Merge "ashmem: ensure ashmem fds are CLOEXEC."

2 files changed, 12 insertions, 3 deletions

diff --git a/libcutils/ashmem-dev.cpp b/libcutils/ashmem-dev.cpp
index 233d400e0..6a27f9a20 100644
--- a/libcutils/ashmem-dev.cpp
+++ b/libcutils/ashmem-dev.cpp
@@ -159,9 +159,11 @@ static bool __has_memfd_support() {
         return false;
     }
 
-    /* Check if kernel support exists, otherwise fall back to ashmem */
+    // Check if kernel support exists, otherwise fall back to ashmem.
+    // This code needs to build on old API levels, so we can't use the libc
+    // wrapper.
     android::base::unique_fd fd(
-            syscall(__NR_memfd_create, "test_android_memfd", MFD_ALLOW_SEALING));
+            syscall(__NR_memfd_create, "test_android_memfd", MFD_CLOEXEC | MFD_ALLOW_SEALING));
     if (fd == -1) {
         ALOGE("memfd_create failed: %s, no memfd support.\n", strerror(errno));
         return false;
@@ -333,7 +335,9 @@ int ashmem_valid(int fd)
 }
 
 static int memfd_create_region(const char* name, size_t size) {
-    android::base::unique_fd fd(syscall(__NR_memfd_create, name, MFD_ALLOW_SEALING));
+    // This code needs to build on old API levels, so we can't use the libc
+    // wrapper.
+    android::base::unique_fd fd(syscall(__NR_memfd_create, name, MFD_CLOEXEC | MFD_ALLOW_SEALING));
 
     if (fd == -1) {
         ALOGE("memfd_create(%s, %zd) failed: %s\n", name, size, strerror(errno));
diff --git a/libcutils/ashmem_test.cpp b/libcutils/ashmem_test.cpp
index b37d020fb..fb657f6e6 100644
--- a/libcutils/ashmem_test.cpp
+++ b/libcutils/ashmem_test.cpp
@@ -35,6 +35,11 @@ void TestCreateRegion(size_t size, unique_fd &fd, int prot) {
     ASSERT_TRUE(ashmem_valid(fd));
     ASSERT_EQ(size, static_cast<size_t>(ashmem_get_size_region(fd)));
     ASSERT_EQ(0, ashmem_set_prot_region(fd, prot));
+
+    // We've been inconsistent historically about whether or not these file
+    // descriptors were CLOEXEC. Make sure we're consistent going forward.
+    // https://issuetracker.google.com/165667331
+    ASSERT_EQ(FD_CLOEXEC, (fcntl(fd, F_GETFD) & FD_CLOEXEC));
 }
 
 void TestMmap(const unique_fd& fd, size_t size, int prot, void** region, off_t off = 0) {