mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size

[ Upstream commit 655111b838cdabdb604f3625a9ff08c5eedb11da ]

ssn_offset field is u32 and is placed into the netlink response with
nla_put_u32(), but only 2 bytes are reserved for the attribute payload
in subflow_get_info_size() (even though it makes no difference
in the end, as it is aligned up to 4 bytes).  Supply the correct
argument to the relevant nla_total_size() call to make it less
confusing.

Fixes: 5147dfb50832 ("mptcp: allow dumping subflow context to userspace")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240812065024.GA19719@asgard.redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c
index 3ae46b545d2c2b7b7bf55ea9b101bcce798489f9..2d3efb405437d85c0bca70d7a92ca3a7363365e1 100644 (file)
--- a/net/mptcp/diag.c
+++ b/net/mptcp/diag.c
@@ -94,7 +94,7 @@ static size_t subflow_get_info_size(const struct sock *sk)
                nla_total_size(4) +     /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */
                nla_total_size_64bit(8) +       /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */
                nla_total_size(4) +     /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */
-               nla_total_size(2) +     /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
+               nla_total_size(4) +     /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
                nla_total_size(2) +     /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */
                nla_total_size(4) +     /* MPTCP_SUBFLOW_ATTR_FLAGS */
                nla_total_size(1) +     /* MPTCP_SUBFLOW_ATTR_ID_REM */