From 3cdb7781aca3cfff24485f7a9dbe704a4824d5e1 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Mon, 13 Aug 2012 14:42:00 +0200
Subject: [snmp] Add bug compatible fixes to TimeTicks decode

Add handling of incorrectly encoded TimeTicks and Unsigned32.
---
 lib/snmp/src/misc/snmp_pdus.erl | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

(limited to 'lib/snmp/src')

diff --git a/lib/snmp/src/misc/snmp_pdus.erl b/lib/snmp/src/misc/snmp_pdus.erl
index e15be4a298..5b8be90a71 100644
--- a/lib/snmp/src/misc/snmp_pdus.erl
+++ b/lib/snmp/src/misc/snmp_pdus.erl
@@ -298,22 +298,30 @@ dec_value([65 | Bytes]) ->
 %% Unsigned32
 dec_value([66 | Bytes]) ->
     {Value, Rest} = dec_integer_notag(Bytes),
-    if 
-	(Value >= 0) andalso (Value =< 16#ffffffff) ->
-    	    {{'Unsigned32', Value}, Rest};
-    	true ->
-    	    exit({error, {bad_unsigned32, Value}})
-    end;
+    Value2 = 
+	if 
+	    (Value >= 0) andalso (Value =< 16#ffffffff) ->
+		Value;
+	    (Value < 0) ->
+		16#ffffffff + Value + 1;
+	    true ->
+		exit({error, {bad_unsigned32, Value}})
+	end,
+    {{'Unsigned32', Value2}, Rest};
 
 %% TimeTicks
 dec_value([67 | Bytes]) ->
     {Value, Rest} = dec_integer_notag(Bytes),
-    if
-	(Value >= 0) andalso (Value =< 16#ffffffff) ->
-	    {{'TimeTicks', Value}, Rest};
+    Value2 = 
+	if
+	    (Value >= 0) andalso (Value =< 16#ffffffff) ->
+		Value;
+	    (Value < 0) ->
+		16#ffffffff + Value + 1;
 	true ->
 	    exit({error, {bad_timeticks, Value}})
-    end;
+	end,
+    {{'TimeTicks', Value2}, Rest};
 
 %% Opaque
 dec_value([68 | Bytes]) ->
-- 
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