main/spice: fix for CVE-2017-7506. Fixes #7590

2 files changed, 157 insertions, 2 deletions

diff --git a/main/spice/APKBUILD b/main/spice/APKBUILD
index 830f972cbe..0cafecbf69 100644
--- a/main/spice/APKBUILD
+++ b/main/spice/APKBUILD
@@ -2,7 +2,7 @@
 # Maintainer: Natanael Copa <ncopa@alpinelinux.org>
 pkgname=spice
 pkgver=0.12.8
-pkgrel=3
+pkgrel=4
 pkgdesc="Implements the SPICE protocol"
 url="http://www.spice-space.org/"
 arch="all"
@@ -17,10 +17,13 @@ source="http://www.spice-space.org/download/releases/$pkgname-$pkgver.tar.bz2
 	CVE-2016-9577.patch
 	CVE-2016-9578-1.patch
 	CVE-2016-9578-2.patch
+	CVE-2017-7506.patch
 	"
 builddir="$srcdir/$pkgname-$pkgver"
 
 # secfixes:
+#   0.12.8-r4:
+#     - CVE-2017-7506
 #   0.12.8-r3:
 #     - CVE-2016-9577
 #     - CVE-2016-9578
@@ -62,4 +65,5 @@ server() {
 sha512sums="6485d3522af1cde93d2c0abad7f7ef9f2e4d3e5049314fb93b6dd4b86e33d67d353a3ff42a355c8fd991bad447bbde1e6320c083bbc6f02b576bd9cebe7269ed  spice-0.12.8.tar.bz2
 51c38766c9582376c95e63515d0c009f8c3e95cc03a1751c01974cab9295159eb74d35a08157e1eaa44e99a7bb5b2fdad83d9a8c7e38850741d9b5d534133bc7  CVE-2016-9577.patch
 ffae544784bd98da10cd86db3f5c5753c4833aee6b16e4e671160e92103d84a3dbc4da9f132f35e3b3b71a515e09b68b689c49e5f4265363b9eef39c42d70719  CVE-2016-9578-1.patch
-62ba3844fa11c65eba7d013c209962e39af051885bdf55943410f9122d99135ce30495263f34580ce959355eb60a6026125b181f6b10f0bfab19bbd4ff54f92b  CVE-2016-9578-2.patch"
+62ba3844fa11c65eba7d013c209962e39af051885bdf55943410f9122d99135ce30495263f34580ce959355eb60a6026125b181f6b10f0bfab19bbd4ff54f92b  CVE-2016-9578-2.patch
+8a7387fd297aa3d59e38af650f3f12d9b89e46283e2ceaf53ca6e01db6db3c2ac0df164fde05decc4a0d8a05296d3f31195e86e383029804e91b23c84e1292a2  CVE-2017-7506.patch"
diff --git a/main/spice/CVE-2017-7506.patch b/main/spice/CVE-2017-7506.patch
new file mode 100644
index 0000000000..dcdeea6e7d
--- /dev/null
+++ b/main/spice/CVE-2017-7506.patch
@@ -0,0 +1,151 @@
+From 257f69d619fed407493156c8a7b952abc8a51314 Mon Sep 17 00:00:00 2001
+From: Frediano Ziglio <fziglio@...hat.com>
+Date: Mon, 15 May 2017 15:57:28 +0100
+Subject: [spice-server 1/3] 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@...hat.com>
+---
+ server/reds.c | 25 +++++++++++++++++++++++--
+ 1 file changed, 23 insertions(+), 2 deletions(-)
+
+diff --git a/server/reds.c b/server/reds.c
+index f439a3668..7be85fdfc 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)
+-- 
+2.13.0
+
+From ff2b4ef70181087d5abd50bad76d026ec5088a93 Mon Sep 17 00:00:00 2001
+From: Frediano Ziglio <fziglio@...hat.com>
+Date: Mon, 15 May 2017 15:57:28 +0100
+Subject: [spice-server 2/3] reds: Avoid integer overflows handling monitor
+ configuration
+
+Avoid VDAgentMessage::size integer overflows.
+
+Signed-off-by: Frediano Ziglio <fziglio@...hat.com>
+---
+ server/reds.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/server/reds.c b/server/reds.c
+index 7be85fdfc..e1c8c1086 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);
+-- 
+2.13.0
+
+From 8cc3d7df2792751939cc832f4110c57e2addfca5 Mon Sep 17 00:00:00 2001
+From: Frediano Ziglio <fziglio@...hat.com>
+Date: Mon, 15 May 2017 15:57:28 +0100
+Subject: [spice-server 3/3] 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@...hat.com>
+---
+ server/reds.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/server/reds.c b/server/reds.c
+index e1c8c1086..3a42c3755 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();
+-- 
+2.13.0
+