Prevent crash when pjsip_inv_verify_request3() return error

[trengginas]

The pjsip_inv_verify_request3() method will initialize the return argument(p_tdata) to NULL

pjproject/pjsip/src/pjsip-ua/sip_inv.c

Line 1268 in 77b3657

if (p_tdata) *p_tdata = NULL;

So, it might crash here if pjsip_inv_verify_request3() returns error and p_tdata is still not set.

pjproject/pjsip/src/pjsua-lib/pjsua_call.c

Lines 1397 to 1399 in 77b3657

	if (response)
	err_code = (*response)->msg->line.status.code;
	else

This patch will check for the return argument to prevent the crash.

[Copilot]

Pull Request Overview

This PR prevents a potential null-dereference in verify_request by using a temporary response pointer and only accessing it after verifying it's non-NULL.

• Introduces a local pjsip_tx_data *resp initialized to NULL
• Changes the pjsip_inv_verify_request3 call to use &resp
• Updates error handling to check resp before reading status and assign back to *response

Comments suppressed due to low confidence (2)

pjsip/src/pjsua-lib/pjsua_call.c:1382

• [nitpick] The variable name resp is somewhat vague. Consider renaming it to tmp_resp or tx_data_resp to make its purpose clearer.

        pjsip_tx_data *resp = NULL;

pjsip/src/pjsua-lib/pjsua_call.c:1391

• Add a unit or integration test that simulates a failure in pjsip_inv_verify_request3 to verify both branches: when resp remains NULL and when it is set, ensuring the new checks prevent crashes as intended.

                                           pjsua_var.endpt, &resp);