From patchwork Thu May 16 18:18:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 32722 Received: (qmail 82600 invoked by alias); 16 May 2019 18:18:32 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 82592 invoked by uid 89); 16 May 2019 18:18:31 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-19.1 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, SPF_HELO_PASS autolearn=ham version=3.3.1 spammy=HX-Languages-Length:1011 X-HELO: mx1.redhat.com From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH] nss_dns: Check for proper A/AAAA address alignment Date: Thu, 16 May 2019 20:18:27 +0200 Message-ID: <87imuas1os.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 2019-05-16 Florian Weimer * resolv/nss_dns/dns-host.c (getanswer_r): Be more explicit about struct in_addr/struct in6_addr alignment. diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c index 9c15f25f28..9c40051aff 100644 --- a/resolv/nss_dns/dns-host.c +++ b/resolv/nss_dns/dns-host.c @@ -947,8 +947,15 @@ getanswer_r (struct resolv_context *ctx, linebuflen -= nn; } - linebuflen -= sizeof (align) - ((u_long) bp % sizeof (align)); - bp += sizeof (align) - ((u_long) bp % sizeof (align)); + /* Provide sufficient alignment for both address + families. */ + enum { align = 4 }; + _Static_assert ((align % __alignof__ (struct in_addr)) == 0, + "struct in_addr alignment"); + _Static_assert ((align % __alignof__ (struct in6_addr)) == 0, + "struct in6_addr alignment"); + linebuflen -= align - ((u_long) bp % align); + bp += align - ((u_long) bp % align); if (__glibc_unlikely (n > linebuflen)) goto too_small;