Correct a security bug in copyuvm()

copyuvm() should not allow new copied pages to inherit more
permissions than the original pages.

1 files changed, 1 insertions, 0 deletions

diff --git a/mmu.h b/mmu.h
index 5c9ab60..685f51d 100644
--- a/mmu.h
+++ b/mmu.h
@@ -142,6 +142,7 @@ struct segdesc {
 
 // Address in page table or page directory entry
 #define PTE_ADDR(pte)   ((uint)(pte) & ~0xFFF)
+#define PTE_FLAGS(pte)  ((uint)(pte) &  0xFFF)
 
 #ifndef __ASSEMBLER__
 typedef uint pte_t;