From patchwork Tue Mar 29 11:01:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 11544 Received: (qmail 73225 invoked by alias); 29 Mar 2016 11:01:22 -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 73216 invoked by uid 89); 29 Mar 2016 11:01:21 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00, KAM_LAZY_DOMAIN_SECURITY, RP_MATCHES_RCVD, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=C_IN, anslen, T_PTR, sk:2eb2f67 X-HELO: mx1.redhat.com To: GNU C Library From: Florian Weimer Subject: [PATCH] CVE-2016-3075: Stack overflow in _nss_dns_getnetbyname_r [BZ #19879] Message-ID: <56FA607D.4070803@redhat.com> Date: Tue, 29 Mar 2016 13:01:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 This is a minor security issue in nss_dns, triggered by a very long name passed to getnetbyname. The defensive copy is not needed because the name may not alias the output buffer. Florian 2016-03-29 Florian Weimer [BZ #19879] CVE-2016-3075 * resolv/nss_dns/dns-network.c (_nss_dns_getnetbyname_r): Do not copy name. diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c index 2eb2f67..8f301a7 100644 --- a/resolv/nss_dns/dns-network.c +++ b/resolv/nss_dns/dns-network.c @@ -118,17 +118,14 @@ _nss_dns_getnetbyname_r (const char *name, struct netent *result, } net_buffer; querybuf *orig_net_buffer; int anslen; - char *qbuf; enum nss_status status; if (__res_maybe_init (&_res, 0) == -1) return NSS_STATUS_UNAVAIL; - qbuf = strdupa (name); - net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024); - anslen = __libc_res_nsearch (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf, + anslen = __libc_res_nsearch (&_res, name, C_IN, T_PTR, net_buffer.buf->buf, 1024, &net_buffer.ptr, NULL, NULL, NULL, NULL); if (anslen < 0) {