Hello Alan and thanks for your response. You're absolutely right, I need to go back for more research and code review :) Regards, Hadi On Mon, Jan 6, 2025 at 5:34 PM Alan DeKok <aland@deployingradius.com> wrote:
On Jan 5, 2025, at 2:37 PM, Hadi Rezaee <rezaee.hadi@gmail.com> wrote:
I'm trying to figure out how MS-MPPE-Send-Key and MS-MPPE-Recv-Key are getting generated by freeradius-server.
The short answer is "read the RFCs and the code"
Here, it is the sample captured traffic I've for a MS-CHAPv2 (Access-Accept) auth between a radius client and server: MS-MPPE-Recv-Key: a660ce53f31ef08ed6cf209ece137a1dee40aeae5d8e5b9de0f1592324bc92569fc1 MS-MPPE-Send-Key: a81579eb58f0bd25636599778c8689516129db8b25ec2d1e4c15797862efedabb3c
Those are just random values. They don't mean anything.
Correct me if I'm wrong but here I read " mppe_sendkey" and " mppe_recvkey" variables are initialized with 34 bytes (as i expected!), but later by calling mppe_chap2_gen_keys128 only 16 bytes are copied. I was expecting other items (such as 'Salt') to be taken into account too ..
To be honest, I haven't looked at that code in a long time. If it's generating 34-byte keys, then it works. Which means that your reading of the code is wrong.
If you want to know what the code is doing, use a debugger like gdb to step through it.
Alan DeKok.
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