From 03d4458ea0cb00c28f695d99aae5e4c6b15fc237 Mon Sep 17 00:00:00 2001 From: Sally Qi Date: Wed, 5 Oct 2022 11:42:30 -0700 Subject: Mitigate the security vulnerability by sanitizing the transaction flags. - This is part of fix of commit Id9d9012d4ede9c8330f0ce1096bcb78e51b7c5df for backporting. - Part of commit Id9d9012d4ede9c8330f0ce1096bcb78e51b7c5df which sanitizes the transaction flags from DisplayState instead. - In rvc, we only have ACCESS_SURFACE_FLINGER permission check passed as `privileged` argument in SF::applyTransactionState. We can directly utilize it for sanitization in DiaplyState. - In rvc code base, SF::setTransactionState pass a const array of displayState objects and then call SF::applyTransactionState. To successfully sanitize the flags for each displayState object, we convert this const array into non-const one before calling SF::applyTransactionState. Bug: 248031255 Test: test using displaytoken app manually on the phone, test shell screenrecord during using displaytoken; atest android.hardware.camera2.cts.FastBasicsTest Change-Id: Id9d9012d4ede9c8330f0ce1096bcb78e51b7c5df Merged-In: Id9d9012d4ede9c8330f0ce1096bcb78e51b7c5df --- libs/gui/LayerState.cpp | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'libs/gui/LayerState.cpp') diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp index dfcef8fe7a..a76a21c5c4 100644 --- a/libs/gui/LayerState.cpp +++ b/libs/gui/LayerState.cpp @@ -276,6 +276,27 @@ void DisplayState::merge(const DisplayState& other) { } } +void DisplayState::sanitize(bool privileged) { + if (what & DisplayState::eLayerStackChanged) { + if (!privileged) { + what &= ~DisplayState::eLayerStackChanged; + ALOGE("Stripped attempt to set eLayerStackChanged in sanitize"); + } + } + if (what & DisplayState::eDisplayProjectionChanged) { + if (!privileged) { + what &= ~DisplayState::eDisplayProjectionChanged; + ALOGE("Stripped attempt to set eDisplayProjectionChanged in sanitize"); + } + } + if (what & DisplayState::eSurfaceChanged) { + if (!privileged) { + what &= ~DisplayState::eSurfaceChanged; + ALOGE("Stripped attempt to set eSurfaceChanged in sanitize"); + } + } +} + void layer_state_t::merge(const layer_state_t& other) { if (other.what & ePositionChanged) { what |= ePositionChanged; -- cgit v1.2.3-59-g8ed1b