net: fix dev_fill_forward_path with pppoe + bridge

When calling dev_fill_forward_path on a pppoe device, the provided destination
address is invalid. In order for the bridge fdb lookup to succeed, the pppoe
code needs to update ctx->daddr to the correct value.
Fix this by storing the address inside struct net_device_path_ctx

Fixes: f6efc675c9dd ("net: ppp: resolve forwarding path for bridge pppoe devices")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index 3619520..e172743 100644 (file)
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -988,6 +988,7 @@ static int pppoe_fill_forward_path(struct net_device_path_ctx *ctx,
        path->encap.proto = htons(ETH_P_PPP_SES);
        path->encap.id = be16_to_cpu(po->num);
        memcpy(path->encap.h_dest, po->pppoe_pa.remote, ETH_ALEN);
+       memcpy(ctx->daddr, po->pppoe_pa.remote, ETH_ALEN);
        path->dev = ctx->dev;
        ctx->dev = dev;
 

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b1fbe21..f736c02 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -900,7 +900,7 @@ struct net_device_path_stack {
 
 struct net_device_path_ctx {
        const struct net_device *dev;
-       const u8                *daddr;
+       u8                      daddr[ETH_ALEN];
 
        int                     num_vlans;
        struct {

diff --git a/net/core/dev.c b/net/core/dev.c
index 1461c2d..2771fd2 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -681,11 +681,11 @@ int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
        const struct net_device *last_dev;
        struct net_device_path_ctx ctx = {
                .dev    = dev,
-               .daddr  = daddr,
        };
        struct net_device_path *path;
        int ret = 0;
 
+       memcpy(ctx.daddr, daddr, sizeof(ctx.daddr));
        stack->num_paths = 0;
        while (ctx.dev && ctx.dev->netdev_ops->ndo_fill_forward_path) {
                last_dev = ctx.dev;