From: Petr Wozniak validate_xmit_xfrm() returns NULL both when a packet is dropped and when it is stolen by async crypto (-EINPROGRESS from ->xmit()). Callers cannot distinguish the two cases. f53c723902d1 ("net: Add asynchronous callbacks for xfrm on layer 2.") changed the semantics of a NULL return from "dropped" to "stolen or dropped", but __dev_queue_xmit() was not updated. On virtual/bridge interfaces (noqueue qdisc) __dev_queue_xmit() initialises rc=-ENOMEM and jumps to out: when skb is NULL, returning -ENOMEM to the caller even though the packet will be delivered correctly via xfrm_dev_resume(). Return ERR_PTR(-EINPROGRESS) from validate_xmit_xfrm() for the async case so callers can tell it apart from a real drop. Update __dev_queue_xmit() to handle ERR_PTR(-EINPROGRESS) from validate_xmit_skb() correctly. Update validate_xmit_skb_list() to use IS_ERR_OR_NULL() so that ERR_PTR(-EINPROGRESS) is not mistakenly added to the transmitted list. Fixes: f53c723902d1 ("net: Add asynchronous callbacks for xfrm on layer 2.") Suggested-by: Sabrina Dubroca Signed-off-by: Petr Wozniak Signed-off-by: Steffen Klassert --- net/core/dev.c | 10 ++++++++-- net/xfrm/xfrm_device.c | 4 ++-- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 4b3d5cfdf6e0..5933c5dab09e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4018,6 +4018,9 @@ static struct sk_buff *validate_xmit_unreadable_skb(struct sk_buff *skb, return NULL; } +/* Returns the skb on success, NULL if dropped, or ERR_PTR(-EINPROGRESS) + * if stolen by async xfrm crypto (delivered via xfrm_dev_resume()). + */ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device *dev, bool *again) { netdev_features_t features; @@ -4089,7 +4092,7 @@ struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *d skb->prev = skb; skb = validate_xmit_skb(skb, dev, again); - if (!skb) + if (IS_ERR_OR_NULL(skb)) continue; if (!head) @@ -4860,8 +4863,11 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) goto recursion_alert; skb = validate_xmit_skb(skb, dev, &again); - if (!skb) + if (IS_ERR_OR_NULL(skb)) { + if (PTR_ERR(skb) == -EINPROGRESS) + rc = NET_XMIT_SUCCESS; goto out; + } HARD_TX_LOCK(dev, txq, cpu); diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c index 630f3dd31cc5..19c77f09acc9 100644 --- a/net/xfrm/xfrm_device.c +++ b/net/xfrm/xfrm_device.c @@ -182,7 +182,7 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur err = x->type_offload->xmit(x, skb, esp_features); if (err) { if (err == -EINPROGRESS) - return NULL; + return ERR_PTR(-EINPROGRESS); XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); kfree_skb(skb); @@ -224,7 +224,7 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur pskb = skb2; } - return skb; + return skb ? skb : ERR_PTR(-EINPROGRESS); } EXPORT_SYMBOL_GPL(validate_xmit_xfrm); -- 2.43.0