Dear Simon,
server=//1.2.3.4 can be used to specify a server to be used for
unqualified names. However, if we want to combine this feature with
other domains, the server config option is parsed incorrectly.
A fix is attached.
---
Example 1:
> server=//192.168.2.1
> server=/fritz.box/192.168.2.1
Log:
> Aug 20 13:00:34 dnsmasq[1151247]: using nameserver 192.168.2.1#53 for
> unqualified names (no DNSSEC)
> Aug 20 13:00:34 dnsmasq[1151247]: using nameserver 192.168.2.1#53 for
> domain fritz.box (no DNSSEC)
CORRECT
Example 2:
> server=//fritz.box/192.168.2.1
Log:
> Aug 20 12:33:41 dnsmasq[1147692]: using nameserver 192.168.2.1#53 for
> unqualified names (no DNSSEC)
> Aug 20 12:33:41 dnsmasq[1147692]: using nameserver 192.168.2.1#53 for
> unqualified names (no DNSSEC)
WRONG (not using the server for fritz.box)
Example 3:
> server=/fritz.box//192.168.2.1
Log:
> Aug 20 12:30:27 dnsmasq[1147304]: using nameserver 192.168.2.1#53 for
> domain fritz.box (no DNSSEC)
> Aug 20 12:30:27 dnsmasq[1147304]: using nameserver 192.168.2.1#53
WRONG (uses server for all domains instead of only unqualified)
----
The bug has been introduced about two months ago in
12a9aa7c628e2d7dcd34949603848a3fb53fce9c
The issue is now caused by interpreting the server flags only once. If
// is the first domain, SERV_FOR_NODOTS is set to all domains extracted
from a server config line. If // appears later on, SERV_FOR_NODOTS is
never set, leading to the misinterpretation that server=//192.168.2.1
is the same as server=192.168.2.1.
The attached patch fixes this by adding SERV_FOR_NODOTS *selectively*
for empty domains. It does this only when // is detected.
All three examples work as expected now.
Best,
Dominik
From 1b7420af92f474f18ebb74b960a8cefb7fde70cd Mon Sep 17 00:00:00 2001
From: Dominik DL6ER <dl...@dl6er.de>
Date: Fri, 20 Aug 2021 13:05:35 +0200
Subject: [PATCH] Fix empty domain in server option parsing when more than one
domain is given
Signed-off-by: DL6ER <dl...@dl6er.de>
---
src/option.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/src/option.c b/src/option.c
index 3a87097..ffce9fc 100644
--- a/src/option.c
+++ b/src/option.c
@@ -2700,11 +2700,6 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
{
if ((err = parse_server(arg, &serv_addr, &source_addr, interface, &flags)))
ret_err(err);
-
- /* server=//1.2.3.4 is special. */
- if (strlen(domain) == 0 && lastdomain)
- flags |= SERV_FOR_NODOTS;
-
}
if (servers_only && option == 'S')
@@ -2712,6 +2707,12 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
while (1)
{
+ /* server=//1.2.3.4 is special. */
+ if (strlen(domain) == 0 && lastdomain)
+ flags |= SERV_FOR_NODOTS;
+ else
+ flags &= ~SERV_FOR_NODOTS;
+
if (!add_update_server(flags, &serv_addr, &source_addr, interface, domain, &addr))
ret_err(gen_err);
--
2.25.1
_______________________________________________
Dnsmasq-discuss mailing list
Dnsmasq-discuss@lists.thekelleys.org.uk
https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
