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[209.132.180.67]) by mx.google.com with ESMTP id c18si1123593pls.437.2019.06.20.18.21.44; Thu, 20 Jun 2019 18:21:59 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ICMNVRkN; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726951AbfFUBVK (ORCPT + 99 others); Thu, 20 Jun 2019 21:21:10 -0400 Received: from mail-yw1-f74.google.com ([209.85.161.74]:39034 "EHLO mail-yw1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726928AbfFUBVE (ORCPT ); Thu, 20 Jun 2019 21:21:04 -0400 Received: by mail-yw1-f74.google.com with SMTP id w127so4883146ywe.6 for ; Thu, 20 Jun 2019 18:21:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=knoEDxerDamiS2udwBAyDKB2ttd1lX+80CF4AC/SyM0=; b=ICMNVRkNz9HnJz3EvoIc4iF32ARr2jxl8GgTxe7lk2BN+XJU+KaLeMD/xZw/RUgzBj 2IL4z04wtDp23HqSdMnyrxoaA16Rk6s7u8X92iR3qnSMgGiAALWsSPXk8Rbm5iZf1HFJ AKcA2cV/jHmxmTRZu1LPNcYoeYkmR1BjKdhDUXgEAN2OyQgMW1krbjk+tbEoV/1+MYP5 /Uq42xpHhwGYRr2fefqC2TK7cE5w8u6XMt4GStffGhwP6FZ2bof1USBItw3kW7Kd7giP GHViyL8q45sG3E0i5Do1T6WQHdYVQaRRGdkUud8BrJPUj45c8qJIwU9nXrpeons+BrZ/ k/PQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=knoEDxerDamiS2udwBAyDKB2ttd1lX+80CF4AC/SyM0=; b=g2O7RgEOhd49d/FPTH61wKIanZYGc0k7imZePrvkHnZJ9V6BztxkHmYhxQG74tiBOq 0CkW4Kx3Yf/eYEpIYRTL/0cB2PqhsFeCMb+0krm43g5EnVAYrClBOjUS8eEGhy+fFs98 I4juGXwqZEE81Ptbyw/RMgDZ0QBmzuvS82zGiLGYoN/+6Vbh5scnHthDAh9wyjzwr2Ot PhZFu328Pvf20r4Za9lDvoFTejX+5m7Pml5GUDzS4jWTnUlnKj8JR6b+6791O8Vt4dCJ awexLhHGuTJImrQ5damaYgpRokVnEUeHAD+5D6vsC18zh3HIVuHQoRbh0Gb21PApv1Hr hfSg== X-Gm-Message-State: APjAAAWnsq2d0p4/EWoCEINOSLW60UVo8eSf4vuE8XyxV7xd48zEYyKd uNrSdQYtYEWB8DPkgkHUhbIuQuWeEn1RC8sMG6A/Fw== X-Received: by 2002:a81:590a:: with SMTP id n10mr7812986ywb.187.1561080063114; Thu, 20 Jun 2019 18:21:03 -0700 (PDT) Date: Thu, 20 Jun 2019 18:19:41 -0700 In-Reply-To: <20190621011941.186255-1-matthewgarrett@google.com> Message-Id: <20190621011941.186255-31-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190621011941.186255-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH V33 30/30] efi: Restrict efivar_ssdt_load when the kernel is locked down From: Matthew Garrett To: jmorris@namei.org Cc: linux-security@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Matthew Garrett , Matthew Garrett , Ard Biesheuvel , linux-efi@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org efivar_ssdt_load allows the kernel to import arbitrary ACPI code from an EFI variable, which gives arbitrary code execution in ring 0. Prevent that when the kernel is locked down. Signed-off-by: Matthew Garrett Cc: Ard Biesheuvel Cc: linux-efi@vger.kernel.org --- drivers/firmware/efi/efi.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 55b77c576c42..a9ea649e0512 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -31,6 +31,7 @@ #include #include #include +#include #include @@ -242,6 +243,9 @@ static void generic_ops_unregister(void) static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata; static int __init efivar_ssdt_setup(char *str) { + if (security_is_locked_down(LOCKDOWN_ACPI_TABLES)) + return -EPERM; + if (strlen(str) < sizeof(efivar_ssdt)) memcpy(efivar_ssdt, str, strlen(str)); else -- 2.22.0.410.gd8fdbe21b5-goog