On Wed, May 29, 2019 at 10:01 AM Song Liu <liu.song.a23@xxxxxxxxx> wrote:
>
> On Tue, May 28, 2019 at 6:14 PM Andrii Nakryiko <andriin@xxxxxx> wrote:
> >
> > Ensure that size of a section w/ BPF instruction is exactly a multiple
> > of BPF instruction size.
> >
> > Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> > ---
> > tools/lib/bpf/libbpf.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index ca4432f5b067..05a73223e524 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -349,8 +349,11 @@ static int
> > bpf_program__init(void *data, size_t size, char *section_name, int idx,
> > struct bpf_program *prog)
> > {
> > - if (size < sizeof(struct bpf_insn)) {
> > - pr_warning("corrupted section '%s'\n", section_name);
> > + const size_t bpf_insn_sz = sizeof(struct bpf_insn);
> > +
> > + if (size < bpf_insn_sz || size % bpf_insn_sz) {
>
> how about
> if (!size || size % bpf_insn_sz)
sure, why not.
>
> > + pr_warning("corrupted section '%s', size: %zu\n",
> > + section_name, size);
> > return -EINVAL;
> > }
> >
> > @@ -376,9 +379,8 @@ bpf_program__init(void *data, size_t size, char *section_name, int idx,
> > section_name);
> > goto errout;
> > }
> > - prog->insns_cnt = size / sizeof(struct bpf_insn);
> > - memcpy(prog->insns, data,
> > - prog->insns_cnt * sizeof(struct bpf_insn));
> > + prog->insns_cnt = size / bpf_insn_sz;
> > + memcpy(prog->insns, data, prog->insns_cnt * bpf_insn_sz);
>
> Given the check above, we can just use size in memcpy, right?
yep, good point, will update
>
> Thanks,
> Song
>
> > prog->idx = idx;
> > prog->instances.fds = NULL;
> > prog->instances.nr = -1;
> > --
> > 2.17.1
> >
