This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH] nss_dns: Do not replace root domain with empty string
- From: Carlos O'Donell <codonell at redhat dot com>
- To: Florian Weimer <fweimer at redhat dot com>, libc-alpha at sourceware dot org
- Date: Mon, 8 Apr 2019 10:24:27 -0400
- Subject: Re: [PATCH] nss_dns: Do not replace root domain with empty string
- References: <87ftqspwxm.fsf@oldenburg2.str.redhat.com>
On 4/8/19 7:18 AM, Florian Weimer wrote:
The purpose of the bp[0] == '.' check is unclear. Only the root domain
starts with '.'. An empty string is not a valid domain name, so the
subsequent res_dnok check fails.
Was the intent to *cause* a failure if a root domain was unpacked?
Are you certain res_dnok() fails with the empty string? It looks to me
like ns_name_pton() might work, and so would printable_string(), but
the result is obviously garbage, and may fail later.
Logically the code in question doesn't make any sense from first principles,
therefore I think the deletion is warranted, and that we'll fix any fallout.
I'm OK with it for master.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2019-04-08 Florian Weimer <fweimer@redhat.com>
* resolv/nss_dns/dns-network.c (getanswer_r): Do not replace root
domain with empty string.
* resolv/nss_dns/dns-host.c (getanswer_r): Likewise.
diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index a18b8a6bf4..9c15f25f28 100644
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -706,9 +706,6 @@ getanswer_r (struct resolv_context *ctx,
n = -1;
}
- if (n > 0 && bp[0] == '.')
- bp[0] = '\0';
-
if (__glibc_unlikely (n < 0))
{
*errnop = errno;
diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c
index 4b81b1bfdc..21688c19b2 100644
--- a/resolv/nss_dns/dns-network.c
+++ b/resolv/nss_dns/dns-network.c
@@ -345,9 +345,6 @@ getanswer_r (const querybuf *answer, int anslen, struct netent *result,
n = -1;
}
- if (n > 0 && bp[0] == '.')
- bp[0] = '\0';
-
if (n < 0 || res_dnok (bp) == 0)
break;
cp += n;
--
Cheers,
Carlos.