libxc: fix unmap of ACPI guest memory region

Commit fac7f7 changed the value of ptr so that it points to the right memory
area, taking the page offset into account, but failed to remove this when
doing the unmap, which caused the region to not be unmapped. Fix this by not
modifying ptr and instead adding the page offset directly in the memcpy
call.

Coverity-ID: 1394285

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>

diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c
index ad819dd1875618ea6e530a5c3bf04e3d9db11134..36cd3c81704cf14d32290142cdfc89faf026c46a 100644 (file)
--- a/tools/libxc/xc_dom_core.c
+++ b/tools/libxc/xc_dom_core.c
@@ -1119,10 +1119,9 @@ static int xc_dom_load_acpi(struct xc_dom_image *dom)
             goto err;
         }
 
-        ptr = (uint8_t *)ptr +
-              (dom->acpi_modules[i].guest_addr_out & ~XC_PAGE_MASK);
-
-        memcpy(ptr, dom->acpi_modules[i].data, dom->acpi_modules[i].length);
+        memcpy((uint8_t *)ptr +
+               (dom->acpi_modules[i].guest_addr_out & ~XC_PAGE_MASK),
+               dom->acpi_modules[i].data, dom->acpi_modules[i].length);
         munmap(ptr, XC_PAGE_SIZE * num_pages);
 
         free(extents);