neverallow read to shell- and app-writable symlinks.
To reduce the likelihood of malicious symlink attacks, neverallow
read access to shell- and app-writable symlinks.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
(cherry picked from commit 9d439d3d4f6d5aa30b090f638f20841a3e3e72b2)
Bug: 21924438
Change-Id: Icf1ccca71ef4395de8be8503359f76f89cc9e1a5
diff --git a/domain.te b/domain.te
index 9331457..c115f87 100644
--- a/domain.te
+++ b/domain.te
@@ -456,3 +456,20 @@
-runas
-zygote
} shell:process { transition dyntransition };
+
+# Minimize read access to shell- or app-writable symlinks.
+# This is to prevent malicious symlink attacks.
+neverallow {
+ domain
+ -appdomain
+ -installd
+ -uncrypt # TODO: see if we can remove
+} app_data_file:lnk_file read;
+
+neverallow {
+ domain
+ -shell
+ userdebug_or_eng(`-uncrypt')
+ -installd
+ -surfaceflinger # TODO: see if we can remove from mako sepolicy
+} shell_data_file:lnk_file read;
