From 95bee3e1cb676e462750a8c46cf6439a3e3e6cc0 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Sat, 3 May 2014 15:35:29 +0100
Subject: [PATCH] src/setup.c: Check netmask more carefully.

[crybaby ~/src/adns/build]RES_CONF_TEXT="sortlist 172.29.199.1/24" RES_OPTIONS="adns_checkc:entex" adnshost -ta www-cache.distorted.org.uk
adnshost: ../src/check.c:83: checkc_global: Assertion `!(ads->sortlist[i].base.s_addr & ~ads->sortlist[i].mask.s_addr)' failed.
Aborted

Unfortunately, `ccf_sortlist' only checked that the free bits of the
network address are clear when given a general netmask, so if you give a
prefix length or leave it implicit then you hit a consistency check
failure later.

Check the mask later on, after all of the variants are handled.  There's
a little bit of variation in the message.

Signed-off-by: Mark Wooding <mdw@distorted.org.uk>
---
 src/setup.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/setup.c b/src/setup.c
index 96a2a21..f73926c 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -152,6 +152,7 @@ static void ccf_sortlist(adns_state ads, const char *fn,
 			 int lno, const char *buf) {
   const char *word;
   char tbuf[200], *slash, *ep;
+  const char *maskwhat;
   struct in_addr base, mask;
   int l;
   unsigned long initial, baselocal;
@@ -182,16 +183,13 @@ static void ccf_sortlist(adns_state ads, const char *fn,
 
     if (slash) {
       if (strchr(slash,'.')) {
+	maskwhat = "mask";
 	if (!inet_aton(slash,&mask)) {
 	  configparseerr(ads,fn,lno,"invalid mask `%s' in sortlist",slash);
 	  continue;
 	}
-	if (base.s_addr & ~mask.s_addr) {
-	  configparseerr(ads,fn,lno, "mask `%s' in sortlist"
-			 " overlaps address `%s'",slash,tbuf);
-	  continue;
-	}
       } else {
+	maskwhat = "prefix length";
 	initial= strtoul(slash,&ep,10);
 	if (*ep || initial>32) {
 	  configparseerr(ads,fn,lno,"mask length `%s' invalid",slash);
@@ -200,6 +198,7 @@ static void ccf_sortlist(adns_state ads, const char *fn,
 	mask.s_addr= htonl((0x0ffffffffUL) << (32-initial));
       }
     } else {
+      maskwhat = "implied mask";
       baselocal= ntohl(base.s_addr);
       if (!(baselocal & 0x080000000UL)) /* class A */
 	mask.s_addr= htonl(0x0ff000000UL);
@@ -215,6 +214,13 @@ static void ccf_sortlist(adns_state ads, const char *fn,
       }
     }
 
+    if (base.s_addr & ~mask.s_addr) {
+      configparseerr(ads,fn,lno, "%s `%s' in sortlist"
+		     " overlaps address `%s'",maskwhat,
+		     slash ? slash : inet_ntoa(mask), tbuf);
+      continue;
+    }
+
     ads->sortlist[ads->nsortlist].base= base;
     ads->sortlist[ads->nsortlist].mask= mask;
     ads->nsortlist++;
-- 
2.30.2