Don't check eob when handle it_block

bet4it · May 12, 2020 · 2e02dbe · 2e02dbe
1 parent 6f04791
commit 2e02dbe
Showing 1 changed file with 40 additions and 34 deletions.
diff --git a/gum/arch-arm/gumthumbrelocator.c b/gum/arch-arm/gumthumbrelocator.c
@@ -206,40 +206,41 @@ gum_thumb_relocator_read_one (GumThumbRelocator * self,
   if (!cs_disasm_iter (self->capstone, &code, &size, &address, insn))
     return 0;
 
-  switch (insn->id)
-  {
-    case ARM_INS_B:
-    case ARM_INS_BX:
-      self->eob = TRUE;
-      self->eoi = gum_arm_branch_is_unconditional (insn);
-      break;
-    case ARM_INS_CBZ:
-    case ARM_INS_CBNZ:
-    case ARM_INS_BL:
-    case ARM_INS_BLX:
-      self->eob = TRUE;
-      self->eoi = FALSE;
-      break;
-    case ARM_INS_LDR:
-      self->eob = self->eoi = gum_reg_dest_is_pc (insn);
-      break;
-    case ARM_INS_POP:
-      self->eob = self->eoi = gum_reg_list_contains_pc (insn, 0);
-      break;
-    case ARM_INS_LDM:
-      self->eob = self->eoi = gum_reg_list_contains_pc (insn, 1);
-      break;
-    case ARM_INS_IT:
+  if (!self->it_block.active)
+    switch (insn->id)
     {
-      it_block_size = gum_parse_it_instruction_block_size (
-          GUINT16_FROM_LE (*((guint16 *) self->input_cur)));
-      self->eob = FALSE;
-      break;
+      case ARM_INS_B:
+      case ARM_INS_BX:
+        self->eob = TRUE;
+        self->eoi = gum_arm_branch_is_unconditional (insn);
+        break;
+      case ARM_INS_CBZ:
+      case ARM_INS_CBNZ:
+      case ARM_INS_BL:
+      case ARM_INS_BLX:
+        self->eob = TRUE;
+        self->eoi = FALSE;
+        break;
+      case ARM_INS_LDR:
+        self->eob = self->eoi = gum_reg_dest_is_pc (insn);
+        break;
+      case ARM_INS_POP:
+        self->eob = self->eoi = gum_reg_list_contains_pc (insn, 0);
+        break;
+      case ARM_INS_LDM:
+        self->eob = self->eoi = gum_reg_list_contains_pc (insn, 1);
+        break;
+      case ARM_INS_IT:
+      {
+        it_block_size = gum_parse_it_instruction_block_size (
+            GUINT16_FROM_LE (*((guint16 *) self->input_cur)));
+        self->eob = FALSE;
+        break;
+      }
+      default:
+        self->eob = FALSE;
+        break;
     }
-    default:
-      self->eob = FALSE;
-      break;
-  }
 
   gum_thumb_relocator_increment_inpos (self);
 
@@ -249,8 +250,13 @@ gum_thumb_relocator_read_one (GumThumbRelocator * self,
   self->input_cur += insn->size;
   self->input_pc += insn->size;
 
-  while (it_block_size--)
-    gum_thumb_relocator_read_one (self, NULL);
+  if (it_block_size > 0)
+  {
+    self->it_block.active = TRUE;
+    while (it_block_size--)
+      gum_thumb_relocator_read_one(self, NULL);
+    self->it_block.active = FALSE;
+  }
 
   return self->input_cur - input_start;
 }