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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Ping: [PATCH v2] x86: assorted array_index_nospec() insertions
>>> On 26.07.18 at 15:07, wrote:
> 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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