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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2] x86: assorted array_index_nospec() insertions
Don't chance having Spectre v1 (including BCBS) gadgets. In some of the
cases the insertions are more of precautionary nature rather than there
provably being a gadget, but I think we should err on the safe (secure)
side here.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2: Re-base. Drop guest_cpuid() changes. Fix off-by-1 in
{do,compat}_dm_op().
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -28,6 +28,7 @@
#include <xen/hypercall.h> /* for arch_do_domctl */
#include <xsm/xsm.h>
#include <xen/iommu.h>
+#include <xen/nospec.h>
#include <xen/vm_event.h>
#include <public/vm_event.h>
#include <asm/mem_sharing.h>
@@ -93,27 +94,34 @@ static int update_domain_cpuid_info(stru
/* Insert ctl data into cpuid_policy. */
switch ( ctl->input[0] )
{
+ unsigned int idx;
+
case 0x00000000 ... ARRAY_SIZE(p->basic.raw) - 1:
switch ( ctl->input[0] )
{
case 4:
- p->cache.raw[ctl->input[1]] = leaf;
+ idx = array_index_nospec(ctl->input[1], ARRAY_SIZE(p->cache.raw));
+ p->cache.raw[idx] = leaf;
break;
case 7:
- p->feat.raw[ctl->input[1]] = leaf;
+ idx = array_index_nospec(ctl->input[1], ARRAY_SIZE(p->feat.raw));
+ p->feat.raw[idx] = leaf;
break;
case 0xb:
- p->topo.raw[ctl->input[1]] = leaf;
+ idx = array_index_nospec(ctl->input[1], ARRAY_SIZE(p->topo.raw));
+ p->topo.raw[idx] = leaf;
break;
case XSTATE_CPUID:
- p->xstate.raw[ctl->input[1]] = leaf;
+ idx = array_index_nospec(ctl->input[1], ARRAY_SIZE(p->xstate.raw));
+ p->xstate.raw[idx] = leaf;
break;
default:
- p->basic.raw[ctl->input[0]] = leaf;
+ idx = array_index_nospec(ctl->input[0], ARRAY_SIZE(p->basic.raw));
+ p->basic.raw[idx] = leaf;
break;
}
break;
@@ -127,7 +135,9 @@ static int update_domain_cpuid_info(stru
break;
case 0x80000000 ... 0x80000000 + ARRAY_SIZE(p->extd.raw) - 1:
- p->extd.raw[ctl->input[0] - 0x80000000] = leaf;
+ idx = array_index_nospec(ctl->input[0] & 0xffff,
+ ARRAY_SIZE(p->extd.raw));
+ p->extd.raw[idx] = leaf;
break;
}
--- a/xen/arch/x86/hvm/dm.c
+++ b/xen/arch/x86/hvm/dm.c
@@ -17,6 +17,7 @@
#include <xen/event.h>
#include <xen/guest_access.h>
#include <xen/hypercall.h>
+#include <xen/nospec.h>
#include <xen/sched.h>
#include <asm/hap.h>
@@ -232,7 +233,7 @@ static int set_mem_type(struct domain *d
struct xen_dm_op_set_mem_type *data)
{
xen_pfn_t last_pfn = data->first_pfn + data->nr - 1;
- unsigned int iter = 0;
+ unsigned int iter = 0, mem_type;
int rc = 0;
/* Interface types to internal p2m types */
@@ -252,7 +253,9 @@ static int set_mem_type(struct domain *d
unlikely(data->mem_type == HVMMEM_unused) )
return -EINVAL;
- if ( data->mem_type == HVMMEM_ioreq_server )
+ mem_type = array_index_nospec(data->mem_type, ARRAY_SIZE(memtype));
+
+ if ( mem_type == HVMMEM_ioreq_server )
{
unsigned int flags;
@@ -279,10 +282,10 @@ static int set_mem_type(struct domain *d
if ( p2m_is_shared(t) )
rc = -EAGAIN;
- else if ( !allow_p2m_type_change(t, memtype[data->mem_type]) )
+ else if ( !allow_p2m_type_change(t, memtype[mem_type]) )
rc = -EINVAL;
else
- rc = p2m_change_type_one(d, pfn, t, memtype[data->mem_type]);
+ rc = p2m_change_type_one(d, pfn, t, memtype[mem_type]);
put_gfn(d, pfn);
@@ -387,6 +390,8 @@ static int dm_op(const struct dmop_args
goto out;
}
+ op.op = array_index_nospec(op.op, ARRAY_SIZE(op_size));
+
if ( op_args->buf[0].size < offset + op_size[op.op] )
goto out;
@@ -739,7 +744,7 @@ int compat_dm_op(domid_t domid,
return -E2BIG;
args.domid = domid;
- args.nr_bufs = nr_bufs;
+ args.nr_bufs = array_index_nospec(nr_bufs, ARRAY_SIZE(args.buf) + 1);
for ( i = 0; i < args.nr_bufs; i++ )
{
@@ -776,7 +781,7 @@ long do_dm_op(domid_t domid,
return -E2BIG;
args.domid = domid;
- args.nr_bufs = nr_bufs;
+ args.nr_bufs = array_index_nospec(nr_bufs, ARRAY_SIZE(args.buf) + 1);
if ( copy_from_guest_offset(&args.buf[0], bufs, 0, args.nr_bufs) )
return -EFAULT;
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -20,6 +20,7 @@
*/
#include <xen/lib.h>
#include <xen/hypercall.h>
+#include <xen/nospec.h>
#include <asm/hvm/support.h>
@@ -181,8 +182,15 @@ int hvm_hypercall(struct cpu_user_regs *
BUILD_BUG_ON(ARRAY_SIZE(hvm_hypercall_table) >
ARRAY_SIZE(hypercall_args_table));
- if ( (eax >= ARRAY_SIZE(hvm_hypercall_table)) ||
- !hvm_hypercall_table[eax].native )
+ if ( eax >= ARRAY_SIZE(hvm_hypercall_table) )
+ {
+ regs->rax = -ENOSYS;
+ return HVM_HCALL_completed;
+ }
+
+ eax = array_index_nospec(eax, ARRAY_SIZE(hvm_hypercall_table));
+
+ if ( !hvm_hypercall_table[eax].native )
{
regs->rax = -ENOSYS;
return HVM_HCALL_completed;
--- a/xen/arch/x86/mm/mem_access.c
+++ b/xen/arch/x86/mm/mem_access.c
@@ -23,6 +23,7 @@
#include <xen/guest_access.h> /* copy_from_guest() */
#include <xen/mem_access.h>
+#include <xen/nospec.h>
#include <xen/vm_event.h>
#include <xen/event.h>
#include <public/vm_event.h>
@@ -334,6 +335,7 @@ static bool xenmem_access_to_p2m_access(
switch ( xaccess )
{
case 0 ... ARRAY_SIZE(memaccess) - 1:
+ xaccess = array_index_nospec(xaccess, ARRAY_SIZE(memaccess));
*paccess = memaccess[xaccess];
break;
case XENMEM_access_default:
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -21,6 +21,7 @@
#include <xen/compiler.h>
#include <xen/hypercall.h>
+#include <xen/nospec.h>
#include <xen/trace.h>
#define HYPERCALL(x) \
@@ -99,8 +100,15 @@ void pv_hypercall(struct cpu_user_regs *
BUILD_BUG_ON(ARRAY_SIZE(pv_hypercall_table) >
ARRAY_SIZE(hypercall_args_table));
- if ( (eax >= ARRAY_SIZE(pv_hypercall_table)) ||
- !pv_hypercall_table[eax].native )
+ if ( eax >= ARRAY_SIZE(pv_hypercall_table) )
+ {
+ regs->rax = -ENOSYS;
+ return;
+ }
+
+ eax = array_index_nospec(eax, ARRAY_SIZE(pv_hypercall_table));
+
+ if ( !pv_hypercall_table[eax].native )
{
regs->rax = -ENOSYS;
return;
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