Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2022-04-27

We've added 5 non-merge commits during the last 20 day(s) which contain
a total of 6 files changed, 34 insertions(+), 12 deletions(-).

The main changes are:

1) Fix xsk sockets when rx and tx are separately bound to the same umem, also
   fix xsk copy mode combined with busy poll, from Maciej Fijalkowski.

2) Fix BPF tunnel/collect_md helpers with bpf_xmit lwt hook usage which triggered
   a crash due to invalid metadata_dst access, from Eyal Birger.

3) Fix release of page pool in XDP live packet mode, from Toke Høiland-Jørgensen.

4) Fix potential NULL pointer dereference in kretprobes, from Adam Zabrocki.

   (Masami & Steven preferred this small fix to be routed via bpf tree given it's
    follow-up fix to Masami's rethook work that went via bpf earlier, too.)

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  xsk: Fix possible crash when multiple sockets are created
  kprobes: Fix KRETPROBES when CONFIG_KRETPROBE_ON_RETHOOK is set
  bpf, lwt: Fix crash when using bpf_skb_set_tunnel_key() from bpf_xmit lwt hook
  bpf: Fix release of page_pool in BPF_PROG_RUN in test runner
  xsk: Fix l2fwd for copy mode + busy poll combo
====================

Link: https://lore.kernel.org/r/20220427212748.9576-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index 349480ef68a5..8b6b5e72b217 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -159,10 +159,8 @@ static int bpf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 	return dst->lwtstate->orig_output(net, sk, skb);
 }
 
-static int xmit_check_hhlen(struct sk_buff *skb)
+static int xmit_check_hhlen(struct sk_buff *skb, int hh_len)
 {
-	int hh_len = skb_dst(skb)->dev->hard_header_len;
-
 	if (skb_headroom(skb) < hh_len) {
 		int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
 
@@ -274,6 +272,7 @@ static int bpf_xmit(struct sk_buff *skb)
 
 	bpf = bpf_lwt_lwtunnel(dst->lwtstate);
 	if (bpf->xmit.prog) {
+		int hh_len = dst->dev->hard_header_len;
 		__be16 proto = skb->protocol;
 		int ret;
 
@@ -291,7 +290,7 @@ static int bpf_xmit(struct sk_buff *skb)
 			/* If the header was expanded, headroom might be too
 			 * small for L2 header to come, expand as needed.
 			 */
-			ret = xmit_check_hhlen(skb);
+			ret = xmit_check_hhlen(skb, hh_len);
 			if (unlikely(ret))
 				return ret;