Turning a SIGSEGV into a regular function call under Linux, allowing throw

[Vladimir Panteleev]

On Tuesday, 13 March 2012 at 10:09:55 UTC, FeepingCreature wrote:
> However, there is a method to turn a signal handler into a 
> regular function call that you can throw from.

Very nice!

The only similarity with a buffer overflow exploit is that we're 
overriding the continuation address. There is no execution of 
data, so it's closer to a "return-to-libc" attack. This is a very 
clean (and Neat) solution.

Here's a D implementation without inline assembler. It's 
DMD-specific due to a weirdness of its codegen.
http://dump.thecybershadow.net/20f792fa05c020e561137cfaf3d65d7a/sigthrow_32.d

The 64-bit version is a hack, in that it clobbers the last word 
on the stack. If the exception was thrown right after a stack 
frame was created, things might go ugly. The same trick as in my 
32-bit implementation (creating a new stack frame with an 
extern(C) helper) won't work here, and I don't know enough about 
x64 exception handling to know how to fix it.
http://dump.thecybershadow.net/121efc460a01fb4597926ec76352a674/sigthrow_64.d

I think something like this needs to end up in Druntime, at least 
for Linux x86 and x64.