Fix: bytecode linker: validate event and field array/sequence encoding

The bytecode linker should only allow linking filter expressions loading
fields which are string-encoded arrays and sequence for comparison
against a string, and reject arrays and sequences without encoding, so
the filter interpreter does not attempt to load non-NULL terminated
arrays/sequences as if they were strings.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic13fbbb0d601eddbb7d98f4a5e13fe3f45612fd8

diff --git a/liblttng-ust/lttng-filter.c b/liblttng-ust/lttng-filter.c
index d52658ae14dd7f4e135a5e6e0df306069bd94f4b..2db388dc5a3d9ddc3423ee34ab84ae5ab43d7bf9 100644 (file)
--- a/liblttng-ust/lttng-filter.c
+++ b/liblttng-ust/lttng-filter.c
@@ -254,9 +254,23 @@ int apply_field_reloc(struct lttng_event *event,
                        op->op = FILTER_OP_LOAD_FIELD_REF_S64;
                        break;
                case atype_array:
+               {
+                       const struct lttng_basic_type *elem_type = &field->type.u.array.elem_type;
+
+                       if (elem_type != atype_integer || elem_type->u.basic.integer.encoding == lttng_encode_none)
+                               return -EINVAL;
+                       op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
+                       break;
+               }
                case atype_sequence:
+               {
+                       const struct lttng_basic_type *elem_type = &field->type.u.sequence.elem_type;
+
+                       if (elem_type != atype_integer || elem_type->u.basic.integer.encoding == lttng_encode_none)
+                               return -EINVAL;
                        op->op = FILTER_OP_LOAD_FIELD_REF_SEQUENCE;
                        break;
+               }
                case atype_string:
                        op->op = FILTER_OP_LOAD_FIELD_REF_STRING;
                        break;
@@ -329,9 +343,25 @@ int apply_context_reloc(struct lttng_event *event,
                        op->op = FILTER_OP_GET_CONTEXT_REF_S64;
                        break;
                        /* Sequence and array supported as string */
-               case atype_string:
                case atype_array:
+               {
+                       const struct lttng_basic_type *elem_type = &ctx_field->event_field.type.u.array.elem_type;
+
+                       if (elem_type != atype_integer || elem_type->u.basic.integer.encoding == lttng_encode_none)
+                               return -EINVAL;
+                       op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
+                       break;
+               }
                case atype_sequence:
+               {
+                       const struct lttng_basic_type *elem_type = &ctx_field->event_field.type.u.sequence.elem_type;
+
+                       if (elem_type != atype_integer || elem_type->u.basic.integer.encoding == lttng_encode_none)
+                               return -EINVAL;
+                       op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
+                       break;
+               }
+               case atype_string:
                        op->op = FILTER_OP_GET_CONTEXT_REF_STRING;
                        break;
                case atype_float: