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Re: [Qemu-devel] [PATCH] linux-user: return EINVAL from prctl(PR_*_SECCO
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user: return EINVAL from prctl(PR_*_SECCOMP) |
Date: |
Fri, 3 Nov 2017 15:29:42 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
Le 03/11/2017 à 13:07, James Cowgill a écrit :
> If an application tries to install a seccomp filter using
> prctl(PR_SET_SECCOMP), the filter is likely for the target instead of the host
> architecture. This will probably cause qemu to be immediately killed when it
> executes another syscall.
>
> Prevent this from happening by returning EINVAL from both seccomp prctl
> calls. This is the error returned by the kernel when seccomp support is
> disabled.
>
> Fixes: https://bugs.launchpad.net/qemu/+bug/1726394
> Signed-off-by: James Cowgill <address@hidden>
> ---
> linux-user/syscall.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index d4497dec5d..43cd5fb2bb 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -10482,6 +10482,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
> arg1,
> break;
> }
> #endif
> + case PR_GET_SECCOMP:
> + case PR_SET_SECCOMP:
> + ret = -TARGET_EINVAL;
> + break;
> default:
> /* Most prctl options have no pointer arguments */
> ret = get_errno(prctl(arg1, arg2, arg3, arg4, arg5));
>
I think we should allow PR_GET_SECCOMP, and at least all the modes
except SECCOMP_MODE_FILTER for PR_SET_SECCOMP.
Thanks,
Laurent