[ovs-dev] [PATCH ovn 2/2] RA Route Info Option: copy route info string in order to avoid truncated value

Lorenzo Bianconi lorenzo.bianconi at redhat.com
Fri Jan 3 21:01:57 UTC 2020


ipv6_ra_send can run 2 times in a row before prepare_ipv6_ras updates
the route info. Clone route info string before running
packet_put_ra_route_info_opt in order to avoid sending truncated route
info 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: 9f7f466af ("Add support for Route Info Option in RA - RFC 4191")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
---
 controller/pinctrl.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/controller/pinctrl.c b/controller/pinctrl.c
index bb1f0ab5a..6a35a3c42 100644
--- a/controller/pinctrl.c
+++ b/controller/pinctrl.c
@@ -2468,7 +2468,6 @@ packet_put_ra_route_info_opt(struct dp_packet *b, ovs_be32 lifetime,
                              char *route_list)
 {
     size_t prev_l4_size = dp_packet_l4_size(b);
-    struct ip6_hdr *nh = dp_packet_l3(b);
     char *t0, *r0 = NULL;
     size_t size = 0;
 
@@ -2523,6 +2522,7 @@ packet_put_ra_route_info_opt(struct dp_packet *b, ovs_be32 lifetime,
         }
     }
 
+    struct ip6_hdr *nh = dp_packet_l3(b);
     nh->ip6_plen = htons(prev_l4_size + size);
     struct ovs_ra_msg *ra = dp_packet_l4(b);
     ra->icmph.icmp6_cksum = 0;
@@ -2574,8 +2574,12 @@ ipv6_ra_send(struct rconn *swconn, struct ipv6_ra_state *ra)
         ds_destroy(&dnssl);
     }
     if (ra->config->route_info.length) {
+        struct ds route_info;
+
+        ds_clone(&route_info, &ra->config->route_info);
         packet_put_ra_route_info_opt(&packet, htonl(0xffffffff),
-                                     ra->config->route_info.string);
+                                     ds_cstr(&route_info));
+        ds_destroy(&route_info);
     }
 
     uint64_t ofpacts_stub[4096 / 8];
-- 
2.21.0



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