[lwip-devel] [bug #35536] SNMP: error too big response is malformed

[Stephane Lesage]

URL:
  <http://savannah.nongnu.org/bugs/?35536>

                 Summary: SNMP: error too big response is malformed
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: slesage
            Submitted on: mer. 15 févr. 2012 22:07:19 CET
                Category: None
                Severity: 3 - Normal
              Item Group: Faulty Behaviour
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: 
            lwIP version: CVS Head

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Details:


I tested SNMP with various browsers, it seems to work globally fine, but my
firmwares crash on a "GET multiples variables".

After investigation, this comes from ASSERTs when
memp_malloc(MEMP_SNMP_VARBIND) or memp_malloc(MEMP_SNMP_VALUE) fails. These
asserts are not necessary because theses cases are handled and LWIP_DEBUG
messages are output.

After removing these asserts, Wireshark reports that the response is
malformed.
1. the error index must be 0 on error "too big", cf
http://tools.ietf.org/html/rfc1157

2. there are no variables bindings, while RFC states that the response must
return the same as the request

After fixing this, there's another error: the name of the correctly processed
variables are incorrect (could also happen on other errors)

The attached fixes all these issues.




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File Attachments:


-------------------------------------------------------
Date: mer. 15 févr. 2012 22:07:19 CET  Name:
0001-Fix-SNMP-response-for-error-too-big.patch  Size: 5 ko   By: slesage

<http://savannah.nongnu.org/bugs/download.php?file_id=25068>

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