From 6d5fc1957989266006db6ef3dfb9159b42cf0189 Mon Sep 17 00:00:00 2001 From: Toshiaki Makita Date: Thu, 14 Jun 2018 11:07:42 +0900 Subject: [PATCH] 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 Acked-by: Yonghong Song Acked-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 12 ++++++++++++ include/linux/filter.h | 16 ++++++++++++++++ kernel/bpf/devmap.c | 14 ++++++++++++++ net/core/filter.c | 21 ++++----------------- 4 files changed, 46 insertions(+), 17 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 995c3b1e59bf..7df32a3200f7 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -488,12 +488,15 @@ void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth); /* 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 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, 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 108f9812e196..b615df57b7d5 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -19,6 +19,7 @@ #include #include #include +#include #include @@ -802,6 +803,21 @@ static inline bool bpf_dump_raw_ok(void) 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 a7cc7b3494a9..642c97f6d1b8 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -345,6 +345,20 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, 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 3d9ba7e5965a..e7f12e9f598c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3214,20 +3214,6 @@ err: } 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 @@ static int xdp_do_generic_redirect_map(struct net_device *dev, } 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;