diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 395d82411a87..589c3b6e4679 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -3114,10 +3114,14 @@ u32 xfrm_state_mtu(struct xfrm_state *x, int mtu)
 	const struct xfrm_type *type = READ_ONCE(x->type);
 	struct crypto_aead *aead;
 	u32 blksize, net_adj = 0;
+	u32 overhead, payload_mtu;
 
 	if (x->km.state != XFRM_STATE_VALID ||
-	    !type || type->proto != IPPROTO_ESP)
+	    !type || type->proto != IPPROTO_ESP) {
+		if (mtu <= x->props.header_len)
+			return 1;
 		return mtu - x->props.header_len;
+	}
 
 	aead = x->data;
 	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
@@ -3140,8 +3144,17 @@ u32 xfrm_state_mtu(struct xfrm_state *x, int mtu)
 		break;
 	}
 
-	return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
-		 net_adj) & ~(blksize - 1)) + net_adj - 2;
+	overhead = x->props.header_len + crypto_aead_authsize(aead) + net_adj;
+	if (mtu <= overhead)
+		return 1;
+
+	payload_mtu = mtu - overhead;
+	payload_mtu &= ~(blksize - 1);
+	if (payload_mtu <= 2)
+		return 1;
+
+	return payload_mtu + net_adj - 2;
+
 }
 EXPORT_SYMBOL_GPL(xfrm_state_mtu);