From: alexander.levin@verizon.com
To: Dmitry Vyukov <dvyukov@google.com>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
"scientist@fb.com" <scientist@fb.com>,
"glider@google.com" <glider@google.com>,
"andreyknvl@google.com" <andreyknvl@google.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"mathieu.desnoyers@efficios.com" <mathieu.desnoyers@efficios.com>,
"daniel.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC 1/3] abi_spec: basic definitions of constraints, args and syscalls
Date: Tue, 27 Dec 2016 17:23:24 +0000 [thread overview]
Message-ID: <20161227172322.x7vzpsvkyjneii7j@sasha-lappy> (raw)
In-Reply-To: <CACT4Y+ZMorYKjBnpBjmR76o7sNOWDpVnp6LzR4+68bVVo7ttXg@mail.gmail.com>
On Mon, Dec 12, 2016 at 11:29:35AM +0100, Dmitry Vyukov wrote:
> On Wed, Nov 23, 2016 at 3:59 PM, <alexander.levin@verizon.com> wrote:
> > On Mon, Nov 21, 2016 at 03:48:17PM +0100, Dmitry Vyukov wrote:
> > I imagine that this will be handled by specific logical type handlers we'll
> > need to implement. Can you give me an example and I'll try to code that?
>
> One example is te_oper_param here:
> https://android.googlesource.com/kernel/tegra/+/android-tegra-3.10/security/tlk_driver/ote_protocol.h
> next_ptr_user is a pointer to te_oper_param. Thus recursive definition.
>
> Another example is snd_seq_ev_quote:
> http://lxr.free-electrons.com/source/include/uapi/sound/asequencer.h#L194
> it contains struct snd_seq_event *event and snd_seq_event recursively
> contains snd_seq_ev_quote.
>
> In all cases it is pointer recursion via structs.
>
> Sometimes it wish that developers have to write formal descriptions in
> a limited language upfront. That would probably eliminate lots of
> weird one-off "see what I invented here" cases :)
We'll need a special handler for each struct passed as a parameter anyway, no?
In this scenario we just call that handler recursively?
> > But that means I need a custom handler for every syscall to parse the
> > struct fields rather than a generic code that goes through the args and calls
> > the right handler?
>
> No, you don't. We will need generic code that parses a piece of memory
> as a struct and splits it into fields anyway.
> We can just reuse this code to handle syscall arguments as follows.
> Describe syscall arguments as a pseudo struct (array of fields). Then
> syscall handling function accepts pointer to region of memory with
> arguments and description of the struct, and invokes common struct
> handling code.
Oh, I understand your point now - I missed the part about a generic fields
struct and thought you want a specialized struct for each syscall.
Yes, that makes sense.
>
> >> How would you like us to collaborate on this?
> >> If you share your git repo, I could form it into something that would
> >> be suitable for syzkaller and incorporate most of the above.
> >
> > I'd really like to have something that either generates these descriptions from
> > your DSL (it really doesn't have to be perfect (at first)) or something that
> > generates DSL from these C structs.
>
> Do you mean generating C from my DSL of a one-off or as a permanent solution?
I think it depends on what's easier to maintain - the spec in C or a parser
for DSL->C.
--
Thanks,
Sasha
next prev parent reply other threads:[~2016-12-27 17:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-16 17:37 [RFC 0/3] ABI spec - verification alexander.levin
2016-11-16 17:37 ` [RFC 1/3] abi_spec: basic definitions of constraints, args and syscalls alexander.levin
2016-11-21 14:48 ` Dmitry Vyukov
2016-11-23 14:59 ` alexander.levin
2016-12-12 10:29 ` Dmitry Vyukov
2016-12-12 10:45 ` Dmitry Vyukov
2016-12-14 19:46 ` Dmitry Vyukov
2016-12-14 19:48 ` Dmitry Vyukov
2017-01-04 4:52 ` alexander.levin
2016-12-27 17:23 ` alexander.levin [this message]
2016-12-28 7:32 ` Dmitry Vyukov
2016-11-21 15:41 ` Steven Rostedt
2016-11-23 15:03 ` alexander.levin
2016-11-23 15:31 ` Steven Rostedt
2016-11-23 15:33 ` Steven Rostedt
2016-11-16 17:37 ` [RFC 2/3] abi_spec: hooks into syscall to allow pre and post checking alexander.levin
2016-11-21 15:54 ` Steven Rostedt
2016-11-21 15:57 ` Dmitry Vyukov
2016-11-23 15:04 ` alexander.levin
2016-11-16 17:37 ` [RFC 3/3] abi_spec: example spec for open(), placeholder for rest of syscalls alexander.levin
2016-11-16 17:46 ` [RFC 0/3] ABI spec - verification Thomas Gleixner
2016-11-21 14:25 ` Dmitry Vyukov
2016-11-23 14:36 ` alexander.levin
2016-12-12 10:12 ` Dmitry Vyukov
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