[Coverity CID :207971] Negative array index read in subsys/net/l2/ppp/ipcp.c

[zephyrbot]

Static code scan issues found in file:

https://github.com/zephyrproject-rtos/zephyr/tree/a3e89e84a801d9bc048b0ee2177f0fb11d1a925a/subsys/net/l2/ppp/ipcp.c#L190

Category: Memory - illegal accesses
Function: ipcp_config_info_req
Component: Networking
CID: 207971

Details:

184             struct ppp_context *ctx;
185             struct in_addr addr;
186             int ret;
187    
188             ctx = CONTAINER_OF(fsm, struct ppp_context, ipcp.fsm);
189    
>>>     CID 207971:  Memory - illegal accesses  (REVERSE_NEGATIVE)
>>>     You might be using variable "address_option_idx" before verifying that it is >= 0.
190             if (address_option_idx < 0) {
191                 /* Address option was not present */
192                 return -EINVAL;
193             }
194    
195             code = PPP_CONFIGURE_ACK;

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.

[jukkar]

False positive, the code never uses address_option_idx when its value is < 0