From patchwork Wed Mar 7 21:58:23 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Stultz X-Patchwork-Id: 7142 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id 54E5C23E64 for ; Wed, 7 Mar 2012 21:58:42 +0000 (UTC) Received: from mail-gy0-f180.google.com (mail-gy0-f180.google.com [209.85.160.180]) by fiordland.canonical.com (Postfix) with ESMTP id 1ABA0A181D7 for ; Wed, 7 Mar 2012 21:58:42 +0000 (UTC) Received: by ghbz12 with SMTP id z12so3795456ghb.11 for ; Wed, 07 Mar 2012 13:58:41 -0800 (PST) Received: by 10.50.197.135 with SMTP id iu7mr3006482igc.50.1331157521473; Wed, 07 Mar 2012 13:58:41 -0800 (PST) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.231.53.18 with SMTP id k18csp22994ibg; Wed, 7 Mar 2012 13:58:41 -0800 (PST) Received: by 10.68.225.164 with SMTP id rl4mr5799700pbc.117.1331157520593; Wed, 07 Mar 2012 13:58:40 -0800 (PST) Received: from e37.co.us.ibm.com (e37.co.us.ibm.com. [32.97.110.158]) by mx.google.com with ESMTPS id b5si2255692pbj.143.2012.03.07.13.58.40 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 07 Mar 2012 13:58:40 -0800 (PST) Received-SPF: pass (google.com: domain of jstultz@us.ibm.com designates 32.97.110.158 as permitted sender) client-ip=32.97.110.158; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jstultz@us.ibm.com designates 32.97.110.158 as permitted sender) smtp.mail=jstultz@us.ibm.com Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 7 Mar 2012 14:58:37 -0700 Received: from d03dlp01.boulder.ibm.com (9.17.202.177) by e37.co.us.ibm.com (192.168.1.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Wed, 7 Mar 2012 14:58:35 -0700 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 051731FF0047; Wed, 7 Mar 2012 14:58:35 -0700 (MST) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q27LwYGe193832; Wed, 7 Mar 2012 14:58:34 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q27LwXNb032712; Wed, 7 Mar 2012 14:58:34 -0700 Received: from kernel.beaverton.ibm.com (kernel.beaverton.ibm.com [9.47.67.96]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q27LwXrY032642; Wed, 7 Mar 2012 14:58:33 -0700 Received: by kernel.beaverton.ibm.com (Postfix, from userid 1056) id BAE12C0420; Wed, 7 Mar 2012 13:58:30 -0800 (PST) From: John Stultz To: lkml Cc: Nick Kralevich , Greg KH , Android Kernel Team , John Stultz Subject: [PATCH 13/13] android: ram_console: honor dmesg_restrict Date: Wed, 7 Mar 2012 13:58:23 -0800 Message-Id: <1331157503-3413-14-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.7.3.2.146.gca209 In-Reply-To: <1331157503-3413-1-git-send-email-john.stultz@linaro.org> References: <1331157503-3413-1-git-send-email-john.stultz@linaro.org> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12030721-7408-0000-0000-000003491E30 X-Gm-Message-State: ALoCoQmjMYlPJlt0iCfoBjPYGayZnJohzqMl/mv9BK3RvCBAaT3vl++jeiGLj2sng7J4ht/KBKd6 From: Nick Kralevich The Linux kernel has a setting called dmesg_restrict. When true, only processes with CAP_SYSLOG can view the kernel dmesg logs. This helps prevent leaking of kernel information into user space. On Android, it's possible to bypass these restrictions by viewing /proc/last_kmsg. This change makes /proc/last_kmsg require the same permissions as dmesg. Bug: 5555691 CC: Greg KH CC: Android Kernel Team Change-Id: I50ecb74012ef2ac0a3cff7325192634341fddae9 Signed-off-by: Nick Kralevich Signed-off-by: John Stultz --- drivers/staging/android/ram_console.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/staging/android/ram_console.c b/drivers/staging/android/ram_console.c index d956b84..b242be2 100644 --- a/drivers/staging/android/ram_console.c +++ b/drivers/staging/android/ram_console.c @@ -99,6 +99,9 @@ static ssize_t ram_console_read_old(struct file *file, char __user *buf, char *str; int ret; + if (dmesg_restrict && !capable(CAP_SYSLOG)) + return -EPERM; + /* Main last_kmsg log */ if (pos < old_log_size) { count = min(len, (size_t)(old_log_size - pos));