Improve visibility of IMemory security risks
This change renames the IMemory raw pointer accessors to
unsecure*() to make it apparent to coders and code reviewers
that the returned buffer may potentially be shared with
untrusted processes, who may, after the fact, attempt to
read and/or modify the contents. This may lead to hard to
find security bugs and hopefully the rename makes it harder
to forget.
The change also attempts to fix all the callsites to make
everything build correctly, but in the processes, wherever the
callsite code was not obviously secure, I added a TODO requesting
the owners to either document why it's secure or to change the
code. Apologies in advance to the owners if there are some false
positives here - I don't have enough context to reason about all
the different callsites.
Test: Completely syntactic change. Made sure code still builds.
Change-Id: I5fb99aa797c488406083178a6b05355d98710d3b
diff --git a/services/soundtrigger/SoundTriggerHwService.cpp b/services/soundtrigger/SoundTriggerHwService.cpp
index 377d30b..69e5f50 100644
--- a/services/soundtrigger/SoundTriggerHwService.cpp
+++ b/services/soundtrigger/SoundTriggerHwService.cpp
@@ -234,11 +234,11 @@
size_t size = event->data_offset + event->data_size;
eventMemory = mMemoryDealer->allocate(size);
- if (eventMemory == 0 || eventMemory->pointer() == NULL) {
+ if (eventMemory == 0 || eventMemory->unsecurePointer() == NULL) {
eventMemory.clear();
return eventMemory;
}
- memcpy(eventMemory->pointer(), event, size);
+ memcpy(eventMemory->unsecurePointer(), event, size);
return eventMemory;
}
@@ -283,11 +283,11 @@
size_t size = event->data_offset + event->data_size;
eventMemory = mMemoryDealer->allocate(size);
- if (eventMemory == 0 || eventMemory->pointer() == NULL) {
+ if (eventMemory == 0 || eventMemory->unsecurePointer() == NULL) {
eventMemory.clear();
return eventMemory;
}
- memcpy(eventMemory->pointer(), event, size);
+ memcpy(eventMemory->unsecurePointer(), event, size);
return eventMemory;
}
@@ -313,11 +313,11 @@
size_t size = sizeof(sound_trigger_service_state_t);
eventMemory = mMemoryDealer->allocate(size);
- if (eventMemory == 0 || eventMemory->pointer() == NULL) {
+ if (eventMemory == 0 || eventMemory->unsecurePointer() == NULL) {
eventMemory.clear();
return eventMemory;
}
- *((sound_trigger_service_state_t *)eventMemory->pointer()) = state;
+ *((sound_trigger_service_state_t *)eventMemory->unsecurePointer()) = state;
return eventMemory;
}
@@ -557,8 +557,12 @@
return NO_INIT;
}
+ // TODO: Using unsecurePointer() has some associated security pitfalls
+ // (see declaration for details).
+ // Either document why it is safe in this case or address the
+ // issue (e.g. by copying).
struct sound_trigger_sound_model *sound_model =
- (struct sound_trigger_sound_model *)modelMemory->pointer();
+ (struct sound_trigger_sound_model *)modelMemory->unsecurePointer();
size_t structSize;
if (sound_model->type == SOUND_MODEL_TYPE_KEYPHRASE) {
@@ -651,8 +655,12 @@
return NO_INIT;
}
+ // TODO: Using unsecurePointer() has some associated security pitfalls
+ // (see declaration for details).
+ // Either document why it is safe in this case or address the
+ // issue (e.g. by copying).
struct sound_trigger_recognition_config *config =
- (struct sound_trigger_recognition_config *)dataMemory->pointer();
+ (struct sound_trigger_recognition_config *)dataMemory->unsecurePointer();
if (config->data_offset < sizeof(struct sound_trigger_recognition_config) ||
config->data_size > (UINT_MAX - config->data_offset) ||
@@ -734,9 +742,10 @@
{
ALOGV("onCallbackEvent type %d", event->mType);
+ // Memory is coming from a trusted process.
sp<IMemory> eventMemory = event->mMemory;
- if (eventMemory == 0 || eventMemory->pointer() == NULL) {
+ if (eventMemory == 0 || eventMemory->unsecurePointer() == NULL) {
return;
}
if (mModuleClients.isEmpty()) {
@@ -749,7 +758,7 @@
switch (event->mType) {
case CallbackEvent::TYPE_RECOGNITION: {
struct sound_trigger_recognition_event *recognitionEvent =
- (struct sound_trigger_recognition_event *)eventMemory->pointer();
+ (struct sound_trigger_recognition_event *)eventMemory->unsecurePointer();
{
AutoMutex lock(mLock);
sp<Model> model = getModel(recognitionEvent->model);
@@ -769,7 +778,7 @@
} break;
case CallbackEvent::TYPE_SOUNDMODEL: {
struct sound_trigger_model_event *soundmodelEvent =
- (struct sound_trigger_model_event *)eventMemory->pointer();
+ (struct sound_trigger_model_event *)eventMemory->unsecurePointer();
{
AutoMutex lock(mLock);
sp<Model> model = getModel(soundmodelEvent->model);
@@ -1082,7 +1091,8 @@
sp<IMemory> eventMemory = event->mMemory;
- if (eventMemory == 0 || eventMemory->pointer() == NULL) {
+ // Memory is coming from a trusted process.
+ if (eventMemory == 0 || eventMemory->unsecurePointer() == NULL) {
return;
}