Fix coredump if crypt returns NULL.

* libmailutils/auth/system.c: Check return from crypt before passing it
to strcmp.
* libmu_auth/sql.c: Likewise.

@@ -100,12 +100,14 @@ mu_authenticate_generic (struct mu_auth_data **return_data MU_ARG_UNUSED,
 {
 {
   const struct mu_auth_data *auth_data = key;
   const struct mu_auth_data *auth_data = key;
   char *pass = call_data;
   char *pass = call_data;
+  char *crypt_pass;
 
 
   if (!auth_data || !pass)
   if (!auth_data || !pass)
     return EINVAL;
     return EINVAL;
   
   
-  return auth_data->passwd
-         && strcmp (auth_data->passwd, crypt (pass, auth_data->passwd)) == 0 ?
+  return auth_data->passwd &&
+         (crypt_pass = crypt (pass, auth_data->passwd)) != NULL &&
+         strcmp (auth_data->passwd, crypt_pass) == 0 ? 
           0 : MU_ERR_AUTH_FAILURE;
           0 : MU_ERR_AUTH_FAILURE;
 }
 }
 
 
@@ -124,9 +126,12 @@ mu_authenticate_system (struct mu_auth_data **return_data MU_ARG_UNUSED,
   if (auth_data)
   if (auth_data)
     {
     {
       struct spwd *spw;
       struct spwd *spw;
+      char *crypt_pass;
+
       spw = getspnam (auth_data->name);
       spw = getspnam (auth_data->name);
       if (spw)
       if (spw)
-	return strcmp (spw->sp_pwdp, crypt (pass, spw->sp_pwdp)) == 0 ?
+	return (crypt_pass = crypt (pass, spw->sp_pwdp)) != NULL &&
+               strcmp (spw->sp_pwdp, crypt_pass) == 0 ?
 	       0 : MU_ERR_AUTH_FAILURE;
 	       0 : MU_ERR_AUTH_FAILURE;
     }
     }
 #endif
 #endif

@@ -627,7 +627,7 @@ mu_sql_authenticate (struct mu_auth_data **return_data MU_ARG_UNUSED,
 {
 {
   const struct mu_auth_data *auth_data = key;
   const struct mu_auth_data *auth_data = key;
   char *pass = call_data;
   char *pass = call_data;
-  char *sql_pass;
+  char *sql_pass, *crypt_pass;
   int rc;
   int rc;
   
   
   if (!auth_data)
   if (!auth_data)
@@ -639,7 +639,11 @@ mu_sql_authenticate (struct mu_auth_data **return_data MU_ARG_UNUSED,
   switch (mu_sql_module_config.password_type)
   switch (mu_sql_module_config.password_type)
     {
     {
     case password_hash:
     case password_hash:
-      rc = strcmp (sql_pass, crypt (pass, sql_pass));
+      crypt_pass = crypt (pass, sql_pass);
+      if (!crypt_pass)
+        rc = 1;
+      else
+        rc = strcmp (sql_pass, crypt_pass);
       break;
       break;
 
 
     case password_scrambled:
     case password_scrambled: