From patchwork Mon Sep 4 11:52:43 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: 1829539 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=BtSFcIkV; dkim-atps=neutral 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 4RfS3Z4NBLz1yhH for ; Mon, 4 Sep 2023 22:04:10 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qd8Bb-0000sh-Be; Mon, 04 Sep 2023 07:56:07 -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 1qd8BZ-0000ph-8T for qemu-devel@nongnu.org; Mon, 04 Sep 2023 07:56:05 -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 1qd8BX-0000qq-2Z for qemu-devel@nongnu.org; Mon, 04 Sep 2023 07:56:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693828562; 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: in-reply-to:in-reply-to:references:references; bh=tjGC2ML3L2cd08LhzVrXNPJbEDWvTfhWKeJntBP1e6U=; b=BtSFcIkV6D72tnZuWGhrHHEAFRAHIxiaTVVntT7DCzdczvhKezbMditRjiyd/iR36crUtK JQdVA+w8Rkmk0rb2EThcWkblLWSbiNUOQSJPBx//qTG/p6b8Ssyb1wo4dK56yKoBBzkjJN A8g70T13C10DAJhRj+ulWixaUJmK0JM= 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-88-NbbM8DGbNgu22cgBSfmu8Q-1; Mon, 04 Sep 2023 07:56:01 -0400 X-MC-Unique: NbbM8DGbNgu22cgBSfmu8Q-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0427410264C1; Mon, 4 Sep 2023 11:56:01 +0000 (UTC) Received: from localhost (unknown [10.39.208.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 318AA2013570; Mon, 4 Sep 2023 11:55:59 +0000 (UTC) From: marcandre.lureau@redhat.com To: qemu-devel@nongnu.org Cc: stefanha@redhat.com, Peter Maydell , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , Gerd Hoffmann Subject: [PULL 46/52] ui/vnc-enc-hextile: Use static rather than dynamic length stack array Date: Mon, 4 Sep 2023 15:52:43 +0400 Message-ID: <20230904115251.4161397-47-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 10.11.54.6 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: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_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: Peter Maydell In the send_hextile_tile_* function we create a variable length array data[]. In fact we know that the client_pf.bytes_per_pixel is at most 4 (enforced by set_pixel_format()), so we can make the array a compile-time fixed length of 1536 bytes. 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: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé [ Marc-André - rename BPP to MAX_BYTES_PER_PIXEL ] Signed-off-by: Marc-André Lureau Message-Id: <20230818151057.1541189-3-peter.maydell@linaro.org> --- ui/vnc-enc-hextile-template.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/ui/vnc-enc-hextile-template.h b/ui/vnc-enc-hextile-template.h index 0c56262aff..8ee92086ac 100644 --- a/ui/vnc-enc-hextile-template.h +++ b/ui/vnc-enc-hextile-template.h @@ -7,6 +7,8 @@ #define NAME BPP #endif +#define MAX_BYTES_PER_PIXEL 4 + static void CONCAT(send_hextile_tile_, NAME)(VncState *vs, int x, int y, int w, int h, void *last_bg_, @@ -25,10 +27,13 @@ static void CONCAT(send_hextile_tile_, NAME)(VncState *vs, int bg_count = 0; int fg_count = 0; int flags = 0; - uint8_t data[(vs->client_pf.bytes_per_pixel + 2) * 16 * 16]; + uint8_t data[(MAX_BYTES_PER_PIXEL + 2) * 16 * 16]; int n_data = 0; int n_subtiles = 0; + /* Enforced by set_pixel_format() */ + assert(vs->client_pf.bytes_per_pixel <= MAX_BYTES_PER_PIXEL); + for (j = 0; j < h; j++) { for (i = 0; i < w; i++) { switch (n_colors) { @@ -205,6 +210,7 @@ static void CONCAT(send_hextile_tile_, NAME)(VncState *vs, } } +#undef MAX_BYTES_PER_PIXEL #undef NAME #undef pixel_t #undef CONCAT_I