Merge "Add checks to ensure only the ART memfd file is whitelisted." am: 555ffd1c0c (3f879b77) · Commits · e / os / android_frameworks_base

core/jni/fd_utils.cpp

+18 −6

Original line number	Diff line number	Diff line
		@@ -59,8 +59,8 @@ FileDescriptorWhitelist* FileDescriptorWhitelist::Get() {
		return instance_;
		}

		static bool IsMemfd(const std::string& path) {
		return android::base::StartsWith(path, "/memfd:");
		static bool IsArtMemfd(const std::string& path) {
		return android::base::StartsWith(path, "/memfd:/boot-image-methods.art");
		}

		bool FileDescriptorWhitelist::IsAllowed(const std::string& path) const {
		@@ -91,8 +91,8 @@ bool FileDescriptorWhitelist::IsAllowed(const std::string& path) const {
		return true;
		}

		// In-memory files created through memfd_create are allowed.
		if (IsMemfd(path)) {
		// the in-memory file created by ART through memfd_create is allowed.
		if (IsArtMemfd(path)) {
		return true;
		}

		@@ -321,8 +321,8 @@ void FileDescriptorInfo::ReopenOrDetach(fail_fn_t fail_fn) const {
		return DetachSocket(fail_fn);
		}

		// Children can directly use in-memory files created through memfd_create.
		if (IsMemfd(file_path)) {
		// Children can directly use the in-memory file created by ART through memfd_create.
		if (IsArtMemfd(file_path)) {
		return;
		}

		@@ -545,6 +545,10 @@ FileDescriptorTable::FileDescriptorTable(
		}

		void FileDescriptorTable::RestatInternal(std::set<int>& open_fds, fail_fn_t fail_fn) {
		// ART creates a file through memfd for optimization purposes. We make sure
		// there is at most one being created.
		bool art_memfd_seen = false;

		// Iterate through the list of file descriptors we've already recorded
		// and check whether :
		//
		@@ -577,6 +581,14 @@ void FileDescriptorTable::RestatInternal(std::set<int>& open_fds, fail_fn_t fail
		// FD.
		}

		if (IsArtMemfd(it->second->file_path)) {
		if (art_memfd_seen) {
		fail_fn("ART fd already seen: " + it->second->file_path);
		} else {
		art_memfd_seen = true;
		}
		}

		++it;

		// Finally, remove the FD from the set of open_fds. We do this last because