Bug#330002: snmpd: agentx doesn't work properly on little endian 64 bit boxes

[dave medberry]

Package: snmpd
Version: 5.1.2-6.1
Severity: important
Tags: patch



-- System Information:
Debian Release: testing/unstable
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)
Kernel: Linux 2.6.6-dwm-2004060702
Locale: LANG=C, LC_CTYPE=C

Versions of packages snmpd depends on:
ii  libc6                       2.3.2.ds1-21 GNU C Library: Shared libraries an
ii  libsensors3                 1:2.9.1-1    library to read temperature/voltag
ii  libsnmp5                    5.1.2-5      NET SNMP (Simple Network Managemen
ii  libwrap0                    7.6.dbs-6    Wietse Venema's TCP wrappers libra

-- no debconf information


On an IA-64 (and believed to be other little endian 64 bit boxes),
agentx protocol is broken.  This was fixed just after 5.1.2 and there is
a patch available on net-snmp.sf.net (included here).  I'm not sure why
this has never been reported against this package.  It's fairly easy to
reproduce:  build net-snmp-5.1.2/agent/mibgroup/example/notification by
doing the following:
apt-get install snmpd
dpkg-source -x net-snmp_5.1.2-6.1.dsc
cd net-snmp-5.1.2/agent/mibgroup/examples
net-snmp-config --compile-subagent notification notification.c
#That will build the subagent
sudo ./notification
# Will start sending traps to /etc/snmp/snmpd.conf configured trap
# destinations.  You may want to add:
trap2sink localhost public
# to your /etc/snmp/snmpd.conf file and enable snmptrapd with
TRAPDRUN=yes
# in the /etc/default/snmpd configuration file.
# Then traps should begin appearing in /var/log/syslog every 30 seconds
# without the patch they do not, with the patch they do.
# You can also pass the -Dagentx flag in the SNMPDOPTS line of
# /etc/default/snmpd

--- agent/mibgroup/agentx/protocol.c.agentx-little64	2004-03-09 20:35:29.000000000 +0100
+++ agent/mibgroup/agentx/protocol.c	2004-07-23 11:41:55.189470590 +0200
@@ -1153,26 +1153,45 @@
     }
 
 
+#ifdef WORDS_BIGENDIAN
+# define endianoff 1
+#else
+# define endianoff 0
+#endif
     if (*length < 4 * n_subid) {
         DEBUGMSGTL(("agentx", "Incomplete Object ID"));
         return NULL;
     }
 
     if (prefix) {	 
-        if (sizeof(oid) == 8) {  	/* align OID values in 64 bit agent */  
-            int_ptr[0] = int_ptr[2] = int_ptr[4] = int_ptr[6] = int_ptr[8] = 0;
+        if (int_offset == 2) {  	/* align OID values in 64 bit agent */  
+	    memset(int_ptr, 0, 10*sizeof(int_ptr[0])); 
+	    int_ptr[0+endianoff] = 1;
+	    int_ptr[2+endianoff] = 3;
+	    int_ptr[4+endianoff] = 6;
+	    int_ptr[6+endianoff] = 1;
+	    int_ptr[8+endianoff] = prefix;
+        } else { /* assume int_offset == 1 */
+	    int_ptr[0] = 1;
+	    int_ptr[1] = 3;
+	    int_ptr[2] = 6;
+	    int_ptr[3] = 1;
+	    int_ptr[4] = prefix;
         }
-        int_ptr[int_offset - 1] = 1;
-        int_ptr[(int_offset * 2) - 1] = 3;
-        int_ptr[(int_offset * 3) - 1] = 6;
-        int_ptr[(int_offset * 4) - 1] = 1;
-        int_ptr[(int_offset * 5) - 1] = prefix;
         int_ptr = int_ptr + (int_offset * 5);
     }
 
     for (i = 0; i < (int) (int_offset * n_subid); i = i + int_offset) {
-        int_ptr[i] = 0;
-        int_ptr[i + (int_offset - 1)] = agentx_parse_int(buf_ptr, network_byte_order);
+	int x;
+
+	x = agentx_parse_int(buf_ptr, network_byte_order);
+	if (int_offset == 2) {
+            int_ptr[i+0] = 0;
+	    int_ptr[i+1] = 0;
+	    int_ptr[i+endianoff]=x;
+        } else {
+	    int_ptr[i] = x;
+        }
         buf_ptr += 4;
         *length -= 4;
     }