Re: [PATCH v5 2/3] seccomp_filters: system call filtering using BPF

From: Indan Zupancic
Date: Mon Jan 30 2012 - 17:59:29 EST


On Mon, January 30, 2012 23:29, Andrew Lutomirski wrote:
> [not quoting anything because this is a more general question]
>
> How portable across architectures is this supposed to be? At least
> syscall numbering varies widely, and calling conventions can be
> different (x86_64 has four of them, for example). For all I know,
> argument order might be different in some cases.

Apart from the syscall numbering, it is surprisingly consistent.
For e.g. x86 about 190 out of 300/340 system calls are the same,
so about 2/3. The 1/3 that are different are mostly 32-bit only
variants of systemcalls, or obsolete ones. So for the syscall
arguments actually checked, the number is much higher.

Different argument ordering for the same syscall between archs
is very rare.

Greetings,

Indan


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