On Sat, Jan 4, 2020 at 2:32 AM Lorenzo Bianconi
<[email protected]> wrote:
>
> ipv6_ra_send can run 2 times in a row before prepare_ipv6_ras updates
> the dnss list. Clone the dnss dynamic string before running
> packet_put_ra_dnssl_opt in order to avoid sending truncated dnssl list
> on the wire.
> Moreover move ip6_hdr definition just before accessing it because the
> packet can be reallocated if the data area is not big enough for packet
> content
>
> Fixes: 5a12a940f ("Add DNSSL support to OVN")
> Signed-off-by: Lorenzo Bianconi <[email protected]>
> ---
> controller/pinctrl.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/controller/pinctrl.c b/controller/pinctrl.c
> index c886b21d9..bb1f0ab5a 100644
> --- a/controller/pinctrl.c
> +++ b/controller/pinctrl.c
> @@ -2417,7 +2417,6 @@ packet_put_ra_dnssl_opt(struct dp_packet *b, ovs_be32
> lifetime,
> {
> size_t prev_l4_size = dp_packet_l4_size(b);
> size_t size = sizeof(struct ovs_nd_dnssl);
> - struct ip6_hdr *nh = dp_packet_l3(b);
> char *t0, *r0 = NULL, dnssl[255] = {};
> int i = 0;
>
> @@ -2445,6 +2444,8 @@ packet_put_ra_dnssl_opt(struct dp_packet *b, ovs_be32
> lifetime,
> dnssl[i++] = 0;
> }
> size = ROUND_UP(size, 8);
> +
> + struct ip6_hdr *nh = dp_packet_l3(b);
> nh->ip6_plen = htons(prev_l4_size + size);
>
> struct ovs_nd_dnssl *nd_dnssl = dp_packet_put_uninit(b, sizeof
> *nd_dnssl);
> @@ -2566,8 +2567,11 @@ ipv6_ra_send(struct rconn *swconn, struct
> ipv6_ra_state *ra)
> &ra->config->rdnss);
> }
> if (ra->config->dnssl.length) {
> - packet_put_ra_dnssl_opt(&packet, htonl(0xffffffff),
> - ra->config->dnssl.string);
> + struct ds dnssl;
> +
> + ds_clone(&dnssl, &ra->config->dnssl);
> + packet_put_ra_dnssl_opt(&packet, htonl(0xffffffff), ds_cstr(&dnssl));
> + ds_destroy(&dnssl);
Instead of ds_clone and ds_destroy, the function
packet_put_ra_dnssl_opt() can do xstrdup the string
and use that for strtok_r() operations. It can later free the string.
What do you think ?
Same comment for the patch 2 as well.
Thanks
Numan
> }
> if (ra->config->route_info.length) {
> packet_put_ra_route_info_opt(&packet, htonl(0xffffffff),
> --
> 2.21.0
>
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