[CID 16728] libfoundation: MCUnicodeGetProperty(): Incorrect overflow checks

peter-b · peter-b · commit 951ef98693e4 · 2015-02-13T15:08:01.000Z
When a signed integer is compared with an unsigned integer, it is
converted to unsigned *before the comparison*.  Therefore, this
expression is never true:

    -1 &lt; 0U
diff --git a/libfoundation/src/foundation-unicode.cpp b/libfoundation/src/foundation-unicode.cpp
@@ -378,7 +378,7 @@ bool MCUnicodeGetProperty(const unichar_t *p_chars, uindex_t p_char_count, MCUni
             {
                 int32_t t_prop;
                 t_prop = MCUnicodeGetIntegerProperty(t_char, p_property);
-                if (t_prop < UINT8_MIN || t_prop > UINT8_MAX)
+                if (t_prop < 0 || t_prop > UINT8_MAX)
                     return false;
                 ((uint8_t*)x_result_array)[t_offset] = uint8_t(t_prop);
                 if (t_advance == 2)
@@ -390,7 +390,7 @@ bool MCUnicodeGetProperty(const unichar_t *p_chars, uindex_t p_char_count, MCUni
             {
                 int32_t t_prop;
                 t_prop = MCUnicodeGetIntegerProperty(t_char, p_property);
-                if (t_prop < UINT16_MIN || t_prop > UINT16_MAX)
+                if (t_prop < 0 || t_prop > UINT16_MAX)
                     return false;
                 ((uint16_t*)x_result_array)[t_offset] = uint16_t(t_prop);
                 if (t_advance == 2)
@@ -402,7 +402,7 @@ bool MCUnicodeGetProperty(const unichar_t *p_chars, uindex_t p_char_count, MCUni
             {
                 int32_t t_prop;
                 t_prop = MCUnicodeGetIntegerProperty(t_char, p_property);
-                if (t_prop < UINT32_MIN || t_prop > UINT32_MAX)
+                if (t_prop < 0 || t_prop > UINT32_MAX)
                     return false;
                 ((uint32_t*)x_result_array)[t_offset] = uint32_t(t_prop);
                 if (t_advance == 2)
