[PATCH 3/3] dbghelp: fix failing SymInitialize for a live 32bit target from a 64bit caller in WOW64

[Alexandre Julliard]

Gabriel Ivăncescu <gabrielopcode at gmail.com> writes:

> On 31/08/2021 12:53, Alexandre Julliard wrote:
>> Eric Pouech <eric.pouech at gmail.com> writes:
>> 
>>> When:
>>> - caller of dbghelp is a 64bit process,
>>> - invoking SymInitialize on a 32bit live target running under WOW64
>>>
>>> SymInitialize fails because:
>>> - check_live_target() erroneously reads the 64bit PEB of the target,
>>>    while it actually wants the 32bit PEB.
>>> - as the ELF base header address isn't set (hidden in CloudFileFlags)
>>>    in the 64bit PEB, hence causing the failure
>>>
>>> So ensure that check_live_target() actually reads the 32bit PEB when
>>> handling a 32bit process.
>>>
>>>
>>> ----
>>>
>>> I couldn't find a simpler way to fix it :-(
>>> (offsetting PEB address by 0x1000 works but is way too hacky)
>> Offsetting by 0x1000 is fine.
>> But I'd say that the ELF data should be stored in the 64-bit
>> PEB. Also
>> note that once the new Wow64 architecture is enabled, all ELF data
>> inside 32-bit processes is going to be 64-bit.
>> 
>
> Sorry for the off topic remark, but is there some brief documentation
> on how this is going to work posted anywhere? Will it be optional?
> (i.e. if the host supplies 32-bit libs, wine will still use them).

Nothing is defined yet, but I expect there will be some kind of runtime
option.

-- 
Alexandre Julliard
julliard at winehq.org