fdsan: don't do anything when vforked.

Bug: http://b/153926671
Test: 32/64-bit bionic-unit-tests on blueline, x86_64 emulator
Change-Id: Id351a993e396774b68239edfef83d9e81205290b
(cherry picked from commit 65fb2a7f0304fda4463771ae40f8b83728e74a62)

2 files changed, 31 insertions, 0 deletions

diff --git a/libc/bionic/fdsan.cpp b/libc/bionic/fdsan.cpp
index ebc680f3e..4b8991872 100644
--- a/libc/bionic/fdsan.cpp
+++ b/libc/bionic/fdsan.cpp
@@ -246,6 +246,10 @@ uint64_t android_fdsan_get_tag_value(uint64_t tag) {
 }
 
 int android_fdsan_close_with_tag(int fd, uint64_t expected_tag) {
+  if (__get_thread()->is_vforked()) {
+    return __close(fd);
+  }
+
   FDTRACK_CLOSE(fd);
   FdEntry* fde = GetFdEntry(fd);
   if (!fde) {
@@ -296,6 +300,10 @@ uint64_t android_fdsan_get_owner_tag(int fd) {
 }
 
 void android_fdsan_exchange_owner_tag(int fd, uint64_t expected_tag, uint64_t new_tag) {
+  if (__get_thread()->is_vforked()) {
+    return;
+  }
+
   FdEntry* fde = GetFdEntry(fd);
   if (!fde) {
     return;
@@ -332,6 +340,10 @@ android_fdsan_error_level android_fdsan_get_error_level() {
 }
 
 android_fdsan_error_level android_fdsan_set_error_level(android_fdsan_error_level new_level) {
+  if (__get_thread()->is_vforked()) {
+    return android_fdsan_get_error_level();
+  }
+
   return atomic_exchange(&GetFdTable().error_level, new_level);
 }
 
diff --git a/tests/fdsan_test.cpp b/tests/fdsan_test.cpp
index fb3f73dc3..134d62117 100644
--- a/tests/fdsan_test.cpp
+++ b/tests/fdsan_test.cpp
@@ -23,6 +23,7 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <sys/types.h>
+#include <unistd.h>
 
 #if defined(__BIONIC__)
 #include <android/fdsan.h>
@@ -192,3 +193,21 @@ TEST_F(FdsanTest, unique_fd_unowned_close_after_move) {
   EXPECT_FDSAN_DEATH(close(fd_moved.get()), "expected to be unowned, actually owned by unique_fd");
 #endif
 }
+
+TEST_F(FdsanTest, vfork) {
+  android::base::unique_fd fd(open("/dev/null", O_RDONLY));
+
+  pid_t rc = vfork();
+  ASSERT_NE(-1, rc);
+
+  if (rc == 0) {
+    close(fd.get());
+    _exit(0);
+  }
+
+  int status;
+  pid_t wait_result = waitpid(rc, &status, 0);
+  ASSERT_EQ(wait_result, rc);
+  ASSERT_TRUE(WIFEXITED(status));
+  ASSERT_EQ(0, WEXITSTATUS(status));
+}