From patchwork Tue Jan 23 00:27:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526682 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 BB624C47DDF for ; Tue, 23 Jan 2024 00:37:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 69FB710F1C5; Tue, 23 Jan 2024 00:37:26 +0000 (UTC) Received: from mail-pl1-f174.google.com (mail-pl1-f174.google.com [209.85.214.174]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4A2B810F1C2 for ; Tue, 23 Jan 2024 00:37:23 +0000 (UTC) Received: by mail-pl1-f174.google.com with SMTP id d9443c01a7336-1d7354ba334so18317195ad.1 for ; Mon, 22 Jan 2024 16:37:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970183; x=1706574983; 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=uuAginudDA34iqBrsX+BzE2nEMittQE6YVsuxv2qKnM=; b=L8M8Ho0mGJs/TesXNB9lwhLtkGU+zsjRN79foQ0tZL8B0WX/pkqhOjtYvtR/2oMik+ dZbzoBPtb7Iac0IoMsuFlBgjd2celhjeuKc5ToPmGyYNijCcun4rTw5wpljNBpx1sNmv NcOJt8nQJ/Yi7m5/nVLclmiC8BHaSYkxcU/mc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970183; x=1706574983; 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=uuAginudDA34iqBrsX+BzE2nEMittQE6YVsuxv2qKnM=; b=utgnMWummVPRDlpuMWCSuAOMVyXk37CF1y5EQUk9XA6ORo7OZdwHZ7pyC0eJd8j+Ye GjhdnNRmP6Xm5Jvl+htQySFElaouc6QfyufW8CoDrj5aNXgGll28qpHaM5xJL76VnyrS jxkHpmcyFxJM4QSz+ja6G2rNck6O7hqKEcSy08F3893AOuNkZrKBCW92qO24rhlidnvR fx2WyUA5bfhv6847uCBQQ5uldMo4qj9OhUYQWOqNjyOgQgOiTkkN0Il63L1xrAlb2P4T zn/sEEvoDaLio2jtIozuPAXO8O7Q6TueYCpJxu0zrJukSXrs1KRILtcwN65ijq8iE5YO Hm9g== X-Gm-Message-State: AOJu0Yxe1Glcrs14OmsrbU8FgyzGLgleVHqyPbJorikNr3tVlGyU1sWm 3WS5L+tF2BQrAj5iYPxtBH60ke9kTusz11DEbXwbsA45BmSURNHgcnUpv+jCbyeJnhJXkYDT/O4 = X-Google-Smtp-Source: AGHT+IHmJXE2ED2RuBUmR0soC9ICbU5uc/OdRD47vxh5aPLnNlxEs/5VczOR/qkUIL16NOENMz9+bA== X-Received: by 2002:a17:902:8216:b0:1d6:c8e3:c3dd with SMTP id x22-20020a170902821600b001d6c8e3c3ddmr4942676pln.54.1705970183007; Mon, 22 Jan 2024 16:36:23 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id l12-20020a170902e2cc00b001d70af5be17sm7341961plc.229.2024.01.22.16.36.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:36:18 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Subject: [PATCH 36/82] agp: Refactor intentional wrap-around test Date: Mon, 22 Jan 2024 16:27:11 -0800 Message-Id: <20240123002814.1396804-36-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240122235208.work.748-kees@kernel.org> References: <20240122235208.work.748-kees@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1899; i=keescook@chromium.org; h=from:subject; bh=TtGEKwfEht79ULnpSVJcOtpH1GzIiQlRdhb7ZdKErag=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgH4FFulwi6BUqjbAU5ENVQabX98Dt2rrVoU 8g3IEj955KJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBwAKCRCJcvTf3G3A JnjyEACxi6nRzG/TeUzgA19psicAHgLDAObP0xBS4txCdCyuwD6vql4dHmloNCeJb8mV6QVHM+X qtG2DBYHCOfOAx2qlY4HvaVOj3PS5bcfXi6Ekv9oHApUiv9VATvsHzJMWgozbnrtd+ct/kzn1a8 fdEqTsjCD1glzm7trq2UhSUjq7L9mf0ALUL92dfVjQVOuW3SJ9kkPuGgKtP6JPssetdPnVNENjg XGHgUvZbr7FjFWIbhVzk+QWvKkDn9x87RdguxM3yRMNuIU1rIPChiFeHt65F/fM9e/r6JWSqDYJ 28GyQyB9g35uGguB023JwJmsj9WljHMy92O0442XwofQsjSwDoKiP6XK1wSn7N+Ko+xF+yXuo8D aGTAXPJpuMFj3tqUwX0bCJ2y/hZb9LGM68ygSkbs93I9XePUe38ehnUMIKTYBoC/PaH9cZiUO6O WpdtUG+wfYRGfiUetrFcgMqg7lc0bO2mieV7z8f1+ggx/2d+E2Yn9c//8JCWB6dDf3AOuNluFkl TPJTxjpslLZOCOHw60ZZVUW2p1qaNmoLXFmR7hSnVJuahaP/u15jWcSK2aizZflJKuj9uo7I/Jr iZ5+yDhNuVtMJrnevFhrq9ZhFajoLgGALCe41lhJERcPe3APaldrX8Abs0cIpjFwV5xN1XNAYND z2z1RVstb0xjjDA== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 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: , Cc: Kees Cook , Greg Kroah-Hartman , "Gustavo A. R. Silva" , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Bill Wendling , Justin Stitt , David Airlie Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" In an effort to separate intentional arithmetic wrap-around from unexpected wrap-around, we need to refactor places that depend on this kind of math. One of the most common code patterns of this is: VAR + value < VAR Notably, this is considered "undefined behavior" for signed and pointer types, which the kernel works around by using the -fno-strict-overflow option in the build[1] (which used to just be -fwrapv). Regardless, we want to get the kernel source to the position where we can meaningfully instrument arithmetic wrap-around conditions and catch them when they are unexpected, regardless of whether they are signed[2], unsigned[3], or pointer[4] types. Refactor open-coded wrap-around addition test to use add_would_overflow(). This paves the way to enabling the wrap-around sanitizers in the future. Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] Link: https://github.com/KSPP/linux/issues/26 [2] Link: https://github.com/KSPP/linux/issues/27 [3] Link: https://github.com/KSPP/linux/issues/344 [4] Cc: Greg Kroah-Hartman Cc: David Airlie Cc: dri-devel@lists.freedesktop.org Signed-off-by: Kees Cook --- drivers/char/agp/generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c index 3ffbb1c80c5c..fc2d07654154 100644 --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -228,7 +228,7 @@ struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge, cur_memory = atomic_read(&bridge->current_memory_agp); if ((cur_memory + page_count > bridge->max_memory_agp) || - (cur_memory + page_count < page_count)) + (add_would_overflow(page_count, cur_memory))) return NULL; if (type >= AGP_USER_TYPES) {