[Coverity CID :219668] Dereference after null check in drivers/espi/host_subs_npcx.c

[zephyrbot]

Static code scan issues found in file:

https:/zephyrproject-rtos/zephyr/tree/bd97359a5338b2542d19011b6d6aa1d8d1b9cc3f/drivers/espi/host_subs_npcx.c#L801

Category: Null pointer dereferences
Function: npcx_host_periph_write_request
Component: Drivers
CID: 219668

Details:

https:/zephyrproject-rtos/zephyr/blob/bd97359a5338b2542d19011b6d6aa1d8d1b9cc3f/drivers/espi/host_subs_npcx.c

829                 /* FW shouldn't modify these flags directly */
830                 *data &= ~NPCX_KBC_STS_MASK;
831                 inst_kbc->HIKMST |= *data;
832                 break;
833             case E8042_CLEAR_FLAG:
834                 /* FW shouldn't modify these flags directly */
>>>     CID 219668:    (FORWARD_NULL)
>>>     Dereferencing null pointer "data".
835                 *data &= ~NPCX_KBC_STS_MASK;
836                 inst_kbc->HIKMST &= ~(*data);
837                 break;
838             default:
839                 return -EINVAL;
840             }
803                  * Enable KBC OBE interrupt after putting data in
804                  * keyboard data register.
805                  */
806                 inst_kbc->HICTRL |= BIT(NPCX_HICTRL_OBECIE);
807                 break;
808             case E8042_WRITE_MB_CHAR:
>>>     CID 219668:    (FORWARD_NULL)
>>>     Dereferencing null pointer "data".
809                 inst_kbc->HIMDO = *data & 0xff;
810                 /*
811                  * Enable KBC OBE interrupt after putting data in
812                  * mouse data register.
813                  */
814                 inst_kbc->HICTRL |= BIT(NPCX_HICTRL_OBECIE);
824             case E8042_CLEAR_OBF:
825                 /* Clear OBF flag in both STATUS and HIKMST to 0 */
826                 inst_kbc->HICTRL |= BIT(NPCX_HICTRL_FW_OBF);
827                 break;
828             case E8042_SET_FLAG:
829                 /* FW shouldn't modify these flags directly */
>>>     CID 219668:    (FORWARD_NULL)
>>>     Dereferencing null pointer "data".
830                 *data &= ~NPCX_KBC_STS_MASK;
831                 inst_kbc->HIKMST |= *data;
832                 break;
833             case E8042_CLEAR_FLAG:
834                 /* FW shouldn't modify these flags directly */
835                 *data &= ~NPCX_KBC_STS_MASK;
795                 LOG_INF("%s: op 0x%x data %x", __func__, op, *data);
796             else
797                 LOG_INF("%s: op 0x%x only", __func__, op);
798    
799             switch (op) {
800             case E8042_WRITE_KB_CHAR:
>>>     CID 219668:    (FORWARD_NULL)
>>>     Dereferencing null pointer "data".
801                 inst_kbc->HIKDO = *data & 0xff;
802                 /*
803                  * Enable KBC OBE interrupt after putting data in
804                  * keyboard data register.
805                  */
806                 inst_kbc->HICTRL |= BIT(NPCX_HICTRL_OBECIE);

Please fix or provide comments in coverity using the link:

https://scan9.coverity.com/reports.htm#v32951/p12996.

Note: This issue was created automatically. Priority was set based on classification
of the file affected and the impact field in coverity. Assignees were set using the CODEOWNERS file.

[MulinChao]

If my assumption is correct, the driver shouldn't change data content in line 830 and refer it in the other section line 809. If so, I will submit a PR to declare 'data' as const pointer and add related modifications.

BTW, I have no permission to access https://scan9.coverity.com/reports.htm#v32951/p12996. Do I need to do something for authority?