Speed up ssh via caching checksec results (#945)

* Speed up ssh via caching checksec results

Closes #944

* Fix logging message

(cherry picked from commit 8a7bb9b)

Author: zachriggle

pwnlib/tubes/ssh.py

@@ -624,7 +624,7 @@ def getppid():
         try:
             self.info_once(self.checksec())
         except Exception:
-            log.warn_once("Couldn't check security settings on %r" % self.host)
+            self.warn_once("Couldn't check security settings on %r" % self.host)
 
     @property
     def sftp(self):
@@ -1973,6 +1973,16 @@ def preexec():
 
         return self._aslr_ulimit
 
+    def _checksec_cache(self, value=None):
+        path = self._get_cachefile('%s-%s' % (self.host, self.port))
+
+        if value is not None:
+            with open(path, 'w+') as f:
+                f.write(value)
+        else:
+            with open(path, 'r+') as f:
+                return f.read()
+
     def checksec(self, banner=True):
         """checksec()
 
@@ -1981,6 +1991,10 @@ def checksec(self, banner=True):
         Arguments:
             banner(bool): Whether to print the path to the ELF binary.
         """
+        cached = self._checksec_cache()
+        if cached:
+            return cached
+
         red    = text.red
         green  = text.green
         yellow = text.yellow
@@ -2001,5 +2015,6 @@ def checksec(self, banner=True):
         if self.aslr_ulimit:
             res += [ "Note:".ljust(10) + red("Susceptible to ASLR ulimit trick (CVE-2016-3672)")]
 
-        return '\n'.join(res)
-
+        cached = '\n'.join(res)
+        self._checksec_cache(cached)
+        return cached