From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4638FC433E0 for ; Mon, 22 Jun 2020 21:05:25 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 104B220732 for ; Mon, 22 Jun 2020 21:05:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gKa+gBUR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 104B220732 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59734 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jnTd6-0005sz-6f for qemu-devel@archiver.kernel.org; Mon, 22 Jun 2020 17:05:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41760) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jnTc1-0005AX-1q for qemu-devel@nongnu.org; Mon, 22 Jun 2020 17:04:17 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:45831 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jnTbv-00016E-Oc for qemu-devel@nongnu.org; Mon, 22 Jun 2020 17:04:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592859847; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=opzLvPn5lD5JPlLnywj6CYVVvKoY68BQvzOdTgUlnLc=; b=gKa+gBURlg+yxzkWSpogfSDOLHJNfNgWMUr+4R3UpZ7GHzR4qdQbp6jRgNfGrq34CzNobt HnLbroPhglZeqswB08q7u7rjkM2qA1y+VEMLvvCM2snic/Ac+U1/L/TN0XYnW9pMzlSm3p 8sGjjEfdy7yWTsU38x34Djf8te5u41U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-444-Hshe4TSYPuKM03AE4S-j8Q-1; Mon, 22 Jun 2020 17:04:05 -0400 X-MC-Unique: Hshe4TSYPuKM03AE4S-j8Q-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8AAA91009615; Mon, 22 Jun 2020 21:04:02 +0000 (UTC) Received: from blue.redhat.com (ovpn-114-4.phx2.redhat.com [10.3.114.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 93C1F5C661; Mon, 22 Jun 2020 21:03:57 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PATCH] nbd: Avoid off-by-one in long export name truncation Date: Mon, 22 Jun 2020 16:03:55 -0500 Message-Id: <20200622210355.414941-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/22 01:27:42 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , vsementsov@virtuozzo.com, "open list:Network Block Dev..." , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When snprintf returns the same value as the buffer size, the final byte was truncated to ensure a NUL terminator. Fortunately, such long export names are unusual enough, with no real impact other than what is displayed to the user. Fixes: 5c86bdf12089 Reported-by: Max Reitz Signed-off-by: Eric Blake --- block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index eed160c5cda1..8301fcac0589 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -2009,7 +2009,7 @@ static void nbd_refresh_filename(BlockDriverState *bs) len = snprintf(bs->exact_filename, sizeof(bs->exact_filename), "nbd://%s:%s", host, port); } - if (len > sizeof(bs->exact_filename)) { + if (len >= sizeof(bs->exact_filename)) { /* Name is too long to represent exactly, so leave it empty. */ bs->exact_filename[0] = '\0'; } -- 2.27.0