[PATCH] mptcp: bugfix for RM_ADDR option parsing

Geliang Tang
2020-06-08T07:50:29Z

In MPTCPOPT_RM_ADDR option parsing, the pointer "ptr" pointed to the
"Subtype" octet, the pointer "ptr+1" pointed to the "Address ID" octet:

+-------+-------+---------------+
|Subtype|(resvd)| Address ID |
+-------+-------+---------------+
| |
ptr ptr+1

We should set mp_opt->rm_id to the value of "ptr+1", not "ptr". This patch
will fix this bug.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
net/mptcp/options.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 01f1f4cf4902..490b92534afc 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -273,6 +273,8 @@ static void mptcp_parse_option(const struct sk_buff *skb,
if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE)
break;

+ ptr++;
+
mp_opt->rm_addr = 1;
mp_opt->rm_id = *ptr++;
pr_debug("RM_ADDR: id=%d", mp_opt->rm_id);
--
2.17.1