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[Xen-devel] [PATCH 10/22] xen: use XSM instead of IS_PRIV where duplicated



The Xen hypervisor has two basic access control function calls: IS_PRIV
and the xsm_* functions. Most privileged operations currently require
that both checks succeed, and many times the checks are at different
locations in the code. This patch eliminates the explicit and implicit
IS_PRIV checks that are duplicated in XSM hooks.

When XSM_ENABLE is not defined or when the dummy XSM module is used,
this patch should not change any functionality. Because the locations of
privilege checks have sometimes moved below argument validation, error
returns of some functions may change from EPERM to EINVAL or ESRCH if
called with invalid arguments and from a domain without permission to
perform the operation.

Some checks are removed due to non-obvious duplicates in their callers:

 * acpi_enter_sleep is checked in XENPF_enter_acpi_sleep
 * map_domain_pirq has IS_PRIV_FOR checked in its callers:
   * physdev_map_pirq checks when acquiring the RCU lock
   * ioapic_guest_write is checked in PHYSDEVOP_apic_write
 * PHYSDEVOP_{manage_pci_add,manage_pci_add_ext,pci_device_add} are
   checked by xsm_resource_plug_pci in pci_add_device
 * PHYSDEVOP_manage_pci_remove is checked by xsm_resource_unplug_pci
   in pci_remove_device
 * PHYSDEVOP_{restore_msi,restore_msi_ext} are checked by
   xsm_resource_setup_pci in pci_restore_msi_state
 * do_console_io has changed to IS_PRIV from an explicit domid==0

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/acpi/power.c     |  2 +-
 xen/arch/x86/cpu/mcheck/mce.c |  3 ---
 xen/arch/x86/irq.c            |  3 +--
 xen/arch/x86/mm.c             |  3 ---
 xen/arch/x86/physdev.c        | 54 ++-----------------------------------------
 xen/common/kexec.c            |  3 ---
 xen/common/schedule.c         |  6 -----
 xen/drivers/char/console.c    |  6 -----
 xen/include/xsm/dummy.h       | 28 ++++++++++++++++++++++
 xen/xsm/flask/hooks.c         |  5 ++--
 10 files changed, 35 insertions(+), 78 deletions(-)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 9e1f989..c7b37ef 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -238,7 +238,7 @@ static long enter_state_helper(void *data)
  */
 int acpi_enter_sleep(struct xenpf_enter_acpi_sleep *sleep)
 {
-    if ( !IS_PRIV(current->domain) || !acpi_sinfo.pm1a_cnt_blk.address )
+    if ( !acpi_sinfo.pm1a_cnt_blk.address )
         return -EPERM;
 
     /* Sanity check */
diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index a89df6d..f399054 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -1379,9 +1379,6 @@ long do_mca(XEN_GUEST_HANDLE(xen_mc_t) u_xen_mc)
     struct xen_mc_msrinject *mc_msrinject;
     struct xen_mc_mceinject *mc_mceinject;
 
-    if (!IS_PRIV(v->domain) )
-        return x86_mcerr(NULL, -EPERM);
-
     ret = xsm_do_mca();
     if ( ret )
         return x86_mcerr(NULL, ret);
diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index c87027b..70b0f03 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -1853,8 +1853,7 @@ int map_domain_pirq(
     ASSERT(spin_is_locked(&d->event_lock));
 
     if ( !IS_PRIV(current->domain) &&
-         !(IS_PRIV_FOR(current->domain, d) &&
-           irq_access_permitted(current->domain, pirq)))
+         !irq_access_permitted(current->domain, pirq))
         return -EPERM;
 
     if ( pirq < 0 || pirq >= d->nr_pirqs || irq < 0 || irq >= nr_irqs )
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 4ea5334..b370300 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4488,9 +4488,6 @@ long arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
         XEN_GUEST_HANDLE(e820entry_t) buffer;
         unsigned int i;
 
-        if ( !IS_PRIV(current->domain) )
-            return -EINVAL;
-
         rc = xsm_machine_memory_map();
         if ( rc )
             return rc;
diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index 13b85da..515dca3 100644
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -109,12 +109,6 @@ int physdev_map_pirq(domid_t domid, int type, int *index, 
int *pirq_p,
     if ( ret )
         return ret;
 
-    if ( !IS_PRIV_FOR(current->domain, d) )
-    {
-        ret = -EPERM;
-        goto free_domain;
-    }
-
     /* Verify or get irq. */
     switch ( type )
     {
@@ -238,10 +232,6 @@ int physdev_unmap_pirq(domid_t domid, int pirq)
             goto free_domain;
     }
 
-    ret = -EPERM;
-    if ( !IS_PRIV_FOR(current->domain, d) )
-        goto free_domain;
-
     ret = xsm_unmap_domain_pirq(d, domain_pirq_to_irq(d, pirq));
     if ( ret )
         goto free_domain;
@@ -433,9 +423,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         ret = -EFAULT;
         if ( copy_from_guest(&apic, arg, 1) != 0 )
             break;
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
         ret = xsm_apic(v->domain, cmd);
         if ( ret )
             break;
@@ -450,9 +437,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         ret = -EFAULT;
         if ( copy_from_guest(&apic, arg, 1) != 0 )
             break;
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
         ret = xsm_apic(v->domain, cmd);
         if ( ret )
             break;
@@ -467,8 +451,8 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         if ( copy_from_guest(&irq_op, arg, 1) != 0 )
             break;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
+        ret = xsm_apic(v->domain, cmd);
+        if ( ret )
             break;
 
         /* Vector is only used by hypervisor, and dom0 shouldn't
@@ -517,9 +501,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
 
     case PHYSDEVOP_manage_pci_add: {
         struct physdev_manage_pci manage_pci;
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
         ret = -EFAULT;
         if ( copy_from_guest(&manage_pci, arg, 1) != 0 )
             break;
@@ -530,9 +511,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
 
     case PHYSDEVOP_manage_pci_remove: {
         struct physdev_manage_pci manage_pci;
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
         ret = -EFAULT;
         if ( copy_from_guest(&manage_pci, arg, 1) != 0 )
             break;
@@ -545,10 +523,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         struct physdev_manage_pci_ext manage_pci_ext;
         struct pci_dev_info pdev_info;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(current->domain) )
-            break;
-
         ret = -EFAULT;
         if ( copy_from_guest(&manage_pci_ext, arg, 1) != 0 )
             break;
@@ -571,10 +545,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         struct physdev_pci_device_add add;
         struct pci_dev_info pdev_info;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(current->domain) )
-            break;
-
         ret = -EFAULT;
         if ( copy_from_guest(&add, arg, 1) != 0 )
             break;
@@ -595,10 +565,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
     case PHYSDEVOP_pci_device_remove: {
         struct physdev_pci_device dev;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
-
         ret = -EFAULT;
         if ( copy_from_guest(&dev, arg, 1) != 0 )
             break;
@@ -610,10 +576,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
     case PHYSDEVOP_pci_mmcfg_reserved: {
         struct physdev_pci_mmcfg_reserved info;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(current->domain) )
-            break;
-
         ret = xsm_resource_setup_misc();
         if ( ret )
             break;
@@ -631,10 +593,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         struct physdev_restore_msi restore_msi;
         struct pci_dev *pdev;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
-
         ret = -EFAULT;
         if ( copy_from_guest(&restore_msi, arg, 1) != 0 )
             break;
@@ -650,10 +608,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         struct physdev_pci_device dev;
         struct pci_dev *pdev;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
-
         ret = -EFAULT;
         if ( copy_from_guest(&dev, arg, 1) != 0 )
             break;
@@ -668,10 +622,6 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
     case PHYSDEVOP_setup_gsi: {
         struct physdev_setup_gsi setup_gsi;
 
-        ret = -EPERM;
-        if ( !IS_PRIV(v->domain) )
-            break;
-
         ret = -EFAULT;
         if ( copy_from_guest(&setup_gsi, arg, 1) != 0 )
             break;
diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index 2bc3e33..7dc6f24 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -851,9 +851,6 @@ static int do_kexec_op_internal(unsigned long op, 
XEN_GUEST_HANDLE(void) uarg,
     unsigned long flags;
     int ret = -EINVAL;
 
-    if ( !IS_PRIV(current->domain) )
-        return -EPERM;
-
     ret = xsm_kexec();
     if ( ret )
         return ret;
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index eee74be..95142c0 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -919,12 +919,6 @@ ret_t do_sched_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         if ( d == NULL )
             break;
 
-        if ( !IS_PRIV_FOR(current->domain, d) )
-        {
-            rcu_unlock_domain(d);
-            return -EPERM;
-        }
-
         ret = xsm_schedop_shutdown(current->domain, d);
         if ( ret )
         {
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index d97170c..aee3b4b 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -363,12 +363,6 @@ long do_console_io(int cmd, int count, 
XEN_GUEST_HANDLE(char) buffer)
     long rc;
     unsigned int idx, len;
 
-#ifndef VERBOSE
-    /* Only domain 0 may access the emergency console. */
-    if ( current->domain->domain_id != 0 )
-        return -EPERM;
-#endif
-
     rc = xsm_console_io(current->domain, cmd);
     if ( rc )
         return rc;
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index 61c6f13..389d9f6 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -161,6 +161,8 @@ static XSM_DEFAULT(int, pm_op) (void)
 
 static XSM_DEFAULT(int, do_mca) (void)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
@@ -223,6 +225,10 @@ static XSM_DEFAULT(int, memory_stat_reservation) (struct 
domain *d1, struct doma
 
 static XSM_DEFAULT(int, console_io) (struct domain *d, int cmd)
 {
+#ifndef VERBOSE
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
+#endif
     return 0;
 }
 
@@ -233,11 +239,15 @@ static XSM_DEFAULT(int, profile) (struct domain *d, int 
op)
 
 static XSM_DEFAULT(int, kexec) (void)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
 static XSM_DEFAULT(int, schedop_shutdown) (struct domain *d1, struct domain 
*d2)
 {
+    if ( !IS_PRIV_FOR(d1, d2) )
+        return -EPERM;
     return 0;
 }
 
@@ -336,26 +346,36 @@ static XSM_DEFAULT(int, resource_unplug_core) (void)
 
 static XSM_DEFAULT(int, resource_plug_pci) (uint32_t machine_bdf)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
 static XSM_DEFAULT(int, resource_unplug_pci) (uint32_t machine_bdf)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
 static XSM_DEFAULT(int, resource_setup_pci) (uint32_t machine_bdf)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
 static XSM_DEFAULT(int, resource_setup_gsi) (int gsi)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
 static XSM_DEFAULT(int, resource_setup_misc) (void)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
@@ -396,6 +416,8 @@ static XSM_DEFAULT(int, map_domain_pirq) (struct domain *d, 
int irq, void *data)
 
 static XSM_DEFAULT(int, unmap_domain_pirq) (struct domain *d, int irq)
 {
+    if ( !IS_PRIV_FOR(current->domain, d) )
+        return -EPERM;
     return 0;
 }
 
@@ -494,6 +516,8 @@ static XSM_DEFAULT(int, mem_sharing) (struct domain *d)
 
 static XSM_DEFAULT(int, apic) (struct domain *d, int cmd)
 {
+    if ( !IS_PRIV(d) )
+        return -EPERM;
     return 0;
 }
 
@@ -534,6 +558,8 @@ static XSM_DEFAULT(int, efi_call) (void)
 
 static XSM_DEFAULT(int, acpi_sleep) (void)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
@@ -549,6 +575,8 @@ static XSM_DEFAULT(int, getidletime) (void)
 
 static XSM_DEFAULT(int, machine_memory_map) (void)
 {
+    if ( !IS_PRIV(current->domain) )
+        return -EPERM;
     return 0;
 }
 
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 6d4b4f0..10c2163 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1147,10 +1147,11 @@ static int flask_apic(struct domain *d, int cmd)
 
     switch ( cmd )
     {
-    case PHYSDEVOP_APIC_READ:
+    case PHYSDEVOP_apic_read:
+    case PHYSDEVOP_alloc_irq_vector:
         perm = XEN__READAPIC;
         break;
-    case PHYSDEVOP_APIC_WRITE:
+    case PHYSDEVOP_apic_write:
         perm = XEN__WRITEAPIC;
         break;
     default:
-- 
1.7.11.4


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