From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/12012 Path: news.gmane.org!.POSTED!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general,gmane.comp.security.oss.general Subject: CVE request: musl libc 1.1.16 and earlier dns buffer overflow Date: Thu, 19 Oct 2017 16:17:57 -0400 Message-ID: <20171019201757.GA31838@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1508444298 31811 195.159.176.226 (19 Oct 2017 20:18:18 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 19 Oct 2017 20:18:18 +0000 (UTC) User-Agent: Mutt/1.5.21 (2010-09-15) Cc: Felix Wilhelm , musl@lists.openwall.com To: oss-security@lists.openwall.com Original-X-From: musl-return-12025-gllmg-musl=m.gmane.org@lists.openwall.com Thu Oct 19 22:18:14 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1e5HGW-0006O7-MZ for gllmg-musl@m.gmane.org; Thu, 19 Oct 2017 22:18:04 +0200 Original-Received: (qmail 1863 invoked by uid 550); 19 Oct 2017 20:18:10 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 1820 invoked from network); 19 Oct 2017 20:18:09 -0000 Content-Disposition: inline Original-Sender: Rich Felker Xref: news.gmane.org gmane.linux.lib.musl.general:12012 gmane.comp.security.oss.general:23448 Archived-At: Felix Wilhelm has discovered a flaw in the dns response parsing for musl libc 1.1.16 that leads to overflow of a stack-based buffer. Earlier versions are also affected. When an application makes a request via getaddrinfo for both IPv4 and IPv6 results (AF_UNSPEC), an attacker who controls or can spoof the nameservers configured in resolv.conf can reply to both the A and AAAA queries with A results. Since A records are smaller than AAAA records, it's possible to fit more addresses than the precomputed bound, and a buffer overflow occurs. Users are advised to upgrade to 1.1.17 or patch; the patch is simple and should apply cleanly to all recent versions: https://git.musl-libc.org/cgit/musl/patch/?id=45ca5d3fcb6f874bf5ba55d0e9651cef68515395 Users who cannot patch or upgrade immediately can mitigate the issue by running a caching nameserver on localhost and pointing resolv.conf to 127.0.0.1. Rich