<p></p>
<p dir="auto"><a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/henningw/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/henningw">@henningw</a>, the problem could appears not only on FreeBSD environment, but on any ASLR environment.</p>
<p dir="auto">I've wrote a test case for the regression close to Kamailio behavior:</p>
<p dir="auto"><em>libtest.c</em>:</p>
<div class="highlight highlight-source-c"><pre>#<span class="pl-k">include</span> <span class="pl-s"><span class="pl-pds">"</span>modules.h<span class="pl-pds">"</span></span>

<span class="pl-k">static</span> <span class="pl-k">char</span> *str= <span class="pl-s"><span class="pl-pds">"</span>app_lua<span class="pl-pds">"</span></span>;

<span class="pl-k">int</span> <span class="pl-en">mod_register</span>()
{
  <span class="pl-c1">modules_add</span>(str);

  <span class="pl-k">return</span> <span class="pl-c1">0</span>;
}</pre></div>
<p dir="auto"><em>modules.c</em>:</p>
<div class="highlight highlight-source-c"><pre>#<span class="pl-k">include</span> <span class="pl-s"><span class="pl-pds"><</span>stdio.h<span class="pl-pds">></span></span>

<span class="pl-k">void</span> <span class="pl-en">modules_add</span>(<span class="pl-k">char</span> *msg)
{
  <span class="pl-c1">printf</span>(<span class="pl-s"><span class="pl-pds">"</span>modules_add(<span class="pl-c1">%p</span>): <span class="pl-c1">%s</span><span class="pl-cce">\n</span><span class="pl-pds">"</span></span>, msg, msg);
}</pre></div>
<p dir="auto"><em>main.c</em>:</p>
<div class="highlight highlight-source-c"><pre>#<span class="pl-k">include</span> <span class="pl-s"><span class="pl-pds"><</span>stdio.h<span class="pl-pds">></span></span>
#<span class="pl-k">include</span> <span class="pl-s"><span class="pl-pds"><</span>dlfcn.h<span class="pl-pds">></span></span>
#<span class="pl-k">include</span> <span class="pl-s"><span class="pl-pds">"</span>modules.h<span class="pl-pds">"</span></span>

<span class="pl-k">typedef</span> <span class="pl-en">int</span> (*mod_register_function)();

<span class="pl-k">int</span> <span class="pl-en">testlib</span>(<span class="pl-k">int</span> num) {
  mod_register_function mr;
  <span class="pl-k">char</span>* error;

  <span class="pl-k">void</span>* h = <span class="pl-c1">dlopen</span>(<span class="pl-s"><span class="pl-pds">"</span>libtest.so<span class="pl-pds">"</span></span>, RTLD_NOW);
  <span class="pl-k">if</span> (h == <span class="pl-c1">0</span>) {
    <span class="pl-c1">printf</span>(<span class="pl-s"><span class="pl-pds">"</span>Error loading<span class="pl-cce">\n</span><span class="pl-pds">"</span></span>);
    <span class="pl-k">return</span> <span class="pl-c1">1</span>;
  }
  <span class="pl-c1">dlerror</span>();
  mr = (mod_register_function)<span class="pl-c1">dlsym</span>(h, <span class="pl-s"><span class="pl-pds">"</span>mod_register<span class="pl-pds">"</span></span>);
  <span class="pl-k">if</span> ((error = (<span class="pl-k">char</span>*)<span class="pl-c1">dlerror</span>()) != <span class="pl-c1">0</span>) {
    <span class="pl-c1">printf</span>(<span class="pl-s"><span class="pl-pds">"</span>dlsym error: <span class="pl-c1">%s</span><span class="pl-cce">\n</span><span class="pl-pds">"</span></span>, error);
    <span class="pl-k">return</span> <span class="pl-c1">1</span>;
  }
  <span class="pl-c1">printf</span>(<span class="pl-s"><span class="pl-pds">"</span>Call mod_register() #<span class="pl-c1">%d</span>: <span class="pl-pds">"</span></span>, num);
  <span class="pl-c1">mr</span>();
  <span class="pl-c1">dlclose</span>(h);

  <span class="pl-k">return</span> <span class="pl-c1">0</span>;
}

<span class="pl-k">int</span> <span class="pl-en">main</span>()
{
  <span class="pl-k">int</span> err;
  err = <span class="pl-c1">testlib</span>(<span class="pl-c1">1</span>);
  <span class="pl-k">if</span> (err != <span class="pl-c1">0</span>) <span class="pl-k">return</span> err;

  err = <span class="pl-c1">testlib</span>(<span class="pl-c1">2</span>);
  <span class="pl-k">if</span> (err != <span class="pl-c1">0</span>) <span class="pl-k">return</span> err;

  <span class="pl-k">return</span> <span class="pl-c1">0</span>;
}</pre></div>
<p dir="auto">And ran it on non-ASLR and ASLR environment:<br>
<em>non-ASLR</em>:</p>
<pre class="notranslate"><code class="notranslate">boris@boris:~/aslr_test% ./aslr_test
Call mod_register() #1: modules_add(0x800646528): app_lua
Call mod_register() #2: modules_add(0x800646528): app_lua
</code></pre>
<p dir="auto"><em>ASLR</em>:</p>
<pre class="notranslate"><code class="notranslate">boris@boris:~/aslr_test% ./aslr_test
Call mod_register() #1: modules_add(0x825abc528): app_lua
Call mod_register() #2: modules_add(0x825bfe528): app_lua
</code></pre>
<p dir="auto">And how can we see: <code class="notranslate">str</code> address is changed on ASLR environment, and we cannot use it after reloading library.</p>
<p dir="auto">I suppose using static variable after reloading library is incorrect way.</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br />Reply to this email directly, <a href="https://github.com/kamailio/kamailio/issues/3202#issuecomment-1204917683">view it on GitHub</a>, or <a href="https://github.com/notifications/unsubscribe-auth/ABO7UZOXRONQG3W4MVKMZCDVXN3SPANCNFSM54YZSKCA">unsubscribe</a>.<br />You are receiving this because you are subscribed to this thread.<img src="https://github.com/notifications/beacon/ABO7UZJCS5MMEUQOATBVJQTVXN3SPA5CNFSM54YZSKCKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOI7IZLMY.gif" height="1" width="1" alt="" /><span style="color: transparent; font-size: 0; display: none; visibility: hidden; overflow: hidden; opacity: 0; width: 0; height: 0; max-width: 0; max-height: 0; mso-hide: all">Message ID: <span><kamailio/kamailio/issues/3202/1204917683</span><span>@</span><span>github</span><span>.</span><span>com></span></span></p>
<script type="application/ld+json">[
{
"@context": "http://schema.org",
"@type": "EmailMessage",
"potentialAction": {
"@type": "ViewAction",
"target": "https://github.com/kamailio/kamailio/issues/3202#issuecomment-1204917683",
"url": "https://github.com/kamailio/kamailio/issues/3202#issuecomment-1204917683",
"name": "View Issue"
},
"description": "View this Issue on GitHub",
"publisher": {
"@type": "Organization",
"name": "GitHub",
"url": "https://github.com"
}
}
]</script>