This commit results in unexpected termination of the TLS connection.
When 'fd_can_read' returns 0, the code goes on to pass a zero length
buffer to qio_channel_read. The TLS impl calls into gnutls_recv()
with this zero length buffer, at which point GNUTLS returns an error
GNUTLS_E_INVALID_REQUEST. This is treated as fatal by QEMU's TLS code
resulting in the connection being torn down by the chardev.
Simply skipping the qio_channel_read when the buffer length is zero
is also not satisfactory, as it results in a high CPU burn busy loop
massively slowing QEMU's functionality.
The proper solution is to avoid tcp_chr_read being called at all
unless the frontend is able to accept more data. This will be done
in a followup commit.
This reverts commit 462945cd22
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The socket chardev often has 2 GSource object registered against the
same FD. One is registered all the time and is just intended to handle
POLLHUP events, while the other gets registered & unregistered on the
fly as the frontend is ready to receive more data or not.
It is very common for poll() to signal a POLLHUP event at the same time
as there is pending incoming data from the disconnected client. It is
therefore essential to process incoming data prior to processing HUP.
The problem with having 2 GSource on the same FD is that there is no
guaranteed ordering of execution between them, so the chardev code may
process HUP first and thus discard data.
This failure scenario is non-deterministic but can be seen fairly
reliably by reverting a7077b8e35, and
then running 'tests/unit/test-char', which will sometimes fail with
missing data.
Ideally QEMU would only have 1 GSource, but that's a complex code
refactoring job. The next best solution is to try to ensure ordering
between the 2 GSource objects. This can be achieved by lowering the
priority of the HUP GSource, so that it is never dispatched if the
main GSource is also ready to dispatch. Counter-intuitively, lowering
the priority of a GSource is done by raising its priority number.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Commit ffda5db65a ("io/channel-tls: fix handling of bigger read buffers")
changed the behavior of the TLS io channels to schedule a second reading
attempt if there is still incoming data pending. This caused a regression
with backends like the sclpconsole that check in their read function that
the sender does not try to write more bytes to it than the device can
currently handle.
The problem can be reproduced like this:
1) In one terminal, do this:
mkdir qemu-pki
cd qemu-pki
openssl genrsa 2048 > ca-key.pem
openssl req -new -x509 -nodes -days 365000 -key ca-key.pem -out ca-cert.pem
# enter some dummy value for the cert
openssl genrsa 2048 > server-key.pem
openssl req -new -x509 -nodes -days 365000 -key server-key.pem \
-out server-cert.pem
# enter some other dummy values for the cert
gnutls-serv --echo --x509cafile ca-cert.pem --x509keyfile server-key.pem \
--x509certfile server-cert.pem -p 8338
2) In another terminal, do this:
wget https://download.fedoraproject.org/pub/fedora-secondary/releases/39/Cloud/s390x/images/Fedora-Cloud-Base-39-1.5.s390x.qcow2
qemu-system-s390x -nographic -nodefaults \
-hda Fedora-Cloud-Base-39-1.5.s390x.qcow2 \
-object tls-creds-x509,id=tls0,endpoint=client,verify-peer=false,dir=$PWD/qemu-pki \
-chardev socket,id=tls_chardev,host=localhost,port=8338,tls-creds=tls0 \
-device sclpconsole,chardev=tls_chardev,id=tls_serial
QEMU then aborts after a second or two with:
qemu-system-s390x: ../hw/char/sclpconsole.c:73: chr_read: Assertion
`size <= SIZE_BUFFER_VT220 - scon->iov_data_len' failed.
Aborted (core dumped)
It looks like the second read does not trigger the chr_can_read() function
to be called before the second read, which should normally always be done
before sending bytes to a character device to see how much it can handle,
so the s->max_size in tcp_chr_read() still contains the old value from the
previous read. Let's make sure that we use the up-to-date value by calling
tcp_chr_read_poll() again here.
Fixes: ffda5db65a ("io/channel-tls: fix handling of bigger read buffers")
Buglink: https://issues.redhat.com/browse/RHEL-24614
Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com>
Message-ID: <20240229104339.42574-1-thuth@redhat.com>
Reviewed-by: Antoine Damhet <antoine.damhet@blade-group.com>
Tested-by: Antoine Damhet <antoine.damhet@blade-group.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
SocketAddress branch @fd is documented in enum SocketAddressType,
unlike the other branches. That's because the branch's type is String
from common.json.
Use a local copy of String, so we can put the documentation in the
usual place.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240205074709.3613229-14-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The chardev socket backend will unref the QIOChannel object while
it is still potentially open. When using TLS there could be a
pending TLS handshake taking place. If the channel is left open
then when the TLS handshake callback runs, it can end up accessing
free'd memory in the tcp_chr_tls_handshake method.
Closing the QIOChannel will unregister any pending handshake
source.
Reported-by: jiangyegen <jiangyegen@huawei.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
After live migration with virtio block device, qemu crash at:
#0 0x000055914f46f795 in object_dynamic_cast_assert (obj=0x559151b7b090, typename=0x55914f80fbc4 "qio-channel", file=0x55914f80fb90 "/images/testvfe/sw/qemu.gerrit/include/io/channel.h", line=30, func=0x55914f80fcb8 <__func__.17257> "QIO_CHANNEL") at ../qom/object.c:872
#1 0x000055914f480d68 in QIO_CHANNEL (obj=0x559151b7b090) at /images/testvfe/sw/qemu.gerrit/include/io/channel.h:29
#2 0x000055914f4812f8 in qio_net_listener_set_client_func_full (listener=0x559151b7a720, func=0x55914f580b97 <tcp_chr_accept>, data=0x5591519f4ea0, notify=0x0, context=0x0) at ../io/net-listener.c:166
#3 0x000055914f580059 in tcp_chr_update_read_handler (chr=0x5591519f4ea0) at ../chardev/char-socket.c:637
#4 0x000055914f583dca in qemu_chr_be_update_read_handlers (s=0x5591519f4ea0, context=0x0) at ../chardev/char.c:226
#5 0x000055914f57b7c9 in qemu_chr_fe_set_handlers_full (b=0x559152bf23a0, fd_can_read=0x0, fd_read=0x0, fd_event=0x0, be_change=0x0, opaque=0x0, context=0x0, set_open=false, sync_state=true) at ../chardev/char-fe.c:279
#6 0x000055914f57b86d in qemu_chr_fe_set_handlers (b=0x559152bf23a0, fd_can_read=0x0, fd_read=0x0, fd_event=0x0, be_change=0x0, opaque=0x0, context=0x0, set_open=false) at ../chardev/char-fe.c:304
#7 0x000055914f378caf in vhost_user_async_close (d=0x559152bf21a0, chardev=0x559152bf23a0, vhost=0x559152bf2420, cb=0x55914f2fb8c1 <vhost_user_blk_disconnect>) at ../hw/virtio/vhost-user.c:2725
#8 0x000055914f2fba40 in vhost_user_blk_event (opaque=0x559152bf21a0, event=CHR_EVENT_CLOSED) at ../hw/block/vhost-user-blk.c:395
#9 0x000055914f58388c in chr_be_event (s=0x5591519f4ea0, event=CHR_EVENT_CLOSED) at ../chardev/char.c:61
#10 0x000055914f583905 in qemu_chr_be_event (s=0x5591519f4ea0, event=CHR_EVENT_CLOSED) at ../chardev/char.c:81
#11 0x000055914f581275 in char_socket_finalize (obj=0x5591519f4ea0) at ../chardev/char-socket.c:1083
#12 0x000055914f46f073 in object_deinit (obj=0x5591519f4ea0, type=0x5591519055c0) at ../qom/object.c:680
#13 0x000055914f46f0e5 in object_finalize (data=0x5591519f4ea0) at ../qom/object.c:694
#14 0x000055914f46ff06 in object_unref (objptr=0x5591519f4ea0) at ../qom/object.c:1202
#15 0x000055914f4715a4 in object_finalize_child_property (obj=0x559151b76c50, name=0x559151b7b250 "char3", opaque=0x5591519f4ea0) at ../qom/object.c:1747
#16 0x000055914f46ee86 in object_property_del_all (obj=0x559151b76c50) at ../qom/object.c:632
#17 0x000055914f46f0d2 in object_finalize (data=0x559151b76c50) at ../qom/object.c:693
#18 0x000055914f46ff06 in object_unref (objptr=0x559151b76c50) at ../qom/object.c:1202
#19 0x000055914f4715a4 in object_finalize_child_property (obj=0x559151b6b560, name=0x559151b76630 "chardevs", opaque=0x559151b76c50) at ../qom/object.c:1747
#20 0x000055914f46ef67 in object_property_del_child (obj=0x559151b6b560, child=0x559151b76c50) at ../qom/object.c:654
#21 0x000055914f46f042 in object_unparent (obj=0x559151b76c50) at ../qom/object.c:673
#22 0x000055914f58632a in qemu_chr_cleanup () at ../chardev/char.c:1189
#23 0x000055914f16c66c in qemu_cleanup () at ../softmmu/runstate.c:830
#24 0x000055914eee7b9e in qemu_default_main () at ../softmmu/main.c:38
#25 0x000055914eee7bcc in main (argc=86, argv=0x7ffc97cb8d88) at ../softmmu/main.c:48
In char_socket_finalize after s->listener freed, event callback function
vhost_user_blk_event will be called to handle CHR_EVENT_CLOSED.
vhost_user_blk_event is calling qio_net_listener_set_client_func_full which
is still using s->listener.
Setting s->listener = NULL after object_unref(OBJECT(s->listener)) can
solve this issue.
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20230214021430.3638579-1-yajunw@nvidia.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
MSG_PEEK peeks at the channel, The data is treated as unread and
the next read shall still return this data. This support is
currently added only for socket class. Extra parameter 'flags'
is added to io_readv calls to pass extra read flags like MSG_PEEK.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: manish.mishra <manish.mishra@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The has_FOO for pointer-valued FOO are redundant, except for arrays.
They are also a nuisance to work with. Recent commit "qapi: Start to
elide redundant has_FOO in generated C" provided the means to elide
them step by step. This is the step for qapi/char.json.
Said commit explains the transformation in more detail. The invariant
violations mentioned there do not occur here.
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221104160712.3005652-12-armbru@redhat.com>
The qemu_*block() functions are meant to be be used with sockets (the
win32 implementation expects SOCKET)
Over time, those functions where used with Win32 SOCKET or
file-descriptors interchangeably. But for portability, they must only be
used with socket-like file-descriptors. FDs can use
g_unix_set_fd_nonblocking() instead.
Rename the functions with "socket" in the name to prevent bad usages.
This is effectively reverting commit f9e8cacc55 ("oslib-posix:
rename socket_set_nonblock() to qemu_set_nonblock()").
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
After the return from tcp_chr_recv, tcp_chr_sync_read calls into a
function which eventually makes a system call and may clobber errno.
Make a copy of errno right after tcp_chr_recv and restore the errno on
return from tcp_chr_sync_read.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20211111153354.18807-4-rvkagan@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
tcp_chr_recv communicates the specific error condition to the caller via
errno. However, after setting it, it may call into some system calls or
library functions which can clobber the errno.
Avoid this by moving the errno assignment to the end of the function.
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20211111153354.18807-3-rvkagan@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
The following patches are going to use CharSocket as a base class for
sockets that are created with a given fd (without a given address).
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Simple unions predate flat unions. Having both complicates the QAPI
schema language and the QAPI generator. We haven't been using simple
unions in new code for a long time, because they are less flexible and
somewhat awkward on the wire.
To prepare for their removal, convert simple union SocketAddressLegacy
to an equivalent flat one, with existing enum SocketAddressType
replacing implicit enum type SocketAddressLegacyKind. Adds some
boilerplate to the schema, which is a bit ugly, but a lot easier to
maintain than the simple union feature.
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210917143134.412106-9-armbru@redhat.com>
Better reflect the command line version of the socket address arguments,
following the now recommended long-form opt=on syntax.
Complement/fixes commit 9d902d51 "chardev: do not use short form boolean
options in non-QemuOpts character device descriptions".
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Avoid accessing QCryptoTLSCreds internals by using
the qcrypto_tls_creds_check_endpoint() helper.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When changing from chardev-socket (which supports yank) to
chardev-socket again, it fails, because the new chardev attempts
to register a new yank instance. This in turn fails, as there
still is the yank instance from the current chardev. Also,
the old chardev shouldn't unregister the yank instance when it
is freed.
To fix this, now the new chardev only registers a yank instance if
the current chardev doesn't support yank and thus hasn't registered
one already. Also, when the old chardev is freed, it now only
unregisters the yank instance if the new chardev doesn't need it.
If the initialization of the new chardev fails, it still has
chr->handover_yank_instance set and won't unregister the yank
instance when it is freed.
s->registered_yank is always true here, as chardev-change only works
on user-visible chardevs and those are guraranteed to register a
yank instance as they are initialized via
chardev_new()
qemu_char_open()
cc->open() (qmp_chardev_open_socket()).
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Li Zhang <li.zhang@cloud.ionos.com>
Message-Id: <9637888d7591d2971975188478bb707299a1dc04.1617127849.git.lukasstraub2@web.de>
This only makes sense conceptually when used with listener chardevs.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The "delay" option was introduced as a way to enable Nagle's algorithm
with ",nodelay". Since the short form for boolean options has now been
deprecated, introduce a more properly named "nodelay" option. The "delay"
option remains as an undocumented option.
"delay" and "nodelay" are mutually exclusive. Because the check is
done at consumption time, the code also rejects them if one of the
two is specified via -set.
Based-on: <20210226080526.651705-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Options such as "-gdb" or "-serial" accept a part-QemuOpts part-parsed-by-hand
character device description. Do not use short form boolean options in the
QemuOpts part.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Daniel P. Berrangé
Thomas Huth
Peter Maydell
Markus Armbruster
Michael Tokarev
Marc-André Lureau
Yajun WuandMichael S. Tsirkin
manish.mishraandJuan Quintela
Bin MengandMarc-André Lureau
Roman KaganandMichael S. Tsirkin
Philippe Mathieu-DaudéandDaniel P. Berrangé
Lukas StraubandMarc-André Lureau
Paolo Bonzini