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[209.132.180.67]) by mx.google.com with ESMTP id d135si981200pga.557.2019.06.20.18.22.25; Thu, 20 Jun 2019 18:22:40 -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=sbuim71w; 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 S1727028AbfFUBVq (ORCPT + 99 others); Thu, 20 Jun 2019 21:21:46 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:48388 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726699AbfFUBUj (ORCPT ); Thu, 20 Jun 2019 21:20:39 -0400 Received: by mail-pf1-f202.google.com with SMTP id u21so3242510pfn.15 for ; Thu, 20 Jun 2019 18:20:38 -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=LzkRv880sCWOO5kDA1eICQkyZ0YymQEU3SqA2aswVgo=; b=sbuim71wq0khSjkJ8HLdFMG6PzZgQcr3z5mOl7rou1pj/UYQAGxdLEdN9CyfUo6vBc 1G/MdNWAlpeq8IKBBdHXZo9MY0Ny2Adlwo+cuoT2GSLK47+Ha8gzMxY3VxFvLRJWagJe btY6DWqszatmSNHnz+Xn9yImXf0X7UEYnPSB8n5eLFlWRDLGhgiDW0SqjSwsWB625M1/ fo7wnnaIjgQPcs89Any8jZMRL3kL2lgP6xWPL9IGyTRLuoDLbWXMCCxNdzUmczW3DoyG x1oXwxbMgauOFdVDo3w/zwEDo7q7ScGAGtEAcU3yd5nFJh/5iiKzeM4Wy5XBk+TTGKjH KChg== 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=LzkRv880sCWOO5kDA1eICQkyZ0YymQEU3SqA2aswVgo=; b=dN/5LRNqyB/EVFOnbBMplCCveCOlsc9PBzdV+VGGkxUj3rVy92siQ+mEcK19HtCu7a jLilwXWtz7KzbCY7YAWmBwLgZudUCL/IeV/RKeNpokCsQjIya2Xs2sIvLppcfYxKs+V6 UoOeZF3DvZ6xwD57uMSHepKgxdhVVVr4CqlJswH3+oKJh2IPRsFCVydLMvkr/ZRDC0fo RdNrSPo9DIhmWDQArWNOFxIuXQXjit0lho0IgS4i9ME5MDf1GeQjbvY4XVhJFdME7V2T S3iHITs1xmeu+Adsq/fXSKi1LhCsxP5dPyPuHg30Jvr9Uxv5QT4nLRi0MpVLPBhswEnE XCJg== X-Gm-Message-State: APjAAAWIZfqavgFHZLdEDe5rMX4dKdjcqSc66b/YuWHdD/S7ZGEky3Fv h5ybzYi4/kWooxytYhoKGEY6++s6VWNEWNixEwcB2w== X-Received: by 2002:a63:f64a:: with SMTP id u10mr7995559pgj.329.1561080037825; Thu, 20 Jun 2019 18:20:37 -0700 (PDT) Date: Thu, 20 Jun 2019 18:19:31 -0700 In-Reply-To: <20190621011941.186255-1-matthewgarrett@google.com> Message-Id: <20190621011941.186255-21-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 20/30] Lock down module params that specify hardware parameters (eg. ioport) 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 , Alan Cox , 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 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 --- include/linux/security.h | 1 + kernel/params.c | 27 ++++++++++++++++++++++----- security/lockdown/lockdown.c | 1 + 3 files changed, 24 insertions(+), 5 deletions(-) diff --git a/include/linux/security.h b/include/linux/security.h index cb5d74f9b9ff..47ca04ac00f6 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -92,6 +92,7 @@ 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 ce89f757e6da..59544a2ec0b9 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -24,6 +24,7 @@ #include #include #include +#include #ifdef CONFIG_SYSFS /* Protects all built-in parameters, modules use their own param_lock */ @@ -108,13 +109,19 @@ 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, + const char *doing) { 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); } + + if (kp->flags & KERNEL_PARAM_FL_HWPARAM && + security_is_locked_down(LOCKDOWN_MODULE_PARAMETERS)) + return false; + return true; } static int parse_one(char *param, @@ -144,8 +151,10 @@ 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; } @@ -553,6 +562,12 @@ 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, @@ -565,8 +580,10 @@ 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 c6456f300220..0788d4805449 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] = "modified 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", }; -- 2.22.0.410.gd8fdbe21b5-goog