File 1161-snmp-Handle-failed-vacm-lookup.patch of Package erlang

From 36c391a01f70840cb01281c7ef1ebb7a48bd55a0 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Tue, 3 Jan 2023 18:10:07 +0100
Subject: [PATCH 1/2] [snmp] Handle failed vacm lookup

Handle when we fail to lookup info (mask, type and status)
from the vacmViewTreeFamilyTable table. If this happens, we
will throw noSuchView (instead of crashing).

OTP-18379
---
 lib/snmp/src/agent/snmpa_vacm.erl | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/lib/snmp/src/agent/snmpa_vacm.erl b/lib/snmp/src/agent/snmpa_vacm.erl
index d7d588c30d..93850c31a6 100644
--- a/lib/snmp/src/agent/snmpa_vacm.erl
+++ b/lib/snmp/src/agent/snmpa_vacm.erl
@@ -142,12 +142,16 @@ split_prefix(_, _) -> false.
 
 %% ViewName is including length from now on
 loop_mib_view(ViewName, Subtree, Indexes, MibView) ->
-    [{value, Mask}, {value, Type}, {value, Status}] = 
-	snmp_view_based_acm_mib:vacmViewTreeFamilyTable(
-	  get, Indexes,
-	  [?vacmViewTreeFamilyMask, 
-	   ?vacmViewTreeFamilyType,
-	   ?vacmViewTreeFamilyStatus]),
+    {Mask, Type, Status} =
+        case loop_mib_view_get(Indexes) of
+            [{value, M}, {value, T}, {value, S}] ->
+                {M, T, S};
+            Else ->
+                ?vinfo("Failed vacmViewTreeFamilyTable lookup:"
+                       "~n      Indexes: ~p"
+                       "~n      Result:  ~p", [Indexes, Else]),
+                exit(noSuchView)
+        end,
     NextMibView = 
 	case Status of
 	    ?'RowStatus_active' ->
@@ -169,6 +173,13 @@ loop_mib_view(ViewName, Subtree, Indexes, MibView) ->
 	    end
     end.
 
+loop_mib_view_get(Indexes) ->
+    Cols = [?vacmViewTreeFamilyMask, 
+            ?vacmViewTreeFamilyType,
+            ?vacmViewTreeFamilyStatus],
+    snmp_view_based_acm_mib:vacmViewTreeFamilyTable(get, Indexes, Cols).
+
+
 %%%-----------------------------------------------------------------
 %%%  1b.  The ordered ets table that implements vacmAccessTable
 %%%-----------------------------------------------------------------
-- 
2.35.3