void _yr_scan_update_match_chain_length( int tidx, YR_STRING* string, YR_MATCH* match_to_update, int chain_length) { YR_MATCH* match; if (match_to_update->chain_length == chain_length) return; match_to_update->chain_length = chain_length; if (string->chained_to == NULL) return; match = string->chained_to->unconfirmed_matches[tidx].head; while (match != NULL) { int64_t ending_offset = match->offset + match->length; if (ending_offset + string->chain_gap_max >= match_to_update->offset && ending_offset + string->chain_gap_min <= match_to_update->offset) { _yr_scan_update_match_chain_length( tidx, string->chained_to, match, chain_length + 1); } match = match->next; } }
int _yr_scan_verify_chained_string_match( YR_STRING* matching_string, YR_SCAN_CONTEXT* context, uint8_t* match_data, uint64_t match_base, uint64_t match_offset, int32_t match_length) { YR_STRING* string; YR_MATCH* match; YR_MATCH* next_match; YR_MATCH* new_match; uint64_t lower_offset; uint64_t ending_offset; int32_t full_chain_length; int tidx = context->tidx; int add_match = FALSE; if (matching_string->chained_to == NULL) { add_match = TRUE; } else { if (matching_string->unconfirmed_matches[tidx].head != NULL) lower_offset = matching_string->unconfirmed_matches[tidx].head->offset; else lower_offset = match_offset; match = matching_string->chained_to->unconfirmed_matches[tidx].head; while (match != NULL) { next_match = match->next; ending_offset = match->offset + match->length; if (ending_offset + matching_string->chain_gap_max < lower_offset) { _yr_scan_remove_match_from_list( match, &matching_string->chained_to->unconfirmed_matches[tidx]); } else { if (ending_offset + matching_string->chain_gap_max >= match_offset && ending_offset + matching_string->chain_gap_min <= match_offset) { add_match = TRUE; break; } } match = next_match; } } if (add_match) { if (STRING_IS_CHAIN_TAIL(matching_string)) { match = matching_string->chained_to->unconfirmed_matches[tidx].head; while (match != NULL) { ending_offset = match->offset + match->length; if (ending_offset + matching_string->chain_gap_max >= match_offset && ending_offset + matching_string->chain_gap_min <= match_offset) { _yr_scan_update_match_chain_length( tidx, matching_string->chained_to, match, 1); } match = match->next; } full_chain_length = 0; string = matching_string; while(string->chained_to != NULL) { full_chain_length++; string = string->chained_to; } // "string" points now to the head of the strings chain match = string->unconfirmed_matches[tidx].head; while (match != NULL) { next_match = match->next; if (match->chain_length == full_chain_length) { _yr_scan_remove_match_from_list( match, &string->unconfirmed_matches[tidx]); match->length = (int32_t) \ (match_offset - match->offset + match_length); match->data = match_data - match_offset + match->offset; match->prev = NULL; match->next = NULL; FAIL_ON_ERROR(_yr_scan_add_match_to_list( match, &string->matches[tidx], FALSE)); } match = next_match; } } else { if (matching_string->matches[tidx].count == 0 && matching_string->unconfirmed_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( context->matching_strings_arena, &matching_string, sizeof(matching_string), NULL)); } FAIL_ON_ERROR(yr_arena_allocate_memory( context->matches_arena, sizeof(YR_MATCH), (void**) &new_match)); new_match->base = match_base; new_match->offset = match_offset; new_match->length = match_length; new_match->data = match_data; new_match->chain_length = 0; new_match->prev = NULL; new_match->next = NULL; FAIL_ON_ERROR(_yr_scan_add_match_to_list( new_match, &matching_string->unconfirmed_matches[tidx], FALSE)); } } return ERROR_SUCCESS; }
int _yr_scan_verify_chained_string_match( YR_ARENA* matches_arena, YR_STRING* matching_string, uint8_t* match_data, size_t match_offset, int32_t match_length, int tidx) { YR_STRING* string; YR_MATCH* match; YR_MATCH* next_match; YR_MATCH* new_match; size_t lower_offset; size_t ending_offset; int32_t full_chain_length; int add_match = FALSE; if (matching_string->chained_to == NULL) { add_match = TRUE; } else { if (matching_string->unconfirmed_matches[tidx].head != NULL) lower_offset = matching_string->unconfirmed_matches[tidx].head->offset; else lower_offset = match_offset; match = matching_string->chained_to->unconfirmed_matches[tidx].head; while (match != NULL) { next_match = match->next; ending_offset = match->offset + match->length; if (ending_offset + matching_string->chain_gap_max < lower_offset) { _yr_scan_remove_match_from_list( match, &matching_string->chained_to->unconfirmed_matches[tidx]); } else { if (ending_offset + matching_string->chain_gap_max >= match_offset && ending_offset + matching_string->chain_gap_min <= match_offset) { add_match = TRUE; break; } } match = next_match; } } if (add_match) { if (STRING_IS_CHAIN_TAIL(matching_string)) { match = matching_string->chained_to->unconfirmed_matches[tidx].head; while (match != NULL) { ending_offset = match->offset + match->length; if (ending_offset + matching_string->chain_gap_max >= match_offset && ending_offset + matching_string->chain_gap_min <= match_offset) { _yr_scan_update_match_chain_length( tidx, matching_string->chained_to, match, 1); } match = match->next; } full_chain_length = 0; string = matching_string; while(string->chained_to != NULL) { full_chain_length++; string = string->chained_to; } // "string" points now to the head of the strings chain match = string->unconfirmed_matches[tidx].head; while (match != NULL) { next_match = match->next; if (match->chain_length == full_chain_length) { _yr_scan_remove_match_from_list( match, &string->unconfirmed_matches[tidx]); match->length = match_offset - match->offset + match_length; match->data = match_data - match_offset + match->offset; match->prev = NULL; match->next = NULL; FAIL_ON_ERROR(_yr_scan_add_match_to_list( match, &string->matches[tidx])); } match = next_match; } } else { FAIL_ON_ERROR(yr_arena_allocate_memory( matches_arena, sizeof(YR_MATCH), (void**) &new_match)); 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, &matching_string->unconfirmed_matches[tidx])); } } return ERROR_SUCCESS; }