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versat / cntlm

Cntlm is an NTLM / NTLM Session Response / NTLMv2 authenticating HTTP proxy intended to help you break free from the chains of Microsoft proprietary world. More info on http://cntlm.sourceforge.net/ website. This version also supports: SSPI (on Windows, NTLM authentication only), Kerberos authentication, IPv6, proxy PAC files.
GNU General Public License v2.0
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cntlm crashed in sparc solaris 11 #93

Open yfchua opened 8 months ago

yfchua commented 8 months ago

when the cntlm is running in threading mode, and accessing the https website. the cntlm will crash with memory fault.

when the cntlm is running in serial mode, and accessing the https website, it is running ok,

this only happen after there is change of proxy. this is sparc solaris 11, i run ./configure, gmake to make binary.

THank you

fralken commented 8 months ago

Hello @yfchua, can you elaborate better your use case? I guess the issue is "this only happen after there is change of proxy". This can be due to a race condition. Are you using a pac file? What is the sequence of operations that cause the fault?

yfchua commented 8 months ago

I run the cntlm. Cntlm connect to my company blue coat proxy. I set the https_proxy=http://localhost:3128 I run curl https://wew.google.com Cntlm crashed with Bus error

Sending PROXY auth request… Host => www.google.com … … … Reading PROXY auth response… HEAD: HTTP/1.1 407 Proxy Authentication Required …. … … NTLM Challenge: Challenge: …. …. …. ….

NTLMv2: Nonce:27CB870A54274EF3 Timestamp: 31082536

Bus error

yfchua commented 8 months ago

According to internet , bus error occur when a process is trying to access memory cpu cannot physically access.

This only happens after the proxy was upgraded. Cntlm is running fine before proxy upgrade

fralken commented 8 months ago

So the issue happens after an upgrade of the remote proxy, while before this upgrade everything worked fine. It looks like something changed in the NTLM challenge phase. Can you test Cntlm on a windows or mac or linux machine? Just to check if the problem is related to Solaris. This scenario is very difficult to replicate, you could try and debugging it yourself.

yfchua commented 8 months ago

Hi It only happen on the Solaris sparc server. It does not happen on the x86 Linux server. I not a c programmer, so it is hard for me to debug.

fralken commented 8 months ago

Ok, then it is an issue of Sparc Solaris only. Maybe it is related to the cpu endianness. Is it big endian? What is the output of ./configure?

yfchua commented 8 months ago

It is big endian

fralken commented 8 months ago

Can you try this branch on my repo?

git clone -b nonce-endianness https://github.com/fralken/cntlm.git

I guess the nonce is not correctly passed to the NTLM token in case of big endian.

yfchua commented 8 months ago

Hi Thank for the help I will clone it and test it asap

yfchua commented 8 months ago

Unfortunately the fix for the big endian did not work I captured the core dump and did a backtrack please refer to the screen capture IMG_3751

fralken commented 8 months ago

Hello, unfortunately this dump is not helpful, it doesn't show where the program crashed.

Just to understand, you said that cntlm worked until the remote proxy was upgraded. What was the change? which authentication method used the old proxy? The new proxy uses NTLMv2.

This is probably a problem of uint32 alignment.

Also, which compiler are you using? gcc, clang?

Can you try again with this repo? git clone -b nonce-endianness https://github.com/fralken/cntlm.git