[cff, truetype] Integer overflows.

Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2133
  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2137

* src/cff/cf2hints.c (cf2_hint_init): Use OVERFLOW_SUB_INT32.

* src/truetype/ttinterp.c (PROJECT, DUALPROJ): Use
OVERFLOW_SUB_LONG.
3 files changed