[v1.14.0]: panic: runtime error: invalid memory address or nil pointer dereference in protocol/direct.(*Outbound).fetchMyAddresses on FreeBSD

Operating system

Others

System version

FreeBSD v14.4

Installation type

Original sing-box Command Line

Description

sing-box crashes on startup with a SIGSEGV / nil pointer dereference on FreeBSD 14.4 when initializing the direct outbound.

In sing-box v1.14.0, fetchMyAddresses() was introduced into direct.Outbound.Start(). On FreeBSD, the interface monitoring subsystem is unsupported/stubbed, causing h.router.InterfaceMonitor() (or the default interface lookup) to return nil. Attempting to query addresses on a nil reference results in a crash.

Nearly the same configuration works as expected on FreeBSD 14.4 under v1.13.x.

Logs

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x30 pc=0x10669f0]

goroutine 1 [running]:
github.com/sagernet/sing-box/protocol/direct.(*Outbound).fetchMyAddresses(0x87405c300)
        github.com/sagernet/sing-box/protocol/direct/outbound.go:102 +0x30
github.com/sagernet/sing-box/protocol/direct.(*Outbound).Start(0x30c4cf0?, 0xa0?)
        github.com/sagernet/sing-box/protocol/direct/outbound.go:95 +0x37
github.com/sagernet/sing-box/adapter.LegacyStart({0x1cd5ea0?, 0x87405c300}, 0x2?)
        github.com/sagernet/sing-box/adapter/lifecycle_legacy.go:5 +0xa9
github.com/sagernet/sing-box/adapter/outbound.(*Manager).Start(0x8741a8000, 0x2)
        github.com/sagernet/sing-box/adapter/outbound/manager.go:86 +0x39d
github.com/sagernet/sing-box/adapter.Start({0x1eafcd0, 0x86ff52370}, {0x1ed3ad8, 0x874239e48}, 0x2, {0x86fded290?, 0xb, 0x0?})
        github.com/sagernet/sing-box/adapter/lifecycle.go:86 +0x1a8
github.com/sagernet/sing-box.(*Box).start(0x8741aa3c0)
        github.com/sagernet/sing-box/box.go:623 +0x37d
github.com/sagernet/sing-box.(*Box).Start(0x8741aa3c0)
        github.com/sagernet/sing-box/box.go:548 +0x36
main.create({{0x874226000, 0x3a17, 0x4000}, 0x0, {0x0, 0x0}, 0x874266210, 0x8741a3b20, 0x0, 0x0, ...})
        github.com/sagernet/sing-box/cmd/sing-box/cmd_run.go:164 +0x4a9
main.run()
        github.com/sagernet/sing-box/cmd/sing-box/cmd_run.go:190 +0x293
main.init.func86(0x8741eae00?, {0x1d6b9ec?, 0x4?, 0x1d6b9f0?})
        github.com/sagernet/sing-box/cmd/sing-box/cmd_run.go:30 +0x17
github.com/spf13/cobra.(*Command).execute(0x3101920, {0x8741804c0, 0x2, 0x2})
        github.com/spf13/cobra@v1.10.2/command.go:1019 +0xafb
github.com/spf13/cobra.(*Command).ExecuteC(0x30f27a0)
        github.com/spf13/cobra@v1.10.2/command.go:1148 +0x465
github.com/spf13/cobra.(*Command).Execute(...)
        github.com/spf13/cobra@v1.10.2/command.go:1071
main.main()
        github.com/sagernet/sing-box/cmd/sing-box/main.go:8 +0x1e

Start in protocol/direct/outbound.go, especially Outbound.Start and fetchMyAddresses around lines 95-102. Trace how InterfaceMonitor or the default interface lookup behaves on FreeBSD 14.4. Done means sing-box no longer panics during direct outbound startup when that subsystem is unavailable, while preserving the existing behavior on supported systems.