diff options
| -rw-r--r-- | net/mptcp/sockopt.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index fcca9433c858..a77b33488176 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -999,6 +999,10 @@ static int mptcp_getsockopt_info(struct mptcp_sock *msk, char __user *optval, in if (get_user(len, optlen)) return -EFAULT; + /* When used only to check if a fallback to TCP happened. */ + if (len == 0) + return 0; + len = min_t(unsigned int, len, sizeof(struct mptcp_info)); mptcp_diag_fill_info(msk, &m_info); |