From nobody Fri Dec 19 14:35:19 2025 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B87D3BBF7 for ; Fri, 26 Apr 2024 23:59:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714175948; cv=none; b=j33qkRLJKy7zopBr8o3RgRMTewxcx6F6VBdOoQiREfz/ocXteVMf7LZTpmOUSvemaOwK/98bAQxMY5Re3dLgVJnhku+7SAefmTzN2l6W+fIqf9wz3GPeqauyuWFs+gi/2mUImvHti+hSp62zQYMWw3/x7t1vywSHEqwn3pWV/H8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714175948; c=relaxed/simple; bh=pjcvWuzCy6xoTHSAqk88pHgPJcX+90n8EGDGZPTH4b4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dO6HohEpUU41zY113e31wIjdUgNy2qfYIh5/gwbn1PtAc7uz/0XE4avZ0JqufsDzynbZjKKNnRomGBTXXt/pZwCX4EaGMjvltHA9Tv4i9w7fNYFOI2i4IbPtdvGloe54bDy7YOTIAxCO9iLz3ejEkLsGdL/z8zTSJdqh8I6E5uY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=OfM7t9HQ; arc=none smtp.client-ip=209.85.216.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="OfM7t9HQ" Received: by mail-pj1-f42.google.com with SMTP id 98e67ed59e1d1-2a55a3d0b8eso1991360a91.1 for ; Fri, 26 Apr 2024 16:59:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1714175947; x=1714780747; darn=vger.kernel.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=yeW0pSyEBhS0ojeIyWBVzu7M8GLRFtARAotr9ut3TYg=; b=OfM7t9HQDyxMxmzxmHClkOP4Ik3WvzSl/qFYsmNQ9h3prM4oFE92pn9IXX6zncuerK FkFEiv3lGxHy6IP/dey0qeYuVDcOcwgs0nNg9FSbPKDZmsuOkroyyMhKj4nedA8k0LkS xB83gCpr38MThJStJw/PneomVQw9OIceVTFWc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714175947; x=1714780747; 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=yeW0pSyEBhS0ojeIyWBVzu7M8GLRFtARAotr9ut3TYg=; b=lHoebaq681A09aKjWFcnGk0CMU4r2QDnEB8fsgL2q0UT4oic0U1sPGbLT0ltudCXBh /HW4blA80idguWaCZ9H1n727ZvarDNzOnwE1Z+6OvNFKOLNxCikZUgdpsKDG1fqi1dfv j3t3G3qwkVH5aHR+C0bdTvxcalh7LxZ1lG/WXK55VYLwQ/FdLBrsJitDQwbIrnX92elr Qo2gXzfMPzIv8hXlLCJM/n8JvZeFTxHuVtr8HPlgV6DehgXZGDVe5aMQ/TzE++253B4O mFVWwz9J9E+mDnbdBJRofRH8jw7L2VI+Yk6ugywvA1q/rM939V9v2mbKNImLb/YlWXQH wUKw== X-Forwarded-Encrypted: i=1; AJvYcCXONRyeOnYudwAsi4cWuDvlffw+qLryIRMMqmSPK8cNdQjGRq+A/AsZGiqxe8ILYBXfNSZ5Sxu0AlowFS7ZSe/GuPW1VvKCgSH4yyUZ X-Gm-Message-State: AOJu0YyftyR7B3IVRfXbyaE5tm+/1TDeM+cMGXrAB6AicyTy5L/2ywnt wam0vw3P+AoEmfk6V5IC1yAujWjTTMt9UCPrXIqnQfeI8kvWNUP0N5k0HqOL3g== X-Google-Smtp-Source: AGHT+IH6XTJ9QQDWPzgo8X8I8bDLXm7/WGqdQG4aZWPTMylSuC2+pMH0ddw57O7ZuDywVmWBbG/TSg== X-Received: by 2002:a17:90a:1f88:b0:2aa:8130:e3eb with SMTP id x8-20020a17090a1f8800b002aa8130e3ebmr1501128pja.11.1714175946787; Fri, 26 Apr 2024 16:59:06 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2620:15c:9d:2:fca:3ae2:20e6:82bb]) by smtp.gmail.com with ESMTPSA id n4-20020a17090aab8400b002af41bd563esm5111939pjq.33.2024.04.26.16.59.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Apr 2024 16:59:06 -0700 (PDT) From: Douglas Anderson To: dri-devel@lists.freedesktop.org Cc: Linus Walleij , lvzhaoxiong@huaqin.corp-partner.google.com, Jani Nikula , Hsin-Yi Wang , Javier Martinez Canillas , Neil Armstrong , Joel Selvaraj , Dmitry Baryshkov , Cong Yang , Sam Ravnborg , Douglas Anderson , Daniel Vetter , David Airlie , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , linux-kernel@vger.kernel.org Subject: [PATCH v2 1/8] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_dcs_write_seq() Date: Fri, 26 Apr 2024 16:58:34 -0700 Message-ID: <20240426165839.v2.1.I30fa4c8348ea316c886ef8a522a52fed617f930d@changeid> X-Mailer: git-send-email 2.44.0.769.g3c40516874-goog In-Reply-To: <20240426235857.3870424-1-dianders@chromium.org> References: <20240426235857.3870424-1-dianders@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 --- Changes in v2: - New include/drm/drm_mipi_dsi.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h index 82b1cc434ea3..b3576be22bfa 100644 --- a/include/drm/drm_mipi_dsi.h +++ b/include/drm/drm_mipi_dsi.h @@ -337,12 +337,12 @@ int mipi_dsi_dcs_get_display_brightness_large(struct = mipi_dsi_device *dsi, do { \ static const u8 d[] =3D { cmd, seq }; \ struct device *dev =3D &dsi->dev; \ - int ret; \ + ssize_t ret; \ ret =3D 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); \ + cmd, (int)ret); \ return ret; \ } \ } while (0) --=20 2.44.0.769.g3c40516874-goog