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[Xen-devel] Invalid VA => ptr conversion with xc_dom_* API after XSA-55 fox

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).


[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

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