Name glitches

2006-05-07 06:41:37 pm

First of all I know I should've posted this in the glitches topic, but it kinda seems different... How come some players have more letters like 15 in their license and some names flash in a glitchy manner...
There was a discussion on GFQS but I don't remember...

Thread title:

primetime

2006-05-07 07:25:14 pm

Yeah, I saw that with one person. Their name was a bunch of random characters and it went off the screen. I have no idea why it happened though.

Derek

2006-05-07 08:29:07 pm

I've seen it once, and I saw a bunch of topic about it at the Nintendo WiFi forums, but I've never seen an explanation.

SkippyJr

2006-05-07 08:56:01 pm

printf() strikes again!

It appears that the player name is at some time copied through some form of sprintf() or the like. The printf() family of functions read strings and pull out %<something> as a sign to replace those placeholders with a number, string, or whatever. (It gets more complicated than that, but that's the gist of it.)

Example: printf("There are %d metroid games.", 9);
Becomes: There are 9 metroid games.

%d = integer, %x = hex number, %f = float, %g = double, %s = string

In the YouTube videos, you can see %g (from "%g%u%e%s%s") and %x.

Why the funny values? Because printf() has to replace those tokens with something, and it just happens to be some other info (on the stack or some such thing).

It makes sence that %s could break the game as it copies memory until it runs into a null byte. And it copies that looong string of data overtop of possibly really important information. Haha, Hunters has a buffer overflow. Laughing

As to why it only works on the first, leading %, your guess is as good as mine.

printf() strikes again!

It appears that the player name is at some time copied through some form of sprintf() or the like.  The printf() family of functions read strings and pull out %<something> as a sign to replace those placeholders with a number, string, or whatever.  (It gets more complicated than that, but that's the gist of it.)

Example:  printf("There are %d metroid games.", 9);
Becomes: There are 9 metroid games.

%d = integer, %x = hex number, %f = float, %g = double, %s = string

In the YouTube videos, you can see %g (from "%g%u%e%s%s") and %x.

Why the funny values?  Because printf() has to replace those tokens with something, and it just happens to be some other info (on the stack or some such thing).

It makes sence that %s could break the game as it copies memory until it runs into a null byte.  And it copies that looong string of data overtop of possibly really important information.  Haha, Hunters has a buffer overflow.  :lol:

As to why it only works on the first, leading %, your guess is as good as mine.

Falcomi

2006-05-08 10:43:35 pm

I wonder if you can get your whole name to go crazy like the numbers are on steroids. :?