On Sun, Oct 07, 2018 at 08:16:44PM -0700, David Ahern wrote:
> From: David Ahern <dsah...@gmail.com>
>
> Update rtnl_fdb_dump for strict data checking. If the flag is set,
> the dump request is expected to have an ndmsg struct as the header
> potentially followed by one or more attributes. Any data passed in the
> header or as an attribute is taken as a request to influence the data
> returned. Only values supported by the dump handler are allowed to be
> non-0 or set in the request. At the moment only the NDA_IFINDEX and
> NDA_MASTER attributes are supported.
>
> Signed-off-by: David Ahern <dsah...@gmail.com>
Acked-by: Christian Brauner <christ...@brauner.io>
> ---
> net/core/rtnetlink.c | 62
> ++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 60 insertions(+), 2 deletions(-)
>
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index c7509c789fb6..c894c4af8981 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -3799,6 +3799,60 @@ int ndo_dflt_fdb_dump(struct sk_buff *skb,
> }
> EXPORT_SYMBOL(ndo_dflt_fdb_dump);
>
> +static int valid_fdb_dump_strict(const struct nlmsghdr *nlh,
> + int *br_idx, int *brport_idx,
> + struct netlink_ext_ack *extack)
> +{
> + struct nlattr *tb[NDA_MAX + 1];
> + struct ndmsg *ndm;
> + int err, i;
> +
> + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndm))) {
> + NL_SET_ERR_MSG(extack, "Invalid header for fdb dump request");
> + return -EINVAL;
> + }
> +
> + ndm = nlmsg_data(nlh);
> + if (ndm->ndm_pad1 || ndm->ndm_pad2 || ndm->ndm_state ||
> + ndm->ndm_flags || ndm->ndm_type) {
> + NL_SET_ERR_MSG(extack, "Invalid values in header for fbd dump
> request");
> + return -EINVAL;
> + }
> +
> + err = nlmsg_parse_strict(nlh, sizeof(struct ndmsg), tb, NDA_MAX,
> + NULL, extack);
> + if (err < 0)
> + return err;
> +
> + *brport_idx = ndm->ndm_ifindex;
> + for (i = 0; i <= NDA_MAX; ++i) {
> + if (!tb[i])
> + continue;
> +
> + switch (i) {
> + case NDA_IFINDEX:
> + if (nla_len(tb[i]) != sizeof(u32)) {
> + NL_SET_ERR_MSG(extack, "Invalid IFINDEX
> attribute in fdb dump request");
> + return -EINVAL;
> + }
> + *brport_idx = nla_get_u32(tb[NDA_IFINDEX]);
> + break;
> + case NDA_MASTER:
> + if (nla_len(tb[i]) != sizeof(u32)) {
> + NL_SET_ERR_MSG(extack, "Invalid MASTER
> attribute in fdb dump request");
> + return -EINVAL;
> + }
> + *br_idx = nla_get_u32(tb[NDA_MASTER]);
> + break;
> + default:
> + NL_SET_ERR_MSG(extack, "Unsupported attribute in fdb
> dump request");
> + return -EINVAL;
> + }
> + }
> +
> + return 0;
> +}
> +
> static int valid_fdb_dump_legacy(const struct nlmsghdr *nlh,
> int *br_idx, int *brport_idx,
> struct netlink_ext_ack *extack)
> @@ -3846,8 +3900,12 @@ static int rtnl_fdb_dump(struct sk_buff *skb, struct
> netlink_callback *cb)
> int err = 0;
> int fidx = 0;
>
> - err = valid_fdb_dump_legacy(cb->nlh, &br_idx, &brport_idx,
> - cb->extack);
> + if (cb->strict_check)
> + err = valid_fdb_dump_strict(cb->nlh, &br_idx, &brport_idx,
> + cb->extack);
> + else
> + err = valid_fdb_dump_legacy(cb->nlh, &br_idx, &brport_idx,
> + cb->extack);
> if (err < 0)
> return err;
>
> --
> 2.11.0
>
