RE: Code Signing Examples
RE: Code Signing Examples
- Subject: RE: Code Signing Examples
- From: "Tom Fortmann" <email@hidden>
- Date: Fri, 20 Feb 2009 15:17:41 -0600
That is a good point. Someone else also pointed out that once a hacker gets
root authority all bets are off. Ideally this level of authentication
belongs in the OS. Once a signed application or process is installed the OS
should enforce the signature before executing the process. Not sure if this
can be done with 10.5 or 10.6. And I'm not sure how you prevent someone
from replacing the module with a corrupt unsigned version. For now we are
just looking for a reasonable approach to validate the authenticity of our
application components.
___________________________________
Thomas Fortmann
Director of Development
Xcape Solutions, Inc.
207 Crystal Grove Blvd.
Lutz, FL 33548
TEL 847 228 9831
www.xcapesolutions.net
email@hidden
-----Original Message-----
From: Damien Sorresso [mailto:email@hidden]
Sent: Friday, February 20, 2009 2:40 PM
To: Tom Fortmann
Cc: email@hidden; email@hidden
Subject: Re: Code Signing Examples
On Feb 20, 2009, at 6:47 AM, Tom Fortmann wrote:
> Can anyone point me to sample code on how to verify an application
> or process is signed? My application executes a couple other
> processes and I would like to validate their signatures before I
> blindly execute them. I've found a ton of Apple documentation on
> the theory but not a lot on practical application within my code.
> I've also looked at simply running the codesign utility and parsing
> its XML output, but this seems like a weak design. What is codesign
> gets replaced?
Keep in mind that you'll be subject to a "time of check versus time of
use" race condition. Even if you verify that the binaries on-disk are
valid, someone could swap out the binary for an evil one just after
the check and just before the exec(2).
--
Damien Sorresso
BSD Engineering
Apple Inc.
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