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authorDavide Caratti <dcaratti@redhat.com>2021-03-08 10:00:04 +0100
committerDavid S. Miller <davem@davemloft.net>2021-03-08 15:02:03 -0800
commit27ab92d9996e4e003a726d22c56d780a1655d6b4 (patch)
tree15407c0d32223e9648dc6f6463ed206d5c001eb3 /net
parent2055a99da8a253a357bdfd359b3338ef3375a26c (diff)
mptcp: fix length of ADD_ADDR with port sub-option
in current Linux, MPTCP peers advertising endpoints with port numbers use a sub-option length that wrongly accounts for the trailing TCP NOP. Also, receivers will only process incoming ADD_ADDR with port having such wrong sub-option length. Fix this, making ADD_ADDR compliant to RFC8684 ยง3.4.1. this can be verified running tcpdump on the kselftests artifacts: unpatched kernel: [root@bottarga mptcp]# tcpdump -tnnr unpatched.pcap | grep add-addr reading from file unpatched.pcap, link-type LINUX_SLL (Linux cooked v1), snapshot length 65535 IP 10.0.1.1.10000 > 10.0.1.2.53078: Flags [.], ack 101, win 509, options [nop,nop,TS val 214459678 ecr 521312851,mptcp add-addr v1 id 1 a00:201:2774:2d88:7436:85c3:17fd:101], length 0 IP 10.0.1.2.53078 > 10.0.1.1.10000: Flags [.], ack 101, win 502, options [nop,nop,TS val 521312852 ecr 214459678,mptcp add-addr[bad opt]] patched kernel: [root@bottarga mptcp]# tcpdump -tnnr patched.pcap | grep add-addr reading from file patched.pcap, link-type LINUX_SLL (Linux cooked v1), snapshot length 65535 IP 10.0.1.1.10000 > 10.0.1.2.38178: Flags [.], ack 101, win 509, options [nop,nop,TS val 3728873902 ecr 2732713192,mptcp add-addr v1 id 1 10.0.2.1:10100 hmac 0xbccdfcbe59292a1f,nop,nop], length 0 IP 10.0.1.2.38178 > 10.0.1.1.10000: Flags [.], ack 101, win 502, options [nop,nop,TS val 2732713195 ecr 3728873902,mptcp add-addr v1-echo id 1 10.0.2.1:10100,nop,nop], length 0 Fixes: 22fb85ffaefb ("mptcp: add port support for ADD_ADDR suboption writing") CC: stable@vger.kernel.org # 5.11+ Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Acked-and-tested-by: Geliang Tang <geliangtang@gmail.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/mptcp/protocol.h14
1 files changed, 8 insertions, 6 deletions
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 91827d949766..e21a5bc36cf0 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -52,14 +52,15 @@
#define TCPOLEN_MPTCP_DSS_MAP64 14
#define TCPOLEN_MPTCP_DSS_CHECKSUM 2
#define TCPOLEN_MPTCP_ADD_ADDR 16
-#define TCPOLEN_MPTCP_ADD_ADDR_PORT 20
+#define TCPOLEN_MPTCP_ADD_ADDR_PORT 18
#define TCPOLEN_MPTCP_ADD_ADDR_BASE 8
-#define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT 12
+#define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT 10
#define TCPOLEN_MPTCP_ADD_ADDR6 28
-#define TCPOLEN_MPTCP_ADD_ADDR6_PORT 32
+#define TCPOLEN_MPTCP_ADD_ADDR6_PORT 30
#define TCPOLEN_MPTCP_ADD_ADDR6_BASE 20
-#define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT 24
-#define TCPOLEN_MPTCP_PORT_LEN 4
+#define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT 22
+#define TCPOLEN_MPTCP_PORT_LEN 2
+#define TCPOLEN_MPTCP_PORT_ALIGN 2
#define TCPOLEN_MPTCP_RM_ADDR_BASE 4
#define TCPOLEN_MPTCP_PRIO 3
#define TCPOLEN_MPTCP_PRIO_ALIGN 4
@@ -701,8 +702,9 @@ static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
if (!echo)
len += MPTCPOPT_THMAC_LEN;
+ /* account for 2 trailing 'nop' options */
if (port)
- len += TCPOLEN_MPTCP_PORT_LEN;
+ len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
return len;
}