[PATCH v9] Add getentropy, getrandom, <sys/random.h> [BZ #17252]

[Florian Weimer]

On 12/06/2016 05:55 PM, Joseph Myers wrote:
> On Tue, 6 Dec 2016, Zack Weinberg wrote:
>
>> On the assumption that this _is_ the issue, I am going to write a script
>> that scans the Debian archive for existing binaries containing
>> definitions (exported or not) of getentropy and/or getrandom, and will
>> report what it tells me -- this will probably take a couple days to
>> cycle all the way through.
>
> You can't generally tell for a stripped executable whether there's a
> getentropy function in there - only if it's unstripped, or linked with
> -rdynamic, or linked with glibc that defines getentropy and so exports it
> in the dynamic symbol table for that reason.  You could scan shared
> libraries for bogus exports, but I don't see how you could test for
> executables that would cause a problem when linked with new glibc without
> doing a full archive rebuild with patched glibc.

Agreed.  Another complication is that there are cases where you get 
getentropy only if HAVE_GETRANDOM is defined.

What do you suggest we should do if we detect unintended interposition 
(assuming we decide to use the version without redirection first)?

Thanks,
Florian