netdev - [PATCH v2 3/8] ipconfig: BOOTP: Don't request IEN-116 name servers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 24 Apr 2018 03:56:34 +0100
From:   Chris Novakovic <chris@...isn.me.uk>
To:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Cc:     Chris Novakovic <chris@...isn.me.uk>
Subject: [PATCH v2 3/8] ipconfig: BOOTP: Don't request IEN-116 name servers

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() allocates 8 bytes for tag 5 ("Name
Server" [1, §3.7]), but tag 5 in the response isn't processed by
ic_do_bootp_ext(). Instead, allocate the 8 bytes to tag 6 ("Domain Name
Server" [1, §3.8]), which is processed by ic_do_bootp_ext(), and appears
to have been the intended tag to request.

This won't cause any breakage for existing users, as tag 5 responses
provided by BOOTP servers weren't being processed anyway.

[1] RFC 2132, "DHCP Options and BOOTP Vendor Extensions":
    https://tools.ietf.org/rfc/rfc2132.txt

Signed-off-by: Chris Novakovic <chris@...isn.me.uk>
---
 net/ipv4/ipconfig.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index d0ea0ecc9008..bcf3c4f9882d 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -721,7 +721,7 @@ static void __init ic_bootp_init_ext(u8 *e)
 	*e++ = 3;		/* Default gateway request */
 	*e++ = 4;
 	e += 4;
-	*e++ = 5;		/* Name server request */
+	*e++ = 6;		/* (DNS) name server request */
 	*e++ = 8;
 	e += 8;
 	*e++ = 12;		/* Host name request */
-- 
2.14.1