/postinstall/* does not search for a lib in /vendor or /odm
There has been no section in the linker config file for the binaries
under /postinstall. As a result, the binaries were run with the legacy
default config where /vendor/lib and /odm/lib are added to the search
paths. This is causing selinux denials as the binaries for OTA are not
allowed to access /vendor/lib or /odm/lib, but the dynamic linker calls
realpath(3) on the paths to canonicalize them.
Fixing the issue by letting /postinstall/* binaries to run with a
dedicated linker namespace config, where /vendor/lib and /odm/lib are
not added to the search paths. Not having the paths is okay because
he OTA binaries should not have dependency to the libs there.
Bug: 75287236
Test: do the OTA, selinux denials on postinstall_file is not shown
Test: above test should pass on wahoo, marlin and pre-treble devices
Change-Id: I49c11a0929002adfef667890c0a375c2b41054f4
diff --git a/rootdir/etc/ld.config.txt b/rootdir/etc/ld.config.txt
index 6e46295..94465f4 100644
--- a/rootdir/etc/ld.config.txt
+++ b/rootdir/etc/ld.config.txt
@@ -24,6 +24,8 @@
dir.system = /data/benchmarktest
dir.system = /data/benchmarktest64
+dir.postinstall = /postinstall
+
[system]
additional.namespaces = sphal,vndk,rs
@@ -315,3 +317,15 @@
namespace.system.asan.search.paths = /data/asan/system/${LIB}
namespace.system.asan.search.paths += /system/${LIB}
+
+###############################################################################
+# Namespace config for binaries under /postinstall.
+# Only one default namespace is defined and it has no directories other than
+# /system/lib in the search paths. This is because linker calls realpath on the
+# search paths and this causes selinux denial if the paths (/vendor, /odm) are
+# not allowed to the poinstall binaries. There is no reason to allow the
+# binaries to access the paths.
+###############################################################################
+[postinstall]
+namespace.default.isolated = false
+namespace.default.search.paths = /system/${LIB}