Re: [Qemu-devel] [RFC] [PATCHv2 2/2] Adding basic calls to libseccomp in vl.c

[Daniel P. Berrange]

On Wed, Jun 13, 2012 at 04:20:22PM -0300, Eduardo Otubo wrote:
> I added a syscall struct using priority levels as described in the
> libseccomp man page. The priority numbers are based to the frequency
> they appear in a sample strace from a regular qemu guest run under
> libvirt.
> 
> Libseccomp generates linear BPF code to filter system calls, those rules
> are read one after another. The priority system places the most common
> rules first in order to reduce the overhead when processing them.
> 
> Also, since this is just a first RFC, the whitelist is a little raw. We
> might need your help to improve, test and fine tune the set of system
> calls.
> 
> v2: Fixed some style issues
>       Removed code from vl.c and created qemu-seccomp.[ch]
>       Now using ARRAY_SIZE macro
>       Added more syscalls without priority/frequency set yet
>
> +static struct QemuSeccompSyscall seccomp_whitelist[] = {
> +    { SCMP_SYS(timer_settime), 255 },
> +    { SCMP_SYS(timer_gettime), 254 },
> +    { SCMP_SYS(futex), 253 },
> +    { SCMP_SYS(select), 252 },
> +    { SCMP_SYS(recvfrom), 251 },
> +    { SCMP_SYS(sendto), 250 },
> +    { SCMP_SYS(read), 249 },
> +    { SCMP_SYS(brk), 248 },
> +    { SCMP_SYS(clone), 247 },
> +    { SCMP_SYS(mmap), 247 },
> +    { SCMP_SYS(mprotect), 246 },
> +    { SCMP_SYS(ioctl), 245 },
> +    { SCMP_SYS(recvmsg), 245 },
> +    { SCMP_SYS(sendmsg), 245 },
> +    { SCMP_SYS(accept), 245 },
> +    { SCMP_SYS(connect), 245 },
> +    { SCMP_SYS(bind), 245 },
> +    { SCMP_SYS(listen), 245 },
> +    { SCMP_SYS(ioctl), 245 },
> +    { SCMP_SYS(eventfd), 245 },
> +    { SCMP_SYS(rt_sigprocmask), 245 },
> +    { SCMP_SYS(write), 244 },
> +    { SCMP_SYS(fcntl), 243 },
> +    { SCMP_SYS(tgkill), 242 },
> +    { SCMP_SYS(rt_sigaction), 242 },
> +    { SCMP_SYS(pipe2), 242 },
> +    { SCMP_SYS(munmap), 242 },
> +    { SCMP_SYS(mremap), 242 },
> +    { SCMP_SYS(getsockname), 242 },
> +    { SCMP_SYS(getpeername), 242 },
> +    { SCMP_SYS(fdatasync), 242 },
> +    { SCMP_SYS(close), 242 }
> +};

Hmm, this is still missing the 'open' syscall. How does QEMU work
at all with these patches applied, without this syscall listed ?

Daniel
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