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Re: [Qemu-devel] [PATCH v2] linux-user: return EINVAL from prctl(PR_*_SE
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH v2] linux-user: return EINVAL from prctl(PR_*_SECCOMP) |
Date: |
Mon, 6 Nov 2017 20:41:28 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
Le 06/11/2017 à 19:03, 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>
> ---
> Changes from v1:
> - add comment
>
> linux-user/syscall.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index d4497dec5d..419991e834 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -10482,6 +10482,12 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
> arg1,
> break;
> }
> #endif
> + case PR_GET_SECCOMP:
> + case PR_SET_SECCOMP:
> + /* Disable seccomp to prevent the target disabling syscalls we
> + * need. */
> + ret = -TARGET_EINVAL;
> + break;
> default:
> /* Most prctl options have no pointer arguments */
> ret = get_errno(prctl(arg1, arg2, arg3, arg4, arg5));
>
Reviewed-by: Laurent Vivier <address@hidden>