diff --git a/cfg/posix.cfg b/cfg/posix.cfg
index 8da76f08e..e780827d0 100644
--- a/cfg/posix.cfg
+++ b/cfg/posix.cfg
@@ -89,6 +89,7 @@
     <arg nr="1" direction="in">
       <not-bool/>
       <not-uninit/>
+      <valid>0:</valid>
     </arg>
     <arg nr="2" direction="in">
       <not-null/>
@@ -100,6 +101,40 @@
       <valid>0:</valid>
     </arg>
   </function>
+  <!-- int listen(int sockfd, int backlog); -->
+  <function name="listen">
+    <noreturn>false</noreturn>
+    <returnValue type="int"/>
+    <leak-ignore/>
+    <arg nr="1" direction="in">
+      <not-bool/>
+      <not-uninit/>
+      <valid>0:</valid>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-bool/>
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- int getpeername(int sockfd, struct sockaddr *addr, socklen_t *addrlen); -->
+  <!-- int getsockname(int sockfd, struct sockaddr *addr, socklen_t *addrlen); -->
+  <function name="getpeername,getsockname">
+    <noreturn>false</noreturn>
+    <returnValue type="int"/>
+    <leak-ignore/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+      <not-bool/>
+      <valid>0:</valid>
+    </arg>
+    <arg nr="2" direction="out">
+      <not-null/>
+    </arg>
+    <arg nr="3" direction="in">
+      <not-null/>
+      <not-uninit/>
+    </arg>
+  </function>
   <!-- int connect(int socket, const struct sockaddr *address, socklen_t address_len); -->
   <function name="connect">
     <noreturn>false</noreturn>
@@ -107,6 +142,7 @@
     <arg nr="1" direction="in">
       <not-uninit/>
       <not-bool/>
+      <valid>0:</valid>
     </arg>
     <arg nr="2" direction="in">
       <not-null/>