qemu-kvm/SOURCES/kvm-Revert-chardev-char-soc...

61 lines
2.3 KiB
Diff

From 2e0e4355b2d4edb66b7d8c198339e17940abd682 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Mon, 18 Mar 2024 13:03:19 +0000
Subject: [PATCH 2/3] Revert "chardev/char-socket: Fix TLS io channels sending
too much data to the backend"
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Daniel P. Berrangé <berrange@redhat.com>
RH-MergeRequest: 233: Fix handling of TLS sessions in chardevs
RH-Jira: RHEL-24614
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
RH-Commit: [2/3] 1cb3d72b86ced0f70a09dfa0d325ae8a85db1b2b (berrange/centos-src-qemu)
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 462945cd22d2bcd233401ed3aa167d83a8e35b05
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
(cherry picked from commit e8ee827ffdb86ebbd5f5213a1f78123c25a90864)
---
chardev/char-socket.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index f48d341ebc..51d0943fce 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -492,9 +492,9 @@ static gboolean tcp_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
s->max_size <= 0) {
return TRUE;
}
- len = tcp_chr_read_poll(opaque);
- if (len > sizeof(buf)) {
- len = sizeof(buf);
+ len = sizeof(buf);
+ if (len > s->max_size) {
+ len = s->max_size;
}
size = tcp_chr_recv(chr, (void *)buf, len);
if (size == 0 || (size == -1 && errno != EAGAIN)) {
--
2.39.3