This patch introduces GWP-ASan - a sampled allocator framework that
finds use-after-free and heap-buffer-overflow bugs in production
environments.
GWP-ASan is being introduced in an always-disabled mode. This means that
GWP-ASan will be permanently disabled until a further patch turns on
support. As such, there should be no visible functional change for the
time being.
GWP-ASan requires -fno-emulated-tls wherever it's linked from. We
intentionally link GWP-ASan into libc so that it's part of the initial
set of libraries, and thus has static TLS storage (so we can use
Initial-Exec TLS instead of Global-Dynamic). As a benefit, this reduces
overhead for a sampled process.
GWP-ASan is always initialised via. a call to
mallopt(M_INITIALIZE_GWP_ASAN, which must be done before a process is
multithreaded).
More information about GWP-ASan can be found in the upstream
documentation: http://llvm.org/docs/GwpAsan.html
Bug: 135634846
Test: atest bionic
Change-Id: Ib9bd33337d17dab39ac32f4536bff71bd23498b0
Introduce an M_SET_ALLOCATION_LIMIT enumerator for android_mallopt(),
which can be used to set an upper bound on the total size of all
allocations made using the memory allocation APIs.
This is useful for programs such as audioextractor and mediaserver
which need to set such a limit as a security mitigation. Currently
these programs are using setrlimit(RLIMIT_AS) which isn't exactly
what these programs want to control. RLIMIT_AS is also problematic
under sanitizers which allocate large amounts of address space as
shadow memory, and is especially problematic under shadow call stack,
which requires 16MB of address space per thread.
Add new unit tests for bionic.
Add new unit tests for malloc debug that verify that when the limit
is enabled, malloc debug still functions for nearly every allocation
function.
Bug: 118642754
Test: Ran bionic-unit-tests/bionic-unit-tests-static.
Test: Ran malloc debug tests and perfetto integration tests.
Change-Id: I735403c4d2c87f00fb2cdef81d00af0af446b2bb
The pieces:
- The malloc common shared by static and dynamic code (malloc_common.cpp).
- The code for shared libraries that includes any dlopen'ing
(malloc_common_dynamic.cpp).
- The implementation of perfetto's heapprofd (malloc_heapprofd.cpp).
This makes it easier to see what's going on in the many different areas.
It should also make it easier to add the allocation capping option.
Other related changes:
- Update the unit tests for android_mallopt. All of the current options
don't work on static binaries, so make sure that is reflected in the test.
- A few names changes to make sure that all code is consistent.
Test: Ran tests (malloc hooks/malloc debug/perfetto/bionic unit tests).
Change-Id: I0893bfbc0f83d82506fac5d1f37cf92fbdef6f59
