On 06/30/2015 01:33 PM, Chris Angelico wrote:
From the software's point of view, it has two distinct
modes: server, in which it listens on a socket and receives data, and
client, in which it connects to other people's sockets and sends data.
As such, the "server" mode is the only one that receiv
On 06/29/2015 03:49 PM, Jon Ribbens wrote:
On 2015-06-29, Randall Smith wrote:
Same reason newer filesystems like BTRFS use checkusms (BTRFS uses
CRC32). The storage machine runs periodic file integrity checks. It
has no control over the underlying filesystem.
True, but presumably neither
On 06/29/2015 10:00 PM, Steven D'Aprano wrote:
On Tue, 30 Jun 2015 06:52 am, Randall Smith wrote:
Not sure why you posted the link. The crc32 checksum is just to check
for possible filesystem corruption. The system does periodic data
corruption checks. BTRFS uses crc32 checksums
On 06/27/2015 01:50 PM, Steven D'Aprano wrote:
On Sun, 28 Jun 2015 03:08 am, Randall Smith wrote:
Though I didn't mention it in the description, the storage server is
appending a CRC32 checksum for routine integrity checks. So by the time
the data hits the disk, it will have added
On 06/28/2015 09:21 AM, Jon Ribbens wrote:
On 2015-06-27, Randall Smith wrote:
Thankyou. Nice points. I do think given the risks (there are always
risks) discussed, a successful attack of this nature is not very likely.
Worse case, something that looks like this would land on the disk
On 06/27/2015 07:38 AM, Grant Edwards wrote:
On 2015-06-26, Randall Smith wrote:
The only person who can read a file is the owner.
That's always the plan, but many a successful exploit has been based
on breaking that assumption. If privacy actually matters, that's not
a good ass
On 06/27/2015 03:29 AM, Peter Otten wrote:
Would it be sufficient to prepend the chunk with one block, say, of random
data? To unmangle you'd just strip off that block.
BLOCK = os.urandom(BLOCKSIZE)
def mangle(source, dest):
dest.write(BLOCK)
shutil.copyfileobj(source, dest)
def un
On 06/26/2015 08:21 PM, Chris Angelico wrote:
On Sat, Jun 27, 2015 at 6:09 AM, Randall Smith wrote:
Give me one plausible scenario where an attacker can cause malware to hit
the disk after bytearray.translate with a 256 byte translation table and
I'll be thankful to you.
The entire 256
On 06/26/2015 05:42 PM, Johannes Bauer wrote:
On 26.06.2015 23:29, Jon Ribbens wrote:
While you seem to think that Steven is rampaging about nothing, he does
have a fair point: You consistently were vague about wheter you want to
have encryption, authentication or obfuscation of data. This sugg
On 06/26/2015 04:07 PM, Johannes Bauer wrote:
You consistently were vague about wheter you want to
have encryption, authentication or obfuscation of data.
I knew (possibly extra) encryption wasn't necessary at this stage, but I
also knew that encryption would provide good obfuscation. Problem
On 06/26/2015 04:55 PM, Mark Lawrence wrote:
To be perfectly blunt I gave up days ago trying to follow what was being
said, just too many words from all angles and too few diagrams for me to
follow. I sincerely hope it doesn't end in tears.
Mark.
There's not much to follow. The solution w
On 06/26/2015 12:06 PM, Steven D'Aprano wrote:
On Fri, 26 Jun 2015 11:01 am, Ian Kelly wrote:
You're making the same mistake that Steven did in misunderstanding the
threat model.
I don't think I'm misunderstanding the threat, I think I'm pointing out a
threat which the OP is hoping to just ig
On 06/24/2015 08:33 PM, Dennis Lee Bieber wrote:
On Wed, 24 Jun 2015 13:20:07 -0500, Randall Smith
declaimed the following:
On 06/24/2015 06:36 AM, Steven D'Aprano wrote:
I don't understand how mangling the data is supposed to protect the
recipient. Don't they have the abili
On 06/24/2015 11:27 PM, Devin Jeanpierre wrote:
On Wed, Jun 24, 2015 at 9:07 PM, Steven D'Aprano wrote:
But just sticking to the three above, the first one is partially mitigated
by allowing virus scanners to scan the data, but that implies that the
owner of the storage machine can spy on the f
Thanks Jon. I couldn't have answered those questions better myself, and
I wrote the software in question.
I didn't intend to describe the entire system, but rather just enough of
it to present the issue at hand. You seem to understand it quite well.
I'm now using a randomly generated 256 by
On 06/24/2015 04:24 PM, Grant Edwards wrote:
OK. But if the recipient (the server) mangles the data and then never
unmangles or reads the data, there doesn't seem to be any point in
storing it. I must be misunderstanding your statement that the data
is never read/unmangled.
When the storag
On 06/24/2015 01:29 PM, Grant Edwards wrote:
On 2015-06-24, Randall Smith wrote:
On 06/24/2015 06:36 AM, Steven D'Aprano wrote:
I don't understand how mangling the data is supposed to protect the
recipient. Don't they have the ability unmangle the data, and thus
expose themsel
On 06/24/2015 07:19 AM, Dennis Lee Bieber wrote:
Pardon, but that description has me confused. Perhaps I just don't
understand the full use-case.
Who exactly is supposed to be protected from what? You state "data
senders are supposed to encrypt" which, if the recipient doesn't
On 06/24/2015 02:44 AM, Devin Jeanpierre wrote:
How about a random substitution cipher? This will be ultra-weak, but
fast (using bytes.translate/bytes.maketrans) and seems to be the kind
of thing you're asking for.
-- Devin
I tried this out and it seems to be just what I need. Thanks Devin!
On 06/24/2015 06:36 AM, Steven D'Aprano wrote:
I don't understand how mangling the data is supposed to protect the
recipient. Don't they have the ability unmangle the data, and thus expose
themselves to whatever nasties are in the files?
They never look at the data and wouldn't care to unmangle
Chunks of data (about 2MB) are to be stored on machines using a
peer-to-peer protocol. The recipient of these chunks can't assume that
the payload is benign. While the data senders are supposed to encrypt
data, that's not guaranteed, and I'd like to protect the recipient
against exposure to n
Now that I've done some homework, everything you said is clear.
Mike Kazantsev wrote:
Pickle has nothing to do with the problem since it lay much deeper: in
the OS.
From kernel point of view, every process has it's own "descriptor
table" and the integer id of the descriptor is all the process
Mike Kazantsev wrote:
On Sat, 13 Jun 2009 02:23:37 -0500
Randall Smith wrote:
I've got a situation in which I'd like to hand one end of a pipe to
another process. First, in case you ask why, a spawner process is
created early before many modules are imported. That spawner
I've got a situation in which I'd like to hand one end of a pipe to
another process. First, in case you ask why, a spawner process is
created early before many modules are imported. That spawner process is
responsible for creating new processes and giving a proxy to the parent
process.
(
Thanks Piet. You gave a good explanation and I think I understand much
better now.
Piet van Oostrum wrote:
Randall Smith (RS) wrote:
RS> I'm trying to get a grasp on how memory usage is affected when forking as
RS> the multiprocessing module does. I've got a program with
I'm trying to get a grasp on how memory usage is affected when forking
as the multiprocessing module does. I've got a program with a parent
process using wx and other memory intensive modules. It spawns child
processes (by forking) that should be very lean (no wx required, etc).
Based on inspe
I'd like to bundle Python with my app, which will be targeted at Linux,
Windows and Mac. Discussions I've found about this tend to lead to
py2exe, freeze, etc, but I'd like to do something rather simple and am
seeking advice.
What I'd like to do is just copy the standard libraries and
execut
Jive Dadson wrote:
The traceback routine prints out stuff like,
NameError: global name 'foo' is not defined
NameError is a standard exception type.
What if I want to print out something like that?
I've determined that "global name 'foo' is not defined" comes
from the __str__ member of the
I've noticed the push by Guido and others to use absolute imports
instead of relative imports. I've always enjoyed the ease of relative
imports, but am starting to understand that "explicit is better than
implicitly" as the Python philosophy goes. I'm trying to develop a
strategy for writing
? Would it be a good idea for the software I write to check for the
version of the interpreter?
Randall Smith
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