tools: bpftool: fix crash on bad parameters with JSON

If bad or unrecognised parameters are specified after JSON output is
requested, `usage()` will try to output null JSON object before the
writer is created.

To prevent this, create the writer as soon as the `--json` option is
parsed.

Fixes: 004b45c0e5 ("tools: bpftool: provide JSON output for all possible commands")
Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Quentin Monnet 2017-11-28 17:44:28 -08:00 committed by Daniel Borkmann
parent a39e17b2d8
commit 9b85c2d450

View File

@ -291,7 +291,15 @@ int main(int argc, char **argv)
pretty_output = true;
/* fall through */
case 'j':
json_output = true;
if (!json_output) {
json_wtr = jsonw_new(stdout);
if (!json_wtr) {
p_err("failed to create JSON writer");
return -1;
}
json_output = true;
}
jsonw_pretty(json_wtr, pretty_output);
break;
case 'f':
show_pinned = true;
@ -306,15 +314,6 @@ int main(int argc, char **argv)
if (argc < 0)
usage();
if (json_output) {
json_wtr = jsonw_new(stdout);
if (!json_wtr) {
p_err("failed to create JSON writer");
return -1;
}
jsonw_pretty(json_wtr, pretty_output);
}
bfd_init();
ret = cmd_select(cmds, argc, argv, do_help);