Commit 0c413ba0 authored by Peter Maydell's avatar Peter Maydell
Browse files

vmstate.h: Type check VMSTATE_STRUCT_VARRAY macros 



The VMSTATE_STRUCT_VARRAY_UINT32 macro is intended to handle
migrating a field which is an array of structs, but where instead of
migrating the entire array we only migrate a variable number of
elements of it.

The VMSTATE_STRUCT_VARRAY_POINTER_UINT32 macro is intended to handle
migrating a field which is of pointer type, and points to a
dynamically allocated array of structs of variable size.

We weren't actually checking that the field passed to
VMSTATE_STRUCT_VARRAY_UINT32 really is an array, with the result that
accidentally using it where the _POINTER_ macro was intended would
compile but silently corrupt memory on migration.

Add type-checking that enforces that the field passed in is
really of the right array type. This applies to all the VMSTATE
macros which use flags including VMS_VARRAY_* but not VMS_POINTER.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarDamien Hedde <damien.hedde@greensocs.com>
Tested-by: default avatarDamien Hedde <damien.hedde@greensocs.com>
Message-id: 20190725163710.11703-3-peter.maydell@linaro.org
parent 372e458e

include/migration/vmstate.h

+24 −6
Original line number Diff line number Diff line
@@ -227,8 +227,22 @@ extern const VMStateInfo vmstate_info_bitmap; 
extern const VMStateInfo vmstate_info_qtailq;



#define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0)

/*

 * Check that type t2 is an array of type t1 of size n,

 * e.g. if t1 is 'foo' and n is 32 then t2 must be 'foo[32]'

 */

#define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0)

#define type_check_pointer(t1,t2) ((t1**)0 - (t2*)0)

/*

 * type of element 0 of the specified (array) field of the type.

 * Note that if the field is a pointer then this will return the

 * pointed-to type rather than complaining.

 */

#define typeof_elt_of_field(type, field) typeof(((type *)0)->field[0])

/* Check that field f in struct type t2 is an array of t1, of any size */

#define type_check_varray(t1, t2, f)                                 \

    (type_check(t1, typeof_elt_of_field(t2, f))                      \

     + QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(((t2 *)0)->f)))



#define vmstate_offset_value(_state, _field, _type)                  \

    (offsetof(_state, _field) +                                      \
@@ -253,6 +267,10 @@ extern const VMStateInfo vmstate_info_qtailq; 
    vmstate_offset_array(_state, _field, uint8_t,                    \

                         sizeof(typeof_field(_state, _field)))



#define vmstate_offset_varray(_state, _field, _type)                 \

    (offsetof(_state, _field) +                                      \

     type_check_varray(_type, _state, _field))



/* In the macros below, if there is a _version, that means the macro's

 * field will be processed only if the version being received is >=

 * the _version specified.  In general, if you add a new field, you
@@ -347,7 +365,7 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .info       = &(_info),                                          \

    .size       = sizeof(_type),                                     \

    .flags      = VMS_VARRAY_UINT32|VMS_MULTIPLY_ELEMENTS,           \

    .offset     = offsetof(_state, _field),                          \

    .offset     = vmstate_offset_varray(_state, _field, _type),      \

}



#define VMSTATE_ARRAY_TEST(_field, _state, _num, _test, _info, _type) {\
@@ -376,7 +394,7 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .info       = &(_info),                                          \

    .size       = sizeof(_type),                                     \

    .flags      = VMS_VARRAY_INT32,                                  \

    .offset     = offsetof(_state, _field),                          \

    .offset     = vmstate_offset_varray(_state, _field, _type),      \

}



#define VMSTATE_VARRAY_INT32(_field, _state, _field_num, _version, _info, _type) {\
@@ -416,7 +434,7 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .info       = &(_info),                                          \

    .size       = sizeof(_type),                                     \

    .flags      = VMS_VARRAY_UINT16,                                 \

    .offset     = offsetof(_state, _field),                          \

    .offset     = vmstate_offset_varray(_state, _field, _type),      \

}



#define VMSTATE_VSTRUCT_TEST(_field, _state, _test, _version, _vmsd, _type, _struct_version) { \
@@ -520,7 +538,7 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .vmsd       = &(_vmsd),                                          \

    .size       = sizeof(_type),                                     \

    .flags      = VMS_STRUCT|VMS_VARRAY_UINT8,                       \

    .offset     = offsetof(_state, _field),                          \

    .offset     = vmstate_offset_varray(_state, _field, _type),      \

}



/* a variable length array (i.e. _type *_field) but we know the
@@ -573,7 +591,7 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .vmsd       = &(_vmsd),                                          \

    .size       = sizeof(_type),                                     \

    .flags      = VMS_STRUCT|VMS_VARRAY_INT32,                       \

    .offset     = offsetof(_state, _field),                          \

    .offset     = vmstate_offset_varray(_state, _field, _type),      \

}



#define VMSTATE_STRUCT_VARRAY_UINT32(_field, _state, _field_num, _version, _vmsd, _type) { \
@@ -583,7 +601,7 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .vmsd       = &(_vmsd),                                          \

    .size       = sizeof(_type),                                     \

    .flags      = VMS_STRUCT|VMS_VARRAY_UINT32,                      \

    .offset     = offsetof(_state, _field),                          \

    .offset     = vmstate_offset_varray(_state, _field, _type),      \

}



#define VMSTATE_STRUCT_VARRAY_ALLOC(_field, _state, _field_num, _version, _vmsd, _type) {\