pygrub: trap exception when python module import fails

Fix the issue when importing 'crypt' module or crypt.crypt fails in
pygrub. The exception is written on the same line like "Failed!"
message but only if there is an exception. If there is no exception,
we don't bother users with details (probably the password they entered
was wrong) so we just display "Failed!" message. Also, the code for
hasPassword() was rewritten not to have try/except block here.

Signed-off-by: Michal Novotny <minovotn@redhat.com>

2 files changed, 22 insertions, 15 deletions

diff --git a/tools/pygrub/src/GrubConf.py b/tools/pygrub/src/GrubConf.py
index 7d7652f945..4aac8c189b 100644
--- a/tools/pygrub/src/GrubConf.py
+++ b/tools/pygrub/src/GrubConf.py
@@ -158,6 +158,7 @@ class GrubConfigFile(object):
         self.timeout = -1
         self._default = 0
         self.passwordAccess = True
+        self.passExc = None
 
         if fn is not None:
             self.parse()
@@ -197,7 +198,6 @@ class GrubConfigFile(object):
             if self.commands.has_key(com):
                 if self.commands[com] is not None:
                     setattr(self, self.commands[com], arg.strip())
-                    #print "%s = %s => %s" % (com, self.commands[com], arg.strip() )
                 else:
                     logging.info("Ignored directive %s" %(com,))
             else:
@@ -216,25 +216,28 @@ class GrubConfigFile(object):
         self.passwordAccess = val
 
     def hasPassword(self):
-        try:
-            getattr(self, self.commands['password'])
-            return True
-        except:
-            return False
+        return hasattr(self, 'password')
 
     def checkPassword(self, password):
-        try:
-            pwd = getattr(self, self.commands['password']).split()
-            if pwd[0] == '--md5':
+        # Always allow if no password defined in grub.conf
+        if not self.hasPassword:
+            return True
+
+        # If we're here, we're having 'password' attribute set
+        pwd = getattr(self, 'password').split()
+
+        # We check whether password is in MD5 hash for comparison
+        if pwd[0] == '--md5':
+            try:
                 import crypt
                 if crypt.crypt(password, pwd[1]) == pwd[1]:
                     return True
+            except Exception, e:
+                self.passExc = "Can't verify password: %s" % str(e)
+                return False
 
-            if pwd[0] == password:
-                return True
-
-            return False
-        except:
+        # ... and if not, we compare it as a plain text
+        if pwd[0] == password:
             return True
 
     def set(self, line):
diff --git a/tools/pygrub/src/pygrub b/tools/pygrub/src/pygrub
index b5b87f02a1..84603e9c93 100644
--- a/tools/pygrub/src/pygrub
+++ b/tools/pygrub/src/pygrub
@@ -483,7 +483,11 @@ class Grub:
                 pwd = self.text_win.getstr(6, 8)
                 if not self.cf.checkPassword(pwd):
                     self.text_win.addstr(6, 1, "Password: ")
-                    self.text_win.addstr(7, 0, "Failed!")
+                    if self.cf.passExc is not None:
+                        self.text_win.addstr(7, 0, "Exception: %s"
+                                                  % self.cf.passExc)
+                    else:
+                        self.text_win.addstr(7, 0, "Failed!")
                     self.cf.setPasswordAccess( False )
                 else:
                     self.cf.setPasswordAccess( True )