[gentoo-hardened] rsbac+pax fixation Patch to kernel 3.8

[Javier Juan Martínez Cabezón]

Hi folks, I have made another rsbac fixation patch to rsbac kernel 3.8

http://git.rsbac.org/cgi-bin/gitweb.cgi?p=linux-3.8.y.git;a=summary

and with PaX 3.8.13

http://grsecurity.net/test/pax-linux-3.8.13-test24.patch


I'm not sure if the stuff related with namei.c file is correct



#ifdef CONFIG_RSBAC_SYM_REDIR
    rsbac_name = rsbac_symlink_redirect(dentry-
>d_inode, link, buflen);
    if (rsbac_name) {
        len = strlen(rsbac_name);
        if (copy_to_user(buffer, rsbac_name, len))
            len = -EFAULT;
        kfree(rsbac_name);
    }
    else
#endif
    if (len < sizeof(tmpbuf)) {
        memcpy(tmpbuf, link, len);
        newlink = tmpbuf;
    } else
        newlink = link;

    if (copy_to_user(buffer, newlink, len))
        len = -EFAULT;
out:
    return len;
}

/*


PaX tries to do this modification to rsbac git code:

--- fs/namei.c    2013-03-19 01:53:21.091281869 +0100
+++ fs/namei.c    2013-03-19 01:53:31.251281326 +0100
@@ -3954,7 +3956,14 @@
     len = strlen(link);
     if (len > (unsigned) buflen)
         len = buflen;
-    if (copy_to_user(buffer, link, len))
+
+    if (len < sizeof(tmpbuf)) {
+        memcpy(tmpbuf, link, len);
+        newlink = tmpbuf;
+    } else
+        newlink = link;
+
+    if (copy_to_user(buffer, newlink, len))
         len = -EFAULT;
 out:
     return len;

In fixation patch if CONFIG_RSBAC_SYM_REDIR is defined then test is:

   if (copy_to_user(buffer, rsbac_name, len))
            len = -EFAULT;

if you don't think this is correct any stuff is highly appreciated.