From patchwork Mon Oct 17 17:37:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 13009182 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 58F9FC43217 for ; Mon, 17 Oct 2022 17:42:30 +0000 (UTC) Received: from localhost ([::1]:48892 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1okU8B-0001Se-V3 for qemu-devel@archiver.kernel.org; Mon, 17 Oct 2022 13:42:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35688) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1okU3W-00087E-F1 for qemu-devel@nongnu.org; Mon, 17 Oct 2022 13:37:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:41328) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1okU3S-0003Xx-Rj for qemu-devel@nongnu.org; Mon, 17 Oct 2022 13:37:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666028253; 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=M7m1sAW0B7/XBcnTsrnF2OIn4+D5WPTlfN5770bIApk=; b=BnhTInBQ8PbuxIeSkj3owJYYV4//TamoYckHh8wxjK5ZFVFEocRlZjzlGUD9BaOwqMHrsI TqM3SMwEgF4KVJP9oIekzct+qkz0j//MzpUOnNraFNAlRb98nXy5nzZUJ9CqVmsR5Qyy3F FLP3H2K0ad5D12M6nnpzegl8Hq1NLeo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-444-nkU9b4ejNjKVlc8FWko3Jg-1; Mon, 17 Oct 2022 13:37:30 -0400 X-MC-Unique: nkU9b4ejNjKVlc8FWko3Jg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3CFA3802C17; Mon, 17 Oct 2022 17:37:30 +0000 (UTC) Received: from green.redhat.com (unknown [10.2.16.89]) by smtp.corp.redhat.com (Postfix) with ESMTP id AED03C15BA5; Mon, 17 Oct 2022 17:37:29 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Cc: "Dr . David Alan Gilbert" , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org (open list:Network Block Dev...) Subject: [PATCH] nbd/server: Use smarter assert Date: Mon, 17 Oct 2022 12:37:27 -0500 Message-Id: <20221017173727.1246179-1-eblake@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.255, 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Assigning strlen() to a uint32_t and then asserting that it isn't too large doesn't catch the case of an input string 4G in length. Thankfully, the incoming string can never be that large: if the export name is reflecting what the client asked about, we already guarantee that we drop the NBD connection if the client tries to send more than 32M in a single NBD_OPT_* request; and if the export name is coming from qemu, nbd_receive_negotiate() asserted that strlen(info->name) <= NBD_MAX_STRING_SIZE. Still, it doesn't hurt to be more explicit in how we write our assertion that we are aware that no wraparound is possible. Fixes: 93676c88 ("nbd: Don't send oversize strings", v4.2.0) Reported-by: Dr. David Alan Gilbert Signed-off-by: Eric Blake Reviewed-by: Dr. David Alan Gilbert --- nbd/client.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/nbd/client.c b/nbd/client.c index 60c9f4941a..b601ee97e5 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -658,7 +658,7 @@ static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt, char *p; data_len = sizeof(export_len) + export_len + sizeof(queries); - assert(export_len <= NBD_MAX_STRING_SIZE); + assert(strlen(export) <= NBD_MAX_STRING_SIZE); if (query) { query_len = strlen(query); data_len += sizeof(query_len) + query_len;