From: Lorenz Bauer lmb@cloudflare.com
[ Upstream commit f9b7ff0d7f7a466a920424246e7ddc2b84c87e52 ]
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 Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Song Liu songliubraving@fb.com Link: https://lore.kernel.org/bpf/20201105115230.296657-1-lmb@cloudflare.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 d393eb8263a60..994506540e564 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -741,7 +741,7 @@ static int parse_attach_detach_args(int argc, char **argv, int *progfd, }
if (*attach_type == BPF_FLOW_DISSECTOR) { - *mapfd = -1; + *mapfd = 0; return 0; }