From patchwork Tue Jan 23 00:26:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526721 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 1E0FA6167B for ; Tue, 23 Jan 2024 00:45:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970759; cv=none; b=DXjUPRqvGGdPR4Afd7rB9ALKbZWxAceHBl6kQw9XLGwgZQ1337mifjNaMtq+Fe0TDwUZUW092uyS2tdAc1MZdZreVVJYdRaOzYtWBlh1FtvokS6Q82XZd3BueWPSJL5dEPovve8v1RB57OJxxVC2ckmUjh1gIpFkqtXC4tBOq0I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970759; c=relaxed/simple; bh=7SK+CeaptbBP/v+CP2JEux9OatqqjJKzGmyq2Voqx04=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=RoxGkoKvrkbjTU0M/kq9K+c0awSphaK5DJc7+9d0M3SwdyMaQV2tEQ5wvf4b98W7XaRaXvJ4E8LZaKs1UbiI4C+UvB8htC8CEuOXw3u8bPAEqbI9338q5EyAF6zL2aYC48/3zv1BS9d1j23KrDv/kwudItoDeiHSfroopryw/hc= 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=NdcyDFzU; arc=none smtp.client-ip=209.85.214.176 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="NdcyDFzU" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-1d7393de183so8820285ad.3 for ; Mon, 22 Jan 2024 16:45:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970757; x=1706575557; 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=iBzwhtxHV7+0pkueVEdOMj16Ew6MX43q2RtCRgBYnfE=; b=NdcyDFzUhvzwX4yoUH4hoUPRRbxPVswsvgSrjYNQ54x5uzW9pV54KelUvXlN97GcLf LKSb1v1TQQEQ1HC134EB+87lJrhokCugQ1IC/LJwPjt0ndO4rBR7kCnNeaKMXfItHDYK HyNNFIBlgVVW+LRphKpcKBrr6QAdLpoZz+XIs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970757; x=1706575557; 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=iBzwhtxHV7+0pkueVEdOMj16Ew6MX43q2RtCRgBYnfE=; b=PhYS5xDFp6YnDp1p0WL/l6GS8yGcuqOrhtzzweoN8fzZtVXMuacOuMHpXHjVj9fYyQ Z5mjDXAUzyzA/wUD7rfaEuV5VV6HIyIhSXtD31C+o2F96l732c0RmxUr1LTw89+wKJ+O 5roo2Bely9a/i4x/N4HW1S7FLNnJjMJ4t/GIahE3TJp5wns554GkZofSsehSuHywChvS qCEfB3GEffWcRx5/FRJQjN1pAgLtl2R3Fjh7a3mo90L0aw6B7EKNYCQO+nipvmU6qYHL YEm3X+YiO70yY3WgumCkaV4RYEkNydrzffwsbzd3fvqCjbuHi0mtHA/JtvpmSrmeEhAd kPVw== X-Gm-Message-State: AOJu0Yw6coIZFgzebEToRwnsY4y4rCOD06VyxjhhIUSCVOdtwF4dsw/G 7nu9Kcnj3oG7ydm01CfScf3b2KWA2n5bRWm9axJEurJWL54e3raLYoFe8ijXLw== X-Google-Smtp-Source: AGHT+IF8yhCmkJNt7Ij2XpjUMJOmTKGRgOFOqqmGAHzjTF1WQ4RIpNJnjNIqKXh4JiYJsFhdhzQmyQ== X-Received: by 2002:a17:903:249:b0:1d7:4f6:931b with SMTP id j9-20020a170903024900b001d704f6931bmr2578303plh.18.1705970757393; Mon, 22 Jan 2024 16:45:57 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id e6-20020a170902784600b001d66b134f53sm8013882pln.233.2024.01.22.16.45.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:45:55 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Paolo Bonzini , kvm@vger.kernel.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 23/82] KVM: Refactor intentional wrap-around calculation Date: Mon, 22 Jan 2024 16:26:58 -0800 Message-Id: <20240123002814.1396804-23-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: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2091; i=keescook@chromium.org; h=from:subject; bh=7SK+CeaptbBP/v+CP2JEux9OatqqjJKzGmyq2Voqx04=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgGMUghWI+PGsPguK5zp1jJTO9Udx8kDt3JM m98iBkuTfCJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBgAKCRCJcvTf3G3A JsIxEACt5a2RN2oZ+4JYd2ymbmpv5B6nOsrUIqOPauBUQY+OHeVN8nMnsBdASH58oAT8jCD9WVQ 7HAb+2ANB08IYc8/R0h6xkBqa2lCZk/3c5dpFUtpIlCTzY+hAfPnj3l7atArhXefRspVNbsJft8 hYD5qHs7sMR4xnQPCwbKLBjLn46735BXMxnSYAn9JYVGEL740vCDkxpqmQgFiSX23MaRZDi2p8U v1qhycBB3BSMK6Lo8r85YYSK2XJ9x47dytKFlfuqi371X3bi2J4T1Zmf1zmU0ALDy4G3/NJIlX2 JhbQiOfH98N9+MtqcBMq3RWtHRqVRJsqM4nPVlbzO4D0Z5EKX7HzxzAg+wZOWXOJqZBUflBMu00 jbo8OBTZLfp9yRmymYTGlNNuanwYU4YZpdO9MQx9rvC1YQM+HdtO9YWpu+++sAgjyvdln94rlUO sMJ9ZmFXRxInaysdaafEyQBh06ugVvFdamYsCf6FILZP9XmKMUKSGcyiRVCG0f2brI9Fuyw3SRn cbpJzb9ATyxDFZyuhMI/7g3fuPMKee7yNNoMul1dOGNFcLCtwSAgsgOVJEGFdCgdgXj7MmvUulL ZBQpjnBa8JFB3UeWkmEc5ex6AaaLMKyDaTl9rbXMZXXt2w178+78kcYV5TBWH9Pt2AyakcqiqaQ C0S0f0g8Orqog+w== 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 Notable, 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, unsigned, or pointer types. Refactor open-coded unsigned wrap-around addition test to use check_add_overflow(), retaining the result for later usage (which removes the redundant open-coded addition). This paves the way to enabling the unsigned wrap-around sanitizer[2] in the future. Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] Link: https://github.com/KSPP/linux/issues/27 [2] Cc: Paolo Bonzini Cc: kvm@vger.kernel.org Signed-off-by: Kees Cook --- virt/kvm/coalesced_mmio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c index 1b90acb6e3fe..0a3b706fbf4c 100644 --- a/virt/kvm/coalesced_mmio.c +++ b/virt/kvm/coalesced_mmio.c @@ -25,17 +25,19 @@ static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev) static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev, gpa_t addr, int len) { + gpa_t sum; + /* is it in a batchable area ? * (addr,len) is fully included in * (zone->addr, zone->size) */ if (len < 0) return 0; - if (addr + len < addr) + if (check_add_overflow(addr, len, &sum)) return 0; if (addr < dev->zone.addr) return 0; - if (addr + len > dev->zone.addr + dev->zone.size) + if (sum > dev->zone.addr + dev->zone.size) return 0; return 1; } From patchwork Tue Jan 23 00:27:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526722 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 4E61413D4EA for ; Tue, 23 Jan 2024 00:46:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970767; cv=none; b=O+1nMFCg/TF7QdMw0PtuQJFEVZYUtQ+4Muixak8cFPdOKwkWAkoHzIJLOAqRKLvoKztCXSBzzuieAFRGstGNxqpLrdLMe7HP6P0Odu3ywg6CgaBtxljeHIAOx32Eqy+OhqLLKJnR/LyIfZry9KAlogRD8H51cX6BbIVeL9NkRvk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970767; c=relaxed/simple; bh=afM5LZaCnX07Bbe5JWJGuHF/X6uWMNRJXTDiQd0kjMs=; 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Mon, 22 Jan 2024 16:46:05 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id ji14-20020a170903324e00b001d72d3f9f3fsm4430426plb.104.2024.01.22.16.45.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:46:03 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 25/82] KVM: SVM: Refactor intentional wrap-around calculation Date: Mon, 22 Jan 2024 16:27:00 -0800 Message-Id: <20240123002814.1396804-25-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: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2478; i=keescook@chromium.org; h=from:subject; bh=afM5LZaCnX07Bbe5JWJGuHF/X6uWMNRJXTDiQd0kjMs=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgGUJoQyo2htNqioa5FWNemKH9GelxjiONaI nFBVYcw2o6JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBgAKCRCJcvTf3G3A JqgLEACGR9pBif5bfE/Fp9APHiLwK4tCsaxVu9HuOM4LqZcBVK9RT4sWkLw1sa7ZA399NQJ7xqO qNf67b0E3MBPRFRC0wFggz5dAloMTDb19z7jhsHWDnefmrxf3KKjsEqVe6xhhWIAvfAzGdgi+nc FzQZ1niID+l1yb9LaTvZZHot9lrk5PajrODBYmdYRrMq77eQP5Pb4BHFIZyOHp2UtegxLXzbUC6 0y4bH6GFEO917ps0m47gmJOfX4BMZyrhuzuA11o+q7yKJMTDTgO1aKwWRiTUw+wBGHUExa56zVU CtdNUJy7igPhmA4odmyr620vUPAoSbAf6iIQKgBlro1AWkWuNO02eBJh4nYzFZ+8Ppm8iI+ofqf MIOuQIr6O4nLXLcO9zTWJF/7c3IWPeH1GQF1DcYdSRrmvlpw7k2Yun3kJg4Al6otIViYBTb3Yp8 q8qYZwfcAIjOV3blL0+F494sbI1QpB8KsAaawy2q9I036/tRKMiLFIVnOkUyj838HE6oxhuFgvN njQcjbhVq11/o+7hWYjpCYp7Tk16HpJDJ+BTxbC/RQc/ZTpIHfC6DiItv4snrcHLLzrMKdNGEST uYlkr5Nsq0zN5LBNZDWgRjFbaz2Vq3+EIoxmRJrLfBXZkOXXu0pt15SZhxscXnE7+qDusGqsliB rmYY5X++4rNj3Sw== 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 unsigned wrap-around addition test to use check_add_overflow(), retaining the result for later usage (which removes the redundant open-coded addition). 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: Sean Christopherson Cc: Paolo Bonzini Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: kvm@vger.kernel.org Signed-off-by: Kees Cook --- arch/x86/kvm/svm/sev.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index f760106c31f8..12a6a2b1ac81 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -400,16 +400,17 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr, unsigned long locked, lock_limit; struct page **pages; unsigned long first, last; + unsigned long sum; int ret; lockdep_assert_held(&kvm->lock); - if (ulen == 0 || uaddr + ulen < uaddr) + if (ulen == 0 || check_add_overflow(uaddr, ulen, &sum)) return ERR_PTR(-EINVAL); /* Calculate number of pages. */ first = (uaddr & PAGE_MASK) >> PAGE_SHIFT; - last = ((uaddr + ulen - 1) & PAGE_MASK) >> PAGE_SHIFT; + last = ((sum - 1) & PAGE_MASK) >> PAGE_SHIFT; npages = (last - first + 1); locked = sev->pages_locked + npages; From patchwork Tue Jan 23 00:27:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526720 Received: from mail-oo1-f44.google.com (mail-oo1-f44.google.com [209.85.161.44]) (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 31536612F1 for ; Tue, 23 Jan 2024 00:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970757; cv=none; b=Wv5mwuI/YgmoeaghTHq+Y06JwGWotstT6lVkCGsTcaPCoRh6xTPFcjwDuKD4uvu8jyz5BBlYIC+Bw3Ljn45X3faKIoDotuSPM7Vt6LedslZBXkQYKPBTQLVct4FKl4+R5cKbiDMiuJGiM48JvgKxygt8XO9dcXJO3eNv7jVHTK8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970757; c=relaxed/simple; bh=wEJz6ncP+qRtXKX7k2D+joSrafVF4O5OSdQFr3cojK4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=oLBLCXQDu/zxeKe11MnT+LmuI/1qiIHdDRr+z7KqwQ4n3V87KpZ2Y5m1HA48ZIVHiUlAONILUR99LpE9MxeWYDkScDailtBXmOxLiBlrzV2oNbwYTGETN03maGGL00AV2Xar0iXN27FTL3XLieGiQvf1p+QE4uqLtIy5OLfJ1hE= 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=G3Lo3qW7; arc=none smtp.client-ip=209.85.161.44 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="G3Lo3qW7" Received: by mail-oo1-f44.google.com with SMTP id 006d021491bc7-599a5266066so54703eaf.1 for ; Mon, 22 Jan 2024 16:45:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970755; x=1706575555; 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=dOtaS8Q/PpRJgiodelWT3IFfX/962bDrzicKtXvnvo8=; b=G3Lo3qW7qs+sdo6ikHuS/j4yt/01dQGAj9Ib1ApRTJyVwP3IEiI4DgknpJ89s7oXCh aVFUzX2sLjVajlDTA9YmvkTVVJVylqhmBNcZV7VzqZKuSA4tWuWouW9/FkvqsoGjpREQ w6k9tubHuLfMzKDj5I3iOuYTQh5vxAE8WY+q0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970755; x=1706575555; 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=dOtaS8Q/PpRJgiodelWT3IFfX/962bDrzicKtXvnvo8=; b=usw6yuwNv5z2OJWpVc/iKzoKlFshaQM6NNUBrSRSqA1ctmiAfERf6f1aoExJFbeZ9O +qFQxdxow4WlGHUgQsXaDmv1CxVpg9XBSL9IboU2RyVO4fgXTzQulqpG7cQD+UDwDfGu q7AxSSydusNnUntiztGGY7amD05UJICA0DYE2y8pzeIjO/OHXisTgPytUJcl5/MHiXse jAeNutPBofRrfExoNeBel8AwxxBjznYmJmowdERxNUbcgSjQZRat93pQ0os3yOiXvfPf yQl81o/pZ7kZvi5/Zv6lfv0DYtKtVzNa5wehR9yW4DcsJV2qKMXXNgAaBcdIKCQA2Drj K0xw== X-Gm-Message-State: AOJu0YzAf/qsUq98Rd6+09Ey/wgRHy367b4YElxA0NUxQZeO9IGYN/ay xg0xQw/ktai1ClMgnPBr6KWUjZGHayrHpzLBy0+kbmb+gL78W1zpQrDQBpjJwg== X-Google-Smtp-Source: AGHT+IGQwShADBm43GhljCU0u40cOaLZ1q4WsuoH3YKek1HoSlz9pHA07/Hox4IaetxxaQSRrpFeCQ== X-Received: by 2002:a05:6358:99a0:b0:176:3e0d:9910 with SMTP id j32-20020a05635899a000b001763e0d9910mr4500624rwb.0.1705970755199; Mon, 22 Jan 2024 16:45:55 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id g4-20020aa78744000000b006d9bb4400f0sm10234582pfo.88.2024.01.22.16.45.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:45:54 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , "Michael S. Tsirkin" , Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 32/82] vringh: Refactor intentional wrap-around calculation Date: Mon, 22 Jan 2024 16:27:07 -0800 Message-Id: <20240123002814.1396804-32-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: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2682; i=keescook@chromium.org; h=from:subject; bh=wEJz6ncP+qRtXKX7k2D+joSrafVF4O5OSdQFr3cojK4=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgHD0u3YhpYy/8Dc5chh0+01JehokeF1vpzI BT65uKVfgWJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBwAKCRCJcvTf3G3A JpFyEACdChSCT4Y0X47ea6T+PsrgS42Vou9eXn9FDMWCPIbD1kW1gHAFP1FAqkYnEij+0625LYZ 2RtZVv0zZFrtRaGdtFZFQFDJTSr6QNj3uxivVtsmwb1pLXXDnFTFWikADuH5v60qkgSrb2bTZMY knyNpBo6L+ItzkaxgMhFX1rtdBM2iTj2HOYKmNkYIwvxCNExT4h+7TKnDNipWpdd5EwB3nV3F2p 1pExl5eEqmY2Ma6oIf7cypf/bIKRIjUW1Ilre5bbCngLzeYZMqOG35bUlr3WC3w88nu6tYBXolx Erl0eGsiamN+wyuoxNKoT/h+WyXer3JpoxEq/sl38I39B23XaYVff/d+6Suvc+F3tV6jNdbyaem JxwjjNG4ksbLc5PdSetTuaRGyP3xwIiVRJmS3tlng0ghnRbKVS/FFw+qU64g1HMXFJ/qj6Ldypv ORamulyXPJU2FWA/g8/Ld+OnSQn41XCT6619haypc24tpwo9TMSlKhckwkeIgqTxMWBfiha0co8 ANuXzPXBosDOYCZNhGhwsT9JNpMKS9otU4fcb4uoJ2RtASuAmGm82JgroIBM/MhrLeYmlZOwIk4 jIzar8S+YFZz03aIUIiOxVH9cIhd+DZLz1UZb5Pc9SBnZc4u8HlyhSQOPf8eOZtvyR3Q+n8534w TxS3x9dEXm4+h9g== 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 unsigned wrap-around addition test to use check_add_overflow(), retaining the result for later usage (which removes the redundant open-coded addition). This paves the way to enabling the unsigned wrap-around sanitizer[2] 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: kvm@vger.kernel.org Cc: virtualization@lists.linux.dev Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Acked-by: Eugenio Pérez --- drivers/vhost/vringh.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 7b8fd977f71c..07442f0a52bd 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -145,6 +145,8 @@ static inline bool range_check(struct vringh *vrh, u64 addr, size_t *len, bool (*getrange)(struct vringh *, u64, struct vringh_range *)) { + u64 sum; + if (addr < range->start || addr > range->end_incl) { if (!getrange(vrh, addr, range)) return false; @@ -152,20 +154,20 @@ static inline bool range_check(struct vringh *vrh, u64 addr, size_t *len, BUG_ON(addr < range->start || addr > range->end_incl); /* To end of memory? */ - if (unlikely(addr + *len == 0)) { + if (unlikely(U64_MAX - addr == *len)) { if (range->end_incl == -1ULL) return true; goto truncate; } /* Otherwise, don't wrap. */ - if (addr + *len < addr) { + if (check_add_overflow(addr, *len, &sum)) { vringh_bad("Wrapping descriptor %zu@0x%llx", *len, (unsigned long long)addr); return false; } - if (unlikely(addr + *len - 1 > range->end_incl)) + if (unlikely(sum - 1 > range->end_incl)) goto truncate; return true; From patchwork Tue Jan 23 00:27:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526633 Received: from mail-pg1-f172.google.com (mail-pg1-f172.google.com [209.85.215.172]) (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 22B1815B0F7 for ; Tue, 23 Jan 2024 00:29:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705969754; cv=none; b=FSaLvaTFNR5nrV6Bxk70U6c33ByNNvqTV1uu38j9YrLVtDKCeSsCe/eXk9A5zXxvMLkcAGFNlexOUXzH80aAz6qhS5OMqV30G2QUdmLi9Nioi3NDv57iTb4bwKkyXAzKHvLHkHyEEXNGiK5PS0h7kuiXVY3+oLQX+QVcdWK5WAk= ARC-Message-Signature: i=1; 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Mon, 22 Jan 2024 16:29:12 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id 4-20020a170902e9c400b001d706e373a9sm7559865plk.292.2024.01.22.16.28.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:29:02 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , David Hildenbrand , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Sven Schnelle , kvm@vger.kernel.org, linux-s390@vger.kernel.org, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 58/82] s390/mm: Refactor intentional wrap-around test Date: Mon, 22 Jan 2024 16:27:33 -0800 Message-Id: <20240123002814.1396804-58-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: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2557; i=keescook@chromium.org; h=from:subject; bh=DQU4joanXRgd1mS+gxXcm4BfbB4iNwIjQJ9FPFqx45U=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgKR1fdbTlXCSNHaLsraY4kCN0NXjk4wrN/9 ptrTecUkUCJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8ICgAKCRCJcvTf3G3A Juo/D/0Rijh7xs7t+z0k5sUC01Phuw7CfMgDm7ealxIpjEnqcPeKLdz3mD2xMlnLAWp8AQgMX7x UsVZepQBCW+mbZNcyaU8P17kkR/DVc7kuurh6A9/qg0Doo0FWrmPWygvxpM4QDhE0BWg+HnMgku n6+MLAW3qZ38qFK2TNKcR1VOhVuLWxTkckPN8Nec/7/x4EA/IrvviqK5ppVmcCCP1kkU6yqRS9V GLUxRZfvGVuFMMnb0GKhKAWo7DZdHEZR5LzYBFF10XJes46hmqVlAymMFxiN7EIxv0ywKkw+/jo nLiBSpXgpdEeNMvEbekQ9g18cBvZowM9RckCdGzvVuhqEE8wlYliS3Cl6xZFQKeDcLXNaS5Iddd l6LypkhXu8RsRGFMSTTeST3NLd2MV50Ak5N7MwlYwztrZhji/SUmMGdL6wI/FRsTLYy80nbrjy8 fyZyR3PPt/w66FT/FbS1YpSxHVHI4lBm2rBauWi2Lt61XzIBNU5xedEqaQEl1dEb4INlRI7CV64 nbqMv8Q+wAg8JFTpkVL0iRqSD8sKKxtAw4q49K9wuS9FmVtOcyDAcXkG7QMZPbW6fnyVYVPSPbY tEhStv2vcp7DGK/BOSTiwcIMprY0XAIyqKXaQ77rYBqq5JxZIOFNPSPAu/upxkCHl+TQQK0n5j7 tszHYawERVCbBMA== 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: Christian Borntraeger Cc: Janosch Frank Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Alexander Gordeev Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Sven Schnelle Cc: kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org Signed-off-by: Kees Cook --- arch/s390/mm/gmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 6f96b5a71c63..977b61ab59f2 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -411,7 +411,7 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len) BUG_ON(gmap_is_shadow(gmap)); if ((to | len) & (PMD_SIZE - 1)) return -EINVAL; - if (len == 0 || to + len < to) + if (len == 0 || add_would_overflow(to, len)) return -EINVAL; flush = 0; @@ -443,7 +443,7 @@ int gmap_map_segment(struct gmap *gmap, unsigned long from, BUG_ON(gmap_is_shadow(gmap)); if ((from | to | len) & (PMD_SIZE - 1)) return -EINVAL; - if (len == 0 || from + len < from || to + len < to || + if (len == 0 || add_would_overflow(from, len) || add_would_overflow(to, len) || from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end) return -EINVAL;