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From: Jamie Landeg-Jones <jamie@dyslexicfish.net>
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Date: Mon, 21 Apr 2014 03:10:22 +0100
To: na@rtfm.net, jamie@dyslexicfish.net
Subject: Re: De Raadt + FBSD + OpenSSH + hole?
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Nathan Dorfman <na@rtfm.net> wrote:

> free() doesn't usually "free memory back to the system." It just puts
> it back onto a "free list" managed by libc, entirely within the
> process's address space.
>
> "Use after free" is actually a rather common type of bug -- do a web
> search on that term to see just how often it comes up.

Ahhh, so (simplifying it here somewhat), malloc/free don't always affect
the kernels own representation of the processes memory allocation, as
part of libc behaves a bit like a cache - buffering and managing requests
in userspace, so as to make things run more efficiently.

Thanks for the reply - my question wasn't quite as stupid as I feared!

Cheers, Jamie