genode/repos/base-linux/lib/mk/base-linux.mk
Norman Feske 132569d12b base-linux: socket descriptor caps for RPC
On Linux, Genode used to represent each RPC object by a socket
descriptor of the receiving thread (entrypoint) and a globally-unique
value that identifies the object. Because the latter was transferred as
plain message payload, clients had to be trusted to not forge the
values. For this reason, Linux could not be considered as a productive
Genode base platform but remained merely a development vehicle.

This patch changes the RPC mechanism such that each RPC object is
represented by a dedicated socket pair. Entrypoints wait on a set of
the local ends of the socket pairs of all RPC objects managed by the
respective entrypoint. The epoll kernel interface is used as the
underlying mechanism to wait for a set of socket descriptors at the
server side.

When delegating a capability, the remote end of the socket pair is
transferred to the recipient along with a plaintext copy of the
socket-descriptor value of the local end. The latter value serves as a
hint for re-identifiying a capability whenever it is delegated back to
its origin. Note that the client is not trusted to preserve this
information. The integrity of the hint value is protected by comparing
the inode values of incoming and already present capablities at the
originating site (whenever the capability is invoked or presented to the
owner of the RPC object).

The new mechanism effectively equips base-linux with Genode's capablity
model as described in the Chapter 3 of the Genode Foundations book.
That said, the sandboxing of components cannot be assumed at this point
because each component has still direct access to the Linux system-call
interface.

This patch is based on the extensive exploration work conducted by
Stefan Thoeni who strongly motivated the inclusion of this feature into
Genode.

Issue #3581
2020-04-17 12:40:13 +02:00

15 lines
402 B
Makefile

#
# \brief Base lib parts that are not used by hybrid applications
# \author Sebastian Sumpf
# \date 2014-02-21
#
include $(REP_DIR)/lib/mk/base-linux.inc
LIBS += startup-linux base-linux-common cxx
SRC_CC += thread.cc thread_myself.cc thread_linux.cc
SRC_CC += capability_space.cc capability_raw.cc
SRC_CC += attach_stack_area.cc
SRC_CC += signal_transmitter.cc signal.cc
SRC_CC += platform.cc