commit f14208e0390d8ee20ee4a5d7605d614e8b1abaf1
author Jeff Sharkey <jsharkey@android.com> Mon Oct 31 11:22:19 2016 -0600
committer gitbuildkicker <android-build@google.com> Mon Oct 31 18:14:15 2016 -0700
tree e2a4c7ca37ef773863beee22646383acbd503a7d
parent 822312b8dc9137c3d289359304a4a0aa076fde8d

Check and restorecon cache/code_cache directories.

To speed up boot times, we recently relaxed SELinux restorecon logic
to only consider relabeling app storage when the top level SELinux
label changed.

However, if an app manually deletes either their cache or code_cache
directories, installd will helpfully recreate those directories at
the next boot, but they'll be stuck with incorrect SELinux labels
which an app can't fix.  (Our historically aggressive restorecons had
relabeled them, which is why we didn't observe until now.)

This change checks the labels of the cache/code_cache directories,
and runs a restorecon if needed, fixing the issue above.

Test: delete cache and verify recreated with correct label
Bug: 32504081
Change-Id: I0114ae4129223e5909b1075d56a9b1145ebc5ef4
(cherry picked from commit 397ec266753a675e6891c479971e6506491b1b44)

cmds/installd/commands.cpp

diff --git a/cmds/installd/commands.cpp b/cmds/installd/commands.cpp
index 4ed8997..271c75b 100644
--- a/cmds/installd/commands.cpp
+++ b/cmds/installd/commands.cpp
@@ -104,7 +104,7 @@
  * if the label of that top-level file actually changed.  This can save us
  * significant time by avoiding no-op traversals of large filesystem trees.
  */
-static int restorecon_app_data_lazy(const char* path, const char* seinfo, uid_t uid) {
+static int restorecon_app_data_lazy(const std::string& path, const char* seinfo, uid_t uid) {
     int res = 0;
     char* before = nullptr;
     char* after = nullptr;
@@ -112,15 +112,15 @@
     // Note that SELINUX_ANDROID_RESTORECON_DATADATA flag is set by
     // libselinux. Not needed here.
 
-    if (lgetfilecon(path, &before) < 0) {
+    if (lgetfilecon(path.c_str(), &before) < 0) {
         PLOG(ERROR) << "Failed before getfilecon for " << path;
         goto fail;
     }
-    if (selinux_android_restorecon_pkgdir(path, seinfo, uid, 0) < 0) {
+    if (selinux_android_restorecon_pkgdir(path.c_str(), seinfo, uid, 0) < 0) {
         PLOG(ERROR) << "Failed top-level restorecon for " << path;
         goto fail;
     }
-    if (lgetfilecon(path, &after) < 0) {
+    if (lgetfilecon(path.c_str(), &after) < 0) {
         PLOG(ERROR) << "Failed after getfilecon for " << path;
         goto fail;
     }
@@ -130,7 +130,7 @@
     if (strcmp(before, after)) {
         LOG(DEBUG) << "Detected label change from " << before << " to " << after << " at " << path
                 << "; running recursive restorecon";
-        if (selinux_android_restorecon_pkgdir(path, seinfo, uid,
+        if (selinux_android_restorecon_pkgdir(path.c_str(), seinfo, uid,
                 SELINUX_ANDROID_RESTORECON_RECURSE) < 0) {
             PLOG(ERROR) << "Failed recursive restorecon for " << path;
             goto fail;
@@ -146,6 +146,11 @@
     return res;
 }
 
+static int restorecon_app_data_lazy(const std::string& parent, const char* name, const char* seinfo,
+        uid_t uid) {
+    return restorecon_app_data_lazy(StringPrintf("%s/%s", parent.c_str(), name), seinfo, uid);
+}
+
 static int prepare_app_dir(const std::string& path, mode_t target_mode, uid_t uid) {
     if (fs_prepare_dir_strict(path.c_str(), target_mode, uid, uid) != 0) {
         PLOG(ERROR) << "Failed to prepare " << path;
@@ -172,7 +177,9 @@
         }
 
         // Consider restorecon over contents if label changed
-        if (restorecon_app_data_lazy(path.c_str(), seinfo, uid)) {
+        if (restorecon_app_data_lazy(path, seinfo, uid) ||
+                restorecon_app_data_lazy(path, "cache", seinfo, uid) ||
+                restorecon_app_data_lazy(path, "code_cache", seinfo, uid)) {
             return -1;
         }
 
@@ -191,7 +198,7 @@
         }
 
         // Consider restorecon over contents if label changed
-        if (restorecon_app_data_lazy(path.c_str(), seinfo, uid)) {
+        if (restorecon_app_data_lazy(path, seinfo, uid)) {
             return -1;
         }