detect memory leaks with mbedtls-3.5

[xuchao0915170]

Hi，

I built lws-4.3-stable with mbedtls-3.5.2, ASAN option OPEN.
When I ran the lws-minimal-ws-client-ping demo，I found a memory leak warning below:

Then I rebuilt the lws demo with mbedtls-3.2.1, the warning is gone, so I guess this is a new version adapting problem.
I tried several ways to fix it but failed, so I report this issue instead, hope it will help~

[lws-team]

Does the problem still exist on main branch? It sounds like an internal allocation from mbedtls side that either didn't used to exist or was freed somewhere else before exit on earlier versions.

There's this but doesn't seem like a great fit Mbed-TLS/mbedtls#3486

[xuchao0915170]

I tried the newest develop version(mbedtls-3.6), the memory leak still exists:

[lws-team]

This really seems like a change in mbedtls allocating something in its entropy function that now has to be freed in a step we didn't have to do on mbedtls earlier than 3.5. You're better off asking mbedtls since without a crystal ball we can't know that later versions of mbedtls than exist at the time we integrated them are later going to start doing that.

They should tell you that "you now need to free those allocations by calling xxx" and then you can provide a patch on lws to do that (preferably included after checking MBEDTLS version requires it).