spice: add upstream security fixes for CVE-2017-7506

Fixes CVE-2017-7506 - Possible buffer overflow via invalid monitor
configurations.

For more details, see:
https://marc.info/?l=oss-security&m=150001782924095

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/package/spice/0006-reds-Avoid-buffer-overflows-handling-monitor-configu.patch b/package/spice/0006-reds-Avoid-buffer-overflows-handling-monitor-configu.patch
new file mode 100644
index 0000000000..212645b44f
--- /dev/null
+++ b/package/spice/0006-reds-Avoid-buffer-overflows-handling-monitor-configu.patch
@@ -0,0 +1,48 @@
+From a957a90baf2c62d31f3547e56bba7d0e812d2331 Mon Sep 17 00:00:00 2001
+From: Frediano Ziglio <fziglio@redhat.com>
+Date: Mon, 15 May 2017 15:57:28 +0100
+Subject: [PATCH] reds: Avoid buffer overflows handling monitor
+ configuration
+
+It was also possible for a malicious client to set
+VDAgentMonitorsConfig::num_of_monitors to a number larger
+than the actual size of VDAgentMOnitorsConfig::monitors.
+This would lead to buffer overflows, which could allow the guest to
+read part of the host memory. This might cause write overflows in the
+host as well, but controlling the content of such buffers seems
+complicated.
+
+Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ server/reds.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/server/reds.c b/server/reds.c
+index e1c8c108..3a42c375 100644
+--- a/server/reds.c
++++ b/server/reds.c
+@@ -1000,6 +1000,7 @@ static void reds_on_main_agent_monitors_config(
+     VDAgentMessage *msg_header;
+     VDAgentMonitorsConfig *monitors_config;
+     RedsClientMonitorsConfig *cmc = &reds->client_monitors_config;
++    uint32_t max_monitors;
+ 
+     // limit size of message sent by the client as this can cause a DoS through
+     // memory exhaustion, or potentially some integer overflows
+@@ -1028,6 +1029,12 @@ static void reds_on_main_agent_monitors_config(
+         goto overflow;
+     }
+     monitors_config = (VDAgentMonitorsConfig *)(cmc->buffer + sizeof(*msg_header));
++    // limit the monitor number to avoid buffer overflows
++    max_monitors = (msg_header->size - sizeof(VDAgentMonitorsConfig)) /
++                   sizeof(VDAgentMonConfig);
++    if (monitors_config->num_of_monitors > max_monitors) {
++        goto overflow;
++    }
+     spice_debug("%s: %d", __func__, monitors_config->num_of_monitors);
+     red_dispatcher_client_monitors_config(monitors_config);
+     reds_client_monitors_config_cleanup();
+-- 
+2.11.0
+