xdp: Fix handling of devmap in generic XDP
Commit 67f29e07e131 ("bpf: devmap introduce dev_map_enqueue") changed
the return value type of __devmap_lookup_elem() from struct net_device *
to struct bpf_dtab_netdev * but forgot to modify generic XDP code
accordingly.
Thus generic XDP incorrectly used struct bpf_dtab_netdev where struct
net_device is expected, then skb->dev was set to invalid value.
v2:
- Fix compiler warning without CONFIG_BPF_SYSCALL.
Fixes: 67f29e07e131 ("bpf: devmap introduce dev_map_enqueue")
Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 995c3b1..7df32a3 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -488,12 +488,15 @@
/* Map specifics */
struct xdp_buff;
+struct sk_buff;
struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
void __dev_map_insert_ctx(struct bpf_map *map, u32 index);
void __dev_map_flush(struct bpf_map *map);
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
struct net_device *dev_rx);
+int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
+ struct bpf_prog *xdp_prog);
struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key);
void __cpu_map_insert_ctx(struct bpf_map *map, u32 index);
@@ -586,6 +589,15 @@
return 0;
}
+struct sk_buff;
+
+static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst,
+ struct sk_buff *skb,
+ struct bpf_prog *xdp_prog)
+{
+ return 0;
+}
+
static inline
struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
{
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 108f981..b615df5 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -19,6 +19,7 @@
#include <linux/cryptohash.h>
#include <linux/set_memory.h>
#include <linux/kallsyms.h>
+#include <linux/if_vlan.h>
#include <net/sch_generic.h>
@@ -802,6 +803,21 @@
struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
const struct bpf_insn *patch, u32 len);
+static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb,
+ struct net_device *fwd)
+{
+ unsigned int len;
+
+ if (unlikely(!(fwd->flags & IFF_UP)))
+ return -ENETDOWN;
+
+ len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN;
+ if (skb->len > len)
+ return -EMSGSIZE;
+
+ return 0;
+}
+
/* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the
* same cpu context. Further for best results no more than a single map
* for the do_redirect/do_flush pair should be used. This limitation is
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index a7cc7b3..642c97f 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -345,6 +345,20 @@
return bq_enqueue(dst, xdpf, dev_rx);
}
+int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
+ struct bpf_prog *xdp_prog)
+{
+ int err;
+
+ err = __xdp_generic_ok_fwd_dev(skb, dst->dev);
+ if (unlikely(err))
+ return err;
+ skb->dev = dst->dev;
+ generic_xdp_tx(skb, xdp_prog);
+
+ return 0;
+}
+
static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key);
diff --git a/net/core/filter.c b/net/core/filter.c
index 3d9ba7e..e7f12e9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3214,20 +3214,6 @@
}
EXPORT_SYMBOL_GPL(xdp_do_redirect);
-static int __xdp_generic_ok_fwd_dev(struct sk_buff *skb, struct net_device *fwd)
-{
- unsigned int len;
-
- if (unlikely(!(fwd->flags & IFF_UP)))
- return -ENETDOWN;
-
- len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN;
- if (skb->len > len)
- return -EMSGSIZE;
-
- return 0;
-}
-
static int xdp_do_generic_redirect_map(struct net_device *dev,
struct sk_buff *skb,
struct xdp_buff *xdp,
@@ -3256,10 +3242,11 @@
}
if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
- if (unlikely((err = __xdp_generic_ok_fwd_dev(skb, fwd))))
+ struct bpf_dtab_netdev *dst = fwd;
+
+ err = dev_map_generic_redirect(dst, skb, xdp_prog);
+ if (unlikely(err))
goto err;
- skb->dev = fwd;
- generic_xdp_tx(skb, xdp_prog);
} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
struct xdp_sock *xs = fwd;
