Zebediah Figura : server: Fix pointer arithmetic in get_selector_entry().

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: 6a6b6ba69cf6f78028c2a2144c0e168847ff793f
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=6a6b6ba69cf6f78028c2a2144...

Author: Zebediah Figura <z.figura12(a)gmail.com>
Date:   Sat Feb 10 10:46:07 2018 -0600

server: Fix pointer arithmetic in get_selector_entry().

The selector table is exclusively 32-bit, so trying to get selector entries
with a 64-bit wineserver will return the wrong values due to the different
size of (long *).

Signed-off-by: Zebediah Figura <z.figura12(a)gmail.com>
Signed-off-by: Alexandre Julliard <julliard(a)winehq.org>
(cherry picked from commit c6dfce272309c1ad869886a0fce186c795f3e5b7)
Signed-off-by: Michael Stefaniuc <mstefani(a)winehq.org>

---

 server/ptrace.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/server/ptrace.c b/server/ptrace.c
index a647df9..704b17d 100644
--- a/server/ptrace.c
+++ b/server/ptrace.c
@@ -517,13 +517,13 @@ void get_selector_entry( struct thread *thread, int entry, unsigned int *base,
     }
     if (suspend_for_ptrace( thread ))
     {
-        unsigned char flags_buf[sizeof(long)];
-        long *addr = (long *)(unsigned long)thread->process->ldt_copy + entry;
-        if (read_thread_long( thread, addr, (long *)base ) == -1) goto done;
-        if (read_thread_long( thread, addr + 8192, (long *)limit ) == -1) goto done;
-        addr = (long *)(unsigned long)thread->process->ldt_copy + 2*8192 + (entry / sizeof(long));
-        if (read_thread_long( thread, addr, (long *)flags_buf ) == -1) goto done;
-        *flags = flags_buf[entry % sizeof(long)];
+        unsigned char flags_buf[4];
+        unsigned long addr = (unsigned long)thread->process->ldt_copy + (entry * 4);
+        if (read_thread_long( thread, (long *)addr, (long *)base ) == -1) goto done;
+        if (read_thread_long( thread, (long *)(addr + (8192 * 4)), (long *)limit ) == -1) goto done;
+        addr = (unsigned long)thread->process->ldt_copy + (2 * 8192 * 4) + (entry & ~3);
+        if (read_thread_long( thread, (long *)addr, (long *)flags_buf ) == -1) goto done;
+        *flags = flags_buf[entry % 4];
     done:
         resume_after_ptrace( thread );
     }