Hide storage directories from non-owner apps
Bug: 219958836
Test: atest CtsScopedStorageHostTest passes
Call of Duty installs, runs, launch time is unchanged
adb shell correctly hides folders when you:
cd storage/emulated/0/Android/data
ls -al # as root shows all
su uid-of-on-of-the-apps
ls -al # shows only that app's folder(s)
Have ran overnight on personal phone, ran audible etc
Change-Id: I09132569314c7805f3ae7302c4e746451ef84b16
diff --git a/fuseMedia.c b/fuseMedia.c
index cba94c5..41d5406 100644
--- a/fuseMedia.c
+++ b/fuseMedia.c
@@ -34,16 +34,34 @@
const char* name = fa->in_args[0].value;
bpf_printk("LOOKUP_PREFILTER: %lx %s", fa->nodeid, name);
- // Using backing implementation but remove bpf_action for children files/directories
- // in the postfilter.
return FUSE_BPF_BACKING | FUSE_BPF_POST_FILTER;
}
case FUSE_LOOKUP | FUSE_POSTFILTER: {
+ struct fuse_entry_out* feo = fa->out_args[0].value;
struct fuse_entry_bpf_out* febo = fa->out_args[1].value;
+ uint64_t uid_gid = bpf_get_current_uid_gid();
+ uint32_t uid = uid_gid;
+ uint32_t gid = uid_gid >> 32;
febo->bpf_action = FUSE_ACTION_REMOVE;
- return FUSE_BPF_BACKING;
+
+ /* If the decision is easy, make it here for performance */
+ if (fa->error_in || (feo->attr.mode & 0001) ||
+ ((feo->attr.mode & 0010) && gid == feo->attr.gid) ||
+ ((feo->attr.mode & 0100) && uid == feo->attr.uid))
+ return 0;
+
+ /* Delegate to the daemon */
+ return FUSE_BPF_USER_FILTER;
+ }
+
+ case FUSE_READDIR | FUSE_PREFILTER: {
+ return FUSE_BPF_BACKING | FUSE_BPF_POST_FILTER;
+ }
+
+ case FUSE_READDIR | FUSE_POSTFILTER: {
+ return FUSE_BPF_USER_FILTER;
}
default:
