linux-kernel - Re: [PATCH] uprobes/x86: fix detection of 32-bit user mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <32D5D6B1-B29E-426E-90B6-48565A3B8F3B@amacapital.net>
Date:   Fri, 23 Aug 2019 16:57:14 -0700
From:   Andy Lutomirski <luto@...capital.net>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Sebastian Mayr <me@....st>, Ingo Molnar <mingo@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Dmitry Safonov <dsafonov@...tuozzo.com>,
        Oleg Nesterov <oleg@...hat.com>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Subject: Re: [PATCH] uprobes/x86: fix detection of 32-bit user mode



> On Aug 23, 2019, at 4:44 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
> 
>> On Sat, 24 Aug 2019, Thomas Gleixner wrote:
>>> On Sun, 28 Jul 2019, Sebastian Mayr wrote:
>>> 
>>> -static inline int sizeof_long(void)
>>> +static inline int sizeof_long(struct pt_regs *regs)
>>> {
>>> -    return in_ia32_syscall() ? 4 : 8;
>> 
>>  This wants a comment.
>> 
>>> +    return user_64bit_mode(regs) ? 8 : 4;
> 
> The more simpler one liner is to check
> 
>    test_thread_flag(TIF_IA32)

I still want to finish killing TIF_IA32 some day.  Let’s please not add new users.