[reactos] 01/01: [NTOS] Implement support for opting out of NX policy

[Timo Kreuzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=8227c5d380fa1fbee6649…
commit 8227c5d380fa1fbee6649e4dbb686447ab8e7ff1
Author:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
AuthorDate: Sun Jan 1 18:11:26 2023 +0100
Commit:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
CommitDate: Tue Sep 26 18:04:19 2023 +0300
    [NTOS] Implement support for opting out of NX policy
    Fixes crash in ntdll_winetest info on x64.
---
 ntoskrnl/mm/ARM3/pagfault.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff --git a/ntoskrnl/mm/ARM3/pagfault.c b/ntoskrnl/mm/ARM3/pagfault.c
index b9a855662d9..14460552b1c 100644
--- a/ntoskrnl/mm/ARM3/pagfault.c
+++ b/ntoskrnl/mm/ARM3/pagfault.c
@@ -2333,14 +2333,26 @@ UserFault:
             }
         }
+#if _MI_HAS_NO_EXECUTE
         /* Check for execution of non-executable memory */
         if (MI_IS_INSTRUCTION_FETCH(FaultCode) &&
             !MI_IS_PAGE_EXECUTABLE(&TempPte))
         {
+            /* Check if execute enable was set */
+            if (CurrentProcess->Pcb.Flags.ExecuteEnable)
+            {
+                /* Fix up the PTE to be executable */
+                TempPte.u.Hard.NoExecute = 0;
+                MI_UPDATE_VALID_PTE(PointerPte, TempPte);
+                MiUnlockProcessWorkingSet(CurrentProcess, CurrentThread);
+                return STATUS_SUCCESS;
+            }
+
             /* Return the status */
             MiUnlockProcessWorkingSet(CurrentProcess, CurrentThread);
             return STATUS_ACCESS_VIOLATION;
         }
+#endif
         /* The fault has already been resolved by a different thread */
         MiUnlockProcessWorkingSet(CurrentProcess, CurrentThread);