1 files changed, 18 insertions, 33 deletions

diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 10e809b296ec..5c967764041f 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #define pr_fmt(fmt) "IPsec: " fmt
 
 #include <crypto/aead.h>
@@ -32,8 +33,6 @@ struct esp_output_extra {
 
 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
 
-static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
-
 /*
  * Allocate an AEAD request structure with extra space for SG and IV.
  *
@@ -226,7 +225,7 @@ static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
 	tail[plen - 1] = proto;
 }
 
-static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
+static int esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
 {
 	int encap_type;
 	struct udphdr *uh;
@@ -234,6 +233,7 @@ static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, stru
 	__be16 sport, dport;
 	struct xfrm_encap_tmpl *encap = x->encap;
 	struct ip_esp_hdr *esph = esp->esph;
+	unsigned int len;
 
 	spin_lock_bh(&x->lock);
 	sport = encap->encap_sport;
@@ -241,11 +241,14 @@ static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, stru
 	encap_type = encap->encap_type;
 	spin_unlock_bh(&x->lock);
 
+	len = skb->len + esp->tailen - skb_transport_offset(skb);
+	if (len + sizeof(struct iphdr) >= IP_MAX_MTU)
+		return -EMSGSIZE;
+
 	uh = (struct udphdr *)esph;
 	uh->source = sport;
 	uh->dest = dport;
-	uh->len = htons(skb->len + esp->tailen
-		  - skb_transport_offset(skb));
+	uh->len = htons(len);
 	uh->check = 0;
 
 	switch (encap_type) {
@@ -262,6 +265,8 @@ static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, stru
 
 	*skb_mac_header(skb) = IPPROTO_UDP;
 	esp->esph = esph;
+
+	return 0;
 }
 
 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
@@ -275,8 +280,12 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
 	int tailen = esp->tailen;
 
 	/* this is non-NULL only with UDP Encapsulation */
-	if (x->encap)
-		esp_output_udp_encap(x, skb, esp);
+	if (x->encap) {
+		int err = esp_output_udp_encap(x, skb, esp);
+
+		if (err < 0)
+			return err;
+	}
 
 	if (!skb_cloned(skb)) {
 		if (tailen <= skb_tailroom(skb)) {
@@ -495,7 +504,7 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 		u32 padto;
 
-		padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
+		padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
 		if (skb->len < padto)
 			esp.tfclen = padto - skb->len;
 	}
@@ -777,28 +786,6 @@ out:
 	return err;
 }
 
-static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
-{
-	struct crypto_aead *aead = x->data;
-	u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
-	unsigned int net_adj;
-
-	switch (x->props.mode) {
-	case XFRM_MODE_TRANSPORT:
-	case XFRM_MODE_BEET:
-		net_adj = sizeof(struct iphdr);
-		break;
-	case XFRM_MODE_TUNNEL:
-		net_adj = 0;
-		break;
-	default:
-		BUG();
-	}
-
-	return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
-		 net_adj) & ~(blksize - 1)) + net_adj - 2;
-}
-
 static int esp4_err(struct sk_buff *skb, u32 info)
 {
 	struct net *net = dev_net(skb->dev);
@@ -1024,7 +1011,6 @@ static const struct xfrm_type esp_type =
 	.flags		= XFRM_TYPE_REPLAY_PROT,
 	.init_state	= esp_init_state,
 	.destructor	= esp_destroy,
-	.get_mtu	= esp4_get_mtu,
 	.input		= esp_input,
 	.output		= esp_output,
 };
@@ -1055,8 +1041,7 @@ static void __exit esp4_fini(void)
 {
 	if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
 		pr_info("%s: can't remove protocol\n", __func__);
-	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
-		pr_info("%s: can't remove xfrm type\n", __func__);
+	xfrm_unregister_type(&esp_type, AF_INET);
 }
 
 module_init(esp4_init);