Security implications of debugging features

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

Hi,

It occurred to me that our security exceptions are silent on our policy 
with debugging features.  This was specifically in the context of mcheck 
but I think it extends to other debugging features too.  mcheck is 
technically a supported glibc feature and may have been used in code 
bases for a while.  However given the lack of mcheck bugs (and boy is it 
buggy!), the latter seems to be not as common.

Given that debugging features must not be enabled in production, should 
we add the following exception for our security process?  I've kept the 
wording generic to cover any debugging features (source based or 
otherwise) that I may have missed or we end up adding in future.

~~~~~~~~~~
Debugging features

glibc comes with a number of debugging features that allow developers to 
isolate root causes of problems.  Bugs in debugging features that are 
enabled by explicitly compiling applications or glibc to use them are 
not considered security vulnerabilities and will be treated as regular 
bugs.  Examples of such features are mcheck and mtrace, which allow 
debugging and tracing of glibc malloc functions.

Bugs in debugging features that are enabled by exporting an environment 
variable in the environment of a program may for now be considered 
security issues in a local context.
~~~~~~~~~~

Siddhesh