31–40 of 66 posts
I love reading weird bug stories like this. Is there a place where lots of these types of stories are aggregated? Maybe a book about them?
* F-Secure's blog and some other AV companies' blogs
* Ramond Chen's The Old New Thing
* Anything written by Mark Russinovich
* Slightly off topic, but http://www.devttys0.com/ manages some crazy reverse engineering feats, which I feel are similar to this story.
We tracked it down to a switch that was corrupting packets enough that the TCP checksum wasn't sufficient protection, and the packets would simply pass their checksum despite having been altered.
The out come was that we always use compression, or encryption, as an added layer of protection.
Off-topic: can someone provide a good reason why SSH w/ the HPN patches is not the default for every SSH install on every platform? Today, people are relying on SSH for binary transfer more than ever. SFTP and SCP are the new defacto file transfer standards between machine to machine over a secured connection. Source control like GIT (or even SVN) make heavy use of binary transfers over SSH. The performance benefit t…
I had a similar problem, less hairy, involving a bad bit in a disk drive's cache RAM. Took a day or so to figure out a solid repro.
Stuff like this does happen. Handling bit errors in consumer electronics storage systems is an interesting problem, and one that I'd love to see more attention paid to.
Reminds me of a problem I had with a T1 circuit corrupting packets. Shortly after bringing up a second T1 into a remote location we discovered that some web pages would show broken JPG images at the remote site. Some troubleshooting revealed that this only happened when traffic was routed over the new T1. The old T1 worked just fine. Pings, and other IP traffic seemed to work over either line but we kept seeing the b…
The way he diagnosed it was to do a transfer of /dev/zero out one link. It worked. But it stopped almost immediately out the problem link. It turned out to be the same problem -- no zero bit stuffing configured on the line.
By the way, this same technique, known as "weak bits", was used as a floppy and CD/DVD copy protection scheme.
Reminded me of this: http://www.ibiblio.org/harris/500milemail.html
The numbers in this story do not add up. For a connection to be made within 3ms, there needs to be a round-trip within that time, which reduces the maximum possible radius by half.
Reminds me of a problem I had with a T1 circuit corrupting packets. Shortly after bringing up a second T1 into a remote location we discovered that some web pages would show broken JPG images at the remote site. Some troubleshooting revealed that this only happened when traffic was routed over the new T1. The old T1 worked just fine. Pings, and other IP traffic seemed to work over either line but we kept seeing the b…
Can anybody think of an explanation why the 'bug' happened only after the 576th byte?
I loves me some speculation! Here goes: 576 decimal looks like this in other common bases: binary: 0000 00010 0100 0000 octal: 1100 hexadecimal: 240 My first inclination would be a firmware problem: was it upgraded recently? Are there any known problems with the version that was installed? Did you build it yourself? If we have access to the code, the information about the 'shape' of 576 may come in handy. Or maybe we…
In practice, on the modern Internet, you'll see tons of packets larger. So who knows; perhaps some massively outdated optimization in an ASIC somewhere resulted in different hardware paths for >576 bytes.
Off-topic: can someone provide a good reason why SSH w/ the HPN patches is not the default for every SSH install on every platform? Today, people are relying on SSH for binary transfer more than ever. SFTP and SCP are the new defacto file transfer standards between machine to machine over a secured connection. Source control like GIT (or even SVN) make heavy use of binary transfers over SSH. The performance benefit t…
Off-topic: can someone provide a good reason why SSH w/ the HPN patches is not the default for every SSH install on every platform? Today, people are relying on SSH for binary transfer more than ever. SFTP and SCP are the new defacto file transfer standards between machine to machine over a secured connection. Source control like GIT (or even SVN) make heavy use of binary transfers over SSH. The performance benefit t…
The none cipher switch was always a turn off for a lot of people.
Even when enabled, it'll only not encrypt binary blobs; TTY input will remain encrypted. Obviously many times that is not an option, but sometimes it is.