Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Lorenz Bauer <lmb@cloudflare.com>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Lorenz Bauer <lmb@cloudflare.com>
Cc:     kernel-team@cloudflare.com, Jiri Benc <jbenc@redhat.com>,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH bpf] tools/bpftool: fix attaching flow dissector
Date:   Thu,  5 Nov 2020 11:52:30 +0000
Message-Id: <20201105115230.296657-1-lmb@cloudflare.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

My earlier patch to reject non-zero arguments to flow dissector attach
broke attaching via bpftool. Instead of 0 it uses -1 for target_fd.
Fix this by passing a zero argument when attaching the flow dissector.

Fixes: 1b514239e859 ("bpf: flow_dissector: Check value of unused flags to BPF_PROG_ATTACH")
Reported-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
 tools/bpf/bpftool/prog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index d942c1e3372c..acdb2c245f0a 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -940,7 +940,7 @@ static int parse_attach_detach_args(int argc, char **argv, int *progfd,
 	}
 
 	if (*attach_type == BPF_FLOW_DISSECTOR) {
-		*mapfd = -1;
+		*mapfd = 0;
 		return 0;
 	}
 
-- 
2.25.1