifr_name);
+@@ -420,6 +421,77 @@ int set_ipv6pktinfo(int fd)
+   return 0;
+ }
+ #endif
++
++
++/* Find the interface on which a TCP connection arrived, if possible, or zero otherwise.
*/
++int tcp_interface(int fd, int af)
++{ 
++  int if_index = 0;
++
++#ifdef HAVE_LINUX_NETWORK
++  int opt = 1;
++  struct cmsghdr *cmptr;
++  struct msghdr msg;
++  
++  /* use mshdr do that the CMSDG_* macros are available */
++  msg.msg_control = daemon->packet;
++  msg.msg_controllen = daemon->packet_buff_sz;
++  
++  /* we overwrote the buffer... */
++  daemon->srv_save = NULL;
++  
++  if (af == AF_INET)
++    {
++      if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &opt, sizeof(opt)) != -1
&&
++	  getsockopt(fd, IPPROTO_IP, IP_PKTOPTIONS, msg.msg_control, (socklen_t
*)&msg.msg_controllen) != -1)
++	for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
++	  if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO)
++            {
++              union {
++                unsigned char *c;
++                struct in_pktinfo *p;
++              } p;
++	      
++	      p.c = CMSG_DATA(cmptr);
++	      if_index = p.p->ipi_ifindex;
++	    }
++    }
++#ifdef HAVE_IPV6
++  else
++    {
++      /* Only the RFC-2292 API has the ability to find the interface for TCP
connections,
++	 it was removed in RFC-3542 !!!! 
++
++	 Fortunately, Linux kept the 2292 ABI when it moved to 3542. The following code always
++	 uses the old ABI, and should work with pre- and post-3542 kernel headers */
++
++#ifdef IPV6_2292PKTOPTIONS   
++#  define PKTOPTIONS IPV6_2292PKTOPTIONS
++#else
++#  define PKTOPTIONS IPV6_PKTOPTIONS
++#endif
++
++      if (set_ipv6pktinfo(fd) &&
++	  getsockopt(fd, IPPROTO_IPV6, PKTOPTIONS, msg.msg_control, (socklen_t
*)&msg.msg_controllen) != -1)
++	{
++          for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg,
cmptr))
++            if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type ==
daemon->v6pktinfo)
++              {
++                union {
++                  unsigned char *c;
++                  struct in6_pktinfo *p;
++                } p;
++                p.c = CMSG_DATA(cmptr);
++		
++		if_index = p.p->ipi6_ifindex;
++              }
++	}
++    }
++#endif /* IPV6 */
++#endif /* Linux */
++ 
++  return if_index;
++}
+       
+ static struct listener *create_listeners(union mysockaddr *addr, int do_tftp, int
dienow)
+ {
diff --git a/dnsmasq.spec b/dnsmasq.spec
index 40cc1b8..72a8be9 100644
--- a/dnsmasq.spec
+++ b/dnsmasq.spec
@@ -11,7 +11,7 @@
 
 Name:           dnsmasq
 Version:        2.65
-Release:        1%{?extraversion}%{?dist}
+Release:        2%{?extraversion}%{?dist}
 Summary:        A lightweight DHCP/caching DNS server
 
 Group:          System Environment/Daemons
@@ -20,6 +20,9 @@ URL:            http://www.thekelleys.org.uk/dnsmasq/
 Source0:       
http://www.thekelleys.org.uk/dnsmasq/%{?extrapath}%{name}-%{version}%{?ex...
 Source1:        %{name}.service
 
+#
http://www.thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=22ce550e534...
+Patch0:         %{name}-2.65-Correct-behaviour-for-TCP-queries-to-allowed-address.patch
+
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  dbus-devel
@@ -53,6 +56,8 @@ query/remove a DHCP server's leases.
 %prep
 %setup -q -n %{name}-%{version}%{?extraversion}
 
+%patch0 -p1 -b .CVE-2013-0198
+
 # 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
     sed -i 's|/var/lib/misc/dnsmasq.leases|/var/lib/dnsmasq/dnsmasq.leases|g'
"$file"
@@ -131,6 +136,9 @@ rm -rf $RPM_BUILD_ROOT
 %{_mandir}/man1/dhcp_*
 
 %changelog
+* Tue Jan 22 2013 Tomas Hozza <thozza(a)redhat.com&gt; - 2.65-2
+- Fix for CVE-2013-0198 (checking of TCP connection interfaces) (#901555)
+
 * Sat Dec 15 2012 Tomas Hozza <thozza(a)redhat.com&gt; - 2.65-1
 - new version 2.65