That is both pretty impressive and horrific.
I wonder if they patched this way because they wanted to maintain as much binary compatibility as possible, or if they don't have the original source/couldn't reproduce the build process.
I wonder if they patched this way because they wanted to maintain as much binary compatibility as possible, or if they don't have the original source/couldn't reproduce the build process.
Compiling the software with a modern compiler or linking to a modern runtime is very likely to bring obscure bugs in the codebase to the surface. It's pretty hard to replicate the entire build process that produced the original binary, even if they have the source code and everything else on hand.
Horrific, because the average programmer would consider patching the binary a worst-case scenario.
> there is nothing wrong about patching a binary
I would only trust a skilled assembly programmer to do this task without creating other problems, and most businesses don't have those on retainer.
That says more about the average programmer than it does about the reasonableness of binary patches.
I used to table in MASM on the 8088 and have dabbled a little on microcontrollers (6800) as well. But the last time I looked at modern x86, I was pretty lost.
I seem to recall Microsoft rebuilds everything from source daily (or weekly?). This is a common practice in companies with a large code base. "Nightly Builds" even come from Mozilla. The reason is simple - if you wait until it's time to release, you're gonna have problems. Even if a developer tests his changes locally, they need to be integrated in with everything else and retested.
If you're really serious about things you will have your tool chain under revision control. As a result you can reproduce binaries to the byte from source code, with the possible exception of embedded dates pulled in at compile time. This is actually a good fallback when someone finds a critical problem in old code - you start by finding the code and then verify by reproducing the affected binary from source. This is not technically hard, it requires discipline and best practices.