[CRIU] [PATCH] compel: Do not loose sign of result in compat syscall

[Dmitry Safonov]

2017-10-30 20:22 GMT+00:00 Cyrill Gorcunov <gorcunov at gmail.com>:
> On Mon, Oct 30, 2017 at 01:14:13PM -0700, Andrey Vagin wrote:
>> >
>> > This code has nothing to do with such issues, it's up to a caller
>> > to verify the values obtained.
>>
>> This code modifies a valid value, so you fix one issue and create a new
>> one. Could you fix both of them? ;)
>
> It doesn't create new one but rather reveal arhitecture problem,
> which I missed in first place, don't you see? For vz7 instance
> the additional fix is. For vanilla instance i will merge them
> into one, hopefully tomorrow.
> ---
> From: Cyrill Gorcunov <gorcunov at virtuozzo.com>
> Date: Mon, 30 Oct 2017 23:16:58 +0300
> Subject: [PATCH] compel: x86,compat -- Make sure mmap fits compat task size
>
> In addition to
>
>  | commit 702d51315bdd337b9ab3d32c952bb8a150440d45
>  | Author: Cyrill Gorcunov <gorcunov at virtuozzo.com>
>  |
>  |     compel: Do not loose sign of result in compat syscall
>
> It's due to compel interface which operates inside ia-32e mode
> where we have to keep sign of syscall up to a caller layer.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
> ---
>  compel/arch/x86/src/lib/infect.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/compel/arch/x86/src/lib/infect.c b/compel/arch/x86/src/lib/infect.c
> index ac5f8b0..e546ee3 100644
> --- a/compel/arch/x86/src/lib/infect.c
> +++ b/compel/arch/x86/src/lib/infect.c
> @@ -348,6 +348,13 @@ void *remote_mmap(struct parasite_ctl *ctl,
>                 return NULL;
>         }
>
> +       /*
> +        * For compat tasks the address in foreign process
> +        * must lay inside 4 bytes.
> +        */
> +       if (compat_task)
> +               map &= 0xfffffffful;

A nit:
TASK_SIZE_IA32?

-- 
             Dmitry