Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752966Ab3DVOaV (ORCPT ); Mon, 22 Apr 2013 10:30:21 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51612 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754856Ab3DVOaQ (ORCPT ); Mon, 22 Apr 2013 10:30:16 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ingo Molnar" , "Namhyung Kim" , "Namhyung Kim" , "Frederic Weisbecker" , "Steven Rostedt" Date: Mon, 22 Apr 2013 15:25:59 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [38/75] tracing: Fix possible NULL pointer dereferences In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:6834:ff73:7553:7f84 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2707 Lines: 85 3.2.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Namhyung Kim commit 6a76f8c0ab19f215af2a3442870eeb5f0e81998d upstream. Currently set_ftrace_pid and set_graph_function files use seq_lseek for their fops. However seq_open() is called only for FMODE_READ in the fops->open() so that if an user tries to seek one of those file when she open it for writing, it sees NULL seq_file and then panic. It can be easily reproduced with following command: $ cd /sys/kernel/debug/tracing $ echo 1234 | sudo tee -a set_ftrace_pid In this example, GNU coreutils' tee opens the file with fopen(, "a") and then the fopen() internally calls lseek(). Link: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt [bwh: Backported to 3.2: ftrace_regex_lseek() is static] Signed-off-by: Ben Hutchings --- --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2316,7 +2316,7 @@ ftrace_notrace_open(struct inode *inode, } static loff_t -ftrace_regex_lseek(struct file *file, loff_t offset, int origin) +ftrace_filter_lseek(struct file *file, loff_t offset, int origin) { loff_t ret; @@ -3134,7 +3134,7 @@ static const struct file_operations ftra .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; @@ -3142,7 +3142,7 @@ static const struct file_operations ftra .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; @@ -3350,8 +3350,8 @@ static const struct file_operations ftra .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, + .llseek = ftrace_filter_lseek, .release = ftrace_graph_release, - .llseek = seq_lseek, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ @@ -3843,7 +3843,7 @@ static const struct file_operations ftra .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, - .llseek = seq_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_pid_release, }; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/