capabilities: Check ambient caps, last valid runtime cap.
Partners have expressed interest in using the 'capabilities' keyword
in init, so make the code more resilient:
-Check that ambient capabilities are supported by the kernel.
-Check that the last valid cap at runtime is not higher than what's in
kernel headers.
-Check that the user is not requesting a capability present in kernel
headers but not supported by the kernel at runtime.
-Don't attempt to drop bounding set capabilities not supported at
runtime.
This CL also fixes a small bug where < should have been used instead of
<=, and uses 'static' instead of anonymous namespaces.
Bug: 32438163
Test: Use a test service that uses capabilities.
Test: Apply in internal tree and test with angler and rild.
Change-Id: Ia271cc7eb389d1d526d61f897261e4bac4d19e5d
diff --git a/init/capabilities.h b/init/capabilities.h
index 368178d..abd7fb2 100644
--- a/init/capabilities.h
+++ b/init/capabilities.h
@@ -12,6 +12,9 @@
// See the License for the specific language governing permissions and
// limitations under the License.
+#ifndef _INIT_CAPABILITIES_H
+#define _INIT_CAPABILITIES_H
+
#include <linux/capability.h>
#include <bitset>
@@ -20,4 +23,8 @@
using CapSet = std::bitset<CAP_LAST_CAP + 1>;
int LookupCap(const std::string& cap_name);
+bool CapAmbientSupported();
+unsigned int GetLastValidCap();
bool SetCapsForExec(const CapSet& to_keep);
+
+#endif // _INIT_CAPABILITIES_H