Trucha Bug What is this? Any info is appreciated! :Dhttp://forum.wiibrew.org/read.php?24,21853,21853#msg-21853Wed, 22 Apr 2026 04:04:04 +0200 Phorum 5.2.23 http://forum.wiibrew.org/read.php?24,21853,22023#msg-22023 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,22023#msg-22023
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PhoenixTank
nice, albeit problematic slide show.
That's an understatement :-P, but yes it was very informative.]]> Kage52124 Getting StartedWed, 24 Jun 2009 20:15:37 +0200 http://forum.wiibrew.org/read.php?24,21853,21961#msg-21961 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21961#msg-21961http://www.youtube.com/watch?v=lyVuY_S5VcI&feature=PlayList&p=72658A55B19C8634&index=0
Unfortunately, I forget how far into the video(s) it is. Either way, this should practically be considered "required reading" if you are wanting to start to learn.
Enjoy!]]> PhoenixTank Getting StartedWed, 24 Jun 2009 07:26:56 +0200 http://forum.wiibrew.org/read.php?24,21853,21957#msg-21957 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21957#msg-21957 WaxyPumpkin72 Getting StartedWed, 24 Jun 2009 06:36:37 +0200 http://forum.wiibrew.org/read.php?24,21853,21891#msg-21891 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21891#msg-21891
EDIT: btw I was just curious :-P]]> Kage52124 Getting StartedWed, 24 Jun 2009 03:16:56 +0200 http://forum.wiibrew.org/read.php?24,21853,21886#msg-21886 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21886#msg-21886
[wiibrew.org]


I did not find it half a hour ago and now I stumbled upon it while reading about Datel's freeloader.
If I found it earlier I could have saved me from writing a wall of text :D
At least I learned something in the process :D]]> daniel_c_w Getting StartedWed, 24 Jun 2009 03:07:53 +0200 http://forum.wiibrew.org/read.php?24,21853,21882#msg-21882 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21882#msg-21882
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Kage52124
Sorry to be picky, but isn't it actually not 0, but /0 ?

The byte has a value of 0.
"\0" is just a way to write that that in C.

(I assume you meant "\0" not "/0")


Be as picky as you can, please. A complex topic like this requires that.
Is anything not clear?]]> daniel_c_w Getting StartedWed, 24 Jun 2009 02:55:36 +0200 http://forum.wiibrew.org/read.php?24,21853,21881#msg-21881 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21881#msg-21881 Kage52124 Getting StartedWed, 24 Jun 2009 02:50:49 +0200 http://forum.wiibrew.org/read.php?24,21853,21877#msg-21877 Re: Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21877#msg-21877
Before data is executed or copied to the Wii, a mathematical function returns a rather unique and very large number, it's hash. That number is then stored in memory and will be compared to another number in the signature that comes along with the data.
For reasons that would take a lot of text to explain just consider the second number to be secure.

Both numbers are now present, and the Wii compares them. If they are equal, it will it to be executed or copied, or whatever.

Though it is not known what the real source code looks like, it is very likely, that the programmer responsible for the signature check used the c library function "strncmp", instead of "memcmp".
Both compare memory areas, byte for byte, but strcmp does handle the memory as a string (str).
Strings usually contain printable bytes and can have any length.
In many implementations a byte filled with zeros is considered to mark the end of a string, that's called a "null terminated string".
If the function "strncmp" finds a byte full of zeros, it will consider it to be the end of a string.
If the part before the zero byte is equal, both strings are considered equal, or at least the code found on the wii does.
An exception is the first byte, it has to be a match. A byte on the Wii can have 256 differnet values.

A fake signature can be created easily by testing all 256 combinations for the first byte, on will be a match, and setting the second byte to 0.

This takes just about a second.

If the bug were not present, we would have to try a lot more combinations: a 15 with 47 zeros behind.]]> daniel_c_w Getting StartedWed, 24 Jun 2009 02:37:08 +0200 http://forum.wiibrew.org/read.php?24,21853,21853#msg-21853 Trucha Bughttp://forum.wiibrew.org/read.php?24,21853,21853#msg-21853 WaxyPumpkin72 Getting StartedTue, 23 Jun 2009 23:41:16 +0200