mapMemory: Do not map if size is > SIZE_MAX
Bug: 79376389
Test: hidl_test
Test: POC in bug
Change-Id: Ibaced858aa07bfd7ab6e938cc1339b974b0de14f
Merged-In: Ibaced858aa07bfd7ab6e938cc1339b974b0de14f
(cherry picked from commit 694bd8d1b43b9e60623cb3d5bd3f21662680dd7c)
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/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) {
