logger: validate hdr_size field in logger entry

- check hdr_size to make sure it is in the expected range
  from sizeof entry_v1 to entry (entry_v4).
- alter msg() method to report NULL on invalid hdr_size
- alter all users of msg() method.

Bug: 30947841
Change-Id: I9bc1740d7aa9f37df5be966c18de1fb9de63d5dd
6 files changed
tree: 3779a96196e9f70c1afe57dfc5099ef2a6474a75
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/