xnu-4570.51.1.tar.gz

[apple/xnu.git] / san / kasan-x86_64.c

diff --git a/san/kasan-x86_64.c b/san/kasan-x86_64.c
index 93e8e416e6aadef7698e86096bae899199adbe0a..e2cb6d3bdd0beb85e1921a720a501498edd43436 100644 (file)
--- a/san/kasan-x86_64.c
+++ b/san/kasan-x86_64.c
@@ -194,14 +194,12 @@ kasan_map_shadow_superpage_zero(vm_offset_t address, vm_size_t size)
 void
 kasan_map_shadow(vm_offset_t address, vm_size_t size, bool is_zero)
 {
-       size = vm_map_round_page(size, PAGE_MASK);
-       vm_size_t j;
-
-       for (j = 0; j < size; j += I386_PGBYTES) {
+       vm_offset_t shadow_base = vm_map_trunc_page(SHADOW_FOR_ADDRESS(address), PAGE_MASK);
+       vm_offset_t shadow_top = vm_map_round_page(SHADOW_FOR_ADDRESS(address + size), PAGE_MASK);
 
-               vm_offset_t virt_shadow_target = (vm_offset_t)SHADOW_FOR_ADDRESS(address + j);
+       for (; shadow_base < shadow_top; shadow_base += I386_PGBYTES) {
 
-               split_addr_t addr = split_address(virt_shadow_target);
+               split_addr_t addr = split_address(shadow_base);
                assert(addr.pml4 == 507 || addr.pml4 == 508);
 
                uint64_t *L3;
@@ -260,10 +258,10 @@ kasan_map_shadow(vm_offset_t address, vm_size_t size, bool is_zero)
                        L1[addr.pt] = newpte
                                | INTEL_PTE_VALID
                                | INTEL_PTE_NX;
-               }
 
-               /* adding a new entry, this is not strictly required */
-               invlpg(virt_shadow_target);
+                       /* adding a new entry, this is not strictly required */
+                       invlpg(shadow_base);
+               }
        }
 }
 
@@ -334,3 +332,42 @@ kasan_reserve_memory(void *_args)
        panic("KASAN: could not reserve memory");
 }
 
+bool
+kasan_is_shadow_mapped(uintptr_t shadowp)
+{
+       split_addr_t addr = split_address(shadowp);
+       assert(addr.pml4 == 507 || addr.pml4 == 508);
+
+       uint64_t *L3;
+       uint64_t *L2;
+       uint64_t *L1;
+
+       L3 = (uint64_t *)(IdlePML4[addr.pml4] & ~PAGE_MASK);
+       if (L3 == NULL) {
+               return false;
+       }
+       L3 = (uint64_t *)phys2virt(L3);
+
+       L2 = (uint64_t *)(L3[addr.pdpt] & ~PAGE_MASK);
+       if (L2 == NULL) {
+               return false;
+       }
+       L2 = (uint64_t *)phys2virt(L2);
+
+       uint64_t pde = L2[addr.pd];
+       if ((pde & (INTEL_PTE_VALID|INTEL_PTE_PS)) == (INTEL_PTE_VALID|INTEL_PTE_PS)) {
+               /* mapped as superpage */
+               return true;
+       }
+       L1 = (uint64_t *)(pde & ~PAGE_MASK);
+       if (L1 == NULL) {
+               return false;
+       }
+       L1 = (uint64_t *)phys2virt(L1);
+
+       if (L1[addr.pt] & INTEL_PTE_VALID) {
+               return true;
+       }
+
+       return false;
+}