From ea9681e4cdf30340b583dc27cb6c6474926ddaee Mon Sep 17 00:00:00 2001
From: Martijn Coenen <maco@google.com>
Date: Mon, 1 Feb 2021 07:57:02 +0000
Subject: [PATCH] Revert "Revert "Set a default ACL on /data/media/userId.""

This reverts commit b276e80aec54c139587bbc510f503ced9414cf0f.

Reason for revert: b/177926359 is now fixed

Change-Id: I8ec5d80a44fc9e491ab3430592e17d10a82f40ea
---
 FsCrypt.cpp | 11 ++++++++++-
 Utils.cpp   |  4 ++--
 Utils.h     |  3 +++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/FsCrypt.cpp b/FsCrypt.cpp
index 8f6ba9c..be51963 100644
--- a/FsCrypt.cpp
+++ b/FsCrypt.cpp
@@ -74,6 +74,7 @@ using android::vold::KeyBuffer;
 using android::vold::KeyGeneration;
 using android::vold::retrieveKey;
 using android::vold::retrieveOrGenerateKey;
+using android::vold::SetDefaultAcl;
 using android::vold::SetQuotaInherit;
 using android::vold::SetQuotaProjectId;
 using android::vold::writeStringToFile;
@@ -867,7 +868,15 @@ bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_
             if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false;
             if (!prepare_dir(vendor_ce_path, 0771, AID_ROOT, AID_ROOT)) return false;
         }
-        if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false;
+        if (!prepare_dir(media_ce_path, 02770, AID_MEDIA_RW, AID_MEDIA_RW)) return false;
+        // On devices without sdcardfs (kernel 5.4+), the path permissions aren't fixed
+        // up automatically; therefore, use a default ACL, to ensure apps with MEDIA_RW
+        // can keep reading external storage; in particular, this allows app cloning
+        // scenarios to work correctly on such devices.
+        int ret = SetDefaultAcl(media_ce_path, 02770, AID_MEDIA_RW, AID_MEDIA_RW, {AID_MEDIA_RW});
+        if (ret != android::OK) {
+            return false;
+        }
 
         if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false;
 
diff --git a/Utils.cpp b/Utils.cpp
index d5648f7..98797b2 100644
--- a/Utils.cpp
+++ b/Utils.cpp
@@ -136,8 +136,8 @@ status_t DestroyDeviceNode(const std::string& path) {
 }
 
 // Sets a default ACL on the directory.
-int SetDefaultAcl(const std::string& path, mode_t mode, uid_t uid, gid_t gid,
-                  std::vector<gid_t> additionalGids) {
+status_t SetDefaultAcl(const std::string& path, mode_t mode, uid_t uid, gid_t gid,
+                       std::vector<gid_t> additionalGids) {
     if (IsSdcardfsUsed()) {
         // sdcardfs magically takes care of this
         return OK;
diff --git a/Utils.h b/Utils.h
index cf3fd9b..8975adc 100644
--- a/Utils.h
+++ b/Utils.h
@@ -52,6 +52,9 @@ std::string GetFuseMountPathForUser(userid_t user_id, const std::string& relativ
 status_t CreateDeviceNode(const std::string& path, dev_t dev);
 status_t DestroyDeviceNode(const std::string& path);
 
+status_t SetDefaultAcl(const std::string& path, mode_t mode, uid_t uid, gid_t gid,
+                       std::vector<gid_t> additionalGids);
+
 status_t AbortFuseConnections();
 
 int SetQuotaInherit(const std::string& path);