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[PATCH] LSM networking: ipv4 hooks for 2.5.42 (4/7)

To: "David S. Miller" <davem@xxxxxxxxxx>, <kuznet@xxxxxxxxxxxxx>
Subject: [PATCH] LSM networking: ipv4 hooks for 2.5.42 (4/7)
From: James Morris <jmorris@xxxxxxxxxxxxxxxx>
Date: Wed, 16 Oct 2002 00:38:21 +1000 (EST)
Cc: netdev@xxxxxxxxxxx, <linux-security-module@xxxxxxxxx>
Sender: netdev-bounce@xxxxxxxxxxx
diff -urN -X dontdiff linux-2.5.42.w0/include/linux/ip.h 
linux-2.5.42.w1/include/linux/ip.h
--- linux-2.5.42.w0/include/linux/ip.h  Fri Aug  2 07:16:17 2002
+++ linux-2.5.42.w1/include/linux/ip.h  Tue Oct 15 20:58:32 2002
@@ -58,6 +58,7 @@
 #define IPOPT_SEC      (2 |IPOPT_CONTROL|IPOPT_COPY)
 #define IPOPT_LSRR     (3 |IPOPT_CONTROL|IPOPT_COPY)
 #define IPOPT_TIMESTAMP        (4 |IPOPT_MEASUREMENT)
+#define IPOPT_CIPSO    (6 |IPOPT_CONTROL|IPOPT_COPY)
 #define IPOPT_RR       (7 |IPOPT_CONTROL)
 #define IPOPT_SID      (8 |IPOPT_CONTROL|IPOPT_COPY)
 #define IPOPT_SSRR     (9 |IPOPT_CONTROL|IPOPT_COPY)
diff -urN -X dontdiff linux-2.5.42.w0/include/linux/security.h 
linux-2.5.42.w1/include/linux/security.h
--- linux-2.5.42.w0/include/linux/security.h    Tue Oct 15 20:58:10 2002
+++ linux-2.5.42.w1/include/linux/security.h    Tue Oct 15 20:58:32 2002
@@ -794,6 +794,48 @@
  *     @skb contains the incoming network data.
  *     Return 0 if permission is granted.
  *
+ * IPv4 networking hooks.
+ *
+ * @ip_fragment:
+ *     This is called for each fragment generated when an outgoing packet is
+ *     being fragmented, and may be used to copy security attributes from the
+ *     original packet to each fragment.
+ *     @newskb contains the newly created fragment.
+ *     @oldskb contains the original packet being fragmented.
+ * @ip_defragment:
+ *     This hook is called when an incoming fragment is about to be inserted
+ *     into a reassembly queue.  It's purpose is to enable the validation of
+ *     security attributes for each fragment.  An LSM module using this hook
+ *     will likely need to maintain its own fragment queue information, handle
+ *     fragment expiration and implement DoS countermeasures.
+ *     @skb contains the incoming fragment.
+ *     Returns 0 on success.
+ * @ip_encapsulate:
+ *     This hook is called when an IP packet is encapsulated, and may be used
+ *     to update security attributes prior to reprocessing via the local_out
+ *     or forward hooks.
+ *     @skb contains the encapsulated packet.
+ * @ip_decapsulate:
+ *     This hook is called when a packet is decapsulated, and may be used to
+ *     process security attributes at each level of encapsulation.  An example
+ *     of this would be keeping track of nested security associations for an
+ *     incoming packet.
+ *     @skb contains the decapsulated packet.
+ * @ip_decode_options:
+ *     This hook is used for processing IP security options at the network
+ *     layer when labeled networking (e.g. CIPSO) is implemented.
+ *     For outgoing packets, IP options passed down from the application or
+ *     transport layers may be verified here prior the packet being built.
+ *     For incoming packets, IP options may be verified and their values
+ *     recorded via the &sk_buff security blob for later processing.
+ *     @skb contains the &sk_buff containing IP packet (usually NULL for 
outgoing).
+ *     @optptr contains the &ip_options structure.
+ *     @pp_ptr contains the parameter problem pointer.
+ *     Returns 0 on success.
+ *     A non-zero return value will cause an ICMP parameter problem message to
+ *     be generated and transmitted to the sender.  The @pp_ptr parameter may
+ *     be used to point to the offending option parameter.
+ *
  * @ptrace:
  *     Check permission before allowing the @parent process to trace the
  *     @child process.
@@ -1044,6 +1086,14 @@
        void (*socket_sock_free_security) (struct sock * sk);
        int (*socket_sock_rcv_skb) (struct sock * sk, struct sk_buff * skb);
 
+       void (*ip_fragment) (struct sk_buff * newskb,
+                            const struct sk_buff * oldskb);
+       int (*ip_defragment) (struct sk_buff * skb);
+       void (*ip_encapsulate) (struct sk_buff * skb);
+       void (*ip_decapsulate) (struct sk_buff * skb);
+       int (*ip_decode_options) (struct sk_buff * skb,
+                                 const char *optptr, unsigned char **pp_ptr);
+
        int (*ipc_permission) (struct kern_ipc_perm * ipcp, short flag);
 
        int (*msg_queue_alloc_security) (struct msg_queue * msq);
diff -urN -X dontdiff linux-2.5.42.w0/net/ipv4/ip_fragment.c 
linux-2.5.42.w1/net/ipv4/ip_fragment.c
--- linux-2.5.42.w0/net/ipv4/ip_fragment.c      Fri Aug  2 07:16:16 2002
+++ linux-2.5.42.w1/net/ipv4/ip_fragment.c      Tue Oct 15 20:58:32 2002
@@ -37,6 +37,7 @@
 #include <linux/udp.h>
 #include <linux/inet.h>
 #include <linux/netfilter_ipv4.h>
+#include <linux/security.h>
 
 /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6
  * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
@@ -372,7 +373,11 @@
 {
        struct sk_buff *prev, *next;
        int flags, offset;
-       int ihl, end;
+       int ihl, end, ret;
+
+       ret = security_ops->ip_defragment(skb);
+       if (ret)
+               goto err;
 
        if (qp->last_in & COMPLETE)
                goto err;
diff -urN -X dontdiff linux-2.5.42.w0/net/ipv4/ip_gre.c 
linux-2.5.42.w1/net/ipv4/ip_gre.c
--- linux-2.5.42.w0/net/ipv4/ip_gre.c   Sat Oct 12 15:09:44 2002
+++ linux-2.5.42.w1/net/ipv4/ip_gre.c   Tue Oct 15 20:58:32 2002
@@ -653,6 +653,7 @@
                skb->nf_debug = 0;
 #endif
 #endif
+               security_ops->ip_decapsulate(skb);
                ipgre_ecn_decapsulate(iph, skb);
                netif_rx(skb);
                read_unlock(&ipgre_lock);
@@ -885,6 +886,7 @@
        skb->nf_debug = 0;
 #endif
 #endif
+       security_ops->ip_encapsulate(skb);
 
        IPTUNNEL_XMIT();
        tunnel->recursion--;
diff -urN -X dontdiff linux-2.5.42.w0/net/ipv4/ip_options.c 
linux-2.5.42.w1/net/ipv4/ip_options.c
--- linux-2.5.42.w0/net/ipv4/ip_options.c       Tue Sep 24 19:22:50 2002
+++ linux-2.5.42.w1/net/ipv4/ip_options.c       Tue Oct 15 20:58:32 2002
@@ -433,7 +433,11 @@
                                opt->router_alert = optptr - iph;
                        break;
                      case IPOPT_SEC:
+                     case IPOPT_CIPSO:
                      case IPOPT_SID:
+                       if (security_ops->ip_decode_options(skb, optptr, 
&pp_ptr))
+                               goto error;
+                       break;
                      default:
                        if (!skb && !capable(CAP_NET_RAW)) {
                                pp_ptr = optptr;
diff -urN -X dontdiff linux-2.5.42.w0/net/ipv4/ip_output.c 
linux-2.5.42.w1/net/ipv4/ip_output.c
--- linux-2.5.42.w0/net/ipv4/ip_output.c        Wed Oct  9 22:39:39 2002
+++ linux-2.5.42.w1/net/ipv4/ip_output.c        Tue Oct 15 20:58:32 2002
@@ -898,6 +898,7 @@
                skb2->nf_debug = skb->nf_debug;
 #endif
 #endif
+               security_ops->ip_fragment(skb2, skb);
 
                /*
                 *      Put this fragment into the sending queue.
diff -urN -X dontdiff linux-2.5.42.w0/net/ipv4/ipip.c 
linux-2.5.42.w1/net/ipv4/ipip.c
--- linux-2.5.42.w0/net/ipv4/ipip.c     Sat Oct 12 15:09:44 2002
+++ linux-2.5.42.w1/net/ipv4/ipip.c     Tue Oct 15 20:58:32 2002
@@ -500,6 +500,7 @@
                skb->nf_debug = 0;
 #endif
 #endif
+               security_ops->ip_decapsulate(skb);
                ipip_ecn_decapsulate(iph, skb);
                netif_rx(skb);
                read_unlock(&ipip_lock);
@@ -652,6 +653,8 @@
 #endif
 #endif
 
+       security_ops->ip_encapsulate(skb);
+
        IPTUNNEL_XMIT();
        tunnel->recursion--;
        return 0;
diff -urN -X dontdiff linux-2.5.42.w0/net/ipv4/ipmr.c 
linux-2.5.42.w1/net/ipv4/ipmr.c
--- linux-2.5.42.w0/net/ipv4/ipmr.c     Sat Oct 12 15:09:44 2002
+++ linux-2.5.42.w1/net/ipv4/ipmr.c     Tue Oct 15 20:58:32 2002
@@ -1105,6 +1105,7 @@
        nf_conntrack_put(skb->nfct);
        skb->nfct = NULL;
 #endif
+       security_ops->ip_encapsulate(skb);
 }
 
 static inline int ipmr_forward_finish(struct sk_buff *skb)
@@ -1450,6 +1451,7 @@
        nf_conntrack_put(skb->nfct);
        skb->nfct = NULL;
 #endif
+       security_ops->ip_decapsulate(skb);
        netif_rx(skb);
        dev_put(reg_dev);
        return 0;
@@ -1517,6 +1519,7 @@
        nf_conntrack_put(skb->nfct);
        skb->nfct = NULL;
 #endif
+       security_ops->ip_decapsulate(skb);
        netif_rx(skb);
        dev_put(reg_dev);
        return 0;
diff -urN -X dontdiff linux-2.5.42.w0/security/capability.c 
linux-2.5.42.w1/security/capability.c
--- linux-2.5.42.w0/security/capability.c       Tue Oct 15 20:58:10 2002
+++ linux-2.5.42.w1/security/capability.c       Tue Oct 15 20:58:32 2002
@@ -841,6 +841,37 @@
        return 0;
 }
 
+static void cap_ip_fragment (struct sk_buff *newskb,
+                            const struct sk_buff *oldskb)
+{
+       return;
+}
+
+static int cap_ip_defragment (struct sk_buff *skb)
+{
+       return 0;
+}
+
+static void cap_ip_encapsulate (struct sk_buff *skb)
+{
+       return;
+}
+
+static void cap_ip_decapsulate (struct sk_buff *skb)
+{
+       return;
+}
+
+static int cap_ip_decode_options (struct sk_buff *skb, const char *optptr,
+                                 unsigned char **pp_ptr)
+{
+       if (!skb && !capable (CAP_NET_RAW)) {
+               (const unsigned char *) *pp_ptr = optptr;
+               return -EPERM;
+       }
+       return 0;
+}
+
 static int cap_register (const char *name, struct security_operations *ops)
 {
        return -EINVAL;
@@ -969,6 +1000,12 @@
        .socket_sock_free_security =    cap_socket_sock_free_security,
        .socket_sock_rcv_skb =          cap_socket_sock_rcv_skb,
 
+       .ip_fragment =                  cap_ip_fragment,
+       .ip_defragment =                cap_ip_defragment,
+       .ip_encapsulate =               cap_ip_encapsulate,
+       .ip_decapsulate =               cap_ip_decapsulate,
+       .ip_decode_options =            cap_ip_decode_options,
+
        .ipc_permission =               cap_ipc_permission,
 
        .msg_queue_alloc_security =     cap_msg_queue_alloc_security,
diff -urN -X dontdiff linux-2.5.42.w0/security/dummy.c 
linux-2.5.42.w1/security/dummy.c
--- linux-2.5.42.w0/security/dummy.c    Tue Oct 15 20:58:10 2002
+++ linux-2.5.42.w1/security/dummy.c    Tue Oct 15 20:58:32 2002
@@ -658,6 +658,37 @@
        return 0;
 }
 
+static void dummy_ip_fragment (struct sk_buff *newskb,
+                              const struct sk_buff *oldskb)
+{
+       return;
+}
+
+static int dummy_ip_defragment (struct sk_buff *skb)
+{
+       return 0;
+}
+
+static void dummy_ip_decapsulate (struct sk_buff *skb)
+{
+       return;
+}
+
+static void dummy_ip_encapsulate (struct sk_buff *skb)
+{
+       return;
+}
+
+static int dummy_ip_decode_options (struct sk_buff *skb, const char *optptr,
+                                   unsigned char **pp_ptr)
+{
+       if (!skb && !capable (CAP_NET_RAW)) {
+               (const unsigned char *) *pp_ptr = optptr;
+               return -EPERM;
+       }
+       return 0;
+}
+
 static int dummy_register (const char *name, struct security_operations *ops)
 {
        return -EINVAL;
@@ -786,6 +817,12 @@
        .socket_sock_free_security =    dummy_socket_sock_free_security,
        .socket_sock_rcv_skb =          dummy_socket_sock_rcv_skb,
 
+       .ip_fragment =                  dummy_ip_fragment,
+       .ip_defragment =                dummy_ip_defragment,
+       .ip_encapsulate =               dummy_ip_encapsulate,
+       .ip_decapsulate =               dummy_ip_decapsulate,
+       .ip_decode_options =            dummy_ip_decode_options,
+
        .ipc_permission =               dummy_ipc_permission,
        
        .msg_queue_alloc_security =     dummy_msg_queue_alloc_security,



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