From patchwork Wed Jul 31 22:16:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11069675 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 B99681395 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 AA5C927F17 for ; Wed, 31 Jul 2019 22:18:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9E9BA27F3E; Wed, 31 Jul 2019 22:18:57 +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 CC79927F81 for ; Wed, 31 Jul 2019 22:18:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731369AbfGaWS4 (ORCPT ); Wed, 31 Jul 2019 18:18:56 -0400 Received: from mail-pl1-f201.google.com ([209.85.214.201]:35346 "EHLO mail-pl1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731335AbfGaWRP (ORCPT ); Wed, 31 Jul 2019 18:17:15 -0400 Received: by mail-pl1-f201.google.com with SMTP id s21so38298364plr.2 for ; Wed, 31 Jul 2019 15:17:15 -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=ar9F1ezXL3PnxEqF0y9aMqfwFMY9y395H3iSelAOa90=; b=KWryge+ybANXRbNwbUlERn6tPnwObLcAGOMqHbxqjgpCmsk/Mut4arFhCyIb2hfV9o EB8iIwoveNQHMvvNvyxTyS/VzhNO7cqfI1jcH5rLsrEgZtM0txb1f5q8bGplFaDdTsci Hs5qgHmgKnDAxCCreraAX4kWLdnl9aI+/ysG9zmGFWxnMHaI7YpHKqGUYXKrNByUNwLA IYXzRZxeDx2m8D5owUvvR/boWpHMxnOTFIEe9l3Ogpxti1aHnVn8g4VRwrDHOBdXGeqH q8NuCf8RuwoDuvwll7S3PdWmI2wr9oFVVsM7EWoWcwcvLfKfMVMHOmO20T0SXWJ7JDzD mTOQ== 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=ar9F1ezXL3PnxEqF0y9aMqfwFMY9y395H3iSelAOa90=; b=ScjTYV2Mqx4qCXt2KEvOL3EnnthZB2Hi6GfXs4MedNtLKqNeIYqc+jVRlNSnuXJUVc yNU1oOSFPtzWG9R2WSHqHOfKrpB1Ov6tRzQvjJJJI8u8QjwZOTpViZ1cLKVnL3WNopG1 VRXZCB6Fwd1lObamLeLo44mDfyDdN8gavESjbKT49HMcL7stsb74+2dapTFG4XUWDKfM kGCCecJS8WxIFp4bO0dNbN0OjUho7BlMCTtNx7Hy7MfwVz+xsCunZfyExOotzzP5J90t DiCfmnCKMHtNBdqgWTPPOqLK+AgfApsHs2lSyNt+G4T/U4vpeygayXoedwLqdupKZhV9 NkjQ== X-Gm-Message-State: APjAAAV9VP5FPR94Gm2DPJxpMSnF97s83a491STVjSw/pBqv26oyB/bF ZQ2+994/zBuE1rEhMjlsttgTTSTatY21P/bZOmvDPg== X-Google-Smtp-Source: APXvYqwJSSTh2CmEEh9mZY1CZ3A0484iF1hyOxUMQ7arAImv2uOzpLvnEyasM52OJEs0/dbgDoUYiDnStbZtl54N/RNuwQ== X-Received: by 2002:a65:5342:: with SMTP id w2mr31174414pgr.261.1564611434315; Wed, 31 Jul 2019 15:17:14 -0700 (PDT) Date: Wed, 31 Jul 2019 15:16:07 -0700 In-Reply-To: <20190731221617.234725-1-matthewgarrett@google.com> Message-Id: <20190731221617.234725-20-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 19/29] 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 | 28 +++++++++++++++++++++++----- security/lockdown/lockdown.c | 1 + 3 files changed, 25 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..f2779a76d39a 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 +97,20 @@ 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, + const char *doing) { + 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 +140,10 @@ 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], doing)) + err = params[i].ops->set(val, ¶ms[i]); + else + err = -EPERM; kernel_param_unlock(params[i].mod); return err; } @@ -541,6 +551,12 @@ static ssize_t param_attr_show(struct module_attribute *mattr, return count; } +#ifdef CONFIG_MODULES +#define mod_name(mod) ((mod)->name) +#else +#define mod_name(mod) "unknown" +#endif + /* sysfs always hands a nul-terminated string in buf. We rely on that. */ static ssize_t param_attr_store(struct module_attribute *mattr, struct module_kobject *mk, @@ -553,8 +569,10 @@ 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, mod_name(mk->mod))) + 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", };