package_qa_sourcery: add host user ownership test

Check for files outside of /home which are owned by the user running bitbake.

Add `package_qa_sourcery` to `PACKAGE_CLASSES`, and `${SOURCERY_QA}` to your
`WARN_QA` or `ERROR_QA` to use.

This will be submitted to oe-core's package_qa.

JIRA: SB-4185

Signed-off-by: Christopher Larson <kergoth@gmail.com>

classes/package_qa_sourcery.bbclass

@@ -0,0 +1,36 @@
+inherit package
+
+SOURCERY_QA = "host-user-contaminated"
+
+# We need to test in fakeroot context to check file ownership
+do_package_qa[fakeroot] = "1"
+
+HOST_USER_UID := "${@os.getuid()}"
+HOST_USER_UID[type] = "integer"
+HOST_USER_GID := "${@os.getgid()}"
+HOST_USER_GID[type] = "integer"
+
+QAPATHTEST[host-user-contaminated] = "package_qa_check_host_user"
+def package_qa_check_host_user(path, name, d, elf, messages):
+    """Check for files outside of /home which are owned by the user running bitbake."""
+
+    if not os.path.lexists(path):
+        return
+
+    check_uid = oe.data.typed_value('HOST_USER_UID', d)
+    check_gid = oe.data.typed_value('HOST_USER_GID', d)
+
+    dest = d.getVar('PKGDEST', True)
+    home = os.path.join(dest, 'home')
+    if path == home or path.startswith(home + os.sep):
+        return
+
+    stat = os.lstat(path)
+    if stat.st_uid == check_uid:
+        messages["host-user-contaminated"] = "%s is owned by uid %d, which is the same as the user running bitbake. This may be due to host contamination" % (path, check_uid)
+        return False
+
+    if stat.st_gid == check_gid:
+        messages["host-user-contaminated"] = "%s is owned by gid %d, which is the same as the user running bitbake. This may be due to host contamination" % (path, check_gid)
+        return False
+    return True