From patchwork Wed Jul 31 22:16:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11069673 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0700F1395 for ; Wed, 31 Jul 2019 22:18:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB22627F17 for ; Wed, 31 Jul 2019 22:18:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DE62027F94; Wed, 31 Jul 2019 22:18:56 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3901A27F17 for ; Wed, 31 Jul 2019 22:18:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728174AbfGaWSt (ORCPT ); Wed, 31 Jul 2019 18:18:49 -0400 Received: from mail-qk1-f202.google.com ([209.85.222.202]:36986 "EHLO mail-qk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731351AbfGaWRV (ORCPT ); Wed, 31 Jul 2019 18:17:21 -0400 Received: by mail-qk1-f202.google.com with SMTP id k13so59407416qkj.4 for ; Wed, 31 Jul 2019 15:17:20 -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=FIo2fvd2ZRzAOCkOenwujWvUsEXtgcv+etTkEkyg1xI=; b=ZhaBOeUn+nS6E4T1+sBKPnygtWezzpdPerEqfA5uqkD0XE7ajx1N3BtNS+gYIFvTMv m5/OTl8rt5TML9cNVvxzr00+WM4rpnQh6KtnkCsy852F9N/KziU4WPdi4AoTxbrZOIGD ZOFwSYsTuejxhPisUAE8hIyWXaA2sjlt5OXBzdmnDWJ5pncwcDuVfcYf0NntTSKlpQjp rKKZtgFGHKjLXws/EcubYglXFByM0y93MDCDhUiun16sMe93nN1WtD4on0KReHoc1RCd b6udBfRpp4S+HJiB9HNdkFhA4hO9S++7vB0TtCj9NlX8THX3Qm4rDqKyBqdn1siC5g4u RUoA== 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=FIo2fvd2ZRzAOCkOenwujWvUsEXtgcv+etTkEkyg1xI=; b=q2+3A5ejU0hRwTjaWZ45jmr+cgEAy9D+2Qjp6ehyB8RpZKy6LyGsY8/E7l/Yp6CFzL nRoSNDHDPELQnPCqJIdBi3W/NKSIxZvhp2lg1Zq2B7LdDOvXRXjpstmX27BJFgX+QyqL LuyTCKlJnV/MyjNt+1KNG/QeSP0pG+0aVwLzBxlXnTh1DLLKzz0NO6sJlfpYAljD0Krh zkyMTW+tjpDeEPZUZPA7dZH97+0fLlaMNJyMw7owwxOKaKgM84n/c61wNx6F+vYfoa29 m6NvqF9PvCFRGzczZFTx38Q7WAL4+K9VxOw7cK0fJX5lX3vx/M6Zj5WAfMhax9m3A1Gj 2ubw== X-Gm-Message-State: APjAAAU/lWtvOHb9ofS+twOdLVnfe1ELsRovat10t+aOLChHnmBxXaSB LCzxHulC05F4JmKdyeilQUkeoY5YMC0qHtPbkEAPxQ== X-Google-Smtp-Source: APXvYqxuoZZS41br52XXtB1It9wntwqv+gu5vKv5JgSETNL3oo/Kz9hO3JnuMiwnS1ORMBDzqM9a9+iQGWlIZZ9K5OtTDA== X-Received: by 2002:a0c:8690:: with SMTP id 16mr91555482qvf.228.1564611439834; Wed, 31 Jul 2019 15:17:19 -0700 (PDT) Date: Wed, 31 Jul 2019 15:16:09 -0700 In-Reply-To: <20190731221617.234725-1-matthewgarrett@google.com> Message-Id: <20190731221617.234725-22-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190731221617.234725-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog Subject: [PATCH V37 21/29] Lock down /proc/kcore From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, David Howells , Matthew Garrett , Kees Cook Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: David Howells Disallow access to /proc/kcore when the kernel is locked down to prevent access to cryptographic data. This is limited to lockdown confidentiality mode and is still permitted in integrity mode. Signed-off-by: David Howells Signed-off-by: Matthew Garrett Reviewed-by: Kees Cook --- fs/proc/kcore.c | 5 +++++ include/linux/security.h | 1 + security/lockdown/lockdown.c | 1 + 3 files changed, 7 insertions(+) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index f5834488b67d..ee2c576cc94e 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include "internal.h" @@ -545,6 +546,10 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) static int open_kcore(struct inode *inode, struct file *filp) { + int ret = security_locked_down(LOCKDOWN_KCORE); + + if (ret) + return ret; if (!capable(CAP_SYS_RAWIO)) return -EPERM; diff --git a/include/linux/security.h b/include/linux/security.h index 3f7b6a4cd65a..f0cffd0977d3 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -116,6 +116,7 @@ enum lockdown_reason { LOCKDOWN_MODULE_PARAMETERS, LOCKDOWN_MMIOTRACE, LOCKDOWN_INTEGRITY_MAX, + LOCKDOWN_KCORE, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 37b7d7e50474..c050b82c7f9f 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -31,6 +31,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { [LOCKDOWN_MODULE_PARAMETERS] = "unsafe module parameters", [LOCKDOWN_MMIOTRACE] = "unsafe mmio", [LOCKDOWN_INTEGRITY_MAX] = "integrity", + [LOCKDOWN_KCORE] = "/proc/kcore access", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", };