From patchwork Thu Feb 13 15:36:14 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Perret X-Patchwork-Id: 13973562 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 7B3F6C021A0 for ; Thu, 13 Feb 2025 16:09:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:Mime-Version:Date:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; 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d=google.com; s=20230601; t=1739460977; x=1740065777; darn=lists.infradead.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=yY1niH8bXpIvQxfdtYMW2hEB9nSt1maMeFqvo9y07nE=; b=xZU6uhjNLy7ucU+8XEyR3XIfUW/bPfpPd/oRIgO/NgKTBmUlkd6RzUWTncfNNXjvcF iiXS16j6lZOwqAWo1XkxT4S3PPeHuMqvbrG3rIysD8oHbRiCtOG/FV2+rELBngLsP7z8 Z8C2jREfmNBfuVWhXum1+Paz3O9+OP8dNr+eMZGpP4ysVKOERbmrKohydr+G9b3s+dY+ 9FNV46TnFIVKl2nhM9pQlD+RhLfiIntfXn24wEVf7XpcDq+9s3kmQ0ThRbSyM/AtIzdC fZNhGVQEpDsL628NLAzpjRY9x+iyTqQPCQUt139EQPHk3DR4yFPIqJGd8kTkGMzbsCJA pfTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739460977; x=1740065777; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=yY1niH8bXpIvQxfdtYMW2hEB9nSt1maMeFqvo9y07nE=; b=Tt/xDMX6qtoMWrKDfgSKct0raJr8B0NRygWSvXQdJ0Or2q0vtzZc4m21m2nzb68/t3 fG+duADDm5M3Vypl+CxjtVWdMUPP2RQB7JCBdgMZ3HoE4//fBH+/X7Q46qJHxQEegIrr 1HhOqK08mCIJ5iKDD0i7LHVF1R8+OmVV4/WKsjQHwKAJrSKHv4TpmPqh4kZVOiLUM/U8 fV23B79/YloBHk2/WH2ZztNoRrOlHBXIuKOGmd5fHzg+iChrBIlFD+LRQRC9clsgM+4e SGG/t3MGlSh0XcDPHbkirIu6jzXZYx+ZPpCKmMWvNYifX24uCnH0frsdVzbWWbOsnlOI Hclg== X-Forwarded-Encrypted: i=1; AJvYcCXODmRNSVbfSrFaRWkSBajDn34SVOAgM/ErfQBWu6XWO4wA0NBjOwu2THiXlOreGbOa4tMiFAZbMFbRQ5yNekOf@lists.infradead.org X-Gm-Message-State: AOJu0Ywo+ZcHcVx5ClBxdV2aSWkBfO6mGzbCm6cL2Y2f1alVcmOazzd2 y+jtziKy1EocpzhXscuVeCZ+SIOQaGg61XPw0jWY3fMGQerypa9c6bzlAtbVj7ffLMQTdD0Uosk 20/CceQ== X-Google-Smtp-Source: AGHT+IGNnBpl+X2qDDZkAqsl1W2uWg0qrWcC8MQ3Hvm0c9bsOTfUcxx6R0kvEkmQWiyS31Y+rdhEd3ntyWG8 X-Received: from ejkk8.prod.google.com ([2002:a17:906:32c8:b0:ab7:bfda:26f5]) (user=qperret job=prod-delivery.src-stubby-dispatcher) by 2002:a17:906:730f:b0:aae:fd36:f511 with SMTP id a640c23a62f3a-aba501a9d85mr376452566b.47.1739460976992; Thu, 13 Feb 2025 07:36:16 -0800 (PST) Date: Thu, 13 Feb 2025 15:36:14 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.48.1.502.g6dc24dfdaf-goog Message-ID: <20250213153615.3642515-1-qperret@google.com> Subject: [PATCH] KVM: arm64: Fix alignment of kvm_hyp_memcache allocations From: Quentin Perret To: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon Cc: Keir Fraser , Ben Simner , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250213_073619_750230_D6098645 X-CRM114-Status: GOOD ( 11.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When allocating guest stage-2 page-table pages at EL2, pKVM can consume pages from the host-provided kvm_hyp_memcache. As pgtable.c expects zeroed pages, guest_s2_zalloc_page() actively implements this zeroing with a PAGE_SIZE memset. Unfortunately, we don't check the page alignment of the host-provided address before doing so, which could lead to the memset overrunning the page if the host was malicious. Fix this by simply force-aligning all kvm_hyp_memcache allocations to page boundaries. Fixes: 60dfe093ec13 ("KVM: arm64: Instantiate guest stage-2 page-tables at EL2") Reported-by: Ben Simner Signed-off-by: Quentin Perret --- arch/arm64/include/asm/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7cfa024de4e3..d9db6dfbad09 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -100,7 +100,7 @@ static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc, static inline void *pop_hyp_memcache(struct kvm_hyp_memcache *mc, void *(*to_va)(phys_addr_t phys)) { - phys_addr_t *p = to_va(mc->head); + phys_addr_t *p = to_va(mc->head & PAGE_MASK); if (!mc->nr_pages) return NULL;