From patchwork Mon Sep 4 11:52:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marc-Andr=C3=A9_Lureau?= X-Patchwork-Id: 1829514 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RfRvS5vFRz1ygx for ; Mon, 4 Sep 2023 21:57:08 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qd8Bf-0000yI-VU; Mon, 04 Sep 2023 07:56:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qd8Bd-0000vt-Ub for qemu-devel@nongnu.org; Mon, 04 Sep 2023 07:56:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qd8Bb-0000sE-IY for qemu-devel@nongnu.org; Mon, 04 Sep 2023 07:56:09 -0400 Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-266-pR113HOoPLmulbZKm60KnQ-1; Mon, 04 Sep 2023 07:56:05 -0400 X-MC-Unique: pR113HOoPLmulbZKm60KnQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 459752999B2D; Mon, 4 Sep 2023 11:56:05 +0000 (UTC) Received: from localhost (unknown [10.39.208.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 30BB4493110; Mon, 4 Sep 2023 11:56:03 +0000 (UTC) From: marcandre.lureau@redhat.com To: qemu-devel@nongnu.org Cc: stefanha@redhat.com, =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Peter Maydell , Gerd Hoffmann , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= Subject: [PULL 47/52] ui/vnc-enc-tight: Avoid dynamic stack allocation Date: Mon, 4 Sep 2023 15:52:44 +0400 Message-ID: <20230904115251.4161397-48-marcandre.lureau@redhat.com> In-Reply-To: <20230904115251.4161397-1-marcandre.lureau@redhat.com> References: <20230904115251.4161397-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.133.124; envelope-from=marcandre.lureau@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Philippe Mathieu-Daudé Use autofree heap allocation instead of variable-length array on the stack. The codebase has very few VLAs, and if we can get rid of them all we can make the compiler error on new additions. This is a defensive measure against security bugs where an on-stack dynamic allocation isn't correctly size-checked (e.g. CVE-2021-3527). Signed-off-by: Philippe Mathieu-Daudé [PMM: expanded commit message] Signed-off-by: Peter Maydell Reviewed-by: Francisco Iglesias Reviewed-by: Marc-André Lureau Message-Id: <20230818151057.1541189-4-peter.maydell@linaro.org> --- ui/vnc-enc-tight.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/ui/vnc-enc-tight.c b/ui/vnc-enc-tight.c index ee853dcfcb..41f559eb83 100644 --- a/ui/vnc-enc-tight.c +++ b/ui/vnc-enc-tight.c @@ -1097,13 +1097,13 @@ static int send_palette_rect(VncState *vs, int x, int y, switch (vs->client_pf.bytes_per_pixel) { case 4: { - size_t old_offset, offset; - uint32_t header[palette_size(palette)]; + size_t old_offset, offset, palette_sz = palette_size(palette); + g_autofree uint32_t *header = g_new(uint32_t, palette_sz); struct palette_cb_priv priv = { vs, (uint8_t *)header }; old_offset = vs->output.offset; palette_iter(palette, write_palette, &priv); - vnc_write(vs, header, sizeof(header)); + vnc_write(vs, header, palette_sz * sizeof(uint32_t)); if (vs->tight->pixel24) { tight_pack24(vs, vs->output.buffer + old_offset, colors, &offset); @@ -1115,11 +1115,12 @@ static int send_palette_rect(VncState *vs, int x, int y, } case 2: { - uint16_t header[palette_size(palette)]; + size_t palette_sz = palette_size(palette); + g_autofree uint16_t *header = g_new(uint16_t, palette_sz); struct palette_cb_priv priv = { vs, (uint8_t *)header }; palette_iter(palette, write_palette, &priv); - vnc_write(vs, header, sizeof(header)); + vnc_write(vs, header, palette_sz * sizeof(uint16_t)); tight_encode_indexed_rect16(vs->tight->tight.buffer, w * h, palette); break; }