4 files changed, 22 insertions, 9 deletions
diff --git a/include/net/ioam6.h b/include/net/ioam6.h
index 2cbbee6e806a..a75912fe247e 100644
--- a/include/net/ioam6.h
+++ b/include/net/ioam6.h
@@ -60,6 +60,8 @@ void ioam6_fill_trace_data(struct sk_buff *skb,
 			   struct ioam6_trace_hdr *trace,
 			   bool is_input);
 
+u8 ioam6_trace_compute_nodelen(u32 trace_type);
+
 int ioam6_init(void);
 void ioam6_exit(void);
 
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 209fdf1b1aa9..5e3610a926cf 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -931,6 +931,11 @@ static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
 		if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
 			goto drop;
 
+		/* Inconsistent Pre-allocated Trace header */
+		if (trace->nodelen !=
+		    ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32)))
+			goto drop;
+
 		/* Ignore if the IOAM namespace is unknown */
 		ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id);
 		if (!ns)
diff --git a/net/ipv6/ioam6.c b/net/ipv6/ioam6.c
index 9553a3200081..08b7ac8c99b7 100644
--- a/net/ipv6/ioam6.c
+++ b/net/ipv6/ioam6.c
@@ -690,6 +690,20 @@ struct ioam6_namespace *ioam6_namespace(struct net *net, __be16 id)
 	return rhashtable_lookup_fast(&nsdata->namespaces, &id, rht_ns_params);
 }
 
+#define IOAM6_MASK_SHORT_FIELDS 0xff1ffc00
+#define IOAM6_MASK_WIDE_FIELDS  0x00e00000
+
+u8 ioam6_trace_compute_nodelen(u32 trace_type)
+{
+	u8 nodelen = hweight32(trace_type & IOAM6_MASK_SHORT_FIELDS)
+				* (sizeof(__be32) / 4);
+
+	nodelen += hweight32(trace_type & IOAM6_MASK_WIDE_FIELDS)
+				* (sizeof(__be64) / 4);
+
+	return nodelen;
+}
+
 static void __ioam6_fill_trace_data(struct sk_buff *skb,
 				    struct ioam6_namespace *ns,
 				    struct ioam6_trace_hdr *trace,
diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c
index 1fe7894f14dd..b9f6d892a566 100644
--- a/net/ipv6/ioam6_iptunnel.c
+++ b/net/ipv6/ioam6_iptunnel.c
@@ -22,9 +22,6 @@
 #include <net/ip6_route.h>
 #include <net/addrconf.h>
 
-#define IOAM6_MASK_SHORT_FIELDS 0xff100000
-#define IOAM6_MASK_WIDE_FIELDS 0xe00000
-
 struct ioam6_lwt_encap {
 	struct ipv6_hopopt_hdr eh;
 	u8 pad[2];			/* 2-octet padding for 4n-alignment */
@@ -93,13 +90,8 @@ static bool ioam6_validate_trace_hdr(struct ioam6_trace_hdr *trace)
 	    trace->type.bit21 | trace->type.bit23)
 		return false;
 
-	trace->nodelen = 0;
 	fields = be32_to_cpu(trace->type_be32);
-
-	trace->nodelen += hweight32(fields & IOAM6_MASK_SHORT_FIELDS)
-				* (sizeof(__be32) / 4);
-	trace->nodelen += hweight32(fields & IOAM6_MASK_WIDE_FIELDS)
-				* (sizeof(__be64) / 4);
+	trace->nodelen = ioam6_trace_compute_nodelen(fields);
 
 	return true;
 }