[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 27/28] libxl: Limit qemu physmap entries
On Tue, 2015-12-22 at 18:45 +0000, Ian Jackson wrote: > Add a maximum limit of physmap entries to save, so that when the guest > gets write access to physmap it cannot DOS the toolstack. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> > Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> Can we have a reference for where the number 12 comes from please. With that I think this doesn't need to wait for the rest of the series? > --- > v6: Split out of xs permissions relaxation patch. > --- > Âtools/libxl/libxl_dom.c |ÂÂÂÂ7 +++++++ > Â1 file changed, 7 insertions(+) > > diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c > index 6ded9c1..60e8f7f 100644 > --- a/tools/libxl/libxl_dom.c > +++ b/tools/libxl/libxl_dom.c > @@ -1431,6 +1431,8 @@ static void append_string(libxl__gc *gc, char > **buf, uint32_t *len, > ÂÂÂÂÂ*len += extralen; > Â} > Â > +#define MAX_PHYSMAP_ENTRIES 12 > + > Âint libxl__save_emulator_xenstore_data(libxl__domain_suspend_state *dss, > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂchar **callee_buf, > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂuint32_t *callee_len) > @@ -1450,6 +1452,11 @@ int > libxl__save_emulator_xenstore_data(libxl__domain_suspend_state *dss, > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&nr_entries); > ÂÂÂÂÂif (!entries || nr_entries == 0) { rc = 0; goto out; } > Â > +ÂÂÂÂif (nr_entries > MAX_PHYSMAP_ENTRIES) { > +ÂÂÂÂÂÂÂÂLOG(ERROR, "Max physmap entries reached"); > +ÂÂÂÂÂÂÂÂreturn ERROR_FAIL; > +ÂÂÂÂ} > + > ÂÂÂÂÂfor (i = 0; i < nr_entries; ++i) { > ÂÂÂÂÂÂÂÂÂstatic const char *const physmap_subkeys[] = { > ÂÂÂÂÂÂÂÂÂÂÂÂÂ"start_addr", "size", "name" _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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