Re: [PATCH 2/7] [D] libiberty: Fail if reached end of symbol string

[Jeff Law <law@redhat.com>]

On 05/14/2015 07:36 AM, Iain Buclaw wrote:
> On 14 May 2015 at 14:58, Jeff Law <law@redhat.com> wrote:
>> On 05/13/2015 02:51 AM, Iain Buclaw wrote:
>>>
>>> If a symbol that has so far been valid abruptly ends then we will want
>>> to fail the process rather than silently succeed.
>>>
>>> ---
>>> libiberty/ChangeLog
>>>
>>> 2015-05-13 Iain Buclaw  <ibuclaw@gdcproject.org>
>>>
>>>       * d-demangle.c (dlang_call_convention): Return NULL if have reached
>>> the
>>>       end of the symbol, but expected more.
>>>       (dlang_attributes): Likewise.
>>>       (dlang_function_type): Likewise.
>>>       (dlang_type): Likewise.
>>>       (dlang_identifier): Likewise.
>>>       (dlang_value): Likewise.
>>
>> I spot checked various callers of these functions that not return NULL and
>> they looked reasonable. Though I was a bit concerned about the callers of
>> dlang_type, dlang_value and dlang_identifier.
>>
>> In those cases we'll often still do the string_append, string_setlength and
>> other calls in the caller of dlang_{value,type,identifier}.  I'm assuming
>> that's safe (the error still appears to be bubbling up properly).
>>
>
> The string routines should be safe for that (appending a string with a
> zero length does nothing, for instance).
>
>> If you can confirm that we're OK in those cases, then this is OK for the
>> trunk.
>>
>
> I can start fuzzing mangle strings to test that failures actually fail
> gracefully.  There's already a fuzzer that exists for C++, I think the
> only change that would be required for D is exchanging "_Z" for "_D"
> and calling cplus_demangle with DMGL_DLANG.
Your call whether to fuzz before or after committing the changes.

jeff