Re: GCC Compiler Induced Vulnerability - affects programs compiled with GCC 7 and 8 containing nested functions

[Mikhail Klementev <jollheef () riseup net>]

Hello,

It was described in GCC documentation even from 2003:

https://web.archive.org/web/20030207183940/http://gcc.gnu.org:80/onlinedocs/gccint/Trampolines.html

What's difference between vulnerability you found and behavior that
was described in the documentation?

On Mon, Oct 22, 2018 at 03:07:55PM +0000, Andrew Sandoval wrote:
> ...
> Technical Description of the vulnerability
> When nested C functions are compiled by GCC, code is generated which causes the
> call stack of the currently executing thread to be made executable prior to the
> call to a nested function and for the duration of the thread's lifetime.  This
> is essentially the equivalent of disabling Data Execution Prevention (DEP).
> A stack overflow, etc., that is able to place instructions on the page(s) of
> memory made executable has the potential of gaining execution and running
> malware, etc.  This places the process at substantial risk of being exploited.
> ...

-- 
With eval and apply,
Mikhail Klementev.

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