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[209.132.180.67]) by mx.google.com with ESMTP id z9si990233pgv.286.2019.06.20.18.23.30; Thu, 20 Jun 2019 18:23:46 -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=exdVzCNp; 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 S1727009AbfFUBVk (ORCPT + 99 others); Thu, 20 Jun 2019 21:21:40 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:33958 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726789AbfFUBUo (ORCPT ); Thu, 20 Jun 2019 21:20:44 -0400 Received: by mail-qt1-f201.google.com with SMTP id p34so6139643qtp.1 for ; Thu, 20 Jun 2019 18:20:43 -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=fIFhmiOiT1d1AZu2E6BoXeD1gdoYT5pBASREIuKJk5E=; b=exdVzCNpyG+TXdyx1zMSMEGHDhm1ELXYDImiocGB1OExqvAiPAOVH++8fzdCIkF3cX I1YiXiqr2w28TuEDIdAtd4YiyW+PDnGaeZ3dCuFLFcbkuXJzewsLnKGiBFhcTBE1LOLv AK7gdYYpvYGeDpCTs8HA9RCOCWZeh7VVVUwBcLCo0Nj7m6ze/GupP1FtJGynNn0kTRdN zopBAyVpQUfdyBQWl/9Vh5zUILpPGH7+aJMp5jNFGmE7dCU6RtRNkE4QFHNTcDNhsEAJ k2CRVa100Ba7hesTTMPVHSMcnN9GMc3EZdbG2vTXXYuqgOClRWTcQSJp8ZgNqFsSMSBK Wp1Q== 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=fIFhmiOiT1d1AZu2E6BoXeD1gdoYT5pBASREIuKJk5E=; b=g0ujNDZxU9jzepz9DL6gDN8PGyvdA67hqybeXxgnb+Kl8S00HNMRl3ShUJac0Nu9kZ UTZEoh6Ny2aiRa6kgRHbnpAclIx7HzyaDa8kvVylO8UsDB7xssGyVeW3PR0q5YRjMhSu x+bi3+5d3R57x2U0hDEuw/lNmrLRt0QyHVPl4HWcQlGRl4taLNT4QRSZciQIPfE4U0Is J/nPX9OrC4J94cGz0AVD1Bu6yZyHiadEOF7ua/bb75rHuehkvQ6o6JQsCTlkeEney0qP RdlFCiCHjzUjrCjQ4oAZLDc2fx9PlIZcQcKmfG6q0kmAU19mfTt+slWx+qm80baU3kxy Pmaw== X-Gm-Message-State: APjAAAU/u3ugZXI85ZaBBv7CGFszoxNKEYx3eY3JbIJSrdpv482HiPFU E24DkpoJLVh4pwDCpwkFTCsujUabzIsGgOQpM5kIjQ== X-Received: by 2002:ac8:38c5:: with SMTP id g5mr117018528qtc.299.1561080043098; Thu, 20 Jun 2019 18:20:43 -0700 (PDT) Date: Thu, 20 Jun 2019 18:19:33 -0700 In-Reply-To: <20190621011941.186255-1-matthewgarrett@google.com> Message-Id: <20190621011941.186255-23-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 22/30] Lock down /proc/kcore From: Matthew Garrett To: jmorris@namei.org Cc: linux-security@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, David Howells , Matthew Garrett 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 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 --- fs/proc/kcore.c | 3 +++ include/linux/security.h | 1 + security/lockdown/lockdown.c | 1 + 3 files changed, 5 insertions(+) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index d29d869abec1..b410a16b1960 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 +546,8 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) static int open_kcore(struct inode *inode, struct file *filp) { + if (security_is_locked_down(LOCKDOWN_KCORE)) + return -EPERM; if (!capable(CAP_SYS_RAWIO)) return -EPERM; diff --git a/include/linux/security.h b/include/linux/security.h index 89b7adfae525..6752584729e2 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -95,6 +95,7 @@ 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 215615e67237..80ff4a31d8aa 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", }; -- 2.22.0.410.gd8fdbe21b5-goog