linux-kernel - Re: [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:   Thu, 9 Feb 2017 22:35:20 +0900
From:   Hoeun Ryu <hoeun.ryu@...il.com>
To:     Eric Biggers <ebiggers3@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>, Ingo Molnar <mingo@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Mateusz Guzik <mguzik@...hat.com>,
        linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com
Subject: Re: [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in
 cache when cpus are offline

On Thu, Feb 9, 2017 at 1:22 PM, Eric Biggers <ebiggers3@...il.com> wrote:
> Hi Hoeun,
>
> On Thu, Feb 09, 2017 at 01:03:46PM +0900, Hoeun Ryu wrote:
>> +static int free_vm_stack_cache(unsigned int cpu)
>> +{
>> +     int i;
>> +
>> +     for (i = 0; i < NR_CACHED_STACKS; i++) {
>> +             struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
>> +             if (!vm_stack)
>> +                     continue;
>> +
>> +             vfree(vm_stack->addr);
>> +             this_cpu_write(cached_stacks[i], NULL);
>> +     }
>> +
>> +     return 0;
>> +}
>
> Doesn't this need to free the stacks for the 'cpu' that's passed in, instead of
> "this" CPU?
>

Sorry, Thank you for your correction. I will fix this.

> - Eric