mptcp: do not warn on bad input from the network

warn_bad_map() produces a kernel WARN on bad input coming
from the network. Use pr_debug() to avoid spamming the system
log.

Additionally, when the right bound check fails, warn_bad_map() reports
the wrong ssn value, let's fix it.

Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/107
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ebb898a..e05e05e 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -784,10 +784,10 @@ static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
        return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32));
 }
 
-static void warn_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
+static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
 {
-       WARN_ONCE(1, "Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
-                 ssn, subflow->map_subflow_seq, subflow->map_data_len);
+       pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
+                ssn, subflow->map_subflow_seq, subflow->map_data_len);
 }
 
 static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
@@ -812,13 +812,13 @@ static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
                /* Mapping covers data later in the subflow stream,
                 * currently unsupported.
                 */
-               warn_bad_map(subflow, ssn);
+               dbg_bad_map(subflow, ssn);
                return false;
        }
        if (unlikely(!before(ssn, subflow->map_subflow_seq +
                                  subflow->map_data_len))) {
                /* Mapping does covers past subflow data, invalid */
-               warn_bad_map(subflow, ssn + skb->len);
+               dbg_bad_map(subflow, ssn);
                return false;
        }
        return true;