[PATCH 2/3] ntdll: Validate context xstate at once in NtGetContextThread().

[Paul Gofman]

From: Paul Gofman

Signed-off-by: Paul Gofman 
---
 dlls/ntdll/unix/signal_i386.c   | 4 ++--
 dlls/ntdll/unix/signal_x86_64.c | 4 ++--
 dlls/ntdll/unix/thread.c        | 2 ++
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index a515b21cc2e..95e7a69a6e1 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -1003,6 +1003,8 @@ NTSTATUS WINAPI NtGetContextThread( HANDLE handle, CONTEXT *context )
     BOOL self = (handle == GetCurrentThread());
     NTSTATUS ret;

+    if (!validate_context_xstate( context )) return STATUS_INVALID_PARAMETER;
+
     /* debug registers require a server call */
     if (needed_flags & CONTEXT_DEBUG_REGISTERS) self = FALSE;

@@ -1098,8 +1100,6 @@ NTSTATUS WINAPI NtGetContextThread( HANDLE handle, CONTEXT *context )
             XSTATE *xstate = (XSTATE *)((char *)context_ex + context_ex->XState.Offset);
             unsigned int mask;

-            if (!validate_context_xstate( context )) return STATUS_INVALID_PARAMETER;
-
             mask = (xstate_compaction_enabled ? xstate->CompactionMask : xstate->Mask) & XSTATE_MASK_GSSE;
             xstate->Mask = frame->xstate.Mask & mask;
             xstate->CompactionMask = xstate_compaction_enabled ? (0x8000000000000000 | mask) : 0;
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 3aac1bc3e75..11e652e1dca 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -1832,6 +1832,8 @@ NTSTATUS WINAPI NtGetContextThread( HANDLE handle, CONTEXT *context )
     DWORD needed_flags = context->ContextFlags & ~CONTEXT_AMD64;
     BOOL self = (handle == GetCurrentThread());

+    if (!validate_context_xstate( context )) return STATUS_INVALID_PARAMETER;
+
     /* debug registers require a server call */
     if (needed_flags & CONTEXT_DEBUG_REGISTERS) self = FALSE;

@@ -1918,8 +1920,6 @@ NTSTATUS WINAPI NtGetContextThread( HANDLE handle, CONTEXT *context )
         XSTATE *xstate = (XSTATE *)((char *)context_ex + context_ex->XState.Offset);
         unsigned int mask;

-        if (!validate_context_xstate( context )) return STATUS_INVALID_PARAMETER;
-
         mask = (xstate_compaction_enabled ? xstate->CompactionMask : xstate->Mask) & XSTATE_MASK_GSSE;
         xstate->Mask = frame->xstate.Mask & mask;
         xstate->CompactionMask = xstate_compaction_enabled ? (0x8000000000000000 | mask) : 0;
diff --git a/dlls/ntdll/unix/thread.c b/dlls/ntdll/unix/thread.c
index 6289b8eadca..b393315e6fe 100644
--- a/dlls/ntdll/unix/thread.c
+++ b/dlls/ntdll/unix/thread.c
@@ -159,6 +159,8 @@ BOOL validate_context_xstate( CONTEXT *context )
 {
     CONTEXT_EX *context_ex;

+    if (!((context->ContextFlags & 0x40) && (cpu_info.ProcessorFeatureBits & CPU_FEATURE_AVX))) return TRUE;
+
     context_ex = (CONTEXT_EX *)(context + 1);

if (context_ex->XState.Length < offsetof(XSTATE, YmmContext)