Merge "Ensure input has CAP_BLOCK_SUSPEND"
diff --git a/services/inputflinger/reader/Android.bp b/services/inputflinger/reader/Android.bp
index a64f4dd..3c16070 100644
--- a/services/inputflinger/reader/Android.bp
+++ b/services/inputflinger/reader/Android.bp
@@ -50,6 +50,7 @@
shared_libs: [
"libbase",
+ "libcap",
"libinputflinger_base",
"libcrypto",
"libcutils",
diff --git a/services/inputflinger/reader/EventHub.cpp b/services/inputflinger/reader/EventHub.cpp
index efe3809..c8da0ab 100644
--- a/services/inputflinger/reader/EventHub.cpp
+++ b/services/inputflinger/reader/EventHub.cpp
@@ -24,6 +24,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/capability.h>
#include <sys/epoll.h>
#include <sys/inotify.h>
#include <sys/ioctl.h>
@@ -237,6 +238,47 @@
return !isVirtual && enabled;
}
+/**
+ * Get the capabilities for the current process.
+ * Crashes the system if unable to create / check / destroy the capabilities object.
+ */
+class Capabilities final {
+public:
+ explicit Capabilities() {
+ mCaps = cap_get_proc();
+ LOG_ALWAYS_FATAL_IF(mCaps == nullptr, "Could not get capabilities of the current process");
+ }
+
+ /**
+ * Check whether the current process has a specific capability
+ * in the set of effective capabilities.
+ * Return CAP_SET if the process has the requested capability
+ * Return CAP_CLEAR otherwise.
+ */
+ cap_flag_value_t checkEffectiveCapability(cap_value_t capability) {
+ cap_flag_value_t value;
+ const int result = cap_get_flag(mCaps, capability, CAP_EFFECTIVE, &value);
+ LOG_ALWAYS_FATAL_IF(result == -1, "Could not obtain the requested capability");
+ return value;
+ }
+
+ ~Capabilities() {
+ const int result = cap_free(mCaps);
+ LOG_ALWAYS_FATAL_IF(result == -1, "Could not release the capabilities structure");
+ }
+
+private:
+ cap_t mCaps;
+};
+
+static void ensureProcessCanBlockSuspend() {
+ Capabilities capabilities;
+ const bool canBlockSuspend =
+ capabilities.checkEffectiveCapability(CAP_BLOCK_SUSPEND) == CAP_SET;
+ LOG_ALWAYS_FATAL_IF(!canBlockSuspend,
+ "Input must be able to block suspend to properly process events");
+}
+
// --- EventHub ---
const int EventHub::EPOLL_MAX_EVENTS;
@@ -253,6 +295,7 @@
mPendingEventCount(0),
mPendingEventIndex(0),
mPendingINotify(false) {
+ ensureProcessCanBlockSuspend();
acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);
mEpollFd = epoll_create1(EPOLL_CLOEXEC);