Wikipedia:Reference desk/Archives/Computing/2007 August 2

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[edit] August 2

[edit] trying to recall...

I seem to remember reading a very old (10+ years probably) proposed change to the linux kernel code.. it was an ingenius 1 or 2 character change that would allow an attacker to easily escalate priviliges to root. I think it was inside a conditional. Anyone know what I'm talking about / have a link? --frotht 05:45, 2 August 2007 (UTC)

It was in 2003. The nature of the patch was that some code like:
  if (current_process->uid == 0)
was changed to:
  if (current_process->uid = 0)
, so that rather than testing to see if the user ID was zero (i.e., root), it was actually setting it to zero, thus giving that process full privileges. Here is a thread about it.
This is a weakness of the C language, as that's a very easy thing to miss, and programmers will routinely do the same thing by accident. Some programmers adopt the practice of putting the constant first in the comparison so that the compiler will flag any assignment attempts. --TotoBaggins 15:12, 2 August 2007 (UTC)
Thats a weakness of the programmers, not in C. = is for assignment and == for comparison. How is that a weakness?--Dacium 06:12, 9 August 2007 (UTC)
Oh 2003 really? Well I'm pretty sure that's what I was looking for, thanks. Doesn't seem so ingenious anymore to be honest. You know what, I think the actual code invoved a lot of heavily nested parentheses and bitwise operators or something so the = sign was lost in all the symbols. --frotht 17:38, 2 August 2007 (UTC)
Yes, it was obscured and easily missed. There was a CVS to BitKeeper gateway machine that was broken into, and the change was made there, so I think the hope was that it would only get a cursory review. --TotoBaggins 18:06, 2 August 2007 (UTC)

[edit] Printing Problems

I have a Dell inkjet printer, and despite a full cartridge fails to print blue. I ran the auto nozzle cleaning process a few times, and it still won't work. How can I fix it? Thanks a lot. -- Sturgeonman 13:53, 2 August 2007 (UTC)

The cartridge may happen to be broken.. Considering the fact you'll eventually need to buy another cartridge someday, I would recommend to buy a new one and see if that fix the problem. Other than that I would need more info to help you out like. Is it a new printer ? did the problem appear just after changing the cartridge ? When did the problem appear ? --PhoenixQc 18:38, 2 August 2007 (UTC)
If the cartridge is okay then probably the print head is defective. The last time I priced a print head for both my old Canon inkjet and my dad's HP the cost of the head was almost as much as a new printer. -- Finlay McWalter | Talk 22:22, 2 August 2007 (UTC)

[edit] Ghosts

Are the ghost files remaining from the copying of my hard-drive necessary, or can I delete them without repercussions? Crisco 1492 17:13, 2 August 2007 (UTC)

If you are talking about Symantec Ghost .gho files, thoses are backup of hard drives or partitions used to restore content at the point of their creation, they are not needed for your system to work. Consider em as a save point of your data. If you dont need those anymore you can delete em safely. --PhoenixQc 18:33, 2 August 2007 (UTC)
Thanks. You just cleared up 50 gb of useless memory LOL. I had never run into that file type before. Crisco 1492 23:45, 2 August 2007 (UTC)
I should point out that this limits the usability of Ghost somewhat :) You should really have a backup, in case your HD konks out. --Oskar 08:09, 3 August 2007 (UTC)

[edit] source to jar and losing path

the icons for my program are stored in images folder in source folder. the code is in source folder. when i build out of eclipse it works, but when i build a jar the icons cant be found by the progam, probably because the paths arent saved. how do i fix this; how do i make the images included in the jar?--65.222.152.28 17:58, 2 August 2007 (UTC)

Did you mean this jar? If so, go to the "Archiving subdirectories" section. --Wirbelwindヴィルヴェルヴィント (talk) 22:05, 2 August 2007 (UTC)

[edit] Microsoft Office Communicator 2007

I see an awful lot of sources claiming it will come out Q2 2007, but the official page seems ambiguous. Has it been released? And how do they claim it comes with Office 2007 Enterprise if that was released last fall? --frotht 19:00, 2 August 2007 (UTC)