Re: Memory Leak bug in net-snmp-5.6.2.1, in the procedure snmpv3_parse()

[John Zavgren]

Dear List:




I'm sorry for any confusion or consternation I may have created. :-(

JZ
On 03/12/2014 10:55 AM, John Zavgren wrote:

Let me apologize... the "memory leak" that I reported, IS NOT a memory leak. I should have read my email carefully before sending it.

Greetings:


*/***
**     * securtityParameters OCTET STRING begins after msgGlobalData **
**     */**
**    sec_params = data;**

**    pdu->contextEngineIDLen = SNMP_MAX_ENG_SIZE;**
**
**    /***

**     * limit).  We'll use double that here to be on the safe side. **
**     */**
**

**    pdu->securityEngineIDLen = SNMP_MAX_ENG_SIZE * 2;**
**    pdu->securityName = (char *) calloc(1, SNMP_MAX_SEC_NAME_SIZE);**
**    pdu->securityNameLen = SNMP_MAX_SEC_NAME_SIZE;*

The fix seems obvious, just delete the first allocation?



    *jzavgren@SNMPTest:~/code/net-snmp-5.7.2.1$ make**
    **making all in /home/jzavgren/code/net-snmp-5.7.2.1/snmplib**
    **make[1]: Entering directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/snmplib'**
    **make[1]: Leaving directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/snmplib'**
    **making all in /home/jzavgren/code/net-snmp-5.7.2.1/agent**
    **make[1]: Entering directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/agent'**
    **making all in /home/jzavgren/code/net-snmp-5.7.2.1/agent/helpers**
    **make[2]: Entering directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/agent/helpers'**
    **make[2]: Leaving directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/agent/helpers'**
    **making all in /home/jzavgren/code/net-snmp-5.7.2.1/agent/mibgroup**
    **make[2]: Entering directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/agent/mibgroup'**
    **make[2]: Leaving directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/agent/mibgroup'**
    **/bin/bash ../libtool  --mode=link gcc -fno-strict-aliasing -g
    -O2 -Ulinux -Dlinux=linux -D_REENTRANT -D_GNU_SOURCE -DDEBIAN
    -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include
    -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64
    -I/usr/lib/perl/5.14/CORE   -o snmpd snmpd.lo libnetsnmpagent.la
    libnetsnmpmibs.la ../snmplib/libnetsnmp.la -lm  -Wl,-E **
    **libtool: link: gcc -fno-strict-aliasing -g -O2 -Ulinux
    -Dlinux=linux -D_REENTRANT -D_GNU_SOURCE -DDEBIAN
    -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include
    -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64

    -L/usr/lib/perl/5.14/CORE ./.libs/libnetsnmpmibs.so
    /home/jzavgren/code/net-snmp-5.7.2.1/agent/.libs/libnetsnmpagent.so 
/home/jzavgren/code/net-snmp-5.7.2.1/snmplib/.libs/libnetsnmp.so
    -lperl -ldl -lpthread -lc -lcrypt ../snmplib/.libs/libnetsnmp.so
    -lrt -lcrypto -lm  -Wl,-rpath -Wl,//lib**
    **./.libs/libnetsnmpagent.so: undefined reference to
    `netsnmp_udp6_parse_security'**
    **./.libs/libnetsnmpagent.so: undefined reference to
    `netsnmp_UDPIPv6Domain'**
    **./.libs/libnetsnmpagent.so: undefined reference to
    `netsnmp_udp6_getSecName'**
    **./.libs/libnetsnmpagent.so: undefined reference to
    `netsnmp_TCPIPv6Domain'**
    **collect2: ld returned 1 exit status**
    **make[1]: *** [snmpd] Error 1**
    **make[1]: Leaving directory
    `/home/jzavgren/code/net-snmp-5.7.2.1/agent'**
    **make: *** [subdirs] Error 1**
    *


--
Dr. John Zavgren, Cyber Systems and Technology Group
voice: 781-981-8236
email:john.zavg...@ll.mit.edu
MIT Lincoln Laboratory
244 Wood Street
Lexington, MA 02420-9185

Memory is allocated in the procedure snmv3_parse(), in the file: snmplib/snmp_api.c, at line number 3995, and leaked at line number 4004. ** pdu->contextEngineID = (u_char *) calloc(1, SNMP_MAX_ENG_SIZE); <----- MEMORY ALLOCATED HERE** ** * Note: there is no length limit on the msgAuthoritativeEngineID field,** ** * although we would EXPECT it to be limited to 32 (the SnmpEngineID TC** ** pdu->securityEngineID = (u_char *) calloc(1, SNMP_MAX_ENG_SIZE * 2);<------ MEMORY LEAKED HERE** The bug is present in the 5-7.2.1 version too, but I'm not using that at the moment because it won't compile on my Ubuntu 12.04 machine: -I/usr/lib/perl/5.14/CORE -o .libs/snmpd .libs/snmpd.o -Wl,-E ./.libs/libnetsnmpagent.so -L/usr/local/lib www:http://www.ll.mit.edu/CST

--
Dr. John Zavgren, Cyber Systems and Technology Group
voice: 781-981-8236
email: john.zavg...@ll.mit.edu
MIT Lincoln Laboratory
244 Wood Street
Lexington, MA 02420-9185
www: http://www.ll.mit.edu/CST

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