[v1,RFC] Smack: Inform peer that IPv6 traffic has been blocked

Commit Message

Piotr Sawicki July 18, 2018, 9:49 a.m. UTC

In this patch we're sending an ICMPv6 message to a peer to
immediately inform it that making a connection is not possible.
In case of TCP connections, without this change, the peer
will be waiting until a connection timeout is exceeded.
---
  security/smack/smack_lsm.c | 3 +++
  1 file changed, 3 insertions(+)

  	}

Patch

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index c2282ac..cee8335 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -28,6 +28,7 @@ 
  #include <linux/tcp.h>
  #include <linux/udp.h>
  #include <linux/dccp.h>
+#include <linux/icmpv6.h>
  #include <linux/slab.h>
  #include <linux/mutex.h>
  #include <linux/pipe_fs_i.h>
@@ -4010,6 +4011,8 @@  static int smack_socket_sock_rcv_skb(struct sock 
*sk, struct sk_buff *skb)
  #ifdef SMACK_IPV6_PORT_LABELING
  		rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING);
  #endif /* SMACK_IPV6_PORT_LABELING */
+		if (rc != 0)
+			icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADM_PROHIBITED, 0);
  		break;
  #endif /* CONFIG_IPV6 */