From: Petar Penkov <ppenkov.kernel@gmail.com>
To: netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net,
Petar Penkov <ppenkov@google.com>,
Stanislav Fomichev <sdf@google.com>
Subject: [bpf-next] bpf: fix error check in bpf_tcp_gen_syncookie
Date: Tue, 27 Aug 2019 16:46:22 -0700 [thread overview]
Message-ID: <20190827234622.76209-1-ppenkov.kernel@gmail.com> (raw)
From: Petar Penkov <ppenkov@google.com>
If a SYN cookie is not issued by tcp_v#_gen_syncookie, then the return
value will be exactly 0, rather than <= 0. Let's change the check to
reflect that, especially since mss is an unsigned value and cannot be
negative.
Fixes: 70d66244317e ("bpf: add bpf_tcp_gen_syncookie helper")
Reported-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Petar Penkov <ppenkov@google.com>
---
net/core/filter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 0c1059cdad3d..17bc9af8f156 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5903,7 +5903,7 @@ BPF_CALL_5(bpf_tcp_gen_syncookie, struct sock *, sk, void *, iph, u32, iph_len,
default:
return -EPROTONOSUPPORT;
}
- if (mss <= 0)
+ if (mss == 0)
return -ENOENT;
return cookie | ((u64)mss << 32);
--
2.23.0.187.g17f5b7556c-goog
next reply other threads:[~2019-08-27 23:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 23:46 Petar Penkov [this message]
2019-08-28 19:15 ` [bpf-next] bpf: fix error check in bpf_tcp_gen_syncookie Song Liu
2019-08-30 23:23 ` Daniel Borkmann
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