Invalid VA => ptr conversion with xc_dom_* API after XSA-55 fox

["Jean-Yves Migeon (NetBSD)" <jym%NetBSD.org@localhost>]

Hi list,

Jeff and FastIce pointed out a regression between Xen 4.1.2 and 4.1.6 
when starting NetBSD domU; the kernel syms table gets slightly corrupted 
[1].

After dwelling into libxc code, FastIce noticed that changing back the 
return value to "ptr + offset" (instead of just "ptr") for 
xc_dom_vaddr_to_ptr() makes it work again.

According to [2] while fixing XSA-55, Ian changed the "ptr + offset" 
return value to just "ptr". Is there a reason for this? IMHO the VA => 
ptr conversion should also take into account non-page aligned addresses, 
hence the offset (except for NULL value of course).

Cheers,

[1] http://mail-index.netbsd.org/port-xen/2013/10/16/msg008088.html

[2] 
http://xenbits.xen.org/gitweb/?p=xen.git;a=blobdiff;f=tools/libxc/xc_dom.h;h=ad6fdd49e2b07704c07a0629bf8da59bfdb5fef2;hp=316c5cbefca4f791255bb43f5dcf4085d42d5869;hb=b5a869209998fedadfe205d37addbd50a802998b;hpb=53bfcf585b09eb4ac2240f89d1ade77421cd2451

--
Jean-Yves Migeon
jym@