From 592e355519229762905bac128be31e7982e45875 Mon Sep 17 00:00:00 2001
From: Dan Kortschak <90160302+efd6@users.noreply.github.com>
Date: Tue, 11 Jul 2023 06:32:16 +0930
Subject: [PATCH] filebeat/input/{tcp,udp}: use correct address list in udp
 (#35996)

Also add a check in the common path to check that the addr slice is the
same length as the undefined addr slice, returning an error on mismatch
rather than allowing the panic.
---
 CHANGELOG.next.asciidoc     | 1 +
 filebeat/input/tcp/input.go | 3 +++
 filebeat/input/udp/input.go | 7 +++++--
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.next.asciidoc b/CHANGELOG.next.asciidoc
index e2cd47b2909c..04a63cc62a3b 100644
--- a/CHANGELOG.next.asciidoc
+++ b/CHANGELOG.next.asciidoc
@@ -145,6 +145,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Fix metric collection in GCPPubSub input. {pull}35773[35773]
 - Fix end point deregistration in http_endpoint input. {issue}35899[35899] {pull}35903[35903]
 - Fix duplicate ID panic in filestream metrics. {issue}35964[35964] {pull}35972[35972]
+- Improve error reporting and fix IPv6 handling of TCP and UDP metric collection. {pull}35996[35996]
 
 *Heartbeat*
 
diff --git a/filebeat/input/tcp/input.go b/filebeat/input/tcp/input.go
index bd15e1560c82..7911123a86ed 100644
--- a/filebeat/input/tcp/input.go
+++ b/filebeat/input/tcp/input.go
@@ -338,6 +338,9 @@ func procNetTCP(path string, addr []string, hasUnspecified bool, addrIsUnspecifi
 	if len(addr) == 0 {
 		return 0, nil
 	}
+	if len(addr) != len(addrIsUnspecified) {
+		return 0, errors.New("mismatched address/unspecified lists: please report this")
+	}
 	b, err := os.ReadFile(path)
 	if err != nil {
 		return 0, err
diff --git a/filebeat/input/udp/input.go b/filebeat/input/udp/input.go
index f6f2536614a0..c250089b8aa8 100644
--- a/filebeat/input/udp/input.go
+++ b/filebeat/input/udp/input.go
@@ -272,7 +272,7 @@ func (m *inputMetrics) poll(addr, addr6 []string, each time.Duration, log *logp.
 	if err != nil {
 		log.Warnf("failed to get initial udp stats from /proc: %v", err)
 	}
-	rx6, drops6, err := procNetUDP("/proc/net/udp6", addr, hasUnspecified6, addrIsUnspecified6)
+	rx6, drops6, err := procNetUDP("/proc/net/udp6", addr6, hasUnspecified6, addrIsUnspecified6)
 	if err != nil {
 		log.Warnf("failed to get initial udp6 stats from /proc: %v", err)
 	}
@@ -288,7 +288,7 @@ func (m *inputMetrics) poll(addr, addr6 []string, each time.Duration, log *logp.
 				log.Warnf("failed to get udp stats from /proc: %v", err)
 				continue
 			}
-			rx6, drops6, err := procNetUDP("/proc/net/udp6", addr, hasUnspecified6, addrIsUnspecified6)
+			rx6, drops6, err := procNetUDP("/proc/net/udp6", addr6, hasUnspecified6, addrIsUnspecified6)
 			if err != nil {
 				log.Warnf("failed to get udp6 stats from /proc: %v", err)
 				continue
@@ -333,6 +333,9 @@ func procNetUDP(path string, addr []string, hasUnspecified bool, addrIsUnspecifi
 	if len(addr) == 0 {
 		return 0, 0, nil
 	}
+	if len(addr) != len(addrIsUnspecified) {
+		return 0, 0, errors.New("mismatched address/unspecified lists: please report this")
+	}
 	b, err := os.ReadFile(path)
 	if err != nil {
 		return 0, 0, err