Merge RP1A.190822.001

Change-Id: Iaf90835a99d87f6246798efd2cea6fe9f750ea18

1 files changed, 13 insertions, 3 deletions

diff --git a/libc/private/WriteProtected.h b/libc/private/WriteProtected.h
index 69a68229b..26c239ca1 100644
--- a/libc/private/WriteProtected.h
+++ b/libc/private/WriteProtected.h
@@ -46,6 +46,16 @@ class WriteProtected {
 
   WriteProtectedContents<T> contents;
 
+  int set_protection(int prot) {
+    auto addr = &contents;
+#if __has_feature(hwaddress_sanitizer)
+    // The mprotect system call does not currently untag pointers, so do it
+    // ourselves.
+    addr = untag_address(addr);
+#endif
+    return mprotect(reinterpret_cast<void*>(addr), PAGE_SIZE, prot);
+  }
+
  public:
   WriteProtected() = default;
   BIONIC_DISALLOW_COPY_AND_ASSIGN(WriteProtected);
@@ -55,7 +65,7 @@ class WriteProtected {
     // multiple times by accident.
     memset(&contents, 0, sizeof(contents));
 
-    if (mprotect(&contents, PAGE_SIZE, PROT_READ)) {
+    if (set_protection(PROT_READ)) {
       async_safe_fatal("failed to make WriteProtected nonwritable in initialize");
     }
   }
@@ -70,12 +80,12 @@ class WriteProtected {
 
   template <typename Mutator>
   void mutate(Mutator mutator) {
-    if (mprotect(&contents, PAGE_SIZE, PROT_READ | PROT_WRITE) != 0) {
+    if (set_protection(PROT_READ | PROT_WRITE) != 0) {
       async_safe_fatal("failed to make WriteProtected writable in mutate: %s",
                        strerror(errno));
     }
     mutator(&contents.value);
-    if (mprotect(&contents, PAGE_SIZE, PROT_READ) != 0) {
+    if (set_protection(PROT_READ) != 0) {
       async_safe_fatal("failed to make WriteProtected nonwritable in mutate: %s",
                        strerror(errno));
     }