When a dhcp server responds with a domain name that ends with a ".",
domain name validation is failing which leads to populating domain bad in
resolv.conf
Domain name ending with . is a valid syntax according RFC-1034.
The Patch fixes the domain name validation which ends with "."
The test results are as follows:
1. if DNS server returns with domain name "foo.test.com." , resolv.conf
gets populated with "domain foo.test.com."
2. if DNS server returns with domain name "foo.test.com" , resolv.conf gets
populated with "domain foo.test.com"
Without this Patch:
1. if DNS server returns with domain name "foo.test.com." , resolv.conf
gets populated with "domain bad <http://foo.test.com>"
2. if DNS server returns with domain name "foo.test.com" , resolv.conf gets
populated with "domain foo.test.com"
From 3b87f7407f2be34e1f3da1a17c0da20b64626704 Mon Sep 17 00:00:00 2001
From: Balaji Punnuru <balaji_punn...@cable.comcast.com>
Date: Wed, 3 Feb 2016 13:07:26 -0500
Subject: [PATCH] networking: Fixed issue with domain name validation in dhcp
response.
Details: In Some instances where DNS Servers sends out domain name
in answer with a terminating ".", the validation logic for
domain name is returning as bad domain.
According to RFC 1034 Section 3.1, a character string
which represents a complete domain name(often called "absolute").
For example, "poneria.ISI.EDU."
The fix done is to add a check for end of string after
processing node which allows for presence of "." at the end of the string
Signed-off-by: Balaji Punnuru <balaji_punn...@cable.comcast.com>
---
networking/udhcp/dhcpc.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 915f659..3d5b245 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -201,6 +201,18 @@ static int good_hostname(const char *name)
//Do we want this?
//return ((name - start) < 1025); /* NS_MAXDNAME */
name++;
+ /*
+ According to RFC 1034, section 3.1, trailing dots is allowed,
+
+ Quoting from RFC 1034:
+ ----------------------
+ The most common interpretation uses the root "." as either the
+ single origin or as one of the members of the search list, so
+ a multi-label relative name is often one where the trailing dot
+ has been omitted to save typing.
+ */
+ if (*name == '\0')
+ return 1;
}
}
#else
--
2.1.4
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