diff --git a/SOURCES/0006-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch b/SOURCES/0006-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch new file mode 100644 index 0000000..2db5566 --- /dev/null +++ b/SOURCES/0006-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch @@ -0,0 +1,71 @@ +From 0000000000000000000000000000000000000000 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 +--- + server/reds.c | 25 +++++++++++++++++++++++-- + 1 file changed, 23 insertions(+), 2 deletions(-) + +diff --git a/server/reds.c b/server/reds.c +index 57a93c9..95293dd 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) diff --git a/SOURCES/0007-reds-Avoid-integer-overflows-handling-monitor-config.patch b/SOURCES/0007-reds-Avoid-integer-overflows-handling-monitor-config.patch new file mode 100644 index 0000000..2ea6f24 --- /dev/null +++ b/SOURCES/0007-reds-Avoid-integer-overflows-handling-monitor-config.patch @@ -0,0 +1,26 @@ +From 0000000000000000000000000000000000000000 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 +--- + server/reds.c | 3 +++ + 1 file changed, 3 insertions(+) + +diff --git a/server/reds.c b/server/reds.c +index 95293dd..eda3486 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); diff --git a/SOURCES/0008-reds-Avoid-buffer-overflows-handling-monitor-configu.patch b/SOURCES/0008-reds-Avoid-buffer-overflows-handling-monitor-configu.patch new file mode 100644 index 0000000..47344b7 --- /dev/null +++ b/SOURCES/0008-reds-Avoid-buffer-overflows-handling-monitor-configu.patch @@ -0,0 +1,43 @@ +From 0000000000000000000000000000000000000000 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 +--- + server/reds.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/server/reds.c b/server/reds.c +index eda3486..37d9da8 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(); diff --git a/SPECS/spice.spec b/SPECS/spice.spec index 40a708a..92a0fa4 100644 --- a/SPECS/spice.spec +++ b/SPECS/spice.spec @@ -1,6 +1,6 @@ Name: spice Version: 0.12.8 -Release: 2%{?dist} +Release: 2%{?dist}.1 Summary: Implements the SPICE protocol Group: User Interface/Desktops License: LGPLv2+ @@ -11,6 +11,9 @@ Patch02: 0002-Prevent-possible-DoS-attempts-during-protocol-handsh.patch Patch03: 0003-Prevent-integer-overflows-in-capability-checks.patch Patch04: 0004-main-channel-Prevent-overflow-reading-messages-from-.patch Patch05: 0005-reds-Check-link-header-magic-without-waiting-for-the.patch +Patch06: 0006-reds-Disconnect-when-receiving-overly-big-ClientMoni.patch +Patch07: 0007-reds-Avoid-integer-overflows-handling-monitor-config.patch +Patch08: 0008-reds-Avoid-buffer-overflows-handling-monitor-configu.patch # https://bugzilla.redhat.com/show_bug.cgi?id=613529 %if 0%{?rhel} @@ -97,6 +100,15 @@ mkdir -p %{buildroot}%{_libexecdir} %changelog +* Wed Jul 05 2017 Christophe Fergeau 0.12.8-2.1 +- Redo build properly versioned as a zstream build + Related: CVE-2017-7506 + +* Fri Jun 30 2017 Christophe Fergeau 0.12.8-3 +- Prevent potential buffer/integer overflows with invalid MonitorsConfig messages + sent from an authenticated client + Resolves: CVE-2017-7506 + * Tue Apr 25 2017 Christophe Fergeau 0.12.8-2 - Drop clients immediatly if the magic they send is wrong Resolves: rhbz#1416692