On Sat, Feb 18, 2012 at 12:56 PM, Marcin Slusarz <marcin.slusarz@xxxxxxxxx> wrote: > On Sat, Feb 18, 2012 at 11:38:57AM -0800, Kees Cook wrote: >> @@ -3052,6 +3119,9 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, >> error = mnt_want_write(new_path.mnt); >> if (error) >> goto out_dput; >> + error = may_linkat(&old_path); >> + if (error) >> + goto out_dput; >> error = security_path_link(old_path.dentry, &new_path, new_dentry); >> if (error) >> goto out_drop_write; > > You should give up write access after check failure (i.e. goto out_drop_write). Ah! Thanks, yes, good catch. I will move the check before mnt_want_write(). -Kees -- Kees Cook ChromeOS Security -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
