RE: Searching for blind programmer to start a school for blind programmers
- From: "Ken Perry" <whistler@xxxxxxxxxxxxx>
- To: <programmingblind@xxxxxxxxxxxxx>
- Date: Sun, 10 Apr 2011 15:56:50 -0400
Sina just stop arguing he knows he is right leave it alone it is not
important at all to know how to write your own binary by hand.
ken
-----Original Message-----
From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Christopher
Coale
Sent: Sunday, April 10, 2011 2:46 PM
To: programmingblind@xxxxxxxxxxxxx
Subject: Re: Searching for blind programmer to start a school for blind
programmers
On 4/10/2011 11:20 AM, Sina Bahram wrote:
> A shell exploit about six months ago, maybe a year. Closer to a year
actually.
You wrote a shell exploit by writing an executable via a hex-editor? Not
editing a dll's contents via a hex-editor?
> And then op code by op code for a hypervisor, namely Xen, around their 3.2
3.3 versions, and mainly in their page manager.
Again, you're saying that you wrote code for Xen that was purely writing
an executable using a hex-editor? I'm not referring to emitting opcodes
from a source (in JIT which it sounds like Xen does, since it's a
virtualization software). You actually wrote the body of the software
using a hex-editor, not an IDE? I can't imagine you being picked up on a
development team if you do that.
> Then there was the virtual machine introspection stuff which was bit for
bit analysis, in memory, at real-time. There's actually a
> paper on that one, if you'd like.
In memory, at real time? Tell me.. how can one dynamically write an
application that runs in real-time while editing the bytecode using a
hex-editor? (see my last response)
> Let's see, and then there was some malware analysis with a
friend/colleague of mine, but that was mainly him, and I was just having
> fun.
Again, malware software is going to use a source (C, C++, C#, whatever)
to read in an executables bytecode and determine the behavior. This is
far from writing an application in machine code via a hex-editor.
> Oh yes, and stepping through some code for a friend's engineering project,
byte for byte; however, that was an 8-bit, then a 16-bit
> processor, so if that counts, then wonderful.
I find it odd that your friend consistently decided to write his machine
code instead of writing an assembler for it. Must have been tough. I'm
an EE/CS engineering student -- I would never think of doing that. To
test specific instructions, sure. To test whole programs? Absolutely not.
I hope you realize a consistency in all of my replies here.. all of your
examples were either editing a binary or emitting opcodes JIT. None of
your examples were --writing a program in pure machine code using a
hex-editor--. I think I've said that single phrase about 300 times now,
and it's just not going through for some reason. -- Writing a whole
program in pure machine code using a hex-editor -- is absolutely not an
important skill. It just isn't.
-- Chris
On 4/10/2011 11:20 AM, Sina Bahram wrote:
> Oh, and last year/semester I wrote a compiler, so I guess that counts.
>
> I also collaborated on a paper to automatically prevent every single
possible return oriented programming hack/technique by
> modifying the compiler, namely LLVM, to rewrite all generated op codes
without using a ret, so as to prevent alignment errors along
> any kind of boundary, be they logical, page, byte, or otherwise; such that
unprivileged jumps can't actually escalate themselves.
> The researcher on that one then used this technique to recompile the
entire kernel into a running system, think they settled on BSD
> because of issues with Klang back then, using that protection technique.
That's actually a great paper, and I'd recommend it to
> anyone.
>
> But, *shrug*, it doesn't come up all that often. I'm going to go back to
writing speech recognition code into a computer vision
> algorithm for Android because HCI is way more fun!
>
> Bye for now
>
> Take care,
> Sina
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Ken Perry
> Sent: Sunday, April 10, 2011 12:40 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: RE: Searching for blind programmer to start a school for blind
programmers
>
> I think you might find it was more recent than you think judging by what
> Sina has been doing.
>
> Ken
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Christopher
> Coale
> Sent: Sunday, April 10, 2011 12:27 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: Re: Searching for blind programmer to start a school for blind
> programmers
>
> Stop being ignorant, Sina. You seem to be quite fond of the straw man.
> So please, stop changing my words.
>
> First of all, I agree that computer programmers need to understand the
> basics. I never once said they didn't. I never once said that low-level
> was bad. So if your whole point is that "understanding low-level is
> important", then I agree and nobody is this thread thus far disagreed
> with that claim. So then, given that, what is your point that makes me
> wrong?
>
> Sina, when was the last time you wrote a program from scratch using ONLY
> A HEX-EDITOR?
>
> On 4/10/2011 5:40 AM, Sina Bahram wrote:
>> Well, you definitely proved that I didn't need the other 65%, since your
> message summed up exactly what my impression of the
>> discussion was.
>>
>> And yes, I do feel it's important. Not crucial, or even necessary to be
> successful, but most definitely extremely important.
>> Understanding the fundamentals is something that gets ignored day in and
> day out.
>> Take care,
>> Sina
>>
>>
>> -----Original Message-----
>> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Christopher
> Coale
>> Sent: Saturday, April 09, 2011 10:36 PM
>> To: programmingblind@xxxxxxxxxxxxx
>> Subject: Re: Searching for blind programmer to start a school for blind
> programmers
>> How kind of you to join, master. Can you tell me who said that low-level
>> was NOT important to know and understand? You admittedly stated that you
>> ignored 65% of the messages, but then tell everyone to take Ken's side?
>> Are you kidding me? You admit that you don't know what the argument
>> (friendly argument) is about, yet you still pick a side? Come on now...
>>
>> Ken stated that --being able to write a program in pure machine code (no
>> compiler or assembler)-- is important. I disagreed saying that it is not
>> important. Knowing low-level concepts (like I pointed out earlier.. how
>> the processor works, operating system design, etc.) is definitely
>> important. Writing a program in pure machine code is an unnecessary
>> skill, not an important one.
>>
>> On 4/9/2011 7:27 PM, Sina Bahram wrote:
>>> I haven't read 65% of the messages in this thread, frankly because the
> SNR is far too low.
>>> So can you guys please just listen to Ken on this one?
>>>
>>> low level is important to know and understand. End of conversation.
>>>
>>> Now go do something fun. It's Saturday night.
>>>
>>> Take care,
>>> Sina
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Ken Perry
>>> Sent: Saturday, April 09, 2011 8:06 PM
>>> To: programmingblind@xxxxxxxxxxxxx
>>> Subject: RE: Searching for blind programmer to start a school for blind
> programmers
>>> I think we are just going to have to disagree on this. While I doubt
> anyone
>>> is going to rush out and write a bit of Machine language I think it is
> still
>>> important to know how. It's sort of like saying it's not important to
> know
>>> that there is a linker and what it does most people on this list will
> never
>>> know what the linker does because they deal mainly with High level
> languages
>>> but that doesn't mean the linker is not important. Most people will
> never
>>> write machine language but when creating electronic circuits with
smaller
>>> chips it is a useful tool. True you may never hand write it but in
> creating
>>> hardware it is very useful in reading it. I just found learning to
write
> it
>>> was very useful back in the good old Hack hardware cartridges days.
Sure
>>> the Intel book has both got bigger and more complex but I just saw a
post
>>> where a guy wrote a hello world in Machine language just to prove it
> could
>>> be done. Now I will point out he did it in Linux and he had to make his
> own
>>> linker of sorts well a shell linker all it did was write the file with
> the
>>> numbers he wanted but I think he did that just so he could use a normal
>>> editor and he had to add the Aelf stuff on top but he did it in 120
bites
>>> which I find pretty impressive since 80 of the bites were AELF stuff.
>>> Anyway I am sure we are boring most of the people on this list.
>>>
>>> Ken
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Christopher
>>> Coale
>>> Sent: Saturday, April 09, 2011 7:39 PM
>>> To: programmingblind@xxxxxxxxxxxxx
>>> Subject: Re: Searching for blind programmer to start a school for blind
>>> programmers
>>>
>>> Wait, you are adding new stuff in here. Yes, to me, it is important to
>>> know how to optimize code for either size or speed. It is also important
>>> to know how programs are executed and created (knowing the PE32 format,
>>> for example); however, knowing how to write a program by scratch by
>>> using a hex editor and writing pure byte code is not important. And, you
>>> are misinterpreting my reason for saying it is not important. I'm not
>>> saying it's not important because it is nasty studying. I'm saying it is
>>> not important because it is simply not practical and teaches you no more
>>> than studying assembly and operating systems (assuming you are actually
>>> learning). And I didn't say it wasn't useful, either. Knowledge for
>>> knowledge's sake is always good. But, I said it wasn't important. You
>>> seem to be mixing up the knowledge required to do something and the
>>> knowledge gained from doing said thing. In order to start editing a
>>> program using a hex editor, you have to already have the knowledge to do
>>> it (as in, you have to know that there is a data section, a symbolic
>>> table, etc.). You gain no new knowledge (aside from knowing how to edit
>>> executables) from editing, and/or writing, executables from within a
>>> hex-editor.
>>>
>>> On 4/9/2011 3:59 PM, Ken Perry wrote:
>>>> Oh really? I found it very useful knowing how to minimize code and
data
>>>> sections by hand. It explains what compilers and linkers have to go
>>> through
>>>> and ways to get around problems that exist. It even is nice knowing
how
>>> exe
>>>> files are laid out. I agree that it's a nasty bit of study to get to
> that
>>>> point but I totally disagree that the knowledge is not useful. In fact
> if
>>>> you ever want to get involved with the GNU compiler group believe me
> it's
>>>> useful.
>>>>
>>>>
>>>> Ken
>>>>
>>>> -----Original Message-----
>>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Christopher
>>>> Coale
>>>> Sent: Saturday, April 09, 2011 6:52 PM
>>>> To: programmingblind@xxxxxxxxxxxxx
>>>> Subject: Re: Searching for blind programmer to start a school for blind
>>>> programmers
>>>>
>>>> My knowledge of how the processor works (by means of knowing assembly
>>>> and OS development) is useful. Knowing how to write a program using
only
>>>> byte code is not (and I couldn't do it without many free hours and lots
>>>> of reference manuals, and even then it would be a difficult task). Not
>>>> to belittle your knowledge, but I'm just saying that being able to
write
>>>> a program using a hex-editor (and if you can, more power to you) is not
>>>> very helpful in understanding how computers work; learning assembly and
>>>> learning operating system design is where it is important, I would say.
>>>>
>>>> On 4/9/2011 3:45 PM, Ken Perry wrote:
>>>>> Yes and us true geeks used to dream hex in our sleep. I think there
> are
>>>>> still some of us left and I am no longer one, I know of all the
>>>>> possibilities and I can still code in ASM for burning chips but I no
>>>> longer
>>>>> dream in op codes and registers, memory locations and IRQ's. All I
was
>>>>> saying is learning of the existence and how it works is invaluable to
a
>>>>> programmer even today. Are you telling me your knowledge of the
> subject
>>>> is
>>>>> not useful?
>>>>>
>>>>> Ken
>>>>>
>>>>> -----Original Message-----
>>>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of
Christopher
>>>>> Coale
>>>>> Sent: Saturday, April 09, 2011 3:30 PM
>>>>> To: programmingblind@xxxxxxxxxxxxx
>>>>> Subject: Re: Searching for blind programmer to start a school for
blind
>>>>> programmers
>>>>>
>>>>> I didn't say it was impossible (after all, how else would a compiler
>>>>> work?) I said that it was asinine and impractical. I say this because
>>>>> the x86 instruction set is amazingly complex. Sure someone could use a
>>>>> debugger to look around at machine code, that's not hard at all (in
>>>>> fact, I do it a lot with vc++ to debug things and get performance
>>>>> boosts). But, writing a binary file from scratch? I see it being
>>>>> possible, but you would need to know the encoding of every instruction
>>>>> you use. For example, "int imm8" is apparently 0xCD + the immediate
>>>>> byte, so to do int 80h, you'd have 0xCD80. That is fairly simple, but
>>>>> the "mov" instructions where you can have memory, immediate, and
>>>>> register operands are difficult, and then for each memory, immediate,
>>>>> and register operand you have an 8-bit, 16-bit, 32-bit, and for x64,
>>>>> 64-bit versions. It's no small feat to write a binary by hand.
>>>>>
>>>>>> Laugh yes I have read them and there was a time I could write some
> very
>>>>> good
>>>>>> stuff with nothing but a debugger. Just because it's nasty don't
mean
>>>>> it's
>>>>>> impossible. I was not even in the same class of some of the guys I
> used
>>>>> to
>>>>>> hang out with. I knew one that won a programming contest who wrote a
>>>>>> program to display a naked woman with nothing more than Assembler and
> a
>>>>> text
>>>>>> editor. As for machine language you can write it on your own if you
>>> know
>>>>>> enough. Unfortunately time has dulled my memory of useless
interrupts
>>>>>> because we have so much easier ways to do things now. I think I
could
>>>>>> probably get a command line app to run with nothing but a hex editor
> but
>>>>>> calling the GUI might be beyond me because you would have to do some
>>>>> serious
>>>>>> digging to get that to work and sometimes the information is just not
>>>>>> available anymore.
>>>>>>
>>>>>> Ken
>>>>>>
>>>>>>
>>>>>> Ken
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>>>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of
> Christopher
>>>>>> Coale
>>>>>> Sent: Saturday, April 09, 2011 2:23 AM
>>>>>> To: programmingblind@xxxxxxxxxxxxx
>>>>>> Subject: Re: Searching for blind programmer to start a school for
> blind
>>>>>> programmers
>>>>>>
>>>>>> What? Have you ever read the x86 information sheets? Teaching someone
>>>>>> assembly is a good way to teach them how a computer works -- having
> them
>>>>>> write programs in pure byte code (especially for x86) is both asinine
>>>>>> and impractical. Maybe not so much for an extremely extremely simple
>>>>>> virtual machine or basic processor, but complex instruction sets like
>>>>>> x86 are flat-out beyond writing op-codes by hand. If you don't
believe
>>>>>> me, just take a poke at the NASM source code. ;)
>>>>>>
>>>>>> On 4/8/2011 6:47 PM, Ken Perry wrote:
>>>>>>> I am not quite as old as you but I come from the same time zone. I
> had
>>>>> to
>>>>>>> learn assembler to hack games on the Vic 20 and the commodore 64 and
>>> the
>>>>>> TI
>>>>>>> but more than that when I joined the Air Force and took on
> Electronics
>>>>>>> Assembler made my life easier. Then later in life after I lost my
> site
>>>> I
>>>>>>> took software engineering and had to burn chips and while we could
> have
>>>>>>> wrote stuff in C it was much easier to control the registers and
> stuff
>>>>>> with
>>>>>>> ASM. If we used C we allot of the time had to use special assembler
>>>>>>> keywords to get things to work quite right. If you look on the
Fruit
>>>>>> Basket
>>>>>>> page I was also insane enough to write the fruit basket in Assembler
>>> for
>>>>>>> windows xp and it runs in vista. I am not sure if that runs in
> Windows
>>>> 7
>>>>>>> but I should revisit it and make sure it does. Lost knowledge is
not
> a
>>>>>> good
>>>>>>> thing. Assembler may not be a way I would write a project now days
> but
>>>>> if
>>>>>>> you want to teach someone how your computers work there is only one
>>>> thing
>>>>>>> better. The one thing better is straight opt codes using a debugger
>>> and
>>>>>>> watching what is going on. Well you could also write straight
binary
>>>>>> files
>>>>>>> like a good Fortran coder but who does that any more. That what I
>>>> should
>>>>>> do
>>>>>>> is create the fruit basket with nothing but a hex editor.
>>>>>>>
>>>>>>> Ken
>>>>>>>
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: programmingblind-bounce@xxxxxxxxxxxxx
>>>>>>> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Bill Cox
>>>>>>> Sent: Friday, April 08, 2011 11:40 AM
>>>>>>> To: programmingblind@xxxxxxxxxxxxx
>>>>>>> Subject: Re: Searching for blind programmer to start a school for
> blind
>>>>>>> programmers
>>>>>>>
>>>>>>> On Fri, Apr 8, 2011 at 11:16 AM, Littlefield,
>>> Tyler<tyler@xxxxxxxxxxxxx>
>>>>>>> wrote:
>>>>>>>>> Assember? Really? You must be almost as old
>>>>>>>>> as me! I can't even find people who care about speed or memory
> usage
>>>>>>>>> anymore.
>>>>>>>> I love assembler. It's a great way to teach people what's going on
>>>> under
>>>>>>> the
>>>>>>>> hood and make them think about what they do. Every time I see
> someone
>>>>>>>> reserve a 100k buffer just because, I cringe. :)
>>>>>>> We must be from the same generation. I'm 47, and learned to program
>>>>>>> in machine code on an 8080 based Intel board with a hex keypad and
>>>>>>> some LEDs. It was a couple of years before I found out that people
>>>>>>> programmed using assemblers, rather than entering hex by hand.
>>>>>>>
>>>>>>> I worry that the new generation's early experience with computers is
>>>>>>> amazing games and technology so complex they could never
> realistically
>>>>>>> hope to understand it. What's the natural path now days for kids to
>>>>>>> go from playing computer games to writing them? On the old Apple
> IIs,
>>>>>>> you just typed list instead of run, and there was all the code.
>>>>>>>
>>>>>>> Bill
>>>>>>> __________
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