Peter M. Groen / libmodbus

Commit 5ccdf5ef79d742640355d1132fa9e2abc7fbaefc

Authored by Stéphane Raimbault
1 parent 076992fb

Fix VD-1301 and VD-1302 vulnerabilities 

This patch was contributed by Maor Vermucht and Or Peles from
VDOO Connected Trust.
Inline Side-by-side
Showing 1 changed file with 4 additions and 2 deletions
src/modbus.c
  View file @5ccdf5e
... ... @@ -839,9 +839,10 @@ int modbus_reply(modbus_t *ctx, const uint8_t *req,
839 839 break;
840 840 case MODBUS_FC_WRITE_MULTIPLE_COILS: {
841 841 int nb = (req[offset + 3] << 8) + req[offset + 4];
  842 + int nb_bits = req[offset + 5];
842 843 int mapping_address = address - mb_mapping->start_bits;
843 844  
844   - if (nb < 1 || MODBUS_MAX_WRITE_BITS < nb) {
  845 + if (nb < 1 || MODBUS_MAX_WRITE_BITS < nb || nb_bits * 8 < nb) {
845 846 /* May be the indication has been truncated on reading because of
846 847 * invalid address (eg. nb is 0 but the request contains values to
847 848 * write) so it's necessary to flush. */
... ... @@ -870,9 +871,10 @@ int modbus_reply(modbus_t *ctx, const uint8_t *req,
870 871 break;
871 872 case MODBUS_FC_WRITE_MULTIPLE_REGISTERS: {
872 873 int nb = (req[offset + 3] << 8) + req[offset + 4];
  874 + int nb_bytes = req[offset + 5];
873 875 int mapping_address = address - mb_mapping->start_registers;
874 876  
875   - if (nb < 1 || MODBUS_MAX_WRITE_REGISTERS < nb) {
  877 + if (nb < 1 || MODBUS_MAX_WRITE_REGISTERS < nb || nb_bytes * 8 < nb) {
876 878 rsp_length = response_exception(
877 879 ctx, &sft, MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE, rsp, TRUE,
878 880 "Illegal number of values %d in write_registers (max %d)\n",
... ...