19 Jan
2006
19 Jan
'06
2:47 p.m.
On 1/19/06, Steven Edwards <winehacker(a)gmail.com> wrote:
This analogy is invalid. The legality of this issue stems directly
from whether or not he wrote the code. Robbing a bank is _always_
illegal, writing code is only illegal if you copy/paste it from a
legitimate author, or implement a patented method.
Alex's structured and commented code demonstrates comprehension. In
this case, where the code's function is clear, and constrained by
implementation details, the code will be similar by anyone who
implements it. Alex's comments and code structure shows that he
understands what is going on in the assembly, and most likely shows
that he wrote the code, as opposed to just copy/pasting existing code.
It only looks suspicious since you are not a kernel developer. Again,
not something a judge would concern himself with. Now the
prosecutor.....
Hi,
Speaking as someone that is mostly ignorant of kernel internals, lets
pretend I am a judge....
You are not a judge with years of experience in law. Whether or not
you have any kernel internal knowledge is also irrelevant to this
thought experiment.
On 1/18/06, Alex Ionescu <ionucu(a)videotron.ca> wrote:
Alex clearly stated that there is only one way to perform that stack
check, let's quote him properly:
"Note however, that there is only one way to check the stack: cmp ebp,
esp. Unless you want to consider cmp esp, ebp as an alternate method."
As Casper said, it is legal to use that information, but not legal to
*copy/paste* it into ReactOS. Alex clearly comprehends what that bit
of assembly does.
Yes, when I analyzed the fast call code (yes I
looked at disassembly) I
saw that check, and I copied it.
Why did you have to do this? Is it not possible to write a driver that
abuses fastcall to make a mostly working implementation without having
to 1. look at and 2. copy the existing object code of Windows? I would also like to point out that unlike
certain code which I've found
in ReactOS (The old ftol implementation comes to mind) which comes from
assembly, my code is clearly commented, organized and structured, and
shows that I know what I was doing any not merely copy/pasting some
OK so someone else sneaked something in that violates the rules and it
was not caught. Lets just check your argument for a moment and say you
could be wrong about your development methods. Being ..."clearly
commented, organized and structured..." does not amount to a hill of
beans if I am violating the law and or project rules. I can make bank
robbing plans that are "...clearly commented, organized and
structured..." I don't think that will gain me much ground in court. assembly. This is much unlike the old ftol code,
which was simply an
exact 100% duplicate of the windows code, with 0 comments and using
hardcoded values which were not explained (clearly showing that the
implementer had no idea of what the code did).
Can you explain to me why the magic numbers match Windows in
ke/i386/trap.s? Like I said I am mostly ignorant of kernel internals
but this was asked of me...
The code in ke/i386/trap.s looks kind of suspicious, because it uses
alot of magic numbers...
/* Push previous mode */
push UserMode
/* Skip the other registers */
sub esp, 0x48
/* Hack: it seems that on VMWare someone damages ES/DS on exit.
Investigate! */
mov dword ptr [esp+KTRAP_FRAME_DS], KGDT_R3_DATA + RPL_MASK
mov dword ptr [esp+KTRAP_FRAME_ES], KGDT_R3_DATA + RPL_MASK
/* Make space for us on the stack */
sub ebp, 0x29C
ie. why 0x29C, why 0x48?
Since he is making room on the stack for another frame, this is a
predefined size.
--
Steven Edwards - ReactOS and Wine developer
Alex's explanation (in conjunction with Casper's clarification of our
rules) was enough to satisfy me. I do not think Alex violated the
project rules, and the legality of his code can only be decided in a
court of law, so we are just wasting our time talking about it any
further. Now, I do agree he could have used the safer "clean-room"
method, but I'm not convinced that it would have yielded a
significantly different implementation, and we might still be in the
same position.
IANAL, BIPOOI,
WD
--
(but I play one on IRC) ;0)