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Re: Avoiding memory access vulnerabilities

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On Sat, 27 Feb 2016 07:15:05 GMT
anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:

> Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> writes:

> >Buffer overflows work in C because C uses a combined data stack and
> >return stack, i.e., stack frame.  
> 
> No.

Yes, that's why such attacks work in C, going all the way
back to the original Morris worm.

> Separating the return addresses is not sufficient to preventing
> arbitrary code execution.

True, but that wasn't in the scope of your original post.

> If return addresses were separate, attackers would overwrite
> function pointers.

Yes, if they can find them.  The entire reason that overflow
attacks are used is because:

1) they're easy, and
2) they work

Searching for pointers to functions in code, which may or may
not be over-writable, and which may or may not be executable,
isn't easy.  Accessing a stack with control-flow data or saved
return address via a register or simple function, such as the
return stack in Forth or a stack frame for most C implementations,
is much easier.

> >Forth words in the dictionary, while
> >they may contain an XT, are not buffers that can be written to
> >and overflowed via input and print string functions.  
> 
> Counterexample:
> 
> create buf 100 allot
> create two-xts ' . , ' . ,
> buf 1000 untrusted-file read-file

Then, you may need to separate buffer space and/or variable space
from code space and (fixed) data space.

variable space.

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Thread

Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-26 13:38 +0000
  Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-02-26 16:05 +0000
  Re: Avoiding memory access vulnerabilities Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-02-26 17:18 -0500
    Re: Avoiding memory access vulnerabilities Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-02-26 22:53 -0800
    Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 07:15 +0000
      Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-02-27 04:54 -0600
      Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-02-27 14:27 +0000
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 15:31 +0000
          Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-01 16:30 +0000
            Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-02 10:04 +0000
              Re: Avoiding memory access vulnerabilities Doug Hoffman <glidedog@gmail.com> - 2016-03-02 08:41 -0500
              Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-02 23:22 +0000
                Re: Avoiding memory access vulnerabilities humptydumpty <ouatubi@gmail.com> - 2016-03-02 22:57 -0800
                Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-03 13:50 +0000
                Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-04 21:01 +0000
                Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-06 10:55 +0000
      Re: Avoiding memory access vulnerabilities Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-02-27 11:31 -0500
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 17:14 +0000
  Re: Avoiding memory access vulnerabilities Ron Aaron <rambamist@gmail.com> - 2016-02-27 18:59 +0200
    Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 17:04 +0000
      Re: Avoiding memory access vulnerabilities Ron Aaron <rambamist@gmail.com> - 2016-02-27 19:18 +0200
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-28 14:21 +0000
  Re: Avoiding memory access vulnerabilities "Elizabeth D. Rather" <erather@forth.com> - 2016-03-02 21:18 -1000
    Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-03 10:23 +0000
      Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-03 14:22 +0000
    Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-03 04:53 -0600
      Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-03 13:15 +0000
        Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-04 04:34 -0600
          Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-04 04:56 -0600
            Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-04 12:07 +0000
              Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-04 09:48 -0600
              Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-04 17:11 +0000
          Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-04 11:55 +0000
    Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-03 11:33 +0000
      Re: Avoiding memory access vulnerabilities Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-04 20:55 -0500
    Re: Avoiding memory access vulnerabilities Mark Wills <markwills1970@gmail.com> - 2016-03-05 02:55 -0800
      Re: Avoiding memory access vulnerabilities "Elizabeth D. Rather" <erather@forth.com> - 2016-03-10 22:39 -0800
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 12:44 +0000

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