Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Thursday September 06 2018, @03:28PM   Printer-friendly
from the Security-is-hard,-mmmmkay? dept.

Back when Intel introduced the 80286, they didn't quite document everything right away. Errata were needed. Then the 80386 changed things. And then someone convinced them to add just one more feature at the last minute, which didn't get documented properly again.

The History of a Security Hole takes a look at the problems introduced by the I/O Permission Bitmap (IOPB) in the 80286, and how fallout from the implementation caused a security hole in all versions of OpenBSD up to 6.3 and NetBSD up to 4.4.

Conclusion? This programming thing is hard.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 4, Informative) by Bot on Thursday September 06 2018, @09:13PM (2 children)

    by Bot (3902) on Thursday September 06 2018, @09:13PM (#731511) Journal

    AFAIK you can use mknod or even better MAKEDEV using the same major minor combination as dev/null (1 and 3). It's still cheating because it's the same device, but I don't see the point to patch the kernel to instantiate more of them.
    "Now although the major:minor combination uniquely identifies specific device instances, there's nothing to stop you creating multiple devices nodes (files) that refer to the same device. They don't even have to be created in /dev (but they do have to be on a filesystem that supports creating device nodes, and isn't mounted with the nodev option)".

    For getting dev nodes in a chroot you are usually instructed to mount --bind the device files.

    --
    Account abandoned.
    Starting Score:    1  point
    Moderation   +2  
       Informative=2, Total=2
    Extra 'Informative' Modifier   0  
    Karma-Bonus Modifier   +1  

    Total Score:   4  
  • (Score: 1, Interesting) by Anonymous Coward on Friday September 07 2018, @12:20AM

    by Anonymous Coward on Friday September 07 2018, @12:20AM (#731580)

    beat me to suggesting mknod

    mknod -m666 /dev/null$i c 1 3

  • (Score: 2) by DannyB on Friday September 07 2018, @03:57PM

    by DannyB (5839) Subscriber Badge on Friday September 07 2018, @03:57PM (#731803) Journal

    The reason I had asked about a kernel patch was because I didn't know whether /dev/null was part of the kernel in the sense of /proc or /sys. But actually I did know this from reading about 15-18 years ago. It just didn't strike me until you mentioned it. Then I was like: oh, yeah, right! Not something I would have thought of on my own.

    Thanks for the great (snicker) approach to scaling if you are doing too much IO to /dev/null. :-)

    --
    People today are educated enough to repeat what they are taught but not to question what they are taught.