diff --git a/libhidlmemory/mapping.cpp b/libhidlmemory/mapping.cpp
index 3cb6485..8f0bcf4 100644
--- a/libhidlmemory/mapping.cpp
+++ b/libhidlmemory/mapping.cpp
@@ -24,6 +24,7 @@
 #include <android-base/logging.h>
 #include <android/hidl/memory/1.0/IMapper.h>
 #include <hidl/HidlSupport.h>
+#include <log/log.h>
 
 using android::sp;
 using android::hidl::memory::V1_0::IMemory;
@@ -63,6 +64,15 @@
         return nullptr;
     }
 
+    // hidl_memory's size is stored in uint64_t, but mapMemory's mmap will map
+    // size in size_t. If size is over SIZE_MAX, mapMemory could succeed
+    // but the mapped memory's actual size will be smaller than the reported size.
+    if (memory.size() > SIZE_MAX) {
+        LOG(ERROR) << "Cannot map " << memory.size() << " bytes of memory because it is too large.";
+        android_errorWriteLog(0x534e4554, "79376389");
+        return nullptr;
+    }
+
     Return<sp<IMemory>> ret = mapper->mapMemory(memory);
 
     if (!ret.isOk()) {
diff --git a/transport/HidlBinderSupport.cpp b/transport/HidlBinderSupport.cpp
index fe1ccbc..31e3be8 100644
--- a/transport/HidlBinderSupport.cpp
+++ b/transport/HidlBinderSupport.cpp
@@ -19,6 +19,7 @@
 #include <hidl/HidlBinderSupport.h>
 
 // C includes
+#include <inttypes.h>
 #include <unistd.h>
 
 // C++ includes
@@ -66,6 +67,15 @@
                 parentOffset + hidl_memory::kOffsetOfName);
     }
 
+    // hidl_memory's size is stored in uint64_t, but mapMemory's mmap will map
+    // size in size_t. If size is over SIZE_MAX, mapMemory could succeed
+    // but the mapped memory's actual size will be smaller than the reported size.
+    if (memory.size() > SIZE_MAX) {
+        ALOGE("Cannot use memory with %" PRId64 " bytes because it is too large.", memory.size());
+        android_errorWriteLog(0x534e4554, "79376389");
+        return BAD_VALUE;
+    }
+
     return _hidl_err;
 }
 
diff --git a/transport/memory/1.0/default/Android.bp b/transport/memory/1.0/default/Android.bp
index a4f45cf..470d3b8 100644
--- a/transport/memory/1.0/default/Android.bp
+++ b/transport/memory/1.0/default/Android.bp
@@ -32,6 +32,7 @@
         "libhardware",
         "libhwbinder",
         "libbase",
+        "liblog",
         "libutils",
         "libhidlbase",
         "libhidltransport",
diff --git a/transport/memory/1.0/default/AshmemMapper.cpp b/transport/memory/1.0/default/AshmemMapper.cpp
index bef4767..cefaaa4 100644
--- a/transport/memory/1.0/default/AshmemMapper.cpp
+++ b/transport/memory/1.0/default/AshmemMapper.cpp
@@ -16,6 +16,9 @@
 
 #include "AshmemMapper.h"
 
+#include <inttypes.h>
+
+#include <log/log.h>
 #include <sys/mman.h>
 
 #include "AshmemMemory.h"
@@ -32,6 +35,16 @@
         return nullptr;
     }
 
+    // If ashmem service runs in 32-bit (size_t is uint32_t) and a 64-bit
+    // client process requests a memory > 2^32 bytes, the size would be
+    // converted to a 32-bit number in mmap. mmap could succeed but the
+    // mapped memory's actual size would be smaller than the reported size.
+    if (mem.size() > SIZE_MAX) {
+        ALOGE("Cannot map %" PRIu64 " bytes of memory because it is too large.", mem.size());
+        android_errorWriteLog(0x534e4554, "79376389");
+        return nullptr;
+    }
+
     int fd = mem.handle()->data[0];
     void* data = mmap(0, mem.size(), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
     if (data == MAP_FAILED) {