From 922f81dfd1b94e23f23f05aac0ecafac8645ce46 Mon Sep 17 00:00:00 2001
From: Arrowana <pierre.duval@gadz.org>
Date: Sat, 31 Oct 2020 13:34:58 +1100
Subject: [PATCH] extmod/machine_mem: Only allow integers in machine.memX
 subscript.

Prior to this change machine.mem32['foo'] (or using any other non-integer
subscript) could result in a fault due to 'foo' being interpreted as an
integer.  And when writing code it's hard to tell if the fault is due to a
bad subscript type, or an integer subscript that specifies an invalid
memory address.

The type of the object used in the subscript is now tested to be an
integer by using mp_obj_get_int_truncated instead of
mp_obj_int_get_truncated.  The performance hit of this change is minimal,
and machine.memX objects are more for convenience than performance (there
are many other ways to read/write memory in a faster way),

Fixes issue #6588.
---
 extmod/machine_mem.c         |  2 +-
 ports/unix/modmachine.c      |  2 +-
 tests/extmod/machine1.py     | 20 ++++++++++++++++++++
 tests/extmod/machine1.py.exp |  4 ++++
 4 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/extmod/machine_mem.c b/extmod/machine_mem.c
index a1494bd51a..73e2f7fd1f 100644
--- a/extmod/machine_mem.c
+++ b/extmod/machine_mem.c
@@ -40,7 +40,7 @@
 
 #if !defined(MICROPY_MACHINE_MEM_GET_READ_ADDR) || !defined(MICROPY_MACHINE_MEM_GET_WRITE_ADDR)
 STATIC uintptr_t machine_mem_get_addr(mp_obj_t addr_o, uint align) {
-    uintptr_t addr = mp_obj_int_get_truncated(addr_o);
+    uintptr_t addr = mp_obj_get_int_truncated(addr_o);
     if ((addr & (align - 1)) != 0) {
         mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("address %08x is not aligned to %d bytes"), addr, align);
     }
diff --git a/ports/unix/modmachine.c b/ports/unix/modmachine.c
index a6eb8c01ed..5b462a3b15 100644
--- a/ports/unix/modmachine.c
+++ b/ports/unix/modmachine.c
@@ -47,7 +47,7 @@
 #if MICROPY_PY_MACHINE
 
 uintptr_t mod_machine_mem_get_addr(mp_obj_t addr_o, uint align) {
-    uintptr_t addr = mp_obj_int_get_truncated(addr_o);
+    uintptr_t addr = mp_obj_get_int_truncated(addr_o);
     if ((addr & (align - 1)) != 0) {
         mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("address %08x is not aligned to %d bytes"), addr, align);
     }
diff --git a/tests/extmod/machine1.py b/tests/extmod/machine1.py
index 6ff38cc051..0c7f8122f4 100644
--- a/tests/extmod/machine1.py
+++ b/tests/extmod/machine1.py
@@ -26,3 +26,23 @@ try:
     del machine.mem8[0]
 except TypeError:
     print("TypeError")
+
+try:
+    machine.mem8[0:1]
+except TypeError:
+    print("TypeError")
+
+try:
+    machine.mem8[0:1] = 10
+except TypeError:
+    print("TypeError")
+
+try:
+    machine.mem8["hello"]
+except TypeError:
+    print("TypeError")
+
+try:
+    machine.mem8["hello"] = 10
+except TypeError:
+    print("TypeError")
diff --git a/tests/extmod/machine1.py.exp b/tests/extmod/machine1.py.exp
index bb421ea5cf..2504859690 100644
--- a/tests/extmod/machine1.py.exp
+++ b/tests/extmod/machine1.py.exp
@@ -2,3 +2,7 @@
 ValueError
 ValueError
 TypeError
+TypeError
+TypeError
+TypeError
+TypeError