From nobody Fri Dec 19 18:53:50 2025 Received: from mail-pf1-f181.google.com (mail-pf1-f181.google.com [209.85.210.181]) (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 6BE187F7C8 for ; Tue, 23 Jan 2024 00:45:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970761; cv=none; b=la9+RPEpxTY3psaQbIMQKTHiA84k6wF5E/qXgiOpYQbmFp9sNswKhUMdFfmPjdGiPKCbpZSLQy950vVBi29YxQChZ/9affwUN1xy5MfhCHTZF26Tlf2ZAh0AZWxDrEiAxQq6okenKSWK3xhZesSg6NS0zGgpaQVFtMlJk7CScoA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970761; c=relaxed/simple; bh=otrmpo4br5ciuWiM78a/Ceyb2KdAR01tXk9aBpC8wMw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Ue6Ael8mh12OQgVnNWVQSBR07G3A2rnrpVhPZ9Dhb1/2z2QQXwA/hn3VTbh4RMNy5hUENFfKVpqriyO8Pd285UEe1UwqWpWVc/exRg3FKejfa5mCKKB07uXy/75dE/HG38/vCVdaneC8y6u+HSR+szn2itXwP1OWskO+USCQ/vg= 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=eisSFIOg; arc=none smtp.client-ip=209.85.210.181 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="eisSFIOg" Received: by mail-pf1-f181.google.com with SMTP id d2e1a72fcca58-6da9c834646so3761176b3a.3 for ; Mon, 22 Jan 2024 16:45:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970759; x=1706575559; 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=S7qeKC064ZzlHJa5msLrHHdCXg1stkKcC4+dJKmdneQ=; b=eisSFIOg4fJ3vz+bS/iu3KnkrgcvtlmfD/uWTb7T5vEdGsjqRSMe86hoDv4U/tNV+Y 4Vj4tG2KD3+v7KuRhIlPs7aYoprJNO0SANxUOoVQPNyca6DmEvSB9eGQvrL3ij81cGQa r3jFVmpg6E4I3ga+Km1hyGgbM2j2k2pJdlKr8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970759; x=1706575559; 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=S7qeKC064ZzlHJa5msLrHHdCXg1stkKcC4+dJKmdneQ=; b=b6vGJQHej9AO8uaR0i5vWzS7ngbdOKlwhXGnPGp3BNBhMWWxsBpg+n/R91mwWciJpF SODTJbmBrRiymQbd3LZOqJn/12DRVFnVFd1rlgGolC4LeEKnx4UHJheM2xrV8UyZ3r1Q adiTScq3ki5sAODIcc2dIEr+jj3eQSq9XYj9r74WJVJRK7DoqMgpvdIYBklvTXXh12Hk QjBMCqeLL9ZukC5EXsPnI9mqdYr8s541xb3qcgn/dP+UW1nm4ETfKJNxlpGdKuBXikIo 646l1jC3VNor8/LlzLrBntyj6uMW3EVx/IguNJqq+Demhp5fOHKS23Xge7ohOszTzS0+ fBHA== X-Gm-Message-State: AOJu0Yw9ktbjWF1paXcYkqLDX50iDjkm0ZRfWICQG2kn8jQzeOOf4tnc TpCAwuRINfAHztIG9ol2EpTxWXs2ZCU9RIiZJxlmKSjzR6RVOYRa205xrz094w== X-Google-Smtp-Source: AGHT+IEfPSCAfbNkrsnvfNR/6lrRJTvzZ8aFbU2AhLJiZvXczWMg97ditkNX3fZkM39QiMucgiQfyA== X-Received: by 2002:a05:6a21:32a2:b0:19c:30a5:5c54 with SMTP id yt34-20020a056a2132a200b0019c30a55c54mr4120604pzb.28.1705970758815; Mon, 22 Jan 2024 16:45:58 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id dj11-20020a17090ad2cb00b0029051dad730sm7733772pjb.26.2024.01.22.16.45.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:45:57 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Christian Brauner , Andrew Morton , "Eric W. Biederman" , Dave Chinner , Alexey Gladkov , Jeff Layton , Waiman Long , "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 82/82] mqueue: Refactor intentional wrap-around test Date: Mon, 22 Jan 2024 16:27:57 -0800 Message-Id: <20240123002814.1396804-82-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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2072; i=keescook@chromium.org; h=from:subject; bh=otrmpo4br5ciuWiM78a/Ceyb2KdAR01tXk9aBpC8wMw=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgMplzxY/SLj9+bxbGPriiBi7drTq3OXWSJm svPwIQ44g2JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IDAAKCRCJcvTf3G3A JkmCEACY37o5F1LgKmBQ/X+GY7t3DI3LwjJCZxndVTmZbmKfVSOia2DA4d7XI1UV1bLDavheiOD ZspAXfK1XmENeXellFyMfyPquNHRcsarUQ1eWVcWnrDOE0opNQOc0QFe+6R8uveX/n9ivxN6Wa1 hOaIRaYdtaG0pl0/p61larNEe0AnWHy+RtEMHuE39N9gWCpwcPqHoA5mCo1dxrD2K2uh/qlF7ES OzWJchorCRsC5GNs9Ui0GFKsf6zpgZU/FyCbyLayRLUF4nfFP2LiO3h9b6WRp0vltQF54wKsTNu KqLuPuvIO0elWbihDwdLbI8EutfMxrfBmbbk7MzP7yL8iwl37lrpoXTKwF75rDVE1n9y0I33Z3e kbO+/3Rj0fjARWduA04Taqd3iu+/l1YaEl+sm0k+KsXXpau+AtqNR9KyrfyBDpM8DRtqXNx8mvs P4VT9g7ZVTJqargqoTFlGh5dcyq+u0cZGRvguOrlRuIGifiAE6HPv46NzI8V4HCRdFKqGQ/5XR3 guih4Ak2DS4ygw8ba5mwnBdRsQiwDjfWRY9xwAc10W8T4ZikUx8/kDV0HnL2+ZQNa1zKFuQvnaK AnAki/aXhT0xQPUk4ZlJRdVZJ1v3xn7aOA4UscmWvvlFVA4Yj7/ScJZKtoGdQI2rcgZYM6BAU97 FairA3wiIkm3Fdw== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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: Christian Brauner Cc: Andrew Morton Cc: "Eric W. Biederman" Cc: Dave Chinner Cc: Alexey Gladkov Cc: Jeff Layton Cc: Waiman Long Signed-off-by: Kees Cook --- ipc/mqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 5eea4dc0509e..7ef9d325183a 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -366,7 +366,7 @@ static struct inode *mqueue_get_inode(struct super_bloc= k *sb, min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * sizeof(struct posix_msg_tree_node); mq_bytes =3D info->attr.mq_maxmsg * info->attr.mq_msgsize; - if (mq_bytes + mq_treesize < mq_bytes) + if (add_would_overflow(mq_bytes, mq_treesize)) goto out_inode; mq_bytes +=3D mq_treesize; info->ucounts =3D get_ucounts(current_ucounts()); --=20 2.34.1