int _yr_scan_match_callback( uint8_t* match_data, int32_t match_length, int flags, void* args) { CALLBACK_ARGS* callback_args = (CALLBACK_ARGS*) args; YR_STRING* string = callback_args->string; YR_MATCH* new_match; int result = ERROR_SUCCESS; int tidx = callback_args->context->tidx; size_t match_offset = match_data - callback_args->data; // total match length is the sum of backward and forward matches. match_length += callback_args->forward_matches; if (callback_args->full_word) { if (flags & RE_FLAGS_WIDE) { if (match_offset >= 2 && *(match_data - 1) == 0 && isalnum(*(match_data - 2))) return ERROR_SUCCESS; if (match_offset + match_length + 1 < callback_args->data_size && *(match_data + match_length + 1) == 0 && isalnum(*(match_data + match_length))) return ERROR_SUCCESS; } else { if (match_offset >= 1 && isalnum(*(match_data - 1))) return ERROR_SUCCESS; if (match_offset + match_length < callback_args->data_size && isalnum(*(match_data + match_length))) return ERROR_SUCCESS; } } if (STRING_IS_CHAIN_PART(string)) { result = _yr_scan_verify_chained_string_match( string, callback_args->context, match_data, callback_args->data_base, match_offset, match_length); } else { if (string->matches[tidx].count == 0) { // If this is the first match for the string, put the string in the // list of strings whose flags needs to be cleared after the scan. FAIL_ON_ERROR(yr_arena_write_data( callback_args->context->matching_strings_arena, &string, sizeof(string), NULL)); } result = yr_arena_allocate_memory( callback_args->context->matches_arena, sizeof(YR_MATCH), (void**) &new_match); if (result == ERROR_SUCCESS) { new_match->base = callback_args->data_base; new_match->offset = match_offset; new_match->length = match_length; new_match->data = match_data; new_match->prev = NULL; new_match->next = NULL; FAIL_ON_ERROR(_yr_scan_add_match_to_list( new_match, &string->matches[tidx], STRING_IS_GREEDY_REGEXP(string))); } } return result; }
int _yr_scan_verify_re_match( YR_SCAN_CONTEXT* context, YR_AC_MATCH* ac_match, uint8_t* data, size_t data_size, size_t data_base, size_t offset) { CALLBACK_ARGS callback_args; RE_EXEC_FUNC exec; int forward_matches = -1; int backward_matches = -1; int flags = 0; if (STRING_IS_GREEDY_REGEXP(ac_match->string)) flags |= RE_FLAGS_GREEDY; if (STRING_IS_FAST_HEX_REGEXP(ac_match->string)) exec = _yr_scan_fast_hex_re_exec; else exec = yr_re_exec; if (STRING_IS_ASCII(ac_match->string)) { forward_matches = exec( ac_match->forward_code, data + offset, data_size - offset, offset > 0 ? flags | RE_FLAGS_NOT_AT_START : flags, NULL, NULL); } if (STRING_IS_WIDE(ac_match->string) && forward_matches == -1) { flags |= RE_FLAGS_WIDE; forward_matches = exec( ac_match->forward_code, data + offset, data_size - offset, offset > 0 ? flags | RE_FLAGS_NOT_AT_START : flags, NULL, NULL); } switch(forward_matches) { case -1: return ERROR_SUCCESS; case -2: return ERROR_INSUFICIENT_MEMORY; case -3: return ERROR_TOO_MANY_MATCHES; case -4: return ERROR_TOO_MANY_RE_FIBERS; case -5: return ERROR_INTERNAL_FATAL_ERROR; } if (forward_matches == 0 && ac_match->backward_code == NULL) return ERROR_SUCCESS; callback_args.string = ac_match->string; callback_args.context = context; callback_args.data = data; callback_args.data_size = data_size; callback_args.data_base = data_base; callback_args.forward_matches = forward_matches; callback_args.full_word = STRING_IS_FULL_WORD(ac_match->string); if (ac_match->backward_code != NULL) { backward_matches = exec( ac_match->backward_code, data + offset, offset, flags | RE_FLAGS_BACKWARDS | RE_FLAGS_EXHAUSTIVE, _yr_scan_match_callback, (void*) &callback_args); switch(backward_matches) { case -2: return ERROR_INSUFICIENT_MEMORY; case -3: return ERROR_TOO_MANY_MATCHES; case -4: return ERROR_TOO_MANY_RE_FIBERS; case -5: return ERROR_INTERNAL_FATAL_ERROR; } } else { FAIL_ON_ERROR(_yr_scan_match_callback( data + offset, 0, flags, &callback_args)); } return ERROR_SUCCESS; }
static int _yr_scan_verify_re_match( YR_SCAN_CONTEXT* context, YR_AC_MATCH* ac_match, const uint8_t* data, size_t data_size, uint64_t data_base, size_t offset) { CALLBACK_ARGS callback_args; RE_EXEC_FUNC exec; int forward_matches = -1; int backward_matches = -1; int flags = 0; if (STRING_IS_GREEDY_REGEXP(ac_match->string)) flags |= RE_FLAGS_GREEDY; if (STRING_IS_NO_CASE(ac_match->string)) flags |= RE_FLAGS_NO_CASE; if (STRING_IS_DOT_ALL(ac_match->string)) flags |= RE_FLAGS_DOT_ALL; if (STRING_IS_FAST_REGEXP(ac_match->string)) exec = yr_re_fast_exec; else exec = yr_re_exec; if (STRING_IS_ASCII(ac_match->string)) { FAIL_ON_ERROR(exec( context, ac_match->forward_code, data + offset, data_size - offset, offset, flags, NULL, NULL, &forward_matches)); } if (STRING_IS_WIDE(ac_match->string) && forward_matches == -1) { flags |= RE_FLAGS_WIDE; FAIL_ON_ERROR(exec( context, ac_match->forward_code, data + offset, data_size - offset, offset, flags, NULL, NULL, &forward_matches)); } if (forward_matches == -1) return ERROR_SUCCESS; if (forward_matches == 0 && ac_match->backward_code == NULL) return ERROR_SUCCESS; callback_args.string = ac_match->string; callback_args.context = context; callback_args.data = data; callback_args.data_size = data_size; callback_args.data_base = data_base; callback_args.forward_matches = forward_matches; callback_args.full_word = STRING_IS_FULL_WORD(ac_match->string); if (ac_match->backward_code != NULL) { FAIL_ON_ERROR(exec( context, ac_match->backward_code, data + offset, data_size - offset, offset, flags | RE_FLAGS_BACKWARDS | RE_FLAGS_EXHAUSTIVE, _yr_scan_match_callback, (void*) &callback_args, &backward_matches)); } else { FAIL_ON_ERROR(_yr_scan_match_callback( data + offset, 0, flags, &callback_args)); } return ERROR_SUCCESS; }