init: Drop inheritable capabilities when switching uids
This change explicitly drops all inheritable capabilities (and, by
extension, ambient capabilities) when there are no explicit capabilities
being set by a service and the user is changed. This prevents Android
running in a container from accidentally granting extra capabilities to
services.
Bug: 69320306
Test: aosp_sailfish still boots
Test: sailfish:/ $ grep Cap /proc/`pidof android.hardware.audio@2.0-service`/status
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 0000003fffffffff
CapAmb: 0000000000000000
Test: sailfish:/ $ grep Cap /proc/`pidof logd`/status
CapInh: 0000000000000000
CapPrm: 0000000440000000
CapEff: 0000000440000000
CapBnd: 0000003fffffffff
CapAmb: 0000000000000000
Test: Android in Chrome OS still boots
Test: localhost ~ # grep Cap /proc/`pidof android.hardware.audio@2.0-service`/status
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 000000006daefdff
CapAmb: 0000000000000000
Test: localhost ~ # grep Cap /proc/`pidof logd`/status
CapInh: 0000000000000000
CapPrm: 0000000040000000
CapEff: 0000000040000000
CapBnd: 000000006daefdff
CapAmb: 0000000000000000
Change-Id: I9218f2e27ff4fb4d91d50f9a98c0fdb4e272952c
diff --git a/init/service.cpp b/init/service.cpp
index 481df65..331b859 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -291,6 +291,11 @@
if (!SetCapsForExec(capabilities_)) {
LOG(FATAL) << "cannot set capabilities for " << name_;
}
+ } else if (uid_) {
+ // Inheritable caps can be non-zero when running in a container.
+ if (!DropInheritableCaps()) {
+ LOG(FATAL) << "cannot drop inheritable caps for " << name_;
+ }
}
}