From 5b0447f647b1031595d24a8a50b362726c887d12 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Wed, 28 Jan 2015 15:52:35 +0000 Subject: [PATCH] tools/libxc: Don't leave scratch_pfn uninitialised if the domain has no memory c/s 5b5c40c0d1 "libxc: introduce a per architecture scratch pfn for temporary grant mapping" accidentally an issue whereby there were two paths out of xc_core_arch_get_scratch_gpfn() which returned 0, but only one of which assigned a value to the gpfn parameter. xc_domain_maximum_gpfn() can validly return 0, at which point gpfn 1 is a valid scratch page to use. In addition, widen rc before adding 1 and possibly overflowing. Signed-off-by: Andrew Cooper CC: Julien Grall CC: Jan Beulich CC: Ian Campbell CC: Ian Jackson CC: Wei Liu Acked-by: Ian Campbell --- tools/libxc/xc_core_x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/libxc/xc_core_x86.c b/tools/libxc/xc_core_x86.c index fac99ec947..d8846f1fc5 100644 --- a/tools/libxc/xc_core_x86.c +++ b/tools/libxc/xc_core_x86.c @@ -214,10 +214,10 @@ xc_core_arch_get_scratch_gpfn(xc_interface *xch, domid_t domid, rc = xc_domain_maximum_gpfn(xch, domid); - if ( rc <= 0 ) + if ( rc < 0 ) return rc; - *gpfn = rc + 1; + *gpfn = (xen_pfn_t)rc + 1; return 0; } -- 2.30.2