From 31bd29fe093a258755929a23d764b02323fcdc46 Mon Sep 17 00:00:00 2001 From: Peter Korsgaard Date: Fri, 14 Jul 2017 16:02:03 +0200 Subject: [PATCH] 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 Signed-off-by: Thomas Petazzoni --- ...when-receiving-overly-big-ClientMoni.patch | 75 +++++++++++++++++++ ...er-overflows-handling-monitor-config.patch | 31 ++++++++ ...r-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..070259f2bb --- /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 +Date: Mon, 15 May 2017 15:57:28 +0100 +Subject: [PATCH] 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 +Signed-off-by: Peter Korsgaard +--- + 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..98740520c1 --- /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 +Date: Mon, 15 May 2017 15:57:28 +0100 +Subject: [PATCH] reds: Avoid integer overflows handling monitor + configuration + +Avoid VDAgentMessage::size integer overflows. + +Signed-off-by: Frediano Ziglio +Signed-off-by: Peter Korsgaard +--- + 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..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 +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 +Signed-off-by: Peter Korsgaard +--- + 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 + -- 2.30.2