From: Antonio Quartulli <a@unstable.cc>
Date: Mon, 8 Jun 2020 20:16:13 +0000 (+0200)
Subject: ipv6-pool: get rid of size constraint
X-Git-Tag: v2.5_beta1~125
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1379e5271d0057fcaed82d6985e614ca2ed8c265;p=thirdparty%2Fopenvpn.git

ipv6-pool: get rid of size constraint

Signed-off-by: Antonio Quartulli <a@unstable.cc>

Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20200608201613.23750-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20005.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
---

diff --git a/src/openvpn/helper.c b/src/openvpn/helper.c
index 277e6972a..fbfc287f1 100644
--- a/src/openvpn/helper.c
+++ b/src/openvpn/helper.c
@@ -198,12 +198,17 @@ helper_client_server(struct options *o)
             print_in6_addr( add_in6_addr( o->server_network_ipv6, 2), 0, &o->gc );
         o->ifconfig_ipv6_netbits = o->server_netbits_ipv6;
 
-        /* pool starts at "base address + 0x1000" - leave enough room */
-        ASSERT( o->server_netbits_ipv6 <= 112 );        /* want 16 bits */
+        /* basic sanity check */
+        ASSERT(o->server_netbits_ipv6 >= 64 && o->server_netbits_ipv6 <= 124);
 
         o->ifconfig_ipv6_pool_defined = true;
-        o->ifconfig_ipv6_pool_base =
-            add_in6_addr( o->server_network_ipv6, 0x1000 );
+        /* For large enough pools we keep the original behaviour of adding
+         * 0x1000 when computing the base.
+         *
+         * Smaller pools can't get that far, therefore we just increase by 2
+         */
+        o->ifconfig_ipv6_pool_base = add_in6_addr(o->server_network_ipv6,
+                                                  o->server_netbits_ipv6 < 112 ? 0x1000 : 2);
         o->ifconfig_ipv6_pool_netbits = o->server_netbits_ipv6;
 
         push_option( o, "tun-ipv6", M_USAGE );
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 018f6f18c..9d3a8dfed 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -6718,9 +6718,12 @@ add_option(struct options *options,
             msg(msglevel, "error parsing --server-ipv6 parameter");
             goto err;
         }
-        if (netbits < 64 || netbits > 112)
+        if (netbits < 64 || netbits > 124)
         {
-            msg( msglevel, "--server-ipv6 settings: only /64../112 supported right now (not /%d)", netbits );
+            msg(msglevel,
+                "--server-ipv6 settings: network must be between /64 and /124 (not /%d)",
+                netbits);
+
             goto err;
         }
         options->server_ipv6_defined = true;
@@ -6840,9 +6843,11 @@ add_option(struct options *options,
             msg(msglevel, "error parsing --ifconfig-ipv6-pool parameters");
             goto err;
         }
-        if (netbits < 64 || netbits > 112)
+        if (netbits < 64 || netbits > 124)
         {
-            msg( msglevel, "--ifconfig-ipv6-pool settings: only /64../112 supported right now (not /%d)", netbits );
+            msg(msglevel,
+                "--ifconfig-ipv6-pool settings: network must be between /64 and /124 (not /%d)",
+                netbits);
             goto err;
         }
 
diff --git a/src/openvpn/pool.c b/src/openvpn/pool.c
index 4e303712b..296676230 100644
--- a/src/openvpn/pool.c
+++ b/src/openvpn/pool.c
@@ -207,6 +207,12 @@ ifconfig_pool_init(const bool ipv4_pool, enum pool_type type, in_addr_t start,
                 ASSERT(0);
         }
 
+        if (pool->ipv4.size < 2)
+        {
+            msg(M_FATAL, "IPv4 pool size is too small (%d), must be at least 2",
+                pool->ipv4.size);
+        }
+
         msg(D_IFCONFIG_POOL, "IFCONFIG POOL IPv4: base=%s size=%d",
             print_in_addr_t(pool->ipv4.base, 0, &gc), pool->ipv4.size);
     }
@@ -245,6 +251,12 @@ ifconfig_pool_init(const bool ipv4_pool, enum pool_type type, in_addr_t start,
                           ? (1 << (128 - ipv6_netbits)) - base
                           : IFCONFIG_POOL_MAX;
 
+        if (pool->ipv6.size < 2)
+        {
+            msg(M_FATAL, "IPv6 pool size is too small (%d), must be at least 2",
+                pool->ipv6.size);
+        }
+
         msg(D_IFCONFIG_POOL, "IFCONFIG POOL IPv6: base=%s size=%d netbits=%d",
             print_in6_addr(pool->ipv6.base, 0, &gc), pool->ipv6.size,
             ipv6_netbits);