From patchwork Tue Jan 23 00:27:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526687 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) (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 5AE5B5822E for ; Tue, 23 Jan 2024 00:35:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970159; cv=none; b=Xfe6OU2/HzeO5UXztAsZqelYgzcuVw0K5RwQMgP9LCXsrxYUu34XocWtpsbVbWbJyG2BxQ8aAMugYUXMCwhkTawXwlFqKotN+YpgieO03CQZBDfuCpInTesKd+2PIsyoEzSgDLWNbcKkouIxe3qJ8lCOXG4BYIKTMoijNtY1XuU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970159; c=relaxed/simple; bh=NqZesPGdhPMPIXo9vzbA31ktFf0tGVVn+vj19wjCjyg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=mHwHmrFUXxNgxHDWjncc5lelNRPetvOlxhiUszv2P2aih+KwQa0qLcNplpiOWJoINgBwJsFm9NNEvgLo+qN6cMJ3Uws6my/04WmafgH1u6bjMqxudtpBoULn/zLZA5lpDlyxjzDKViwt25FBBqoGyzdzGX71O2PF0T8siCA1LSo= 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=Q88LuU0a; arc=none smtp.client-ip=209.85.210.173 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="Q88LuU0a" Received: by mail-pf1-f173.google.com with SMTP id d2e1a72fcca58-6dbe5014eb5so888052b3a.0 for ; Mon, 22 Jan 2024 16:35:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970158; x=1706574958; 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=ug/eJpZr5lllg7fGddUawSE71HAAShvEy2mnfZ3dSCI=; b=Q88LuU0aCSdlMIjPCD+2vN4/TKC4zvp5U9k4fGRAOAl/oKS80yxBw8KPyg3uri24yx d+4zNimaNpDjwKiC9iqJUbdfelVkQl/AlM00ynYs9RIKVP0oLp/P+6w6UVHlPSQdg34w /SdaeMsd6/On8+6dUiUn9cmSOvrcLOHav46Nk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970158; x=1706574958; 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=ug/eJpZr5lllg7fGddUawSE71HAAShvEy2mnfZ3dSCI=; b=upCGm4FtOZsXTEatNXicZU+hU35ln1bwCsXqioCHBq3mn1H1svtv9R4N+vs/6nYZYy 3KgyI9T+5tUvjd0ggV09wXLQ4mEpBN156/+QwxQ5EohFEVrHq7fEbSF2zKoOX8wfVqHB BasX1UwYEe9ww5DrHOiRmU7UjAhtTTRrF5d6VEPlNeLGnb5Wr2LCxh7er0TjudaplNVm LUoeTnF7aGdNAqq2C6dQDe+fZF45dyzdxAKMchNhwl+RRcaajncoJikd6ytANq+9F82M cJBjvCyTgxq7sENqnSevoJ8SjkgqSkAzXaSbEqND4LPK682K0Dh27l7rEHGzU9Ai7Nbk kPEw== X-Gm-Message-State: AOJu0YzGLGH9pe8wRG5ckNZ3faxgzIhaz7xwuOCe1p3xbfL7GoY6taOu rWgLMD3VpUa9cK/GHJnE282O5p6UIKLAMQXMVuraRFAAKo2Ofb6reZ6E9cC38Q== X-Google-Smtp-Source: AGHT+IGbHO8F/hVPNAS+cYdBXp0aETE+5zl8nFoMOWvMrZu0haS/FCh6jw4MqmTh+lKcIiTOdQpn4w== X-Received: by 2002:a17:903:189:b0:1d5:c77c:1bad with SMTP id z9-20020a170903018900b001d5c77c1badmr3603424plg.111.1705970157756; Mon, 22 Jan 2024 16:35:57 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id ki12-20020a170903068c00b001d739667fc3sm3599795plb.207.2024.01.22.16.35.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:35:55 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , virtualization@lists.linux.dev, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 77/82] virtio: Refactor intentional wrap-around test Date: Mon, 22 Jan 2024 16:27:52 -0800 Message-Id: <20240123002814.1396804-77-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-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2234; i=keescook@chromium.org; h=from:subject; bh=NqZesPGdhPMPIXo9vzbA31ktFf0tGVVn+vj19wjCjyg=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgMtLBZT/T1zFr3Pk7LIqHdfeKoLB+DZJ6nU eJpFhVGy+SJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IDAAKCRCJcvTf3G3A Jr4wD/wNabBI/0k3KRp2JIInEpH4vZHXxi+YXYN1Q6ldFb4lgheY70n+09zwS5YCFmaS7Phow0q sQ3NGqc/LMQu52WIyo9eugQ66X+NsHyvKquukfCdLtx9jSzToGbIYd3DB7x1EEPHipoH7lvtgRD nHtsh3kq/C+p70AybGlMydqgrrPNb1DfboeLRz6rxhIfDmWVI5kH+L5Z0ZNxYR3cZC1UOdz2GsH KtsEbUpmOKyh2q+iG4Y4H4OtA819vV908Jkbrzzo666no9Hz7D2Hjobm86ELfkhgFZa1vC6CEDk 8U6VsHqeS46f14sFovFnBkEUS94+Z6gIjrvogisCPd9R3N9fV9/0WsPm5aNbWjXhHnCEkAV2gEB aEHMvQSF+FMpizGRzlqkGgFJMIN3SlKmVZH7t/ukK0Lc4kmSKkRYvqf8JMnlbdjnpruwRJf7K+J s2JFixwTZjankT9R4zLLM/lfaoqTW626q9FqA+biBMk7J+INeZZ8mXCYTmjch3KoF7TCRQW0Ix5 cZXEgUMIySr4lY4yafH6qxLzcfXHPLJPd5D38PR+eEu8djg/Lnn9abNdmb3uTneMPskrwx2EaH4 PL3NCneQumc5tifvlHneHC5q0YWKR5J4nwuLNsc3GN0YIAGrN2jiQuCqADn3NM/LbxnUwX7Jsxw lLlz7iPwOj69EMA== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 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: "Michael S. Tsirkin" Cc: Jason Wang Cc: Xuan Zhuo Cc: virtualization@lists.linux.dev Signed-off-by: Kees Cook Reviewed-by: Eugenio Pérez --- drivers/virtio/virtio_pci_modern_dev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c index 0d3dbfaf4b23..710d3bd45b4f 100644 --- a/drivers/virtio/virtio_pci_modern_dev.c +++ b/drivers/virtio/virtio_pci_modern_dev.c @@ -59,7 +59,7 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, length -= start; - if (start + offset < offset) { + if (add_would_overflow(offset, start)) { dev_err(&dev->dev, "virtio_pci: map wrap-around %u+%u\n", start, offset); @@ -81,7 +81,7 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, if (len) *len = length; - if (minlen + offset < minlen || + if (add_would_overflow(minlen, offset) || minlen + offset > pci_resource_len(dev, bar)) { dev_err(&dev->dev, "virtio_pci: map virtio %zu@%u "