From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753869AbeDYLPF (ORCPT ); Wed, 25 Apr 2018 07:15:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:56981 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754043AbeDYLNu (ORCPT ); Wed, 25 Apr 2018 07:13:50 -0400 From: Petr Mladek To: Andy Shevchenko , Rasmus Villemoes Cc: Linus Torvalds , "Tobin C . Harding" , Joe Perches , Andrew Morton , Michal Hocko , Sergey Senozhatsky , Steven Rostedt , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Petr Mladek , Kees Cook Subject: [PATCH v5 08/11] vsprintf: Factor out %pO handler as kobject_string() Date: Wed, 25 Apr 2018 13:12:48 +0200 Message-Id: <20180425111251.13246-9-pmladek@suse.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20180425111251.13246-1-pmladek@suse.com> References: <20180425111251.13246-1-pmladek@suse.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Move code from the long pointer() function. We are going to add a check for the access to the address that will make it even more complicated. Also it is better to warn about unknown specifier instead of falling back to the %p behavior. It will help people to understand what is going wrong. They expect some device node names and not a pointer in this situation. In fact, this avoids leaking the address when invalid %pO format specifier is used. The old code fallen back to printing the non-hashed value. Fixes: commit 7b1924a1d930eb27f ("vsprintf: add printk specifier %px") Signed-off-by: Petr Mladek Cc: Linus Torvalds Cc: Tobin Harding Cc: Kees Cook --- lib/vsprintf.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index e58436ef9f7f..3536796c483c 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1769,6 +1769,17 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, return widen_string(buf, buf - buf_start, end, spec); } +static char *kobject_string(char *buf, char *end, void *ptr, + struct printf_spec spec, const char *fmt) +{ + switch (fmt[1]) { + case 'F': + return device_node_string(buf, end, ptr, spec, fmt + 1); + } + + return valid_string(buf, end, "(%pO?)", spec); +} + /* * Show a '%p' thing. A kernel extension is that the '%p' is followed * by an extra set of alphanumeric characters that are extended format @@ -1962,10 +1973,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'G': return flags_string(buf, end, ptr, spec, fmt); case 'O': - switch (fmt[1]) { - case 'F': - return device_node_string(buf, end, ptr, spec, fmt + 1); - } + return kobject_string(buf, end, ptr, spec, fmt); case 'x': return pointer_string(buf, end, ptr, spec); } -- 2.13.6