Messages in this thread | ![/](/images/icornerl.gif) | | From | Stanislav Fomichev <> | Date | Tue, 11 Jul 2023 10:00:42 -0700 | Subject | Re: [PATCH bpf] xdp: use trusted arguments in XDP hints kfuncs |
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On Tue, Jul 11, 2023 at 7:21 AM Jesper Dangaard Brouer <jbrouer@redhat.com> wrote: > > > On 11/07/2023 12.59, Larysa Zaremba wrote: > > Currently, verifier does not reject XDP programs that pass NULL pointer to > > hints functions. At the same time, this case is not handled in any driver > > implementation (including veth). For example, changing > > > > bpf_xdp_metadata_rx_timestamp(ctx, ×tamp); > > > > to > > > > bpf_xdp_metadata_rx_timestamp(ctx, NULL); > > > > in xdp_metadata test successfully crashes the system. > > > > Add KF_TRUSTED_ARGS flag to hints kfunc definitions, so driver code > > does not have to worry about getting invalid pointers. > > > > Looks good to me, assuming this means verifier will reject BPF-prog's > supplying NULL. > > Acked-by: Jesper Dangaard Brouer <hawk@kernel.org> > > > Fixes: 3d76a4d3d4e5 ("bpf: XDP metadata RX kfuncs") > > Reported-by: Stanislav Fomichev <sdf@google.com> > > Closes: https://lore.kernel.org/bpf/ZKWo0BbpLfkZHbyE@google.com/ > > Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Thank you for the fix!
> > --- > > net/core/xdp.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/net/core/xdp.c b/net/core/xdp.c > > index 41e5ca8643ec..8362130bf085 100644 > > --- a/net/core/xdp.c > > +++ b/net/core/xdp.c > > @@ -741,7 +741,7 @@ __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash, > > __diag_pop(); > > > > BTF_SET8_START(xdp_metadata_kfunc_ids) > > -#define XDP_METADATA_KFUNC(_, name) BTF_ID_FLAGS(func, name, 0) > > +#define XDP_METADATA_KFUNC(_, name) BTF_ID_FLAGS(func, name, KF_TRUSTED_ARGS) > > XDP_METADATA_KFUNC_xxx > > #undef XDP_METADATA_KFUNC > > BTF_SET8_END(xdp_metadata_kfunc_ids) >
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