Re: Compat 32-bit syscall entry from 64-bit task!?

[Will Drewry]

On Wed, Jan 18, 2012 at 1:52 PM, Will Drewry <wad@xxxxxxxxxxxx> wrote:
> On Wed, Jan 18, 2012 at 1:47 PM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>> On Wed, Jan 18, 2012 at 11:44 AM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
>>>
>>> It can securely enable syscall auditing which can catch all syscalls
>>> (however you only get race free memory arguments for the ones with LSM hooks
>>> at the right place). Really need both.
>>>
>>> I agree it's not easy to get tight (and also not pretty), but you have a lot
>>> better chance doing it this way than with ptrace.
>>
>> .. And how the f*^& did you imagine that something like chrome would do that?
>>
>> You need massive amounts of privileges, and it's a total disaster in
>> every single respect.
>>
>> Stop pushing crap. No, ptrace isn't wonderful, but your LSM+auditing
>> idea is a billion times worse in all respects.
>>
>> We can definitely fix the ptrace issue with compat system calls.
>
> FWIW, it looks like audit needs fixing too.  If a process only uses
> TIF_SYSCALL_AUDIT, then the fast-path will properly annotate the entry
> with AUDIT_ARCH_I386, but if it takes the slow path because of some
> other tracing on a thread (ftrace, ptrace, ...), then the audit record
> will incorrectly use TIF_IA32 to write the audit record.  Easy patch
> (I'll write it up shortly), but yet another case of breakage.

Nevermind - mis-derefenced the IS_IA32 define.
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