openvswitch: fix CVE-2020-35498 limitation in the OVS packet parsingdunfell

Upstream-Status: Backport https://github.com/openvswitch/ovs/commit/0625dc79aec73b966f206e55655a2816696246d0

Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

2 files changed, 152 insertions, 0 deletions

diff --git a/recipes-networking/openvswitch/openvswitch-git/CVE-2020-35498.patch b/recipes-networking/openvswitch/openvswitch-git/CVE-2020-35498.patch
new file mode 100644
index 00000000..5093f077
--- /dev/null
+++ b/recipes-networking/openvswitch/openvswitch-git/CVE-2020-35498.patch
@@ -0,0 +1,151 @@
+rom 0625dc79aec73b966f206e55655a2816696246d0 Mon Sep 17 00:00:00 2001
+From: Flavio Leitner <fbl@sysclose.org>
+Date: Mon, 26 Oct 2020 16:03:19 -0300
+Subject: [PATCH] flow: Support extra padding length.
+
+Although not required, padding can be optionally added until
+the packet length is MTU bytes. A packet with extra padding
+currently fails sanity checks.
+
+Vulnerability: CVE-2020-35498
+Fixes: fa8d9001a624 ("miniflow_extract: Properly handle small IP packets.")
+Reported-by: Joakim Hindersson <joakim.hindersson@elastx.se>
+Acked-by: Ilya Maximets <i.maximets@ovn.org>
+Signed-off-by: Flavio Leitner <fbl@sysclose.org>
+Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
+
+Upstream-Status: Backport [https://github.com/openvswitch/ovs/commit/0625dc79aec73b966f206e55655a2816696246d0]
+CVE: CVE-2020-35498
+Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
+---
+ lib/conntrack.c     |  2 +-
+ lib/dp-packet.h     | 10 +++++-----
+ lib/flow.c          |  6 +++---
+ tests/classifier.at | 36 ++++++++++++++++++++++++++++++++++++
+ 4 files changed, 45 insertions(+), 9 deletions(-)
+
+diff --git a/lib/conntrack.c b/lib/conntrack.c
+index ff5a89457..0f486d74c 100644
+--- a/lib/conntrack.c
++++ b/lib/conntrack.c
+@@ -813,7 +813,7 @@ static void
+ reverse_nat_packet(struct dp_packet *pkt, const struct conn *conn)
+ {
+     char *tail = dp_packet_tail(pkt);
+-    uint8_t pad = dp_packet_l2_pad_size(pkt);
++    uint16_t pad = dp_packet_l2_pad_size(pkt);
+     struct conn_key inner_key;
+     const char *inner_l4 = NULL;
+     uint16_t orig_l3_ofs = pkt->l3_ofs;
+diff --git a/lib/dp-packet.h b/lib/dp-packet.h
+index 9f8991faa..45655af46 100644
+--- a/lib/dp-packet.h
++++ b/lib/dp-packet.h
+@@ -81,7 +81,7 @@ struct dp_packet {
+ 
+     /* All the following elements of this struct are copied in a single call
+      * of memcpy in dp_packet_clone_with_headroom. */
+-    uint8_t l2_pad_size;           /* Detected l2 padding size.
++    uint16_t l2_pad_size;          /* Detected l2 padding size.
+                                     * Padding is non-pullable. */
+     uint16_t l2_5_ofs;             /* MPLS label stack offset, or UINT16_MAX */
+     uint16_t l3_ofs;               /* Network-level header offset,
+@@ -118,8 +118,8 @@ void *dp_packet_resize_l2(struct dp_packet *, int increment);
+ void *dp_packet_resize_l2_5(struct dp_packet *, int increment);
+ static inline void *dp_packet_eth(const struct dp_packet *);
+ static inline void dp_packet_reset_offsets(struct dp_packet *);
+-static inline uint8_t dp_packet_l2_pad_size(const struct dp_packet *);
+-static inline void dp_packet_set_l2_pad_size(struct dp_packet *, uint8_t);
++static inline uint16_t dp_packet_l2_pad_size(const struct dp_packet *);
++static inline void dp_packet_set_l2_pad_size(struct dp_packet *, uint16_t);
+ static inline void *dp_packet_l2_5(const struct dp_packet *);
+ static inline void dp_packet_set_l2_5(struct dp_packet *, void *);
+ static inline void *dp_packet_l3(const struct dp_packet *);
+@@ -327,14 +327,14 @@ dp_packet_reset_offsets(struct dp_packet *b)
+     b->l4_ofs = UINT16_MAX;
+ }
+ 
+-static inline uint8_t
++static inline uint16_t
+ dp_packet_l2_pad_size(const struct dp_packet *b)
+ {
+     return b->l2_pad_size;
+ }
+ 
+ static inline void
+-dp_packet_set_l2_pad_size(struct dp_packet *b, uint8_t pad_size)
++dp_packet_set_l2_pad_size(struct dp_packet *b, uint16_t pad_size)
+ {
+     ovs_assert(pad_size <= dp_packet_size(b));
+     b->l2_pad_size = pad_size;
+diff --git a/lib/flow.c b/lib/flow.c
+index 45bb96b54..353d5cd3e 100644
+--- a/lib/flow.c
++++ b/lib/flow.c
+@@ -655,7 +655,7 @@ ipv4_sanity_check(const struct ip_header *nh, size_t size,
+ 
+     tot_len = ntohs(nh->ip_tot_len);
+     if (OVS_UNLIKELY(tot_len > size || ip_len > tot_len ||
+-                size - tot_len > UINT8_MAX)) {
++                size - tot_len > UINT16_MAX)) {
+         return false;
+     }
+ 
+@@ -693,8 +693,8 @@ ipv6_sanity_check(const struct ovs_16aligned_ip6_hdr *nh, size_t size)
+     if (OVS_UNLIKELY(plen + IPV6_HEADER_LEN > size)) {
+         return false;
+     }
+-    /* Jumbo Payload option not supported yet. */
+-    if (OVS_UNLIKELY(size - (plen + IPV6_HEADER_LEN) > UINT8_MAX)) {
++
++    if (OVS_UNLIKELY(size - (plen + IPV6_HEADER_LEN) > UINT16_MAX)) {
+         return false;
+     }
+ 
+diff --git a/tests/classifier.at b/tests/classifier.at
+index 88818618b..cdcd72c15 100644
+--- a/tests/classifier.at
++++ b/tests/classifier.at
+@@ -304,3 +304,39 @@ ovs-ofctl: "conjunction" actions may be used along with "note" but not any other
+ ])
+ OVS_VSWITCHD_STOP
+ AT_CLEANUP
++
++# Flow classifier a packet with excess of padding.
++AT_SETUP([flow classifier - packet with extra padding])
++OVS_VSWITCHD_START
++add_of_ports br0 1 2
++AT_DATA([flows.txt], [dnl
++priority=5,ip,ip_dst=1.1.1.1,actions=1
++priority=5,ip,ip_dst=1.1.1.2,actions=2
++priority=0,actions=drop
++])
++AT_CHECK([ovs-ofctl add-flows br0 flows.txt])
++packet=00020202020000010101010008004500001c00010000401176cc01010101010101020d6a00350008ee3a
++AT_CHECK([ovs-appctl ofproto/trace br0 in_port=1 $packet] , [0], [stdout])
++AT_CHECK([tail -2 stdout], [0],
++  [Megaflow: recirc_id=0,eth,ip,in_port=1,nw_dst=1.1.1.2,nw_frag=no
++Datapath actions: 2
++])
++# normal packet plus 255 bytes of padding (8bit padding).
++# 255 * 2 = 510
++padding=$(printf '%*s' 510 | tr ' ' '0')
++AT_CHECK([ovs-appctl ofproto/trace br0 in_port=1 ${packet}${padding}] , [0], [stdout])
++AT_CHECK([tail -2 stdout], [0],
++  [Megaflow: recirc_id=0,eth,ip,in_port=1,nw_dst=1.1.1.2,nw_frag=no
++Datapath actions: 2
++])
++# normal packet plus padding up to 65535 bytes of length (16bit limit).
++# 65535 - 43 = 65492
++# 65492 * 2 = 130984
++padding=$(printf '%*s' 130984 | tr ' ' '0')
++AT_CHECK([ovs-appctl ofproto/trace br0 in_port=1 ${packet}${padding}], [0], [stdout])
++AT_CHECK([tail -2 stdout], [0],
++  [Megaflow: recirc_id=0,eth,ip,in_port=1,nw_dst=1.1.1.2,nw_frag=no
++Datapath actions: 2
++])
++OVS_VSWITCHD_STOP
++AT_CLEANUP
+-- 
+2.25.1
+
diff --git a/recipes-networking/openvswitch/openvswitch_git.bb b/recipes-networking/openvswitch/openvswitch_git.bb
index 56a9c25f..c1cc23c0 100644
--- a/recipes-networking/openvswitch/openvswitch_git.bb
+++ b/recipes-networking/openvswitch/openvswitch_git.bb
@@ -32,6 +32,7 @@ SRC_URI = "file://openvswitch-switch \
            file://systemd-update-tool-paths.patch \
            file://systemd-create-runtime-dirs.patch \
            file://CVE-2021-3905.patch \
+           file://CVE-2020-35498.patch \
            "
 
 LIC_FILES_CHKSUM = "file://LICENSE;md5=1ce5d23a6429dff345518758f13aaeab"