On Tue, 12 Feb 2002, Huagang Xie wrote: > Thanks for your response. I will sumbmit a patch for that..But when I > try to see if I can get the env string from the bprm->page? I found that > it is complicate for me to decode that envp from brpm->page.. I wonder if > we can use a straight-forward one -- just > > bprm_ops->check_envp(envp) > > ,in the check_envp, we can do the get_user(env,envp) to get the data from > user space and check it. I know if it is not consistence with currenct > implementation..but it is an easy way for me to do. That wouldn't be safe. An application could effectively bypass your checks by changing the environment values between the time that the kernel copies them and the time that your code copies them. This is a very common type of flaw (TOCTTOU - time-of-check-to-time-of-use), and we don't want to encourage it in LSM. You need to check the kernel's copy of the environment if you want to perform such checks. -- Stephen D. Smalley, NAI Labs ssmalleyat_private _______________________________________________ linux-security-module mailing list linux-security-moduleat_private http://mail.wirex.com/mailman/listinfo/linux-security-module
This archive was generated by hypermail 2b30 : Wed Feb 13 2002 - 06:15:29 PST