From 0561e1f01e87b777bcc47971e4ae1f420314f4a0 Mon Sep 17 00:00:00 2001 From: Arianna Avanzini Date: Mon, 8 Sep 2014 17:05:34 +0200 Subject: [PATCH] xen/common: do not implicitly permit access to mapped I/O memory Currently, the XEN_DOMCTL_memory_mapping hypercall implicitly grants to a domain access permission to the I/O memory areas mapped in its guest address space. This conflicts with the presence of a specific hypercall (XEN_DOMCTL_iomem_permission) used to grant such a permission to a domain. This commit separates the functions of the two hypercalls by having only the latter be able to permit I/O memory access to a domain, and the former just performing the mapping after a permissions check on both the granting and the grantee domains. Signed-off-by: Arianna Avanzini Acked-by: Jan Beulich Cc: Dario Faggioli Cc: Paolo Valente Cc: Stefano Stabellini Cc: Julien Grall Cc: Ian Campbell Cc: Ian Jackson Cc: Eric Trudeau Cc: Viktor Kleinik Cc: Andrii Tseglytskyi --- xen/common/domctl.c | 36 ++++++++++-------------------------- 1 file changed, 10 insertions(+), 26 deletions(-) diff --git a/xen/common/domctl.c b/xen/common/domctl.c index 222b140c51..1ad072970d 100644 --- a/xen/common/domctl.c +++ b/xen/common/domctl.c @@ -1031,7 +1031,8 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl) break; ret = -EPERM; - if ( !iomem_access_permitted(current->domain, mfn, mfn_end) ) + if ( !iomem_access_permitted(current->domain, mfn, mfn_end) || + !iomem_access_permitted(d, mfn, mfn_end) ) break; ret = xsm_iomem_mapping(XSM_HOOK, d, mfn, mfn_end, add); @@ -1044,40 +1045,23 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl) "memory_map:add: dom%d gfn=%lx mfn=%lx nr=%lx\n", d->domain_id, gfn, mfn, nr_mfns); - ret = iomem_permit_access(d, mfn, mfn_end); - if ( !ret ) - { - ret = map_mmio_regions(d, gfn, nr_mfns, mfn); - if ( ret ) - { - printk(XENLOG_G_WARNING - "memory_map:fail: dom%d gfn=%lx mfn=%lx nr=%lx ret:%ld\n", - d->domain_id, gfn, mfn, nr_mfns, ret); - if ( iomem_deny_access(d, mfn, mfn_end) && - is_hardware_domain(current->domain) ) - printk(XENLOG_ERR - "memory_map: failed to deny dom%d access to [%lx,%lx]\n", - d->domain_id, mfn, mfn_end); - } - } + ret = map_mmio_regions(d, gfn, nr_mfns, mfn); + if ( ret ) + printk(XENLOG_G_WARNING + "memory_map:fail: dom%d gfn=%lx mfn=%lx nr=%lx ret:%ld\n", + d->domain_id, gfn, mfn, nr_mfns, ret); } else { - int rc = 0; - printk(XENLOG_G_INFO "memory_map:remove: dom%d gfn=%lx mfn=%lx nr=%lx\n", d->domain_id, gfn, mfn, nr_mfns); - rc = unmap_mmio_regions(d, gfn, nr_mfns, mfn); - ret = iomem_deny_access(d, mfn, mfn_end); - if ( !ret ) - ret = rc; + ret = unmap_mmio_regions(d, gfn, nr_mfns, mfn); if ( ret && is_hardware_domain(current->domain) ) printk(XENLOG_ERR - "memory_map: error %ld %s dom%d access to [%lx,%lx]\n", - ret, rc ? "removing" : "denying", d->domain_id, - mfn, mfn_end); + "memory_map: error %ld removing dom%d access to [%lx,%lx]\n", + ret, d->domain_id, mfn, mfn_end); } /* Do this unconditionally to cover errors on above failure paths. */ memory_type_changed(d); -- 2.30.2