diff options
| author | Edward Cree <ecree@solarflare.com> | 2018-07-09 20:09:54 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-07-10 00:55:53 +0300 |
| commit | 8c057efaebb557b60ba514b5e39e8000a1eab0f1 (patch) | |
| tree | 9e179eec6b8563653162dc8c5d933b454e21dcfc /net | |
| parent | c47078d6a33fd78d882200cdaacbcfcd63318234 (diff) | |
| download | linux-8c057efaebb557b60ba514b5e39e8000a1eab0f1.tar.xz | |
net: core: fix uses-after-free in list processing
In netif_receive_skb_list_internal(), all of skb_defer_rx_timestamp(),
do_xdp_generic() and enqueue_to_backlog() can lead to kfree(skb). Thus,
we cannot wait until after they return to remove the skb from the list;
instead, we remove it first and, in the pass case, add it to a sublist
afterwards.
In the case of enqueue_to_backlog() we have already decided not to pass
when we call the function, so we do not need a sublist.
Fixes: 7da517a3bc52 ("net: core: Another step of skb receive list processing")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 89825c1eccdc..ce4583564e00 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4982,25 +4982,30 @@ static void netif_receive_skb_list_internal(struct list_head *head) { struct bpf_prog *xdp_prog = NULL; struct sk_buff *skb, *next; + struct list_head sublist; + INIT_LIST_HEAD(&sublist); list_for_each_entry_safe(skb, next, head, list) { net_timestamp_check(netdev_tstamp_prequeue, skb); - if (skb_defer_rx_timestamp(skb)) - /* Handled, remove from list */ - list_del(&skb->list); + list_del(&skb->list); + if (!skb_defer_rx_timestamp(skb)) + list_add_tail(&skb->list, &sublist); } + list_splice_init(&sublist, head); if (static_branch_unlikely(&generic_xdp_needed_key)) { preempt_disable(); rcu_read_lock(); list_for_each_entry_safe(skb, next, head, list) { xdp_prog = rcu_dereference(skb->dev->xdp_prog); - if (do_xdp_generic(xdp_prog, skb) != XDP_PASS) - /* Dropped, remove from list */ - list_del(&skb->list); + list_del(&skb->list); + if (do_xdp_generic(xdp_prog, skb) == XDP_PASS) + list_add_tail(&skb->list, &sublist); } rcu_read_unlock(); preempt_enable(); + /* Put passed packets back on main list */ + list_splice_init(&sublist, head); } rcu_read_lock(); @@ -5011,9 +5016,9 @@ static void netif_receive_skb_list_internal(struct list_head *head) int cpu = get_rps_cpu(skb->dev, skb, &rflow); if (cpu >= 0) { - enqueue_to_backlog(skb, cpu, &rflow->last_qtail); - /* Handled, remove from list */ + /* Will be handled, remove from list */ list_del(&skb->list); + enqueue_to_backlog(skb, cpu, &rflow->last_qtail); } } } |