Hello Toke,
thanks for this catch, for some weird reason we don't have an autotest
for this.
Changed your code a bit to add an explicit typecast macro, as the
original reason why this slipped through is that plain void pointer cast.
Merged, thanks. Have a nice day!
Maria
On Tue, Feb 25, 2025 at 04:05:10PM +0100, Toke Høiland-Jørgensen via Bird-users
wrote:
> Commit 69d1ffde4c72 ("Split route data structure to storage (ro) /
> manipulation (rw) structures.") changed rte->net from a pointer to a
> 'struct network' to a 'struct net_addr', but kept the address-of (&)
> operator before casting to 'net_addr_ip6_sadr *' when sending a
> source-specific route to the kernel.
>
> Because 'struct network' had an embedded struct member (struct
> fib_node), the address-of was needed to get back to a pointer to the
> data, but with the change in the commit mentioned above, e->net is now a
> straight pointer to the address.
>
> The bug meant that the source prefixes passed to the kernel were
> essentially garbage, leading to routes in the kernel like:
>
> default from b74:9e05:0:1:d8cf:c000::/86 via fe80::1 dev eth0 proto bird
> metric 32 pref medium
>
> Fix this by getting rid of the address-of operator.
>
> Fixes: 69d1ffde4c72 ("Split route data structure to storage (ro) /
> manipulation (rw) structures.")
> Signed-off-by: Toke Høiland-Jørgensen <t...@toke.dk>
> ---
> sysdep/linux/netlink.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c
> index 1703a67595d5..6cc0142c3e00 100644
> --- a/sysdep/linux/netlink.c
> +++ b/sysdep/linux/netlink.c
> @@ -1494,7 +1494,7 @@ nl_send_route(struct krt_proto *p, const rte *e, int op)
> /* Add source address for IPv6 SADR routes */
> if (e->net->type == NET_IP6_SADR)
> {
> - net_addr_ip6_sadr *a = (void *) &e->net;
> + net_addr_ip6_sadr *a = (void *) e->net;
> nl_add_attr_ip6(&r->h, rsize, RTA_SRC, a->src_prefix);
> r->r.rtm_src_len = a->src_pxlen;
> }
> --
> 2.48.1
>
--
Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o.
