int yr_ac_create_automaton(
YR_ARENA* arena,
YR_AC_AUTOMATON** automaton)
{
int result;
YR_AC_STATE* root_state;
result = yr_arena_allocate_struct(
arena,
sizeof(YR_AC_AUTOMATON),
(void**) automaton,
offsetof(YR_AC_AUTOMATON, root),
EOL);
if (result != ERROR_SUCCESS)
return result;
result = yr_arena_allocate_struct(
arena,
sizeof(YR_AC_TABLE_BASED_STATE),
(void**) &root_state,
offsetof(YR_AC_TABLE_BASED_STATE, failure),
offsetof(YR_AC_TABLE_BASED_STATE, matches),
EOL);
if (result != ERROR_SUCCESS)
return result;
(*automaton)->root = root_state;
root_state->depth = 0;
root_state->matches = NULL;
return result;
}
int _yr_compiler_set_namespace(
YR_COMPILER* compiler,
const char* namespace_)
{
YR_NAMESPACE* ns;
char* ns_name;
int result;
int i;
int found;
ns = (YR_NAMESPACE*) yr_arena_base_address(compiler->namespaces_arena);
found = FALSE;
for (i = 0; i < compiler->namespaces_count; i++)
{
if (strcmp(ns->name, namespace_) == 0)
{
found = TRUE;
break;
}
ns = (YR_NAMESPACE*) yr_arena_next_address(
compiler->namespaces_arena,
ns,
sizeof(YR_NAMESPACE));
}
if (!found)
{
result = yr_arena_write_string(
compiler->sz_arena,
namespace_,
&ns_name);
if (result == ERROR_SUCCESS)
result = yr_arena_allocate_struct(
compiler->namespaces_arena,
sizeof(YR_NAMESPACE),
(void**) &ns,
offsetof(YR_NAMESPACE, name),
EOL);
if (result != ERROR_SUCCESS)
return result;
ns->name = ns_name;
for (i = 0; i < MAX_THREADS; i++)
ns->t_flags[i] = 0;
compiler->namespaces_count++;
}
compiler->current_namespace = ns;
return ERROR_SUCCESS;
}
int yr_compiler_define_string_variable(
YR_COMPILER* compiler,
const char* identifier,
const char* value)
{
YR_OBJECT* object;
YR_EXTERNAL_VARIABLE* external;
char* id = NULL;
char* val = NULL;
compiler->last_result = ERROR_SUCCESS;
FAIL_ON_COMPILER_ERROR(yr_arena_write_string(
compiler->sz_arena,
identifier,
&id));
FAIL_ON_COMPILER_ERROR(yr_arena_write_string(
compiler->sz_arena,
value,
&val));
FAIL_ON_COMPILER_ERROR(yr_arena_allocate_struct(
compiler->externals_arena,
sizeof(YR_EXTERNAL_VARIABLE),
(void**) &external,
offsetof(YR_EXTERNAL_VARIABLE, identifier),
offsetof(YR_EXTERNAL_VARIABLE, string),
EOL));
external->type = EXTERNAL_VARIABLE_TYPE_STRING;
external->identifier = id;
external->integer = 0;
external->string = val;
FAIL_ON_COMPILER_ERROR(yr_object_from_external_variable(
external,
&object));
FAIL_ON_COMPILER_ERROR(yr_hash_table_add(
compiler->objects_table,
external->identifier,
NULL,
(void*) object));
return compiler->last_result;
}
YR_META* yr_parser_reduce_meta_declaration(
yyscan_t yyscanner,
int32_t type,
const char* identifier,
const char* string,
int32_t integer)
{
YR_COMPILER* compiler = yyget_extra(yyscanner);
YR_META* meta;
compiler->last_result = yr_arena_allocate_struct(
compiler->metas_arena,
sizeof(YR_META),
(void**) &meta,
offsetof(YR_META, identifier),
offsetof(YR_META, string),
EOL);
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
compiler->last_result = yr_arena_write_string(
compiler->sz_arena,
identifier,
&meta->identifier);
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
if (string != NULL)
compiler->last_result = yr_arena_write_string(
compiler->sz_arena,
string,
&meta->string);
else
meta->string = NULL;
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
meta->integer = integer;
meta->type = type;
return meta;
}
YR_API int yr_compiler_define_float_variable(
YR_COMPILER* compiler,
const char* identifier,
double value)
{
YR_EXTERNAL_VARIABLE* external;
YR_OBJECT* object;
char* id;
compiler->last_result = ERROR_SUCCESS;
FAIL_ON_COMPILER_ERROR(yr_arena_write_string(
compiler->sz_arena,
identifier,
&id));
FAIL_ON_COMPILER_ERROR(yr_arena_allocate_struct(
compiler->externals_arena,
sizeof(YR_EXTERNAL_VARIABLE),
(void**) &external,
offsetof(YR_EXTERNAL_VARIABLE, identifier),
EOL));
external->type = EXTERNAL_VARIABLE_TYPE_FLOAT;
external->identifier = id;
external->value.f = value;
FAIL_ON_COMPILER_ERROR(yr_object_from_external_variable(
external,
&object));
FAIL_ON_COMPILER_ERROR(yr_hash_table_add(
compiler->objects_table,
external->identifier,
NULL,
(void*) object));
return ERROR_SUCCESS;
}
int yr_parser_reduce_meta_declaration(
yyscan_t yyscanner,
int32_t type,
const char* identifier,
const char* string,
int64_t integer,
YR_META** meta)
{
YR_COMPILER* compiler = yyget_extra(yyscanner);
FAIL_ON_ERROR(yr_arena_allocate_struct(
compiler->metas_arena,
sizeof(YR_META),
(void**) meta,
offsetof(YR_META, identifier),
offsetof(YR_META, string),
EOL));
FAIL_ON_ERROR(yr_arena_write_string(
compiler->sz_arena,
identifier,
(char**) &(*meta)->identifier));
if (string != NULL)
{
FAIL_ON_ERROR(yr_arena_write_string(
compiler->sz_arena,
string,
&(*meta)->string));
}
else
{
(*meta)->string = NULL;
}
(*meta)->integer = integer;
(*meta)->type = type;
return ERROR_SUCCESS;
}
int _yr_compiler_compile_rules(
YR_COMPILER* compiler)
{
YARA_RULES_FILE_HEADER* rules_file_header = NULL;
YR_ARENA* arena = NULL;
YR_RULE null_rule;
YR_EXTERNAL_VARIABLE null_external;
YR_AC_TABLES tables;
int8_t halt = OP_HALT;
int result;
// Write halt instruction at the end of code.
yr_arena_write_data(
compiler->code_arena,
&halt,
sizeof(int8_t),
NULL);
// Write a null rule indicating the end.
memset(&null_rule, 0xFA, sizeof(YR_RULE));
null_rule.g_flags = RULE_GFLAGS_NULL;
yr_arena_write_data(
compiler->rules_arena,
&null_rule,
sizeof(YR_RULE),
NULL);
// Write a null external the end.
memset(&null_external, 0xFA, sizeof(YR_EXTERNAL_VARIABLE));
null_external.type = EXTERNAL_VARIABLE_TYPE_NULL;
yr_arena_write_data(
compiler->externals_arena,
&null_external,
sizeof(YR_EXTERNAL_VARIABLE),
NULL);
// Write Aho-Corasick automaton to arena.
result = yr_ac_compile(
compiler->automaton,
compiler->automaton_arena,
&tables);
if (result == ERROR_SUCCESS)
result = yr_arena_create(1024, 0, &arena);
if (result == ERROR_SUCCESS)
result = yr_arena_allocate_struct(
arena,
sizeof(YARA_RULES_FILE_HEADER),
(void**) &rules_file_header,
offsetof(YARA_RULES_FILE_HEADER, rules_list_head),
offsetof(YARA_RULES_FILE_HEADER, externals_list_head),
offsetof(YARA_RULES_FILE_HEADER, code_start),
offsetof(YARA_RULES_FILE_HEADER, match_table),
offsetof(YARA_RULES_FILE_HEADER, transition_table),
EOL);
if (result == ERROR_SUCCESS)
{
rules_file_header->rules_list_head = (YR_RULE*) yr_arena_base_address(
compiler->rules_arena);
rules_file_header->externals_list_head = (YR_EXTERNAL_VARIABLE*)
yr_arena_base_address(compiler->externals_arena);
rules_file_header->code_start = (uint8_t*) yr_arena_base_address(
compiler->code_arena);
rules_file_header->match_table = tables.matches;
rules_file_header->transition_table = tables.transitions;
}
if (result == ERROR_SUCCESS)
{
result = yr_arena_append(
arena,
compiler->code_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->code_arena = NULL;
result = yr_arena_append(
arena,
compiler->re_code_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->re_code_arena = NULL;
result = yr_arena_append(
arena,
compiler->rules_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->rules_arena = NULL;
result = yr_arena_append(
arena,
compiler->strings_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->strings_arena = NULL;
result = yr_arena_append(
arena,
compiler->externals_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->externals_arena = NULL;
result = yr_arena_append(
arena,
compiler->namespaces_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->namespaces_arena = NULL;
result = yr_arena_append(
arena,
compiler->metas_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->metas_arena = NULL;
result = yr_arena_append(
arena,
compiler->sz_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->sz_arena = NULL;
result = yr_arena_append(
arena,
compiler->automaton_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->automaton_arena = NULL;
result = yr_arena_append(
arena,
compiler->matches_arena);
}
if (result == ERROR_SUCCESS)
{
compiler->matches_arena = NULL;
compiler->compiled_rules_arena = arena;
result = yr_arena_coalesce(arena);
}
else
{
yr_arena_destroy(arena);
}
return result;
}
int yr_ac_add_string(
YR_ARENA* arena,
YR_AC_AUTOMATON* automaton,
YR_STRING* string,
YR_ATOM_LIST_ITEM* atom)
{
int result = ERROR_SUCCESS;
int i;
YR_AC_STATE* state;
YR_AC_STATE* next_state;
YR_AC_MATCH* new_match;
// For each atom create the states in the automaton.
while (atom != NULL)
{
state = automaton->root;
for(i = 0; i < atom->atom_length; i++)
{
next_state = yr_ac_next_state(
state, atom->atom[i]);
if (next_state == NULL)
{
next_state = _yr_ac_create_state(
arena,
state,
atom->atom[i]);
if (next_state == NULL)
return ERROR_INSUFICIENT_MEMORY;
}
state = next_state;
}
result = yr_arena_allocate_struct(
arena,
sizeof(YR_AC_MATCH),
(void**) &new_match,
offsetof(YR_AC_MATCH, string),
offsetof(YR_AC_MATCH, forward_code),
offsetof(YR_AC_MATCH, backward_code),
offsetof(YR_AC_MATCH, next),
EOL);
if (result == ERROR_SUCCESS)
{
new_match->backtrack = state->depth + atom->backtrack;
new_match->string = string;
new_match->forward_code = atom->forward_code;
new_match->backward_code = atom->backward_code;
new_match->next = state->matches;
state->matches = new_match;
}
else
{
break;
}
atom = atom->next;
}
return result;
}
YR_AC_STATE* _yr_ac_create_state(
YR_ARENA* arena,
YR_AC_STATE* state,
uint8_t input)
{
int result;
YR_AC_STATE* new_state;
YR_AC_LIST_BASED_STATE* list_based_state;
YR_AC_TABLE_BASED_STATE* table_based_state;
YR_AC_STATE_TRANSITION* new_transition;
if (state->depth < MAX_TABLE_BASED_STATES_DEPTH)
{
result = yr_arena_allocate_struct(
arena,
sizeof(YR_AC_TABLE_BASED_STATE),
(void**) &new_state,
offsetof(YR_AC_TABLE_BASED_STATE, failure),
offsetof(YR_AC_TABLE_BASED_STATE, matches),
EOL);
}
else
{
result = yr_arena_allocate_struct(
arena,
sizeof(YR_AC_LIST_BASED_STATE),
(void**) &new_state,
offsetof(YR_AC_LIST_BASED_STATE, failure),
offsetof(YR_AC_LIST_BASED_STATE, matches),
offsetof(YR_AC_LIST_BASED_STATE, transitions),
EOL);
}
if (result != ERROR_SUCCESS)
return NULL;
if (state->depth <= MAX_TABLE_BASED_STATES_DEPTH)
{
result = yr_arena_make_relocatable(
arena,
state,
offsetof(YR_AC_TABLE_BASED_STATE, transitions[input]),
EOL);
if (result != ERROR_SUCCESS)
return NULL;
table_based_state = (YR_AC_TABLE_BASED_STATE*) state;
table_based_state->transitions[input].state = new_state;
}
else
{
result = yr_arena_allocate_struct(
arena,
sizeof(YR_AC_STATE_TRANSITION),
(void**) &new_transition,
offsetof(YR_AC_STATE_TRANSITION, state),
offsetof(YR_AC_STATE_TRANSITION, next),
EOL);
if (result != ERROR_SUCCESS)
return NULL;
list_based_state = (YR_AC_LIST_BASED_STATE*) state;
new_transition->input = input;
new_transition->state = new_state;
new_transition->next = list_based_state->transitions;
list_based_state->transitions = new_transition;
}
new_state->depth = state->depth + 1;
return new_state;
}
int yr_parser_reduce_rule_declaration(
yyscan_t yyscanner,
int32_t flags,
const char* identifier,
char* tags,
YR_STRING* strings,
YR_META* metas)
{
YR_COMPILER* compiler = yyget_extra(yyscanner);
YR_RULE* rule;
YR_STRING* string;
if (yr_hash_table_lookup(
compiler->rules_table,
identifier,
compiler->current_namespace->name) != NULL)
{
// A rule with the same identifier already exists, return the
// appropriate error.
yr_compiler_set_error_extra_info(compiler, identifier);
compiler->last_result = ERROR_DUPLICATE_RULE_IDENTIFIER;
return compiler->last_result;
}
// Check for unreferenced (unused) strings.
string = compiler->current_rule_strings;
while(!STRING_IS_NULL(string))
{
// Only the heading fragment in a chain of strings (the one with
// chained_to == NULL) must be referenced. All other fragments
// are never marked as referenced.
if (!STRING_IS_REFERENCED(string) &&
string->chained_to == NULL)
{
yr_compiler_set_error_extra_info(compiler, string->identifier);
compiler->last_result = ERROR_UNREFERENCED_STRING;
break;
}
string = yr_arena_next_address(
compiler->strings_arena,
string,
sizeof(YR_STRING));
}
if (compiler->last_result != ERROR_SUCCESS)
return compiler->last_result;
compiler->last_result = yr_arena_allocate_struct(
compiler->rules_arena,
sizeof(YR_RULE),
(void**) &rule,
offsetof(YR_RULE, identifier),
offsetof(YR_RULE, tags),
offsetof(YR_RULE, strings),
offsetof(YR_RULE, metas),
offsetof(YR_RULE, ns),
EOL);
if (compiler->last_result != ERROR_SUCCESS)
return compiler->last_result;
compiler->last_result = yr_arena_write_string(
compiler->sz_arena,
identifier,
&rule->identifier);
if (compiler->last_result != ERROR_SUCCESS)
return compiler->last_result;
compiler->last_result = yr_parser_emit_with_arg_reloc(
yyscanner,
RULE_POP,
PTR_TO_UINT64(rule),
NULL);
if (compiler->last_result != ERROR_SUCCESS)
return compiler->last_result;
rule->g_flags = flags | compiler->current_rule_flags;
rule->tags = tags;
rule->strings = strings;
rule->metas = metas;
rule->ns = compiler->current_namespace;
compiler->current_rule_flags = 0;
compiler->current_rule_strings = NULL;
yr_hash_table_add(
compiler->rules_table,
identifier,
compiler->current_namespace->name,
(void*) rule);
return compiler->last_result;
}
int _yr_parser_write_string(
const char* identifier,
int flags,
YR_COMPILER* compiler,
SIZED_STRING* str,
RE* re,
YR_STRING** string,
int* min_atom_length)
{
SIZED_STRING* literal_string;
YR_AC_MATCH* new_match;
YR_ATOM_LIST_ITEM* atom;
YR_ATOM_LIST_ITEM* atom_list = NULL;
int result;
int max_string_len;
int free_literal = FALSE;
*string = NULL;
result = yr_arena_allocate_struct(
compiler->strings_arena,
sizeof(YR_STRING),
(void**) string,
offsetof(YR_STRING, identifier),
offsetof(YR_STRING, string),
offsetof(YR_STRING, chained_to),
EOL);
if (result != ERROR_SUCCESS)
return result;
result = yr_arena_write_string(
compiler->sz_arena,
identifier,
&(*string)->identifier);
if (result != ERROR_SUCCESS)
return result;
if (flags & STRING_GFLAGS_HEXADECIMAL ||
flags & STRING_GFLAGS_REGEXP)
{
literal_string = yr_re_extract_literal(re);
if (literal_string != NULL)
{
flags |= STRING_GFLAGS_LITERAL;
free_literal = TRUE;
}
}
else
{
literal_string = str;
flags |= STRING_GFLAGS_LITERAL;
}
(*string)->g_flags = flags;
(*string)->chained_to = NULL;
memset((*string)->matches, 0,
sizeof((*string)->matches));
memset((*string)->unconfirmed_matches, 0,
sizeof((*string)->unconfirmed_matches));
if (flags & STRING_GFLAGS_LITERAL)
{
(*string)->length = literal_string->length;
result = yr_arena_write_data(
compiler->sz_arena,
literal_string->c_string,
literal_string->length,
(void*) &(*string)->string);
if (result == ERROR_SUCCESS)
{
result = yr_atoms_extract_from_string(
(uint8_t*) literal_string->c_string,
literal_string->length,
flags,
&atom_list);
}
}
else
{
result = yr_re_emit_code(re, compiler->re_code_arena);
if (result == ERROR_SUCCESS)
result = yr_atoms_extract_from_re(re, flags, &atom_list);
}
if (result == ERROR_SUCCESS)
{
// Add the string to Aho-Corasick automaton.
if (atom_list != NULL)
{
result = yr_ac_add_string(
compiler->automaton_arena,
compiler->automaton,
*string,
atom_list);
}
else
{
result = yr_arena_allocate_struct(
compiler->automaton_arena,
sizeof(YR_AC_MATCH),
(void**) &new_match,
offsetof(YR_AC_MATCH, string),
offsetof(YR_AC_MATCH, forward_code),
offsetof(YR_AC_MATCH, backward_code),
offsetof(YR_AC_MATCH, next),
EOL);
if (result == ERROR_SUCCESS)
{
new_match->backtrack = 0;
new_match->string = *string;
new_match->forward_code = re->root_node->forward_code;
new_match->backward_code = NULL;
new_match->next = compiler->automaton->root->matches;
compiler->automaton->root->matches = new_match;
}
}
}
atom = atom_list;
if (atom != NULL)
*min_atom_length = MAX_ATOM_LENGTH;
else
*min_atom_length = 0;
while (atom != NULL)
{
if (atom->atom_length < *min_atom_length)
*min_atom_length = atom->atom_length;
atom = atom->next;
}
if (flags & STRING_GFLAGS_LITERAL)
{
if (flags & STRING_GFLAGS_WIDE)
max_string_len = (*string)->length * 2;
else
max_string_len = (*string)->length;
if (max_string_len == *min_atom_length)
(*string)->g_flags |= STRING_GFLAGS_FITS_IN_ATOM;
}
if (free_literal)
yr_free(literal_string);
if (atom_list != NULL)
yr_atoms_list_destroy(atom_list);
return result;
}
YR_RULE* yr_parser_reduce_rule_declaration_phase_1(
yyscan_t yyscanner,
int32_t flags,
const char* identifier)
{
YR_COMPILER* compiler = yyget_extra(yyscanner);
YR_RULE* rule = NULL;
if (yr_hash_table_lookup(
compiler->rules_table,
identifier,
compiler->current_namespace->name) != NULL ||
yr_hash_table_lookup(
compiler->objects_table,
identifier,
compiler->current_namespace->name) != NULL)
{
// A rule or variable with the same identifier already exists, return the
// appropriate error.
yr_compiler_set_error_extra_info(compiler, identifier);
compiler->last_result = ERROR_DUPLICATED_IDENTIFIER;
return NULL;
}
compiler->last_result = yr_arena_allocate_struct(
compiler->rules_arena,
sizeof(YR_RULE),
(void**) &rule,
offsetof(YR_RULE, identifier),
offsetof(YR_RULE, tags),
offsetof(YR_RULE, strings),
offsetof(YR_RULE, metas),
offsetof(YR_RULE, ns),
EOL);
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
rule->g_flags = flags;
rule->ns = compiler->current_namespace;
#ifdef PROFILING_ENABLED
rule->clock_ticks = 0;
#endif
compiler->last_result = yr_arena_write_string(
compiler->sz_arena,
identifier,
(char**) &rule->identifier);
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
compiler->last_result = yr_parser_emit_with_arg_reloc(
yyscanner,
OP_INIT_RULE,
PTR_TO_INT64(rule),
NULL,
NULL);
if (compiler->last_result == ERROR_SUCCESS)
compiler->last_result = yr_hash_table_add(
compiler->rules_table,
identifier,
compiler->current_namespace->name,
(void*) rule);
// Clean strings_table as we are starting to parse a new rule.
yr_hash_table_clean(compiler->strings_table, NULL);
compiler->current_rule = rule;
return rule;
}
int _yr_parser_write_string(
const char* identifier,
int flags,
YR_COMPILER* compiler,
SIZED_STRING* str,
RE* re,
YR_STRING** string,
int* min_atom_quality)
{
SIZED_STRING* literal_string;
YR_AC_MATCH* new_match;
YR_ATOM_LIST_ITEM* atom_list = NULL;
int result;
int max_string_len;
int free_literal = FALSE;
*string = NULL;
result = yr_arena_allocate_struct(
compiler->strings_arena,
sizeof(YR_STRING),
(void**) string,
offsetof(YR_STRING, identifier),
offsetof(YR_STRING, string),
offsetof(YR_STRING, chained_to),
EOL);
if (result != ERROR_SUCCESS)
return result;
result = yr_arena_write_string(
compiler->sz_arena,
identifier,
&(*string)->identifier);
if (result != ERROR_SUCCESS)
return result;
if (flags & STRING_GFLAGS_HEXADECIMAL ||
flags & STRING_GFLAGS_REGEXP)
{
literal_string = yr_re_extract_literal(re);
if (literal_string != NULL)
{
flags |= STRING_GFLAGS_LITERAL;
free_literal = TRUE;
}
else
{
// Non-literal strings can't be marked as fixed offset because once we
// find a string atom in the scanned data we don't know the offset where
// the string should start, as the non-literal strings can contain
// variable-length portions.
flags &= ~STRING_GFLAGS_FIXED_OFFSET;
}
}
else
{
literal_string = str;
flags |= STRING_GFLAGS_LITERAL;
}
(*string)->g_flags = flags;
(*string)->chained_to = NULL;
(*string)->fixed_offset = UNDEFINED;
#ifdef PROFILING_ENABLED
(*string)->clock_ticks = 0;
#endif
memset((*string)->matches, 0,
sizeof((*string)->matches));
memset((*string)->unconfirmed_matches, 0,
sizeof((*string)->unconfirmed_matches));
if (flags & STRING_GFLAGS_LITERAL)
{
(*string)->length = (uint32_t) literal_string->length;
result = yr_arena_write_data(
compiler->sz_arena,
literal_string->c_string,
literal_string->length + 1, // +1 to include terminating NULL
(void**) &(*string)->string);
if (result == ERROR_SUCCESS)
{
result = yr_atoms_extract_from_string(
(uint8_t*) literal_string->c_string,
(int32_t) literal_string->length,
flags,
&atom_list);
}
}
else
{
result = yr_re_emit_code(re, compiler->re_code_arena);
if (result == ERROR_SUCCESS)
result = yr_atoms_extract_from_re(re, flags, &atom_list);
}
if (result == ERROR_SUCCESS)
{
// Add the string to Aho-Corasick automaton.
if (atom_list != NULL)
{
result = yr_ac_add_string(
compiler->automaton_arena,
compiler->automaton,
*string,
atom_list);
}
else
{
result = yr_arena_allocate_struct(
compiler->automaton_arena,
sizeof(YR_AC_MATCH),
(void**) &new_match,
offsetof(YR_AC_MATCH, string),
offsetof(YR_AC_MATCH, forward_code),
offsetof(YR_AC_MATCH, backward_code),
offsetof(YR_AC_MATCH, next),
EOL);
if (result == ERROR_SUCCESS)
{
new_match->backtrack = 0;
new_match->string = *string;
new_match->forward_code = re->root_node->forward_code;
new_match->backward_code = NULL;
new_match->next = compiler->automaton->root->matches;
compiler->automaton->root->matches = new_match;
}
}
}
*min_atom_quality = yr_atoms_min_quality(atom_list);
if (flags & STRING_GFLAGS_LITERAL)
{
if (flags & STRING_GFLAGS_WIDE)
max_string_len = (*string)->length * 2;
else
max_string_len = (*string)->length;
if (max_string_len <= MAX_ATOM_LENGTH)
(*string)->g_flags |= STRING_GFLAGS_FITS_IN_ATOM;
}
if (free_literal)
yr_free(literal_string);
if (atom_list != NULL)
yr_atoms_list_destroy(atom_list);
return result;
}
int yr_parser_reduce_rule_declaration_phase_1(
yyscan_t yyscanner,
int32_t flags,
const char* identifier,
YR_RULE** rule)
{
YR_FIXUP *fixup;
YR_INIT_RULE_ARGS *init_rule_args;
YR_COMPILER* compiler = yyget_extra(yyscanner);
*rule = NULL;
if (yr_hash_table_lookup(
compiler->rules_table,
identifier,
compiler->current_namespace->name) != NULL ||
yr_hash_table_lookup(
compiler->objects_table,
identifier,
NULL) != NULL)
{
// A rule or variable with the same identifier already exists, return the
// appropriate error.
yr_compiler_set_error_extra_info(compiler, identifier);
return ERROR_DUPLICATED_IDENTIFIER;
}
FAIL_ON_ERROR(yr_arena_allocate_struct(
compiler->rules_arena,
sizeof(YR_RULE),
(void**) rule,
offsetof(YR_RULE, identifier),
offsetof(YR_RULE, tags),
offsetof(YR_RULE, strings),
offsetof(YR_RULE, metas),
offsetof(YR_RULE, ns),
EOL))
(*rule)->g_flags = flags;
(*rule)->ns = compiler->current_namespace;
(*rule)->num_atoms = 0;
#ifdef PROFILING_ENABLED
(*rule)->time_cost = 0;
memset(
(*rule)->time_cost_per_thread, 0, sizeof((*rule)->time_cost_per_thread));
#endif
FAIL_ON_ERROR(yr_arena_write_string(
compiler->sz_arena,
identifier,
(char**) &(*rule)->identifier));
FAIL_ON_ERROR(yr_parser_emit(
yyscanner,
OP_INIT_RULE,
NULL));
FAIL_ON_ERROR(yr_arena_allocate_struct(
compiler->code_arena,
sizeof(YR_INIT_RULE_ARGS),
(void**) &init_rule_args,
offsetof(YR_INIT_RULE_ARGS, rule),
offsetof(YR_INIT_RULE_ARGS, jmp_addr),
EOL));
init_rule_args->rule = *rule;
// jmp_addr holds the address to jump to when we want to skip the code for
// the rule. It is iniatialized as NULL at this point because we don't know
// the address until emmiting the code for the rule's condition. The address
// is set in yr_parser_reduce_rule_declaration_phase_2.
init_rule_args->jmp_addr = NULL;
// Create a fixup entry for the jump and push it in the stack
fixup = (YR_FIXUP*) yr_malloc(sizeof(YR_FIXUP));
if (fixup == NULL)
return ERROR_INSUFFICIENT_MEMORY;
fixup->address = (void*) &(init_rule_args->jmp_addr);
fixup->next = compiler->fixup_stack_head;
compiler->fixup_stack_head = fixup;
// Clean strings_table as we are starting to parse a new rule.
yr_hash_table_clean(compiler->strings_table, NULL);
FAIL_ON_ERROR(yr_hash_table_add(
compiler->rules_table,
identifier,
compiler->current_namespace->name,
(void*) *rule));
compiler->current_rule = *rule;
return ERROR_SUCCESS;
}
static int _yr_parser_write_string(
const char* identifier,
int flags,
YR_COMPILER* compiler,
SIZED_STRING* str,
RE_AST* re_ast,
YR_STRING** string,
int* min_atom_quality,
int* num_atom)
{
SIZED_STRING* literal_string;
YR_ATOM_LIST_ITEM* atom;
YR_ATOM_LIST_ITEM* atom_list = NULL;
int c, result;
int max_string_len;
bool free_literal = false;
*string = NULL;
result = yr_arena_allocate_struct(
compiler->strings_arena,
sizeof(YR_STRING),
(void**) string,
offsetof(YR_STRING, identifier),
offsetof(YR_STRING, string),
offsetof(YR_STRING, chained_to),
offsetof(YR_STRING, rule),
EOL);
if (result != ERROR_SUCCESS)
return result;
result = yr_arena_write_string(
compiler->sz_arena,
identifier,
&(*string)->identifier);
if (result != ERROR_SUCCESS)
return result;
if (flags & STRING_GFLAGS_HEXADECIMAL ||
flags & STRING_GFLAGS_REGEXP)
{
literal_string = yr_re_ast_extract_literal(re_ast);
if (literal_string != NULL)
{
flags |= STRING_GFLAGS_LITERAL;
free_literal = true;
}
else
{
// Non-literal strings can't be marked as fixed offset because once we
// find a string atom in the scanned data we don't know the offset where
// the string should start, as the non-literal strings can contain
// variable-length portions.
flags &= ~STRING_GFLAGS_FIXED_OFFSET;
}
}
else
{
literal_string = str;
flags |= STRING_GFLAGS_LITERAL;
}
(*string)->g_flags = flags;
(*string)->chained_to = NULL;
(*string)->fixed_offset = UNDEFINED;
(*string)->rule = compiler->current_rule;
memset((*string)->matches, 0,
sizeof((*string)->matches));
memset((*string)->unconfirmed_matches, 0,
sizeof((*string)->unconfirmed_matches));
if (flags & STRING_GFLAGS_LITERAL)
{
(*string)->length = (uint32_t) literal_string->length;
result = yr_arena_write_data(
compiler->sz_arena,
literal_string->c_string,
literal_string->length + 1, // +1 to include terminating NULL
(void**) &(*string)->string);
if (result == ERROR_SUCCESS)
{
result = yr_atoms_extract_from_string(
&compiler->atoms_config,
(uint8_t*) literal_string->c_string,
(int32_t) literal_string->length,
flags,
&atom_list,
min_atom_quality);
}
}
else
{
// Emit forwards code
result = yr_re_ast_emit_code(re_ast, compiler->re_code_arena, false);
// Emit backwards code
if (result == ERROR_SUCCESS)
result = yr_re_ast_emit_code(re_ast, compiler->re_code_arena, true);
if (result == ERROR_SUCCESS)
result = yr_atoms_extract_from_re(
&compiler->atoms_config,
re_ast,
flags,
&atom_list,
min_atom_quality);
}
if (result == ERROR_SUCCESS)
{
// Add the string to Aho-Corasick automaton.
result = yr_ac_add_string(
compiler->automaton,
*string,
atom_list,
compiler->matches_arena);
}
if (flags & STRING_GFLAGS_LITERAL)
{
if (flags & STRING_GFLAGS_WIDE)
max_string_len = (*string)->length * 2;
else
max_string_len = (*string)->length;
if (max_string_len <= YR_MAX_ATOM_LENGTH)
(*string)->g_flags |= STRING_GFLAGS_FITS_IN_ATOM;
}
atom = atom_list;
c = 0;
while (atom != NULL)
{
atom = atom->next;
c++;
}
(*num_atom) += c;
if (free_literal)
yr_free(literal_string);
if (atom_list != NULL)
yr_atoms_list_destroy(atom_list);
return result;
}
YR_STRING* yr_parser_reduce_string_declaration(
yyscan_t yyscanner,
int32_t flags,
const char* identifier,
SIZED_STRING* str)
{
int i;
int error_offset;
int min_atom_length;
char* file_name;
char message[512];
YR_STRING* string;
YR_AC_MATCH* new_match;
ATOM_TREE* atom_tree;
YR_ATOM_LIST_ITEM* atom;
YR_ATOM_LIST_ITEM* atom_list = NULL;
RE* re = NULL;
uint8_t* literal_string;
int literal_string_len;
int max_string_len;
YR_COMPILER* compiler = yyget_extra(yyscanner);
compiler->last_result = yr_arena_allocate_struct(
compiler->strings_arena,
sizeof(YR_STRING),
(void**) &string,
offsetof(YR_STRING, identifier),
offsetof(YR_STRING, string),
EOL);
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
compiler->last_result = yr_arena_write_string(
compiler->sz_arena,
identifier,
&string->identifier);
if (compiler->last_result != ERROR_SUCCESS)
return NULL;
if (strcmp(identifier,"$") == 0)
flags |= STRING_GFLAGS_ANONYMOUS;
if (!(flags & STRING_GFLAGS_WIDE))
flags |= STRING_GFLAGS_ASCII;
// The STRING_GFLAGS_SINGLE_MATCH flag indicates that finding
// a single match for the string is enough. This is true in
// most cases, except when the string count (#) and string offset (@)
// operators are used. All strings are marked STRING_FLAGS_SINGLE_MATCH
// initially, and unmarked later if required.
flags |= STRING_GFLAGS_SINGLE_MATCH;
string->g_flags = flags;
memset(string->matches, 0, sizeof(string->matches));
if (flags & STRING_GFLAGS_HEXADECIMAL ||
flags & STRING_GFLAGS_REGEXP)
{
if (flags & STRING_GFLAGS_HEXADECIMAL)
compiler->last_result = yr_re_compile_hex(
str->c_string, &re);
else
compiler->last_result = yr_re_compile(
str->c_string, &re);
if (compiler->last_result != ERROR_SUCCESS)
{
snprintf(
message,
sizeof(message),
"invalid %s in string \"%s\": %s",
(flags & STRING_GFLAGS_HEXADECIMAL) ?
"hex string" : "regular expression",
identifier,
re->error_message);
yr_compiler_set_error_extra_info(compiler, message);
string = NULL;
goto _exit;
}
if (re->flags & RE_FLAGS_START_ANCHORED)
string->g_flags |= STRING_GFLAGS_START_ANCHORED;
if (re->flags & RE_FLAGS_END_ANCHORED)
string->g_flags |= STRING_GFLAGS_END_ANCHORED;
if (re->flags & RE_FLAGS_FAST_HEX_REGEXP)
string->g_flags |= STRING_GFLAGS_FAST_HEX_REGEXP;
if (re->flags & RE_FLAGS_LITERAL_STRING)
{
string->g_flags |= STRING_GFLAGS_LITERAL;
literal_string = re->literal_string;
literal_string_len = re->literal_string_len;
compiler->last_result = yr_atoms_extract_from_string(
literal_string, literal_string_len, string->g_flags, &atom_list);
}
else
{
compiler->last_result = yr_re_emit_code(
re, compiler->re_code_arena);
if (compiler->last_result != ERROR_SUCCESS)
{
string = NULL;
goto _exit;
}
compiler->last_result = yr_atoms_extract_from_re(
re, string->g_flags, &atom_list);
}
}
else
{
string->g_flags |= STRING_GFLAGS_LITERAL;
literal_string = (uint8_t*) str->c_string;
literal_string_len = str->length;
compiler->last_result = yr_atoms_extract_from_string(
literal_string, literal_string_len, string->g_flags, &atom_list);
}
if (compiler->last_result != ERROR_SUCCESS)
{
string = NULL;
goto _exit;
}
if (STRING_IS_LITERAL(string))
{
compiler->last_result = yr_arena_write_data(
compiler->sz_arena,
literal_string,
literal_string_len,
(void*) &string->string);
if (compiler->last_result != ERROR_SUCCESS)
{
string = NULL;
goto _exit;
}
string->length = literal_string_len;
}
// Add the string to Aho-Corasick automaton.
if (atom_list != NULL)
{
compiler->last_result = yr_ac_add_string(
compiler->automaton_arena,
compiler->automaton,
string,
atom_list);
}
else
{
compiler->last_result = yr_arena_allocate_struct(
compiler->automaton_arena,
sizeof(YR_AC_MATCH),
(void**) &new_match,
offsetof(YR_AC_MATCH, string),
offsetof(YR_AC_MATCH, forward_code),
offsetof(YR_AC_MATCH, backward_code),
offsetof(YR_AC_MATCH, next),
EOL);
if (compiler->last_result == ERROR_SUCCESS)
{
new_match->backtrack = 0;
new_match->string = string;
new_match->forward_code = re->root_node->forward_code;
new_match->backward_code = NULL;
new_match->next = compiler->automaton->root->matches;
compiler->automaton->root->matches = new_match;
}
}
atom = atom_list;
if (atom != NULL)
min_atom_length = MAX_ATOM_LENGTH;
else
min_atom_length = 0;
while (atom != NULL)
{
if (atom->atom_length < min_atom_length)
min_atom_length = atom->atom_length;
atom = atom->next;
}
if (STRING_IS_LITERAL(string))
{
if (STRING_IS_WIDE(string))
max_string_len = string->length * 2;
else
max_string_len = string->length;
if (max_string_len == min_atom_length)
string->g_flags |= STRING_GFLAGS_FITS_IN_ATOM;
}
if (compiler->file_name_stack_ptr > 0)
file_name = compiler->file_name_stack[compiler->file_name_stack_ptr - 1];
else
file_name = NULL;
if (min_atom_length < 2 && compiler->error_report_function != NULL)
{
snprintf(
message,
sizeof(message),
"%s is slowing down scanning%s",
string->identifier,
min_atom_length == 0 ? " (critical!)" : "");
compiler->error_report_function(
YARA_ERROR_LEVEL_WARNING,
file_name,
yyget_lineno(yyscanner),
message);
}
if (compiler->last_result != ERROR_SUCCESS)
string = NULL;
_exit:
if (atom_list != NULL)
yr_atoms_list_destroy(atom_list);
if (re != NULL)
yr_re_destroy(re);
return string;
}
