Commit 0e94d87f authored Apr 02, 2018 by John Fastabend Committed by Daniel Borkmann Apr 04, 2018

bpf: sockmap, duplicates release calls may NULL sk_prot



It is possible to have multiple ULP tcp_release call paths in flight
if a sock is closed and simultaneously being removed from the sockmap
control path. The result would be setting the sk_prot to the saved
values on the first iteration and then on the second iteration setting
the value to NULL.

This patch resolves this by ensuring we only reset the sk_prot pointer
if we have a valid saved state to set.

Fixes: 4f738adb ("bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 820ed3fb

kernel/bpf/sockmap.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -182,8 +182,10 @@ static void bpf_tcp_release(struct sock *sk)
	psock->cork = NULL;		psock->cork = NULL;
	}		}

			if (psock->sk_proto) {
	sk->sk_prot = psock->sk_proto;		sk->sk_prot = psock->sk_proto;
	psock->sk_proto = NULL;		psock->sk_proto = NULL;
			}
	out:		out:
	rcu_read_unlock();		rcu_read_unlock();
	}		}

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