[Buildroot] [PATCH] spice: add upstream security fixes for CVE-2017-7506

[Buildroot] [PATCH] spice: add upstream security fixes for CVE-2017-7506

[Peter Korsgaard]

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>
---
 ...nect-when-receiving-overly-big-ClientMoni.patch | 75 ++++++++++++++++++++++
 ...integer-overflows-handling-monitor-config.patch | 31 +++++++++
 ...buffer-overflows-handling-monitor-configu.patch | 48 ++++++++++++++
 3 files changed, 154 insertions(+)
 create mode 100644 package/spice/0004-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch
 create mode 100644 package/spice/0005-reds-Avoid-integer-overflows-handling-monitor-config.patch
 create mode 100644 package/spice/0006-reds-Avoid-buffer-overflows-handling-monitor-configu.patch

diff --git a/package/spice/0004-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch b/package/spice/0004-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch
new file mode 100644
index 0000000000..e454a30100
--- /dev/null
+++ b/package/spice/0004-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch
@@ -0,0 +1,75 @@
+From f1e7ec03e26ab6b8ca9b7ec060846a5b706a963d Mon Sep 17 00:00:00 2001
+From: Frediano Ziglio <fziglio@redhat.com>
+Date: Mon, 15 May 2017 15:57:28 +0100
+Subject: [PATCH 4/6] reds: Disconnect when receiving overly big
+ ClientMonitorsConfig
+
+Total message size received from the client was unlimited. There is
+a 2kiB size check on individual agent messages, but the MonitorsConfig
+message can be split in multiple chunks, and the size of the
+non-chunked MonitorsConfig message was never checked. This could easily
+lead to memory exhaustion on the host.
+
+Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ server/reds.c | 25 +++++++++++++++++++++++--
+ 1 file changed, 23 insertions(+), 2 deletions(-)
+
+diff --git a/server/reds.c b/server/reds.c
+index f439a366..7be85fdf 100644
+--- a/server/reds.c
++++ b/server/reds.c
+@@ -993,19 +993,34 @@ static void reds_client_monitors_config_cleanup(void)
+ static void reds_on_main_agent_monitors_config(
+         MainChannelClient *mcc, void *message, size_t size)
+ {
++    const unsigned int MAX_MONITORS = 256;
++    const unsigned int MAX_MONITOR_CONFIG_SIZE =
++       sizeof(VDAgentMonitorsConfig) + MAX_MONITORS * sizeof(VDAgentMonConfig);
++
+     VDAgentMessage *msg_header;
+     VDAgentMonitorsConfig *monitors_config;
+     RedsClientMonitorsConfig *cmc = &reds->client_monitors_config;
+ 
++    // limit size of message sent by the client as this can cause a DoS through
++    // memory exhaustion, or potentially some integer overflows
++    if (sizeof(VDAgentMessage) + MAX_MONITOR_CONFIG_SIZE - cmc->buffer_size < size) {
++        goto overflow;
++    }
+     cmc->buffer_size += size;
+     cmc->buffer = realloc(cmc->buffer, cmc->buffer_size);
+     spice_assert(cmc->buffer);
+     cmc->mcc = mcc;
+     memcpy(cmc->buffer + cmc->buffer_pos, message, size);
+     cmc->buffer_pos += size;
++    if (sizeof(VDAgentMessage) > cmc->buffer_size) {
++        spice_debug("not enough data yet. %d", cmc->buffer_size);
++        return;
++    }
+     msg_header = (VDAgentMessage *)cmc->buffer;
+-    if (sizeof(VDAgentMessage) > cmc->buffer_size ||
+-            msg_header->size > cmc->buffer_size - sizeof(VDAgentMessage)) {
++    if (msg_header->size > MAX_MONITOR_CONFIG_SIZE) {
++        goto overflow;
++    }
++    if (msg_header->size > cmc->buffer_size - sizeof(VDAgentMessage)) {
+         spice_debug("not enough data yet. %d", cmc->buffer_size);
+         return;
+     }
+@@ -1013,6 +1028,12 @@ static void reds_on_main_agent_monitors_config(
+     spice_debug("%s: %d", __func__, monitors_config->num_of_monitors);
+     red_dispatcher_client_monitors_config(monitors_config);
+     reds_client_monitors_config_cleanup();
++    return;
++
++overflow:
++    spice_warning("received invalid MonitorsConfig request from client, disconnecting");
++    red_channel_client_disconnect(main_channel_client_get_base(mcc));
++    reds_client_monitors_config_cleanup();
+ }
+ 
+ void reds_on_main_agent_data(MainChannelClient *mcc, void *message, size_t size)
+-- 
+2.11.0
+
diff --git a/package/spice/0005-reds-Avoid-integer-overflows-handling-monitor-config.patch b/package/spice/0005-reds-Avoid-integer-overflows-handling-monitor-config.patch
new file mode 100644
index 0000000000..a4e5a3fa6d
--- /dev/null
+++ b/package/spice/0005-reds-Avoid-integer-overflows-handling-monitor-config.patch
@@ -0,0 +1,31 @@
+From ec6229c79abe05d731953df5f7e9a05ec9f6df79 Mon Sep 17 00:00:00 2001
+From: Frediano Ziglio <fziglio@redhat.com>
+Date: Mon, 15 May 2017 15:57:28 +0100
+Subject: [PATCH 5/6] reds: Avoid integer overflows handling monitor
+ configuration
+
+Avoid VDAgentMessage::size integer overflows.
+
+Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ server/reds.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/server/reds.c b/server/reds.c
+index 7be85fdf..e1c8c108 100644
+--- a/server/reds.c
++++ b/server/reds.c
+@@ -1024,6 +1024,9 @@ static void reds_on_main_agent_monitors_config(
+         spice_debug("not enough data yet. %d", cmc->buffer_size);
+         return;
+     }
++    if (msg_header->size < sizeof(VDAgentMonitorsConfig)) {
++        goto overflow;
++    }
+     monitors_config = (VDAgentMonitorsConfig *)(cmc->buffer + sizeof(*msg_header));
+     spice_debug("%s: %d", __func__, monitors_config->num_of_monitors);
+     red_dispatcher_client_monitors_config(monitors_config);
+-- 
+2.11.0
+
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..0789fdfb08
--- /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 6/6] 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
+
-- 
2.11.0

[Buildroot] [PATCH] spice: add upstream security fixes for CVE-2017-7506

[Thomas Petazzoni]

Hello,

On Fri, 14 Jul 2017 16:02:03 +0200, Peter Korsgaard wrote:
> 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>
> ---
>  ...nect-when-receiving-overly-big-ClientMoni.patch | 75 ++++++++++++++++++++++
>  ...integer-overflows-handling-monitor-config.patch | 31 +++++++++
>  ...buffer-overflows-handling-monitor-configu.patch | 48 ++++++++++++++
>  3 files changed, 154 insertions(+)
>  create mode 100644 package/spice/0004-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch
>  create mode 100644 package/spice/0005-reds-Avoid-integer-overflows-handling-monitor-config.patch
>  create mode 100644 package/spice/0006-reds-Avoid-buffer-overflows-handling-monitor-configu.patch

Applied to master, thanks. However, you forgot to use "git format-patch
-N" to generate the patches, so I removed the numbering from the patch
titles.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[Buildroot] [PATCH] spice: add upstream security fixes for CVE-2017-7506

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

 > Hello,
 > On Fri, 14 Jul 2017 16:02:03 +0200, Peter Korsgaard wrote:
 >> 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>
 >> ---
 >> ...nect-when-receiving-overly-big-ClientMoni.patch | 75 ++++++++++++++++++++++
 >> ...integer-overflows-handling-monitor-config.patch | 31 +++++++++
 >> ...buffer-overflows-handling-monitor-configu.patch | 48 ++++++++++++++
 >> 3 files changed, 154 insertions(+)
 >> create mode 100644 package/spice/0004-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch
 >> create mode 100644 package/spice/0005-reds-Avoid-integer-overflows-handling-monitor-config.patch
 >> create mode 100644 package/spice/0006-reds-Avoid-buffer-overflows-handling-monitor-configu.patch

 > Applied to master, thanks. However, you forgot to use "git format-patch
 > -N" to generate the patches, so I removed the numbering from the patch
 > titles.

Crap, indeed :/ Sorry, and thanks for fixing it!

-- 
Bye, Peter Korsgaard

[Buildroot] [PATCH] spice: add upstream security fixes for CVE-2017-7506

[Peter Korsgaard]

>>>>> "Peter" == Peter Korsgaard <peter@korsgaard.com> writes:

 > 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>

Committed to 2017.02.x and 2017.05.x, thanks.

-- 
Bye, Peter Korsgaard