tree 95339c5cb5d055b8fd2b216b46e6264180c4fc36
parent d2b8149ddad8b21ce535fb02ff752c85c7aa9d43
author Mitch Phillips <mitchp@google.com> 1578440867 -0800
committer Mitch Phillips <mitchp@google.com> 1579129380 -0800

Add tagged pointers to bionic.

This patch introduces tagged pointers to bionic. We add a static tag to
all pointers on arm64 compatible platforms (needs requisite
top-byte-ignore hardware feature and relevant kernel patches).

We dynamically detect TBI-compatible devices (a device with the TBI feature and
kernel support) at process start time, and insert an implementation-dependent
tag into the top byte of the pointer for all heap allocations. We then check
that the tag has not been truncated when deallocating the memory.

If an application incorrectly writes to the top byte of the pointer, we
terminate the process at time of detection. This will allow MTE-incompatible
applications to be caught early.

Bug: 135754954
Bug: 147147490

Test: cd bionic && atest .
Change-Id: I6e5b809fc81f55dd517f845eaf20f3c0ebd4d86e