--- /dev/null
+Subject: CVE-2020-35498: 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.
+Author: Flavio Leitner <fbl@sysclose.org>
+Date: Mon, 26 Oct 2020 16:03:19 -0300
+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>
+Origin: upstream, https://github.com/openvswitch/ovs/commit/0625dc79aec73b966f206e55655a2816696246d0
+Last-Update: 2021-04-10
+
+diff --git a/lib/conntrack.c b/lib/conntrack.c
+index bba38f9f57..feaaec1c3f 100644
+--- a/lib/conntrack.c
++++ b/lib/conntrack.c
+@@ -825,7 +825,7 @@ 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 0430cca8eb..9e2d06b3dd 100644
+--- a/lib/dp-packet.h
++++ b/lib/dp-packet.h
+@@ -125,7 +125,7 @@ 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,
+@@ -162,8 +162,8 @@ 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 *);
+@@ -371,14 +371,14 @@ 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 cc1b3f2db2..729d59b1b3 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 88818618be..cdcd72c156 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
projects / ovs.git / commitdiff