On Fri, Jul 7, 2023 at 6:00 AM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Wed, Jun 28, 2023 at 4:53 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
> >
> > Add a new helper bpf_perf_link_fill_common(), which will be used by
> > perf_link based tracepoint, kprobe and uprobe.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> > ---
> > kernel/bpf/syscall.c | 34 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 34 insertions(+)
> >
> > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> > index 4aa6e5776a04..72de91beabbc 100644
> > --- a/kernel/bpf/syscall.c
> > +++ b/kernel/bpf/syscall.c
> > @@ -3364,6 +3364,40 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
> > kfree(perf_link);
> > }
> >
> > +static int bpf_perf_link_fill_common(const struct perf_event *event,
> > + char __user *uname, u32 ulen,
> > + u64 *probe_offset, u64 *probe_addr,
> > + u32 *fd_type)
> > +{
> > + const char *buf;
> > + u32 prog_id;
> > + size_t len;
> > + int err;
> > +
> > + if (!ulen ^ !uname)
> > + return -EINVAL;
> > + if (!uname)
> > + return 0;
> > +
> > + err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
> > + probe_offset, probe_addr);
> > + if (err)
> > + return err;
> > +
> > + len = strlen(buf);
> > + if (buf) {
>
> if buf is NULL, strlen above will crash, so you need to calculate len
> inside this if branch
Nice catch. Will fix it.
--
Regards
Yafang
