From 97bc402db7821259f6a722cb38e060aa9b35b6e8 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 19 Nov 2016 01:45:00 +0100 Subject: bpf, mlx5: fix mlx5e_create_rq taking reference on prog In mlx5e_create_rq(), when creating a new queue, we call bpf_prog_add() but without checking the return value. bpf_prog_add() can fail since 92117d8443bc ("bpf: fix refcnt overflow"), so we really must check it. Take the reference right when we assign it to the rq from priv->xdp_prog, and just drop the reference on error path. Destruction in mlx5e_destroy_rq() looks good, though. Fixes: 86994156c736 ("net/mlx5e: XDP fast RX drop bpf programs support") Signed-off-by: Daniel Borkmann Acked-by: Saeed Mahameed Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 13 +++++++++---- kernel/bpf/syscall.c | 1 + 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index bd0732d5d219..54bae797b338 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -513,7 +513,13 @@ static int mlx5e_create_rq(struct mlx5e_channel *c, rq->channel = c; rq->ix = c->ix; rq->priv = c->priv; - rq->xdp_prog = priv->xdp_prog; + + rq->xdp_prog = priv->xdp_prog ? bpf_prog_inc(priv->xdp_prog) : NULL; + if (IS_ERR(rq->xdp_prog)) { + err = PTR_ERR(rq->xdp_prog); + rq->xdp_prog = NULL; + goto err_rq_wq_destroy; + } rq->buff.map_dir = DMA_FROM_DEVICE; if (rq->xdp_prog) @@ -590,12 +596,11 @@ static int mlx5e_create_rq(struct mlx5e_channel *c, rq->page_cache.head = 0; rq->page_cache.tail = 0; - if (rq->xdp_prog) - bpf_prog_add(rq->xdp_prog, 1); - return 0; err_rq_wq_destroy: + if (rq->xdp_prog) + bpf_prog_put(rq->xdp_prog); mlx5_wq_destroy(&rq->wq_ctrl); return err; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index ce1b7de7d72c..eb15498b8d55 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -696,6 +696,7 @@ struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) { return bpf_prog_add(prog, 1); } +EXPORT_SYMBOL_GPL(bpf_prog_inc); static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type) { -- cgit v1.2.3