net-dns/djbdns: 1.05-r40

Work around local receive overflow bug.

Bug: https://bugs.gentoo.org/932846
Signed-off-by: Jaco Kroon <jaco@uls.co.za>
Closes: https://github.com/gentoo/gentoo/pull/36841
Signed-off-by: Viorel Munteanu <ceamac@gentoo.org>
This commit is contained in:
Jaco Kroon
2024-05-27 16:37:52 +02:00
committed by Viorel Munteanu
parent 208c21eb43
commit b938f9f9a9
3 changed files with 190 additions and 0 deletions

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@@ -0,0 +1,143 @@
# Copyright 1999-2024 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
inherit flag-o-matic readme.gentoo-r1 toolchain-funcs
DESCRIPTION="Collection of DNS client/server software"
HOMEPAGE="https://cr.yp.to/djbdns.html"
IPV6_PATCH="test32"
SRC_URI="https://cr.yp.to/djbdns/${P}.tar.gz
https://smarden.org/pape/djb/manpages/${P}-man.tar.gz
ipv6? ( https://www.fefe.de/dns/${P}-${IPV6_PATCH}.diff.xz )"
LICENSE="public-domain"
SLOT="0"
KEYWORDS="~alpha ~amd64 ~hppa ~mips ~ppc ~ppc64 ~sparc ~x86"
IUSE="ipv6 selinux"
RDEPEND="
acct-user/dnscache
acct-user/dnslog
acct-user/tinydns
sys-apps/ucspi-tcp
virtual/daemontools
selinux? ( sec-policy/selinux-djbdns )"
src_unpack() {
# Unpack both djbdns and its man pages to separate directories.
default
# Now move the man pages under ${S} so that user patches can be
# applied to them as well in src_prepare().
mv "${PN}-man" "${P}/man" || die "failed to transplant man pages"
}
PATCHES=(
"${FILESDIR}/dnsroots.patch"
"${FILESDIR}/dnstracesort.patch"
"${FILESDIR}/string_length_255.patch"
"${FILESDIR}/srv_record_support.patch"
"${FILESDIR}/increase-cname-recustion-depth.patch"
"${FILESDIR}/CVE2009-0858_0001-check-response-domain-name-length.patch"
"${FILESDIR}/CVE2012-1191_0001-ghost-domain-attack.patch"
"${FILESDIR}/AR-and-RANLIB-support.patch"
"${FILESDIR}/tinydns-softlimit.patch"
"${FILESDIR}/${PN}-dnscache-configurable-truncate-manpages.patch"
)
src_prepare() {
if use ipv6; then
PATCHES=(${PATCHES[@]}
# The big ipv6 patch.
"${WORKDIR}/${P}-${IPV6_PATCH}.diff"
# Fix CVE2008-4392 (ipv6)
"${FILESDIR}/CVE2008-4392_0001-dnscache-merge-similar-outgoing-queries-ipv6-test32.patch"
"${FILESDIR}/CVE2008-4392_0002-dnscache-cache-soa-records-ipv6-test29.patch"
"${FILESDIR}/${PN}-dnscache-configurable-truncate-size-v6.patch"
"${FILESDIR}/${PN}-udp-overflow-response-buffer-truncate-v6.patch"
)
else
PATCHES=(${PATCHES[@]}
"${FILESDIR}/implicit-declarations-nov6.patch"
# Fix CVE2008-4392 (no ipv6)
"${FILESDIR}/CVE2008-4392_0001-dnscache-merge-similar-outgoing-queries-r1.patch"
"${FILESDIR}/CVE2008-4392_0002-dnscache-cache-soa-records.patch"
# Later versions of the ipv6 patch include this
"${FILESDIR}/${PV}-errno-r1.patch"
"${FILESDIR}/${PN}-dnscache-configurable-truncate-size-nov6.patch"
"${FILESDIR}/${PN}-udp-overflow-response-buffer-truncate-nov6.patch"
)
fi
default
# Change "head -X" to the posix-compatible "head -nX" within the
# Makefile. We do this with sed instead of a patch because the ipv6
# patch uses some of the surrounding lines; we'd need two versions
# of the patch.
sed -i Makefile \
-e 's/head[[:space:]]\{1,\}\-\([0-9]\{1,\}\)/head -n\1/g' \
|| die 'failed to sed head in the Makefile'
}
src_compile() {
# Bug 927539. This is beyond our ability to realistically fix due
# to patch conflicts.
append-cflags $(test-flags-CC -Wno-error=incompatible-pointer-types)
echo "$(tc-getCC) ${CFLAGS}" > conf-cc || die
echo "$(tc-getCC) ${LDFLAGS}" > conf-ld || die
echo "/usr" > conf-home || die
emake AR=$(tc-getAR) RANLIB=$(tc-getRANLIB)
}
src_install() {
insinto /etc
doins dnsroots.global
into /usr
dobin *-conf dnscache tinydns walldns rbldns pickdns axfrdns \
*-get *-data *-edit dnsip dnsipq dnsname dnstxt dnsmx \
dnsfilter random-ip dnsqr dnsq dnstrace dnstracesort
if use ipv6; then
dobin dnsip6 dnsip6q
fi
dodoc CHANGES README
doman man/*.[158]
readme.gentoo_create_doc
}
DISABLE_AUTOFORMATTING=1
DOC_CONTENTS='
To configure djbdns, please follow the instructions at,
http://cr.yp.to/djbdns.html
Of particular interest are,
axfrdns : http://cr.yp.to/djbdns/axfrdns-conf.html
dnscache: http://cr.yp.to/djbdns/run-cache-x-home.html
tinydns : http://cr.yp.to/djbdns/run-server.html
Portage has created users for axfrdns, dnscache, and tinydns; the
commands to configure these programs are,
1. axfrdns-conf tinydns dnslog /var/axfrdns /var/tinydns $ip
2. dnscache-conf dnscache dnslog /var/dnscache $ip
3. tinydns-conf tinydns dnslog /var/tinydns $ip
(replace $ip with the ip address on which the server will run).
If you wish to configure rbldns or walldns, you will need to create
those users yourself (although you should still use the "dnslog"
user for the logs):
4. rbldns-conf $username dnslog /var/rbldns $ip $base
5. walldns-conf $username dnslog /var/walldns $ip
'

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--- djbdns-1.05.o/dns_transmit.c 2001-02-11 23:11:45.000000000 +0200
+++ djbdns-1.05/dns_transmit.c 2024-05-27 16:25:11.857369652 +0200
@@ -265,9 +265,9 @@
if (errno == error_connrefused) if (d->udploop == 2) return 0;
return nextudp(d);
}
- if (r + 1 > sizeof udpbuf) return 0;
if (irrelevant(d,udpbuf,r)) return 0;
+ if ((size_t)r + 1 > sizeof udpbuf) return firsttcp(d); /* if udp overflowed, retry with TCP */
if (serverwantstcp(udpbuf,r)) return firsttcp(d);
if (serverfailed(udpbuf,r)) {
if (d->udploop == 2) return 0;

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Deal with local recv() truncation.
In the case where an upstream cache sends a UDP response that would overflow
the djb cache's default receive buffer, then djbdns would treat this as an
invalid response. The norm nowadays is the send >512b UDP responses,
especially for TXT RRs. It looks like up to around 4KB is deemed acceptable in
most cases I've investigated.
So, in the case where we locally end up reciving a truncated packet by way of
recv() because the local UDP buffer is too small, treat that like the TC bit
was set, because really we can know the response was truncated.
Therefor check the irrelevant (inappropriate response) data first, then if the
buffer was fully received (it might be that the response fits exactly, but
short of parsing this buffer there is no simple way to confirm this, so just
assume it's unlikely to get an exact sized buffer back and retry using TCP
anyway). Yes, this is a waste of resources in this specific case, but so be
it.
Signed-off-by: <jaco@uls.co.za>
--- djbdns-1.05.o/dns_transmit.c 2024-05-27 13:20:25.788463090 +0200
+++ djbdns-1.05/dns_transmit.c 2024-05-27 14:13:38.786335627 +0200
@@ -266,9 +266,9 @@
if (errno == error_connrefused) if (d->udploop == 2) return 0;
return nextudp(d);
}
- if ((size_t)r + 1 > sizeof udpbuf) return 0;
if (irrelevant(d,udpbuf,r)) return 0;
+ if ((size_t)r + 1 > sizeof udpbuf) return firsttcp(d); /* if udp overflowed, retry with TCP */
if (serverwantstcp(udpbuf,r)) return firsttcp(d);
if (serverfailed(udpbuf,r)) {
if (d->udploop == 2) return 0;