From patchwork Fri Aug 9 20:58:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11087597 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 D91451399 for ; Fri, 9 Aug 2019 20:58:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C4EBD205F8 for ; Fri, 9 Aug 2019 20:58:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B809A20881; Fri, 9 Aug 2019 20:58:50 +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 EEB65205F8 for ; Fri, 9 Aug 2019 20:58:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726219AbfHIU6t (ORCPT ); Fri, 9 Aug 2019 16:58:49 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:46901 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725985AbfHIU6t (ORCPT ); Fri, 9 Aug 2019 16:58:49 -0400 Received: by mail-pf1-f201.google.com with SMTP id g21so62228789pfb.13 for ; Fri, 09 Aug 2019 13:58:48 -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=eBQXEUJ4xG90qgyQmq59kEIpLR58l2iNnVeP+k7a23g=; b=rMxaNl5AsKq6YNwTXpua2sqDDA43FqhpUtJC7gyxqzGgupGFiMHIUyB7l/nDHPs2OE K1BnIyyLb4DD+tUtFKgJFNisQHq2ugAQS39MnTZyf86sdiRJxTaX2Se11M5G2oXCq1Wg 0XavWtwnmGlFHooR8j5BIhZ/+SzDyom/Ot0q/CX4iFTq/lDouinbfWVfjYMDvCGJ+yos 2GA2CzGK6mxom7oMSYSMg6U4hpjfeX1ncO5zQwsj3yXdv6Ms/GHmfhu1tt8sOp+y1p0G kDb1s2/Z7cxAzLMyBY+zRoZu3brFFWE0QBlXQA+vq0Xo3kTawHhb3EjzQLimYqVmEKZ0 p4gg== 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=eBQXEUJ4xG90qgyQmq59kEIpLR58l2iNnVeP+k7a23g=; b=O/3Z8E4j0p8EpnhwQ2Z3H4EliQ1JX23ywX9y2A8wJz+UVDE6fnpJE8ggp2E9pD106D sLnEadQCud/ovfP/WG266C3TDCcUDRhm7UmxiPqZ9RyFAopqV1B1zADOFVky/Y0PW01W M66dl5eaEtw0y4sOYLvJFNLq7EWSBRdW7DKlNw7TOc4FtKSWoWLQPCJIZQJHiCtGAEzR jICK6L/4TD2KXLnNKUK60/Dw/8LzJ6Gx6Ex8adJZO1+2+fGija9Cq5A4zsGtRVtjpaUV n9Rg8SAkgd8q7w/IQmgpJtm3yI93FaliiBsjEKtvA65fFk3UGITVKgVTOmVBkjuZ1+Zl +5KA== X-Gm-Message-State: APjAAAWS/cHfYZzeiS0KMsn9Ttvpp5VsA8OX8drxPSLmVGMsFGyqxV1B ebKF8Jr0ma+udQllnxm8e9xVXjKZNdPzcdkLSB2fAg== X-Google-Smtp-Source: APXvYqypvyr+nXY4Gz4HIOztkBZe1d5v+Q3txrKEylftEPnO3VwNYP/ngFop0XxwT2lDHqMwviPg9WFhIha741OGjCVzag== X-Received: by 2002:a63:484a:: with SMTP id x10mr18952600pgk.430.1565384328279; Fri, 09 Aug 2019 13:58:48 -0700 (PDT) Date: Fri, 9 Aug 2019 13:58:22 -0700 In-Reply-To: <20190808111246.GA29211@linux-8ccs> Message-Id: <20190809205822.109793-1-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190808111246.GA29211@linux-8ccs> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog Subject: [PATCH V39] Lock down module params that specify hardware parameters (eg. ioport) 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 , Alan Cox , Matthew Garrett , Kees Cook , Jessica Yu Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: David Howells Provided an annotation for module parameters that specify hardware parameters (such as io ports, iomem addresses, irqs, dma channels, fixed dma buffers and other types). Suggested-by: Alan Cox Signed-off-by: David Howells Signed-off-by: Matthew Garrett Reviewed-by: Kees Cook Cc: Jessica Yu --- include/linux/security.h | 1 + kernel/params.c | 21 ++++++++++++++++----- security/lockdown/lockdown.c | 1 + 3 files changed, 18 insertions(+), 5 deletions(-) diff --git a/include/linux/security.h b/include/linux/security.h index 8f7048395114..43fa3486522b 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -113,6 +113,7 @@ enum lockdown_reason { LOCKDOWN_ACPI_TABLES, LOCKDOWN_PCMCIA_CIS, LOCKDOWN_TIOCSSERIAL, + LOCKDOWN_MODULE_PARAMETERS, LOCKDOWN_INTEGRITY_MAX, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/kernel/params.c b/kernel/params.c index cf448785d058..8e56f8b12d8f 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -12,6 +12,7 @@ #include #include #include +#include #ifdef CONFIG_SYSFS /* Protects all built-in parameters, modules use their own param_lock */ @@ -96,13 +97,19 @@ bool parameq(const char *a, const char *b) return parameqn(a, b, strlen(a)+1); } -static void param_check_unsafe(const struct kernel_param *kp) +static bool param_check_unsafe(const struct kernel_param *kp) { + if (kp->flags & KERNEL_PARAM_FL_HWPARAM && + security_locked_down(LOCKDOWN_MODULE_PARAMETERS)) + return false; + if (kp->flags & KERNEL_PARAM_FL_UNSAFE) { pr_notice("Setting dangerous option %s - tainting kernel\n", kp->name); add_taint(TAINT_USER, LOCKDEP_STILL_OK); } + + return true; } static int parse_one(char *param, @@ -132,8 +139,10 @@ static int parse_one(char *param, pr_debug("handling %s with %p\n", param, params[i].ops->set); kernel_param_lock(params[i].mod); - param_check_unsafe(¶ms[i]); - err = params[i].ops->set(val, ¶ms[i]); + if (param_check_unsafe(¶ms[i])) + err = params[i].ops->set(val, ¶ms[i]); + else + err = -EPERM; kernel_param_unlock(params[i].mod); return err; } @@ -553,8 +562,10 @@ static ssize_t param_attr_store(struct module_attribute *mattr, return -EPERM; kernel_param_lock(mk->mod); - param_check_unsafe(attribute->param); - err = attribute->param->ops->set(buf, attribute->param); + if (param_check_unsafe(attribute->param)) + err = attribute->param->ops->set(buf, attribute->param); + else + err = -EPERM; kernel_param_unlock(mk->mod); if (!err) return len; diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 00a3a6438dd2..5177938cfa0d 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -28,6 +28,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { [LOCKDOWN_ACPI_TABLES] = "modifying ACPI tables", [LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage", [LOCKDOWN_TIOCSSERIAL] = "reconfiguration of serial port IO", + [LOCKDOWN_MODULE_PARAMETERS] = "unsafe module parameters", [LOCKDOWN_INTEGRITY_MAX] = "integrity", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", };