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;
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F61E21742
Date:   Thu, 15 Mar 2018 13:07:17 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Petr Mladek <pmladek@suse.com>
Cc:     Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        "Tobin C . Harding" <me@tobin.cc>, Joe Perches <joe@perches.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.cz>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCH v3] vsprintf: Prevent crash when dereferencing invalid
 pointers
Message-ID: <20180315130717.3435b71c@vmware.local.home>
In-Reply-To: <20180315150754.qeshnhmtnob2jhxs@pathway.suse.cz>
References: <1520330185.10722.401.camel@linux.intel.com>
        <20180307155244.b45c3fb5vcxb4q2l@pathway.suse.cz>
        <CA+55aFxr5eg_fWjyhcYFU4CSOoVP_GeB79cYa=8mUk7J1cUG7A@mail.gmail.com>
        <20180308141824.bfk2pr6wmjh4ytdi@pathway.suse.cz>
        <CA+55aFyDbr4JpiPoHXq=3wJu+WVCLZPpAVsmY=5HVStawmEiRw@mail.gmail.com>
        <CA+55aFwaNTC2HV9ERDFWCrmhvgZ58SKMM+ik9Ypr3i-ZUyU6Fw@mail.gmail.com>
        <20180309150153.3sxbbpd6jdn2d5yy@pathway.suse.cz>
        <CA+55aFwT-Vd+sVdAVemUjUvkNYFiLyVMHZxv9hF6KzRM7i4Yrg@mail.gmail.com>
        <20180314140947.rs3b6i5gguzzu5wi@pathway.suse.cz>
        <0c52c2f1-60d8-bb8a-80f2-c699d47659d3@rasmusvillemoes.dk>
        <20180315150754.qeshnhmtnob2jhxs@pathway.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, 15 Mar 2018 16:07:54 +0100
Petr Mladek <pmladek@suse.com> wrote:

> Good point. The following should do the job:
> 
> static const char *check_pointer_access(const void *ptr)
> {
> 	char c;
> 
> 	if (!ptr)
> 		return "(null)";
> 
> 	if ((unsigned long)ptr < TASK_SIZE || probe_kernel_address(ptr, c))

Please don't.

-- Steve

> 		return "(efault)";
> 
> 	return 0;
> }