MFp4 CH=183052 183053 183258:

  In protosw we define pr_protocol as short, while on the wire
  it is an uint8_t.  That way we can have "internal" protocols
  like DIVERT, SEND or gaps for modules (PROTO_SPACER).
  Switch ipproto_{un,}register to accept a short protocol number(*)
  and do an upfront check for valid boundries. With this we
  also consistently report EPROTONOSUPPORT for out of bounds
  protocols, as we did for proto == 0.  This allows a caller
  to not error for this case, which is especially important
  if we want to automatically call these from domain handling.

  (*) the functions have been without any in-tree consumer
  since the initial introducation, so this is considered save.

  Implement ip6proto_{un,}register() similarly to their legacy IP
  counter parts to allow modules to hook up dynamically.

Reviewed by:	philip, will
MFC after:	1 week

1 files changed, 6 insertions, 10 deletions

diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 40b494a..6e1153d 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -1287,12 +1287,12 @@ ip_drain(void)
  * in inetsw[], either statically or through pf_proto_register().
  */
 int
-ipproto_register(u_char ipproto)
+ipproto_register(short ipproto)
 {
 	struct protosw *pr;
 
 	/* Sanity checks. */
-	if (ipproto == 0)
+	if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
 		return (EPROTONOSUPPORT);
 
 	/*
@@ -1310,24 +1310,20 @@ ipproto_register(u_char ipproto)
 	     pr < inetdomain.dom_protoswNPROTOSW; pr++) {
 		if (pr->pr_domain->dom_family == PF_INET &&
 		    pr->pr_protocol && pr->pr_protocol == ipproto) {
-			/* Be careful to only index valid IP protocols. */
-			if (pr->pr_protocol < IPPROTO_MAX) {
-				ip_protox[pr->pr_protocol] = pr - inetsw;
-				return (0);
-			} else
-				return (EINVAL);
+			ip_protox[pr->pr_protocol] = pr - inetsw;
+			return (0);
 		}
 	}
 	return (EPROTONOSUPPORT);
 }
 
 int
-ipproto_unregister(u_char ipproto)
+ipproto_unregister(short ipproto)
 {
 	struct protosw *pr;
 
 	/* Sanity checks. */
-	if (ipproto == 0)
+	if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
 		return (EPROTONOSUPPORT);
 
 	/* Check if the protocol was indeed registered. */