Add an API for per-process disabling memory initialization.
Introduce an android_mallopt(M_DISABLE_MEMORY_MITIGATIONS) API call
that may be used to disable zero- or pattern-init on non-MTE hardware,
or memory tagging on MTE hardware. The intent is that this function
may be called at any time, including when there are multiple threads
running.
Disabling zero- or pattern-init is quite trivial, we just need to set
a global variable to 0 via a Scudo API call (although there will be
some separate work required on the Scudo side to make this operation
thread-safe).
It is a bit more tricky to disable MTE across a process, because
the kernel does not provide an API for disabling tag checking in all
threads in a process, only per-thread. We need to send a signal to each
of the process's threads with a handler that issues the required prctl
call, and lock thread creation for the duration of the API call to
avoid races between thread enumeration and calls to pthread_create().
Bug: 135772972
Change-Id: I81ece86ace916eb6b435ab516cd431ec4b48a3bf
diff --git a/libc/Android.bp b/libc/Android.bp
index c94be62..ba5ef11 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -62,6 +62,7 @@
cppflags: [],
include_dirs: [
"bionic/libc/async_safe/include",
+ "bionic/libc/platform",
// For android_filesystem_config.h.
"system/core/libcutils/include",
],
@@ -1077,6 +1078,7 @@
"bionic/mblen.cpp",
"bionic/mbrtoc16.cpp",
"bionic/mbrtoc32.cpp",
+ "bionic/memory_mitigation_state.cpp",
"bionic/mempcpy.cpp",
"bionic/mkdir.cpp",
"bionic/mkfifo.cpp",