From nobody Thu Dec 18 20:18:25 2025 Received: from mail-ej1-f73.google.com (mail-ej1-f73.google.com [209.85.218.73]) (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 ACF421CEEBB for ; Thu, 13 Feb 2025 15:36:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739460981; cv=none; b=jOtu5gNQPgh49MJReZiuF9+ObEmHHVBHLLM7aLpLU5oKpAPWbmb0Df7tU+fn+Odc2yRdaexGe0ucnwYa/MkVk3xRwzpMSqyN9Algt+S9znkVRc1XrV87tCj5EPfWoPQyiXy4ceekNkSsRFtPUYkhE/YcbmMyiq9VQWTrOoIg9hk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739460981; c=relaxed/simple; bh=rUUmr1qKa0raoRIrehordGqRHzgfGvgm6PX24wnH2XI=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=X6U0BjIpkTH7sJEyPG9d6MAoQUuOTeGxoPDXWMBPGbZRjgTm++bSmHhDlyKZUSMhMNj6LFGP1G21zhoTqOTy0L8PC1/X+C5gB1R3/4fLa6D2g5bCKEVMaQi+JwTAdrmiob+fp2BsgL/e7DRd+a8ifP3Q8taveGvWN4SLBTo3PE8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--qperret.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=gHi5+LjJ; arc=none smtp.client-ip=209.85.218.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--qperret.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gHi5+LjJ" Received: by mail-ej1-f73.google.com with SMTP id a640c23a62f3a-ab39f65dc10so126026766b.1 for ; Thu, 13 Feb 2025 07:36:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1739460977; x=1740065777; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=yY1niH8bXpIvQxfdtYMW2hEB9nSt1maMeFqvo9y07nE=; b=gHi5+LjJ7N5vxzSNkNrM+6Ugu2Jj/m1kWQlmxkhSZFgOmKWUCoqawpPRM0W7rcTUl/ zqc9gt6LRHY6WGm3vBkcs3RvyLs+QThYHg8Ye6VHrs0sKHP4FzQqXtIdknlJ9hwPh5Tr 0NZtc2/8LynfTEMHERNmSVAF2QZfcQkLkiBU9VgOVeSM+w0rYAzDDJfvpwv7OzEf3gIh qVfXty4YEcQSFXJ3CNt9vbV3R2GX3iH6Sankf2dValhDeCPLmu0LkKV/AKAPpjolRa1V uqXXDIL+Viy2nxIzzsst/RcHahIRFZqwk4G/jGnZJvzkXzn4anOHQ3dSwvKukJg9GUF8 xjiw== 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=eLr8xfTdxrhEQAdt22cHQnax319CPx0iRI87z/tTmjTyl1+tqEeYS4v88/DB+MbvN+ ZpvLcs1zWmxq+E8XnGsuSxdIRxTgy/Oev/wEWGaMGMyuwXPjheOSCQT7Obc8lmQq0Q52 FbcSb5GCxaJihLt+Nphna3//gD+1207ebT6e1STqo+Q6o1Z/ClVlqk0G0+xh2CT9a0Sz c5986nbNCdF25cRMOblQOC/Hc0aAM3zWoKHwsUuwRfYC/J77PPn3o4oLbxgNpUAmn60h pbH2/wb+zqMK/XhfNLVYVzG9q+uMl3/zaU0lCBGxpP1hRhCXVaHGE5j5K/ldrVGr9d3s 6YgQ== X-Forwarded-Encrypted: i=1; AJvYcCVH4Akc1m0WGAAt0tB9SNUw8JM04U2O1U4l9XOZm7whT7oQ/hpfKCGWBqCQzErheJnQorC1xIP7Ns7sago=@vger.kernel.org X-Gm-Message-State: AOJu0YwAxYnkP3Hab3D4XxU/DFjl9yyymYrCYT2TIMydX/K0rxTe5tCH fLDsvsro5Yzif94WDK3rmj656zALdW0dssLq5ZgofgU1zJzVrm/ywZUqsOFoX4KE6Aa7FNaGb5f 9TecMrA== 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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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_mem= cache *mc, static inline void *pop_hyp_memcache(struct kvm_hyp_memcache *mc, void *(*to_va)(phys_addr_t phys)) { - phys_addr_t *p =3D to_va(mc->head); + phys_addr_t *p =3D to_va(mc->head & PAGE_MASK); =20 if (!mc->nr_pages) return NULL; --=20 2.48.1.502.g6dc24dfdaf-goog