Merge "File size seal for memory mapped region" into tm-dev am: c23f1b7

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/24776199

Change-Id: I8e1c1c8577936533c67e4a3290285d62a0656de8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

Author: ek9852

libs/binder/MemoryHeapBase.cpp

@@ -73,8 +73,8 @@ MemoryHeapBase::MemoryHeapBase(size_t size, uint32_t flags, char const * name)
         ALOGV("MemoryHeapBase: Attempting to force MemFD");
         fd = memfd_create_region(name ? name : "MemoryHeapBase", size);
         if (fd < 0 || (mapfd(fd, true, size) != NO_ERROR)) return;
-        const int SEAL_FLAGS = ((mFlags & READ_ONLY) ? F_SEAL_FUTURE_WRITE : 0) |
-                ((mFlags & MEMFD_ALLOW_SEALING) ? 0 : F_SEAL_SEAL);
+        const int SEAL_FLAGS = ((mFlags & READ_ONLY) ? F_SEAL_FUTURE_WRITE : 0) | F_SEAL_GROW |
+                F_SEAL_SHRINK | ((mFlags & MEMFD_ALLOW_SEALING) ? 0 : F_SEAL_SEAL);
         if (SEAL_FLAGS && (fcntl(fd, F_ADD_SEALS, SEAL_FLAGS) == -1)) {
             ALOGE("MemoryHeapBase: MemFD %s sealing with flags %x failed with error  %s", name,
                   SEAL_FLAGS, strerror(errno));

libs/binder/tests/binderMemoryHeapBaseUnitTest.cpp

@@ -35,7 +35,8 @@ TEST(MemoryHeapBase, MemfdSealed) {
                                           "Test mapping");
     int fd = mHeap->getHeapID();
     EXPECT_NE(fd, -1);
-    EXPECT_EQ(fcntl(fd, F_GET_SEALS), F_SEAL_SEAL);
+    EXPECT_EQ(fcntl(fd, F_GET_SEALS), F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL);
+    EXPECT_EQ(ftruncate(fd, 4096), -1);
 }
 
 TEST(MemoryHeapBase, MemfdUnsealed) {
@@ -45,7 +46,8 @@ TEST(MemoryHeapBase, MemfdUnsealed) {
                                           "Test mapping");
     int fd = mHeap->getHeapID();
     EXPECT_NE(fd, -1);
-    EXPECT_EQ(fcntl(fd, F_GET_SEALS), 0);
+    EXPECT_EQ(fcntl(fd, F_GET_SEALS), F_SEAL_GROW | F_SEAL_SHRINK);
+    EXPECT_EQ(ftruncate(fd, 4096), -1);
 }
 
 TEST(MemoryHeapBase, MemfdSealedProtected) {
@@ -55,7 +57,9 @@ TEST(MemoryHeapBase, MemfdSealedProtected) {
                                           "Test mapping");
     int fd = mHeap->getHeapID();
     EXPECT_NE(fd, -1);
-    EXPECT_EQ(fcntl(fd, F_GET_SEALS), F_SEAL_SEAL | F_SEAL_FUTURE_WRITE);
+    EXPECT_EQ(fcntl(fd, F_GET_SEALS),
+              F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL | F_SEAL_FUTURE_WRITE);
+    EXPECT_EQ(ftruncate(fd, 4096), -1);
 }
 
 TEST(MemoryHeapBase, MemfdUnsealedProtected) {
@@ -66,7 +70,8 @@ TEST(MemoryHeapBase, MemfdUnsealedProtected) {
                                           "Test mapping");
     int fd = mHeap->getHeapID();
     EXPECT_NE(fd, -1);
-    EXPECT_EQ(fcntl(fd, F_GET_SEALS), F_SEAL_FUTURE_WRITE);
+    EXPECT_EQ(fcntl(fd, F_GET_SEALS), F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_FUTURE_WRITE);
+    EXPECT_EQ(ftruncate(fd, 4096), -1);
 }
 
 #else