[PATCH 5.12 046/178] mptcp: do not warn on bad input from the network

Greg Kroah-Hartman
2021-06-21T16:39:30Z

From: Paolo Abeni <pabeni@redhat.com>

[ Upstream commit 61e710227e97172355d5f150d5c78c64175d9fb2 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mptcp/subflow.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 1ee4d106ce1c..98a5a68ec15d 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -754,10 +754,10 @@ 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)
@@ -782,13 +782,13 @@ 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;
--
2.30.2