02-15-2024 02:05 PM
There's a bug in the GP client code that's encountered when connecting via an iPhone hotspot that's using an IPv6 only cell carrier where NAT64/CLAT are used. Under these conditions PanGPS segfaults and crashes while it's processing gateway's from what appears to be a null pointer dereference. The bugged logic seems to occur from the 192.0.0.2/32 your WiFi interface is receiving from the iPhones DHCP. Apple must have made a change here in one of the recent IOS updates.
As a workaround, change your WiFi interface to a static IP with a netmask that isn't /32:
Something like:
> networksetup -setmanual Wi-Fi 172.20.10.3 255.255.255.240 172.20.10.1
And when you disconnect from your hotspot and reconnect to regular wifi you would need to revert with:
> networksetup -setdhcp Wi-Fi
You can verify if you're encountering the same bug by checking the crash log (.ips extension) in the GP troubleshooting logs.
You'll see:
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000020
Exception Codes: 0x0000000000000001, 0x0000000000000020
The segfault always occurs in the pan_connect_socket() function (3140 bytes in on ARM64; 3408 bytes in on x86), usually in the 'CaptivePortalDetectionThread' thread, but sometimes on other threads such as the "NetworkDiscoverThread".
