There is some commonality between the code for sanity checking
certs when initializing libvirt and the code for validating
certs during a live TLS session handshake. This patchset splits
up the sanity checking function into several smaller functions
each doing a specific type of check. The cert validation code
is then updated to also call into these functions
* src/rpc/virnettlscontext.c: Refactor cert validation code
The gnutls_certificate_type_set_priority method is deprecated.
Since we already set the default gnutls priority, it was not
serving any useful purpose and can be removed
* src/rpc/virnettlscontext.c: Remove gnutls_certificate_type_set_priority
call
If the virStateInitialize call fails we must shutdown libvirtd
since drivers will not be available. Just free'ing the virNetServer
is not sufficient, we must send a SIGTERM to ourselves so that
we interrupt the event loop and trigger a orderly shutdown
* daemon/libvirtd.c: Kill ourselves if state init fails
* src/rpc/virnetserver.c: Add some debugging to event loop
The generator can handle everything except virDomainGetBlockJobInfo().
* src/remote/remote_protocol.x: provide defines for the new entry points
* src/remote/remote_driver.c daemon/remote.c: implement the client and
server side for virDomainGetBlockJobInfo.
* src/remote_protocol-structs: structure definitions for protocol verification
* src/rpc/gendispatch.pl: Permit some unsigned long parameters
The only 'void name(void)' style procedure in the protocol is 'close' that
is handled special, but also programming errors like a missing _args or
_ret suffix on the structs in the .x files can create such a situation by
accident. Making the generator aware of this avoids bogus errors from the
generator such as:
Use of uninitialized value in exists at ./rpc/gendispatch.pl line 967.
Also this allows to get rid of the -c option and the special case code for
the 'close' procedure, as the generator handles it now correctly.
Reported by Michal Privoznik
Though we prefer users to have SSH keys setup, virt-manager users still
depend on remote SSH connections to launch a password dialog. This fixes
launch ssh-askpass
Fix suggested by danpb
If a key purpose or usage field is marked as non-critical in the
certificate, then a data mismatch is not (ordinarily) a cause for
rejecting the connection
* src/rpc/virnettlscontext.c: Honour key usage/purpose criticality
If key usage or purpose data is not present in the cert, the
RFC recommends that access be allowed. Also fix checking of
key usage to include requirements for client/server certs,
and fix key purpose checking to treat data as a list of bits
Gnutls requires that certificates have basic constraints present
to be used as a CA certificate. OpenSSL doesn't add this data
by default, so add a sanity check to catch this situation. Also
validate that the key usage and key purpose constraints contain
correct data
* src/rpc/virnettlscontext.c: Add sanity checking of certificate
constraints
If the libvirt daemon or libvirt client is configured with bogus
certificates, it is very unhelpful to only find out about this
when a TLS connection is actually attempted. Not least because
the error messages you get back for failures are incredibly
obscure.
This adds some basic sanity checking of certificates at the
time the virNetTLSContext object is created. This is at libvirt
startup, or when creating a virNetClient instance.
This checks that the certificate expiry/start dates are valid
and that the certificate is actually signed by the CA that is
loaded.
* src/rpc/virnettlscontext.c: Add certificate sanity checks
Since the I/O callback registered against virNetSocket will
hold a reference on the virNetClient, we can't rely on the
virNetClientFree to be able to close the network connection.
The last reference will only go away when the event callback
fires (likely due to EOF from the server).
This is sub-optimal and can potentially cause a leak of the
virNetClient object if the server were to not explicitly
close the socket itself
* src/remote/remote_driver.c: Explicitly close the client
object when disconnecting
* src/rpc/virnetclient.c, src/rpc/virnetclient.h: Add a
virNetClientClose method
When unregistering an I/O callback from a virNetSocket object,
there is still a chance that an event may come in on the callback.
In this case it is possible that the virNetSocket might have been
freed already. Make use of a virFreeCallback when registering
the I/O callbacks and hold a reference for the entire time the
callback is set.
* src/rpc/virnetsocket.c: Register a free function for the
file handle watch
* src/rpc/virnetsocket.h, src/rpc/virnetserverservice.c,
src/rpc/virnetserverclient.c, src/rpc/virnetclient.c: Add
a free function for the socket I/O watches
Remove the need for a virNetSocket object to be protected by
locks from the object using it, by introducing its own native
locking and reference counting
* src/rpc/virnetsocket.c: Add locking & reference counting
If we get an I/O error in the async event callback for an RPC
client, we might not have consumed all pending data off the
wire. This could result in the callback being immediately
invoked again. At which point the same I/O might occur. And
we're invoked again. And again...And again...
Unregistering the async event callback if an error occurs is
a good safety net. The real error will be seen when the next
RPC method is invoked
* src/rpc/virnetclient.c: Unregister event callback on error
These typos are introduced by file renaming in commit b17b4afaf.
src/remote/qemu_protocol.x \
src/remote/remote_protocol.x \
src/rpc/gendispatch.pl:
s/remote_generator/gendispatch/
src/rpc/genprotocol.pl:
s/remote\/remote_protocol/remote_protocol/
If the server succesfully validates the client cert, it will send
back a single byte, under TLS. If it fails, it will close the
connection. In this case, we were just reporting the standard
I/O error. The original RPC code had a special case hack for the
GNUTLS_E_UNEXPECTED_PACKET_LENGTH error code to make us report
a more useful error message
* src/rpc/virnetclient.c: Return ENOMSG if we get
GNUTLS_E_UNEXPECTED_PACKET_LENGTH
* src/rpc/virnettlscontext.c: Report cert failure if we
see ENOMSG
Rather than trying to clean up the ssh child ourselves, and risk
subtle differences from the socket creation error path, we can
just use the new APIs.
* src/rpc/virnetsocket.c (virNetSocketFree): Use new function.
Continuation of commit 313ac7fd, and enforce things with a syntax
check.
Technically, virNetServerClientCalculateHandleMode is not printing
a mode_t, but rather a collection of VIR_EVENT_HANDLE_* bits;
however, these bits are < 8, so there is no different in the
output, and that was the easiest way to silence the new syntax check.
* cfg.mk (sc_flags_debug): New syntax check.
(exclude_file_name_regexp--sc_flags_debug): Add exemptions.
* src/fdstream.c (virFDStreamOpenFileInternal): Print flags in
hex, mode_t in octal.
* src/libvirt-qemu.c (virDomainQemuMonitorCommand)
(virDomainQemuAttach): Likewise.
* src/locking/lock_driver_nop.c (virLockManagerNopInit): Likewise.
* src/locking/lock_driver_sanlock.c (virLockManagerSanlockInit):
Likewise.
* src/locking/lock_manager.c: Likewise.
* src/qemu/qemu_migration.c: Likewise.
* src/qemu/qemu_monitor.c: Likewise.
* src/rpc/virnetserverclient.c
(virNetServerClientCalculateHandleMode): Print mode with %o.
When replacing the default SEGV/ABORT/BUS signal handlers you
can't rely on the process being terminated after your custom
handler runs. It is neccessary to manually restore the default
handler and then re-raise the signal
* src/rpc/virnetserver.c: Restore default handler and raise
signal
This tweaks the RPC generator to cope with some naming
conventions used for the QEMU specific APIs
* daemon/remote.c: Server side dispatcher
* src/remote/remote_driver.c: Client side dispatcher
* src/remote/qemu_protocol.x: Wire protocol definition
* src/rpc/gendispatch.pl: Use '$structprefix' in method
names, fix QEMU flags and fix dispatcher method names
Set StrictHostKeyChecking=no to auto-accept new ssh host keys if the
no_verify extra parameter was specified. This won't disable host key
checking for already known hosts. Includes a test and documentation.
The dispatch for the CLOSE RPC call was invoking the method
virNetServerClientClose(). This caused the client connection
to be immediately terminated. This meant the reply to the
final RPC message was never sent. Prior to the RPC rewrite
we merely flagged the connection for closing, and actually
closed it when the next RPC call dispatch had completed.
* daemon/remote.c: Flag connection for a delayed close
* daemon/stream.c: Update to use new API for closing
failed connection
* src/rpc/virnetserverclient.c, src/rpc/virnetserverclient.h:
Add support for a delayed connection close. Rename the
virNetServerClientMarkClose method to virNetServerClientImmediateClose
to clarify its semantics
When sending back the final OK or ERROR message on completion
of a stream, we were not decrementing the 'nrequests' tracker
on the client. With the default requests limit of '5', this
meant once a client had created 5 streams, they are unable to
process any further RPC calls. There was also a bug when
handling an error from decoding a message length header, which
meant a client connection would not immediately be closed.
* src/rpc/virnetserverclient.c: Fix release of request after
stream completion & mark client for close on error
In one exit path we forgot to free the virNetMessage object causing
a large memory leak for streams which send a lot of data. Some other
paths were calling VIR_FREE directly instead of virNetMessageFree
although this was (currently) harmless.
* src/rpc/virnetclientstream.c: Fix leak of msg object
* src/rpc/virnetclientprogram.c: Call virNetMessageFree instead
of VIR_FREE
The virNetTLSContextNew was being passed key/cert parameters in
the wrong order. This wasn't immediately visible because if
virNetTLSContextNewPath was used, a second bug reversed the order
of those parameters again.
Only if the paths were manually specified in /etc/libvirt/libvirtd.conf
did the bug appear
* src/rpc/virnettlscontext.c: Fix order of params passed to
virNetTLSContextNew
Coverity noted that 4 out of 5 calls to virNetClientStreamRaiseError
checked the return value. This case expects a particular value, so
warn if our expectations went wrong due to some bug elsewhere.
* src/rpc/virnetclient.c (virNetClientCallDispatchStream): Warn on
unexpected scenario.
Detected by Coverity. The leak is on an error path, but I'm not
sure whether that path is likely to be triggered in practice.
* src/rpc/virnetserverservice.c (virNetServerServiceAccept): Plug leak.
Spotted by Coverity. If we don't update tmp each time through
the loop, then if the filter being removed was not the head of
the list, we accidentally lose all filters prior to the one we
wanted to remove.
* src/rpc/virnetserverclient.c (virNetServerClientRemoveFilter):
Don't lose unrelated filters.
Detected by Coverity. No real harm in leaving these, but fixing
them cuts down on the noise for future analysis.
* src/rpc/virnetserver.c (virNetServerAddService): Delete unused
entry.
* src/util/sysinfo.c (virSysinfoRead): Delete dead assignment to
base.
Detected by Coverity. Both are instances of bad things happening
if pipe2 fails; the virNetClientNew failure could free garbage,
and virNetSocketNewConnectCommand could close random fds.
Note: POSIX doesn't guarantee the contents of fd[0] and fd[1]
after pipe failure: http://austingroupbugs.net/view.php?id=467
We may need to introduce a virPipe2 wrapper that guarantees
that on pipe failure, the fds are explicitly set to -1, rather
than our current state of assuming the fds are unchanged from
their value prior to the failed pipe call.
* src/rpc/virnetclient.c (virNetClientNew): Initialize variable.
* src/rpc/virnetsocket.c (virNetSocketNewConnectCommand):
Likewise.
We ignore any stream data packets which come in for streams which
are not registered, since these packets are async and do not have
a reply. If we get a stream control packet though we must send back
an actual error, otherwise a (broken) client may hang forever
making it hard to diagnose the client bug.
* src/rpc/virnetserverprogram.c: Send back error for unexpected
stream control messages
If a message packet for a invalid stream is received it is just
free'd. This is not good because it doesn't let the client RPC
request counter decrement. If a stream is shutdown with pending
packets the message also isn't released properly because of an
incorrect header type
* daemon/stream.c: Fix message header type
* src/rpc/virnetserverprogram.c: Send dummy reply instead of
free'ing ignored stream message
To save on memory reallocation, virNetMessage instances that
have been transmitted, may be reused for a subsequent incoming
message. We forgot to clear out the old data of the message
fully, which caused later confusion upon read.
* src/rpc/virnetserverclient.c: memset entire message before
reusing it
The virNetServerClient object had a hardcoded limit of 10 requests
per client. Extend constructor to allow it to be passed in as a
configurable variable. Wire this up to the 'max_client_requests'
config parameter in libvirtd
* daemon/libvirtd.c: Pass max_client_requests into services
* src/rpc/virnetserverservice.c, src/rpc/virnetserverservice.h: Pass
nrequests_client_max to clients
* src/rpc/virnetserverclient.c, src/rpc/virnetserverclient.h: Allow
configurable request limit
When the remote client receives end of file on the stream
it never invokes the stream callback. Applications relying
on async event driven I/O will thus never see the EOF
condition on the stream
* src/rpc/virnetclient.c, src/rpc/virnetclientstream.c:
Ensure EOF is dispatched
The client stream object can be used independently of the
virNetClientPtr object, so must have full locking of its
own and not rely on any caller.
* src/remote/remote_driver.c: Remove locking around stream
callback
* src/rpc/virnetclientstream.c: Add locking to all APIs
and callbacks
When a filter steals an RPC message, that message must
not be freed, except by the filter code itself
* src/rpc/virnetserverclient.c: Don't free stolen RPC
messages
Improve log messages issued when encountering a bogus
message length to include the actual length and the
limit violated
* src/rpc/virnetmessage.c: Improve log messages
On stream completion it is neccessary to send back a
message with an empty payload. The message header was
not being filled out correctly, since we were not writing
any payload. Add a method for encoding an empty payload
which updates the message headers correctly.
* src/rpc/virnetmessage.c, src/rpc/virnetmessage.h: Add
a virNetMessageEncodePayloadEmpty method
* src/rpc/virnetserverprogram.c: Write empty payload on
stream completion
The RPC client treats failure to register a socket watch
as non-fatal, since we do not mandate that a libvirt client
application provide an event loop implementation. It is
thus inappropriate to a log a message at VIR_LOG_WARN
* src/rpc/virnetsocket.c: Lower logging level
If a streams error is raised, virNetClientIOEventLoop
returns 0, but an error is set. Check for this and
propagate it if present
* src/rpc/virnetclient.c: Propagate streams error
This guts the libvirtd daemon, removing all its networking and
RPC handling code. Instead it calls out to the new virServerPtr
APIs for all its RPC & networking work
As a fallout all libvirtd daemon error reporting now takes place
via the normal internal error reporting APIs. There is no need
to call separate error reporting APIs in RPC code, nor should
code use VIR_WARN/VIR_ERROR for reporting fatal problems anymore.
* daemon/qemu_dispatch_*.h, daemon/remote_dispatch_*.h: Remove
old generated dispatcher code
* daemon/qemu_dispatch.h, daemon/remote_dispatch.h: New dispatch
code
* daemon/dispatch.c, daemon/dispatch.h: Remove obsoleted code
* daemon/remote.c, daemon/remote.h: Rewrite for new dispatch
APIs
* daemon/libvirtd.c, daemon/libvirtd.h: Remove all networking
code
* daemon/stream.c, daemon/stream.h: Update for new APIs
* daemon/Makefile.am: Link to libvirt-net-rpc-server.la
This guts the current remote driver, removing all its networking
handling code. Instead it calls out to the new virClientPtr and
virClientProgramPtr APIs for all RPC & networking work.
* src/Makefile.am: Link remote driver with generic RPC code
* src/remote/remote_driver.c: Gut code, replacing with RPC
API calls
* src/rpc/gendispatch.pl: Update for changes in the way
streams are handled
Move the daemon/remote_generator.pl to src/rpc/gendispatch.pl
and move the src/remote/rpcgen_fix.pl to src/rpc/genprotocol.pl
* daemon/Makefile.am: Update for new name/location of generator
* src/Makefile.am: Update for new name/location of generator
To facilitate creation of new clients using XDR RPC services,
pull alot of the remote driver code into a set of reusable
objects.
- virNetClient: Encapsulates a socket connection to a
remote RPC server. Handles all the network I/O for
reading/writing RPC messages. Delegates RPC encoding
and decoding to the registered programs
- virNetClientProgram: Handles processing and dispatch
of RPC messages for a single RPC (program,version).
A program can register to receive async events
from a client
- virNetClientStream: Handles generic I/O stream
integration to RPC layer
Each new client program now merely needs to define the list of
RPC procedures & events it wants and their handlers. It does
not need to deal with any of the network I/O functionality at
all.
Allow RPC servers to advertise themselves using MDNS,
via Avahi
* src/rpc/virnetserver.c, src/rpc/virnetserver.h: Allow
registration of MDNS services via avahi
* src/rpc/virnetserverservice.c, src/rpc/virnetserverservice.h: Add
API to fetch the listen port number
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Add API to
fetch the local port number
* src/rpc/virnetservermdns.c, src/rpc/virnetservermdns.h: Represent
an MDNS advertisement
To facilitate creation of new daemons providing XDR RPC services,
pull a lot of the libvirtd daemon code into a set of reusable
objects.
* virNetServer: A server contains one or more services which
accept incoming clients. It maintains the list of active
clients. It has a list of RPC programs which can be used
by clients. When clients produce a complete RPC message,
the server passes this onto the corresponding program for
handling, and queues any response back with the client.
* virNetServerClient: Encapsulates a single client connection.
All I/O for the client is handled, reading & writing RPC
messages.
* virNetServerProgram: Handles processing and dispatch of
RPC method calls for a single RPC (program,version).
Multiple programs can be registered with the server.
* virNetServerService: Encapsulates socket(s) listening for
new connections. Each service listens on a single host/port,
but may have multiple sockets if on a dual IPv4/6 host.
Each new daemon now merely has to define the list of RPC procedures
& their handlers. It does not need to deal with any network related
functionality at all.
This extends the basic virNetSocket APIs to allow them to have
a handle to the TLS/SASL session objects, once established.
This ensures that any data reads/writes are automagically
passed through the TLS/SASL encryption layers if required.
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Wire up
SASL/TLS encryption
This provides two modules for handling SASL
* virNetSASLContext provides the process-wide state, currently
just a whitelist of usernames on the server and a one time
library init call
* virNetTLSSession provides the per-connection state, ie the
SASL session itself. This also include APIs for providing
data encryption/decryption once the session is established
* src/Makefile.am: Add to libvirt-net-rpc.la
* src/rpc/virnetsaslcontext.c, src/rpc/virnetsaslcontext.h: Generic
SASL handling code
This provides two modules for handling TLS
* virNetTLSContext provides the process-wide state, in particular
all the x509 credentials, DH params and x509 whitelists
* virNetTLSSession provides the per-connection state, ie the
TLS session itself.
The virNetTLSContext provides APIs for validating a TLS session's
x509 credentials. The virNetTLSSession includes APIs for performing
the initial TLS handshake and sending/recving encrypted data
* src/Makefile.am: Add to libvirt-net-rpc.la
* src/rpc/virnettlscontext.c, src/rpc/virnettlscontext.h: Generic
TLS handling code
Introduces a simple wrapper around the raw POSIX sockets APIs
and name resolution APIs. Allows for easy creation of client
and server sockets with correct usage of name resolution APIs
for protocol agnostic socket setup.
It can listen for UNIX and TCP stream sockets.
It can connect to UNIX, TCP streams directly, or indirectly
to UNIX sockets via an SSH tunnel or external command
* src/Makefile.am: Add to libvirt-net-rpc.la
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Generic
sockets APIs
* tests/Makefile.am: Add socket test
* tests/virnetsockettest.c: New test case
* tests/testutils.c: Avoid overriding LIBVIRT_DEBUG settings
* tests/ssh.c: Dumb helper program for SSH tunnelling tests
This provides a new struct that contains a buffer for the RPC
message header+payload, as well as a decoded copy of the message
header. There is an API for applying a XDR encoding & decoding
of the message headers and payloads. There are also APIs for
maintaining a simple FIFO queue of message instances.
Expected usage scenarios are:
To send a message
msg = virNetMessageNew()
...fill in msg->header fields..
virNetMessageEncodeHeader(msg)
...loook at msg->header fields to determine payload filter
virNetMessageEncodePayload(msg, xdrfilter, data)
...send msg->bufferLength worth of data from buffer
To receive a message
msg = virNetMessageNew()
...read VIR_NET_MESSAGE_LEN_MAX of data into buffer
virNetMessageDecodeLength(msg)
...read msg->bufferLength-msg->bufferOffset of data into buffer
virNetMessageDecodeHeader(msg)
...look at msg->header fields to determine payload filter
virNetMessageDecodePayload(msg, xdrfilter, data)
...run payload processor
* src/Makefile.am: Add to libvirt-net-rpc.la
* src/rpc/virnetmessage.c, src/rpc/virnetmessage.h: Internal
message handling API.
* testutils.c, testutils.h: Helper for printing binary differences
* virnetmessagetest.c: Validate all XDR encoding/decoding
This patch defines the basics of a generic RPC protocol in XDR.
This is wire ABI compatible with the original remote_protocol.x.
It takes everything except for the RPC calls / events from that
protocol
- The basic header virNetMessageHeader (aka remote_message_header)
- The error object virNetMessageError (aka remote_error)
- Two dummy objects virNetMessageDomain & virNetMessageNetwork
sadly needed to keep virNetMessageError ABI compatible with
the old remote_error
The RPC protocol supports method calls, async events and
bidirectional data streams as before
* src/Makefile.am: Add rules for generating RPC code from
protocol & define a new libvirt-net-rpc.la helper library
* src/rpc/virnetprotocol.x: New generic RPC protocol
