On Wed, Nov 21, 2018 at 02:56:57PM -0800, Andy Lutomirski wrote:
> Please cc linux-api@xxxxxxxxxxxxxxx for future versions.
>
> On Wed, Nov 21, 2018 at 7:58 AM Elvira Khabirova wrote:
> >
> > struct ptrace_syscall_info {
> > __u8 op; /* 0 for entry, 1 for exit */
>
> Can you add proper defines, like:
>
> #define PTRACE_SYSCALL_ENTRY 0
> #define PTRACE_SYSCALL_EXIT 1
> #define PTRACE_SYSCALL_SECCOMP 2
>
> and make seccomp work from the start? I'd rather we don't merge an
> implementation that doesn't work for seccomp and then have to rework
> it later.
What's the difference between PTRACE_EVENT_SECCOMP and syscall-entry-stop
with regards to PTRACE_GET_SYSCALL_INFO request? At least they have the
same entry_info to return.
As long as implementation (ab)uses ptrace_message to tell one kind of stop
from another, it can distinguish syscall-entry-stop and syscall-exit-stop
from each other and from many other kinds of stops, but it cannot
distinguish PTRACE_EVENT_SECCOMP from e.g. PTRACE_EVENT_EXIT.
> > __u8 __pad0[7];
> > union {
> > struct {
> > __s32 nr;
>
> __u64 please. Syscall numbers are, as a practical matter, 64 bits.
> Admittedly, the actual effects of setting the high bits are unclear,
> and seccomp has issues with it, but let's not perpetuate the problem.
I agree. Although the implementation uses syscall_get_nr()
which returns int, this could potentially be fixed in the future.
> > __u32 arch;
> > __u64 instruction_pointer;
> > __u64 args[6];
> > } entry_info;
> > struct {
> > __s64 rval;
> > __u8 is_error;
> > __u8 __pad1[7];
> > } exit_info;
> > };
> > };
>
> Should seccomp events use entry_info or should they just literally
> supply seccomp_data?
It certainly can use entry_info.
I'd prefer to avoid using in uapi/linux/ptrace.h those types
that are defined in uapi/linux/seccomp.h.
--
ldv
Attachment:
signature.asc
Description: PGP signature
