[PATCH] ntdll: Avoid reading TEB in NtCreateThreadEx.

[Paul Gofman]

I am not sure if this is acceptable either way, but wouldn't it be less 
of an application specific hack if to try to handle hardware breakpoints 
for the Unix part in a universal way in trap_handler()? As the DRM may 
apparently want to breakpoint any other TEB or PEB location the same way 
and ntdll.so is unlikely to avoid touching PEB completely.

On 9/28/20 21:59, Myah Caron wrote:
> Wine-bug: https://bugs.winehq.org/show_bug.cgi?id=49903
> Signed-off-by: Myah Caron <qsniyg at protonmail.com>
> ---
> As noted in the bug, some programs hold a breakpoint on memory reads to the TEB, and they get triggered by GetCurrentProcessId. Since this is a syscall, this wouldn't occur under Windows.
>
>   dlls/ntdll/unix/thread.c | 4 +++-
>   server/protocol.def      | 1 +
>   server/thread.c          | 1 +
>   3 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/dlls/ntdll/unix/thread.c b/dlls/ntdll/unix/thread.c
> index ded4b33eb0..9f318eaa4c 100644
> --- a/dlls/ntdll/unix/thread.c
> +++ b/dlls/ntdll/unix/thread.c
> @@ -144,6 +144,7 @@ NTSTATUS WINAPI NtCreateThreadEx( HANDLE *handle, ACCESS_MASK access, OBJECT_ATT
>       data_size_t len;
>       struct object_attributes *objattr;
>       struct ntdll_thread_data *thread_data;
> +    DWORD pid = 0;
>       DWORD tid = 0;
>       int request_pipe[2];
>       SIZE_T extra_stack = PTHREAD_STACK_MIN;
> @@ -200,6 +201,7 @@ NTSTATUS WINAPI NtCreateThreadEx( HANDLE *handle, ACCESS_MASK access, OBJECT_ATT
>           if (!(status = wine_server_call( req )))
>           {
>               *handle = wine_server_ptr_handle( reply->handle );
> +            pid = reply->pid;
>               tid = reply->tid;
>           }
>           close( request_pipe[0] );
> @@ -223,7 +225,7 @@ NTSTATUS WINAPI NtCreateThreadEx( HANDLE *handle, ACCESS_MASK access, OBJECT_ATT
>           goto done;
>       }
>
> -    client_id.UniqueProcess = ULongToHandle( GetCurrentProcessId() );
> +    client_id.UniqueProcess = ULongToHandle( pid );
>       client_id.UniqueThread  = ULongToHandle( tid );
>       teb->ClientId = client_id;
>
> diff --git a/server/protocol.def b/server/protocol.def
> index f538c6dcf5..fe6a44bcda 100644
> --- a/server/protocol.def
> +++ b/server/protocol.def
> @@ -832,6 +832,7 @@ struct rawinput_device
>       int          request_fd;   /* fd for request pipe */
>       VARARG(objattr,object_attributes); /* object attributes */
>   @REPLY
> +    process_id_t pid;          /* process id */
>       thread_id_t  tid;          /* thread id */
>       obj_handle_t handle;       /* thread handle (in the current process) */
>   @END
> diff --git a/server/thread.c b/server/thread.c
> index eb13807973..efd6a00bc4 100644
> --- a/server/thread.c
> +++ b/server/thread.c
> @@ -1373,6 +1373,7 @@ DECL_HANDLER(new_thread)
>       {
>           thread->system_regs = current->system_regs;
>           if (req->suspend) thread->suspend++;
> +        reply->pid = get_process_id( process );
>           reply->tid = get_thread_id( thread );
>           if ((reply->handle = alloc_handle_no_access_check( current->process, thread,
>                                                              req->access, objattr->attributes )))
> --
> 2.28.0
>
>
>