From patchwork Wed May 1 15:41:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 13650960 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 4CD6DC4345F for ; Wed, 1 May 2024 15:43:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4571210F6FB; Wed, 1 May 2024 15:43:23 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.b="OTk6T7Xo"; dkim-atps=neutral Received: from mail-pf1-f169.google.com (mail-pf1-f169.google.com [209.85.210.169]) by gabe.freedesktop.org (Postfix) with ESMTPS id ED97610F157 for ; Wed, 1 May 2024 15:43:21 +0000 (UTC) Received: by mail-pf1-f169.google.com with SMTP id d2e1a72fcca58-6edb76d83d0so5978460b3a.0 for ; Wed, 01 May 2024 08:43:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1714578200; x=1715183000; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=IqSRaJ+I/NgAMp1CRzQlMWp8eVTN4Fv5wLPbhbxPoyI=; b=OTk6T7XoqBocFosoR1dUNJ2RAaesv93u8u19owPSKR9WVG1iVb1FA4uBBjyIeFyEpW /kHuThZU13hPXd0PKK6TXoCu4tlwOjzoeLXBQ49DO1D+INbaSo95yhNi+RBth5dFRBWB pPt7flWdcGbo5Chkip8ZMFlDmNrFp1V1ZAoPU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714578200; x=1715183000; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=IqSRaJ+I/NgAMp1CRzQlMWp8eVTN4Fv5wLPbhbxPoyI=; b=pWCnewYQtuXdr/+nfe70S35IhK1sITGg7y60ik1dtdAj+3ekqHzpWiOHSAc2FsUT1r BXWEWIiNZq1B3FOgIA9yvQ8EtOU0/SZrB6/veHx4XV4PyTALdCyTFFXJw1PfihOk+dok OYepq9/Xj0WC/ZiQ4dyKX9xBTqM86U/+bA3anvxx1V0IqZf/0LzCr1vSUhrkCDwbDfMN hRPbDHOtW2C1hGpQWrMG/DPyysPE/ZC0JoRddItRdr/4qzElOD6JJ/zFWLtIW3SQArHP A9f+LMdzDOiidjt8px07OQ2GKJJfqk/nusSxN2tmVC+JWcEttzR+Z8AYdkYfovl4R6In 9SyQ== X-Gm-Message-State: AOJu0YzDVah6CEO368Pe+QkL3knSjhF3iN3KmZyJVI+WF4FdcXw1mzi0 Ac4qUj4g53amWHFLu8b1eomENjRLx4U0fs3BaIP72UviuDrgSQzai9j1uqCfeHDR3Nl/IT4QvuI = X-Google-Smtp-Source: AGHT+IFI0XRKl4xlF9oA6mVlSbPDXsPwloqxxCaCX7TyGbZ6xYS649sCJKaSQ+96XKkEBKOMHdGtmg== X-Received: by 2002:a05:6a20:2593:b0:1a9:8251:41ba with SMTP id k19-20020a056a20259300b001a9825141bamr3504545pzd.51.1714578200409; Wed, 01 May 2024 08:43:20 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2620:15c:9d:2:e886:8de:19a2:55b0]) by smtp.gmail.com with ESMTPSA id fb12-20020a056a002d8c00b006f3ec69bc09sm7717924pfb.75.2024.05.01.08.43.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 May 2024 08:43:19 -0700 (PDT) From: Douglas Anderson To: dri-devel@lists.freedesktop.org Cc: Linus Walleij , Jani Nikula , Dmitry Baryshkov , Cong Yang , Hsin-Yi Wang , Brian Norris , Sam Ravnborg , Neil Armstrong , Javier Martinez Canillas , Joel Selvaraj , lvzhaoxiong@huaqin.corp-partner.google.com, Douglas Anderson , Daniel Vetter , David Airlie , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , linux-kernel@vger.kernel.org Subject: [PATCH v3 1/9] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_dcs_write_seq() Date: Wed, 1 May 2024 08:41:04 -0700 Message-ID: <20240501084109.v3.1.I30fa4c8348ea316c886ef8a522a52fed617f930d@changeid> X-Mailer: git-send-email 2.45.0.rc0.197.gbae5840b3b-goog In-Reply-To: <20240501154251.3302887-1-dianders@chromium.org> References: <20240501154251.3302887-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The mipi_dsi_dcs_write_seq() macro makes a call to mipi_dsi_dcs_write_buffer() which returns a type ssize_t. The macro then stores it in an int and checks to see if it's negative. This could theoretically be a problem if "ssize_t" is larger than "int". To see the issue, imagine that "ssize_t" is 32-bits and "int" is 16-bits, you could see a problem if there was some code out there that looked like: mipi_dsi_dcs_write_seq(dsi, cmd, <32767 bytes as arguments>); ...since we'd get back that 32768 bytes were transferred and 32768 stored in a 16-bit int would look negative. Though there are no callsites where we'd actually hit this (even if "int" was only 16-bit), it's cleaner to make the types match so let's fix it. Fixes: 2a9e9daf7523 ("drm/mipi-dsi: Introduce mipi_dsi_dcs_write_seq macro") Signed-off-by: Douglas Anderson Reviewed-by: Neil Armstrong Reviewed-by: Linus Walleij --- Changes in v3: - Use %zd in print instead of casting errors to int. Changes in v2: - New include/drm/drm_mipi_dsi.h | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h index 82b1cc434ea3..70ce0b8cbc68 100644 --- a/include/drm/drm_mipi_dsi.h +++ b/include/drm/drm_mipi_dsi.h @@ -333,18 +333,18 @@ int mipi_dsi_dcs_get_display_brightness_large(struct mipi_dsi_device *dsi, * @cmd: Command * @seq: buffer containing data to be transmitted */ -#define mipi_dsi_dcs_write_seq(dsi, cmd, seq...) \ - do { \ - static const u8 d[] = { cmd, seq }; \ - struct device *dev = &dsi->dev; \ - int ret; \ - ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); \ - if (ret < 0) { \ - dev_err_ratelimited( \ - dev, "sending command %#02x failed: %d\n", \ - cmd, ret); \ - return ret; \ - } \ +#define mipi_dsi_dcs_write_seq(dsi, cmd, seq...) \ + do { \ + static const u8 d[] = { cmd, seq }; \ + struct device *dev = &dsi->dev; \ + ssize_t ret; \ + ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); \ + if (ret < 0) { \ + dev_err_ratelimited( \ + dev, "sending command %#02x failed: %zd\n", \ + cmd, ret); \ + return ret; \ + } \ } while (0) /**