small team has been working on finding an exploit for v2.00 based on the fact that $ony uses part of the "libtiff" code for its Image Viewer in v2.00, which has a known bug. Apparently they've managed to exploit this bug as it appears this "proof of concept" has already been confirmed (by dppodge and many other v2.00 owners) as a working exploit for the 2.00 PSP firmware... so basically it's just a matter of time until some more useful code using this exploit is released. The related files are available HERE, and to quote from K3nt's post in THIS Forum thread:
Quote:
First Homebrew Code on 2.00
1. Set wallpaper to frame_buffer.png (without overflow.tif present in the PHOTO directory, or it will crash).
2. Add overflow.tif to the PHOTO directory, and open into the photo viewer. Custom code to paint the screen! Or to write a homebrew app! Not to run illegal games.
How It Works?
1. The PNG contains a small amount of code in a known, fixed place (the VRAM). If to look closely at the wallpaper, sees small coloured pixels in the right down. The pixels are Allegrex opcodes, with the highest byte all zero for the ALPHA. These pixels do:
syscall 0x20C7 ; sceKernelDcacheWritebackInvalidateAll
slt a0, zero, sp ; put 1 into a0
sll a0, a0, 6 ; put 64 into a0
addiu a0, sp, a0 ; get screen painter address over SP
jr a0 ; jump to the screen painter
nop ; branch delay slot
2. The TIFF contains also some code and a buffer to trigger the known BitsPerSample overflow in libtiff in the photo viewer. The buffer makes a jump to the VRAM which has the PNG colours by overwriting the safed ra (return address) on the stack. The VRAM code uses SP and calculates the address of the buffer then runs it. Then it jumps there. The screen is yellow as the colour was 0x12345678 in Hex.
PSP Users:
We didn't do this so you could steal from $ony and game companies. We believe in OSS. There are plenty of amazing programs that have been written for the PSP. Use this as a gift and not as an excuse to steal.
$ony:
If you wanted to find us i know you could. This release wasn't intended as a way to run pirated software on the PSP. We believe that everyone should be able to compile their own code and run it. Nothing is kept secret forever and i'm sure you know this. In the end, if it wasn't us. It would be some one else. Fighting it would be like skating up a hill. You did create the PSP and did an amazing job.
Toc2rta:
To the people of the Toc2rta development network. You're our phone a friend. With out your friendship this would never of happened. I hope this brings you as much happiness as it brings us. Join us on irc.toc2rta.com.
Most importantly... Have fun!"
Quote:
First Homebrew Code on 2.00
1. Set wallpaper to frame_buffer.png (without overflow.tif present in the PHOTO directory, or it will crash).
2. Add overflow.tif to the PHOTO directory, and open into the photo viewer. Custom code to paint the screen! Or to write a homebrew app! Not to run illegal games.
How It Works?
1. The PNG contains a small amount of code in a known, fixed place (the VRAM). If to look closely at the wallpaper, sees small coloured pixels in the right down. The pixels are Allegrex opcodes, with the highest byte all zero for the ALPHA. These pixels do:
syscall 0x20C7 ; sceKernelDcacheWritebackInvalidateAll
slt a0, zero, sp ; put 1 into a0
sll a0, a0, 6 ; put 64 into a0
addiu a0, sp, a0 ; get screen painter address over SP
jr a0 ; jump to the screen painter
nop ; branch delay slot
2. The TIFF contains also some code and a buffer to trigger the known BitsPerSample overflow in libtiff in the photo viewer. The buffer makes a jump to the VRAM which has the PNG colours by overwriting the safed ra (return address) on the stack. The VRAM code uses SP and calculates the address of the buffer then runs it. Then it jumps there. The screen is yellow as the colour was 0x12345678 in Hex.
PSP Users:
We didn't do this so you could steal from $ony and game companies. We believe in OSS. There are plenty of amazing programs that have been written for the PSP. Use this as a gift and not as an excuse to steal.
$ony:
If you wanted to find us i know you could. This release wasn't intended as a way to run pirated software on the PSP. We believe that everyone should be able to compile their own code and run it. Nothing is kept secret forever and i'm sure you know this. In the end, if it wasn't us. It would be some one else. Fighting it would be like skating up a hill. You did create the PSP and did an amazing job.
Toc2rta:
To the people of the Toc2rta development network. You're our phone a friend. With out your friendship this would never of happened. I hope this brings you as much happiness as it brings us. Join us on irc.toc2rta.com.
Most importantly... Have fun!"
(no doubt GTA will too)
