Merge tag 'ipsec-next-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2023-10-28

1) Remove unused function declarations of xfrm4_extract_input and
   xfrm6_extract_input. From Yue Haibing.

2) Annotate struct xfrm_sec_ctx with __counted_by.
   From Kees Cook.

3) Support GRO decapsulation for ESP in UDP encapsulation.
   From Antony Antony et all.

4) Replace the xfrm session decode with flow dissector.
   From Florian Westphal.

5) Fix a use after free in __xfrm6_udp_encap_rcv.

6) Fix the layer 4 flowi decoding.
   From Florian Westphal.

* tag 'ipsec-next-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next:
  xfrm: policy: fix layer 4 flowi decoding
  xfrm Fix use after free in __xfrm6_udp_encap_rcv.
  xfrm: policy: replace session decode with flow dissector
  xfrm: move mark and oif flowi decode into common code
  xfrm: pass struct net to xfrm_decode_session wrappers
  xfrm: Support GRO for IPv6 ESP in UDP encapsulation
  xfrm: Support GRO for IPv4 ESP in UDP encapsulation
  xfrm: Use the XFRM_GRO to indicate a GRO call on input
  xfrm: Annotate struct xfrm_sec_ctx with __counted_by
  xfrm: Remove unused function declarations
====================

Link: https://lore.kernel.org/r/20231028084328.3119236-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 77 insertions, 18 deletions

diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 183f6dc37242..c54676998eb6 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -17,6 +17,8 @@
 #include <linux/netfilter_ipv4.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
+#include <net/protocol.h>
+#include <net/gro.h>
 
 static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
 				   struct sk_buff *skb)
@@ -72,14 +74,7 @@ int xfrm4_transport_finish(struct sk_buff *skb, int async)
 	return 0;
 }
 
-/* If it's a keepalive packet, then just eat it.
- * If it's an encapsulated packet, then pass it to the
- * IPsec xfrm input.
- * Returns 0 if skb passed to xfrm or was dropped.
- * Returns >0 if skb should be passed to UDP.
- * Returns <0 if skb should be resubmitted (-ret is protocol)
- */
-int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
+static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
 {
 	struct udp_sock *up = udp_sk(sk);
 	struct udphdr *uh;
@@ -110,7 +105,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	case UDP_ENCAP_ESPINUDP:
 		/* Check if this is a keepalive packet.  If so, eat it. */
 		if (len == 1 && udpdata[0] == 0xff) {
-			goto drop;
+			return -EINVAL;
 		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
 			/* ESP Packet without Non-ESP header */
 			len = sizeof(struct udphdr);
@@ -121,7 +116,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	case UDP_ENCAP_ESPINUDP_NON_IKE:
 		/* Check if this is a keepalive packet.  If so, eat it. */
 		if (len == 1 && udpdata[0] == 0xff) {
-			goto drop;
+			return -EINVAL;
 		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
 			   udpdata32[0] == 0 && udpdata32[1] == 0) {
 
@@ -139,7 +134,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	 * protocol to ESP, and then call into the transform receiver.
 	 */
 	if (skb_unclone(skb, GFP_ATOMIC))
-		goto drop;
+		return -EINVAL;
 
 	/* Now we can update and verify the packet length... */
 	iph = ip_hdr(skb);
@@ -147,25 +142,89 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	iph->tot_len = htons(ntohs(iph->tot_len) - len);
 	if (skb->len < iphlen + len) {
 		/* packet is too small!?! */
-		goto drop;
+		return -EINVAL;
 	}
 
 	/* pull the data buffer up to the ESP header and set the
 	 * transport header to point to ESP.  Keep UDP on the stack
 	 * for later.
 	 */
-	__skb_pull(skb, len);
-	skb_reset_transport_header(skb);
+	if (pull) {
+		__skb_pull(skb, len);
+		skb_reset_transport_header(skb);
+	} else {
+		skb_set_transport_header(skb, len);
+	}
 
 	/* process ESP */
-	return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
-
-drop:
-	kfree_skb(skb);
 	return 0;
 }
+
+/* If it's a keepalive packet, then just eat it.
+ * If it's an encapsulated packet, then pass it to the
+ * IPsec xfrm input.
+ * Returns 0 if skb passed to xfrm or was dropped.
+ * Returns >0 if skb should be passed to UDP.
+ * Returns <0 if skb should be resubmitted (-ret is protocol)
+ */
+int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	int ret;
+
+	ret = __xfrm4_udp_encap_rcv(sk, skb, true);
+	if (!ret)
+		return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
+				       udp_sk(sk)->encap_type);
+
+	if (ret < 0) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	return ret;
+}
 EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
 
+struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
+					struct sk_buff *skb)
+{
+	int offset = skb_gro_offset(skb);
+	const struct net_offload *ops;
+	struct sk_buff *pp = NULL;
+	int ret;
+
+	offset = offset - sizeof(struct udphdr);
+
+	if (!pskb_pull(skb, offset))
+		return NULL;
+
+	rcu_read_lock();
+	ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
+	if (!ops || !ops->callbacks.gro_receive)
+		goto out;
+
+	ret = __xfrm4_udp_encap_rcv(sk, skb, false);
+	if (ret)
+		goto out;
+
+	skb_push(skb, offset);
+	NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
+
+	pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
+	rcu_read_unlock();
+
+	return pp;
+
+out:
+	rcu_read_unlock();
+	skb_push(skb, offset);
+	NAPI_GRO_CB(skb)->same_flow = 0;
+	NAPI_GRO_CB(skb)->flush = 1;
+
+	return NULL;
+}
+EXPORT_SYMBOL(xfrm4_gro_udp_encap_rcv);
+
 int xfrm4_rcv(struct sk_buff *skb)
 {
 	return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);