[GWP-ASan] Integrate GWP-ASan into bionc's malloc() (using hooks).
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
diff --git a/libc/platform/bionic/malloc.h b/libc/platform/bionic/malloc.h
index 27d79ff..99eefa4 100644
--- a/libc/platform/bionic/malloc.h
+++ b/libc/platform/bionic/malloc.h
@@ -97,6 +97,14 @@
// arg_size = sizeof(bool)
M_GET_PROCESS_PROFILEABLE = 9,
#define M_GET_PROCESS_PROFILEABLE M_GET_PROCESS_PROFILEABLE
+ // Maybe enable GWP-ASan. Set *arg to force GWP-ASan to be turned on,
+ // otherwise this mallopt() will internally decide whether to sample the
+ // process. The program must be single threaded at the point when the
+ // android_mallopt function is called.
+ // arg = bool*
+ // arg_size = sizeof(bool)
+ M_INITIALIZE_GWP_ASAN = 10,
+#define M_INITIALIZE_GWP_ASAN M_INITIALIZE_GWP_ASAN
};
enum HeapTaggingLevel {