On 2022-01-25 11:51 +0200, Nikolay Aleksandrov wrote:
> On 25/01/2022 10:24, Nikolay Aleksandrov wrote:
> > On 25/01/2022 08:19, Benjamin Poirier wrote:
> >> Specifying ifindex in a RTM_GETVLAN dump leads to an infinite repetition
> >> of the same entries. netlink_dump() normally calls the dump function
> >> repeatedly until it returns 0 which br_vlan_rtm_dump() never does in
> >> that case.
> >>
> >> Fixes: 8dcea187088b ("net: bridge: vlan: add rtm definitions and dump support")
> >> Signed-off-by: Benjamin Poirier <bpoirier@xxxxxxxxxx>
> >> ---
> >> net/bridge/br_vlan.c | 6 ++++--
> >> 1 file changed, 4 insertions(+), 2 deletions(-)
> >>
> > [snip]
> >>
> >> diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
> >> index 84ba456a78cc..2e606f2b9a4d 100644
> >> --- a/net/bridge/br_vlan.c
> >> +++ b/net/bridge/br_vlan.c
> >> @@ -2013,7 +2013,7 @@ static int br_vlan_rtm_dump(struct sk_buff *skb, struct netlink_callback *cb)
> >> dump_flags = nla_get_u32(dtb[BRIDGE_VLANDB_DUMP_FLAGS]);
> >>
> >> rcu_read_lock();
> >> - if (bvm->ifindex) {
> >> + if (bvm->ifindex && !s_idx) {
> >> dev = dev_get_by_index_rcu(net, bvm->ifindex);
> >> if (!dev) {
> >> err = -ENODEV;
> >> @@ -2022,7 +2022,9 @@ static int br_vlan_rtm_dump(struct sk_buff *skb, struct netlink_callback *cb)
> >> err = br_vlan_dump_dev(dev, skb, cb, dump_flags);
> >> if (err && err != -EMSGSIZE)
> >> goto out_err;
> >> - } else {
> >> + else if (!err)
> >> + idx++;
> >> + } else if (!bvm->ifindex) {
> >> for_each_netdev_rcu(net, dev) {
> >> if (idx < s_idx)
> >> goto skip;
> >
> > Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
>
> Actually I'd prefer an alternative that would encapsulate handling the single
> device dump in its block, avoid all the "else if"s and is simpler (untested):
>
> diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
> index 84ba456a78cc..43201260e37b 100644
> --- a/net/bridge/br_vlan.c
> +++ b/net/bridge/br_vlan.c
> @@ -2020,7 +2020,8 @@ static int br_vlan_rtm_dump(struct sk_buff *skb, struct netlink_callback *cb)
> goto out_err;
> }
> err = br_vlan_dump_dev(dev, skb, cb, dump_flags);
> - if (err && err != -EMSGSIZE)
> + /* if the dump completed without an error we return 0 here */
> + if (err != -EMSGSIZE)
> goto out_err;
> } else {
> for_each_netdev_rcu(net, dev) {
LGTM, thank you.
