Re: [PATCH 2/2] tools/bpftool: Fix segfault case regarding 'pin' arguments

[Taeung Song]

On 07/19/2018 03:19 AM, Jakub Kicinski wrote:
> On Wed, 18 Jul 2018 22:35:26 +0900, Taeung Song wrote:
> > Arguments of 'pin' subcommand should be checked
> > at the very beginning of do_pin_any().
> > Otherwise segfault errors can occur when using
> > 'map pin' or 'prog pin' commands, so fix it.
> >
> >    # bpftool prog pin id
> >    Segmentation fault
> >
> > Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
> > Cc: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
> > Reported-by: Taehee Yoo <ap420073@xxxxxxxxx>
> > Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
> > ---
> >   tools/bpf/bpftool/common.c | 11 ++++++++---
> >   1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> > index 32f9e397a6c0..b1e1ba9e1c90 100644
> > --- a/tools/bpf/bpftool/common.c
> > +++ b/tools/bpf/bpftool/common.c
> > @@ -217,6 +217,14 @@ int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32))
> >   	int err;
> >   	int fd;
> >   
> > +	if (argc < 3) {
> > +		p_err("too few arguments, id PROG_ID and FILE path is required");
>
> Thanks for the fix!  You can't say PROG_ID here, because this function
> is also called by bpftool map pin id X.  How about s/PROG_ID/ID/ ?

Yep! will fix it :)

--
Thanks,
Taeung

> > +		return -1;
> > +	} else if (argc > 3) {
> > +		p_err("too many arguments");
> > +		return -1;
> > +	}
> > +
> >   	if (!is_prefix(*argv, "id")) {
> >   		p_err("expected 'id' got %s", *argv);
> >   		return -1;
> > @@ -230,9 +238,6 @@ int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32))
> >   	}
> >   	NEXT_ARG();
> >   
> > -	if (argc != 1)
> > -		usage();
> > -
> >   	fd = get_fd_by_id(id);
> >   	if (fd < 0) {
> >   		p_err("can't get prog by id (%u): %s", id, strerror(errno));