Warning offline user crashes RAS

[jgknight]

Subject of the issue

When a client sends a warning for an offline user, retro-aim-server crashes with a segmentation fault.

Deployment environment

• retro-aim-server version: Multiple versions, as of 643b26e

• Install method: source, reproduced on Linux and MacOS

• Clients used: AIM 5.1.3036, AIM 5.9.6089

• Other relevant details:

Steps to reproduce

1. Sign on two users, Alice and Bob
2. Start a conversation between Alice and Bob
3. Sign off Alice
4. Have Bob attempt to warn Alice
5. Observe that when the warning is sent, RAS crashes with a segmentation fault

Expected behaviour

Expect an error back that the user is offline or otherwise indicate the warning was not successful

Actual behaviour

ras crashes with segmentation fault

Troubleshooting data

icbm.go EvilRequest() attempts to check if the user is online before performing the warning, but it is sending an empty snac which causes a crash when marshalling/encoding the empty snac.

[signal SIGSEGV: segmentation violation code=0x1 addr=0x98 pc=0x54cffc]

goroutine 24 gp=0x40000e6fc0 m=5 mp=0x40000b4808 [running]:
panic({0x7b97a0?, 0xab22d0?})
        /usr/local/go/src/runtime/panic.go:779 +0x140 fp=0x40001154f0 sp=0x4000115440 pc=0x43f270
runtime.panicmem(...)
        /usr/local/go/src/runtime/panic.go:261
runtime.sigpanic()
        /usr/local/go/src/runtime/signal_unix.go:881 +0x308 fp=0x4000115550 sp=0x40001154f0 pc=0x459288
github.com/mk6i/retro-aim-server/wire.marshal({0x0, 0x0}, {0x0?, 0x0?, 0x4000173140?}, {0x0, 0x0}, {0x8ab120, 0x4000171500})
        /home/ubuntu/retro-aim-server/wire/encode.go:19 +0x4c fp=0x40001157f0 sp=0x4000115560 pc=0x54cffc
github.com/mk6i/retro-aim-server/wire.Marshal({0x0?, 0x0?}, {0x8ab120?, 0x4000171500?})
        /home/ubuntu/retro-aim-server/wire/encode.go:15 +0xc0 fp=0x4000115870 sp=0x40001157f0 pc=0x54cf70
github.com/mk6i/retro-aim-server/wire.(*FlapClient).SendSNAC(0x4000158870, {0x0, 0x0, 0x0, 0x0}, {0x0, 0x0})
        /home/ubuntu/retro-aim-server/wire/frames.go:189 +0x8c fp=0x40001158c0 sp=0x4000115870 pc=0x54e16c
github.com/mk6i/retro-aim-server/server/oscar/handler.ICBMHandler.EvilRequest({{0x8ad988?, 0x4000075680?}, {0x4000012760?}}, {0x8adb10, 0x4000158960}, 0x40000f89a0, {0x8?, 0x0?, 0x0?, 0x1730
c0?}, ...)
        /home/ubuntu/retro-aim-server/server/oscar/handler/icbm.go:74 +0x17c fp=0x4000115960 sp=0x40001158c0 pc=0x6a3a6c
github.com/mk6i/retro-aim-server/server/oscar/handler.ICBMHandler.EvilRequest-fm({0x8adb10?, 0x4000158960?}, 0x4000115a28?, {0x8d4?, 0x6a?, 0x0?, 0x0?}, {0x8ab220?, 0x4000171380?}, {0x8ab280
?, ...})
        <autogenerated>:1 +0x80 fp=0x40001159d0 sp=0x4000115960 pc=0x6ad5e0
github.com/mk6i/retro-aim-server/server/oscar.HandlerFunc.Handle(0x7b6ac0?, {0x8adb10?, 0x4000158960?}, 0x4000173060?, {0x10?, 0x0?, 0x0?, 0x0?}, {0x8ab220?, 0x4000171380?}, ...)
        /home/ubuntu/retro-aim-server/server/oscar/router.go:50 +0x68 fp=0x4000115a30 sp=0x40001159d0 pc=0x6a07e8
github.com/mk6i/retro-aim-server/server/oscar.Router.Handle({0x79aaa0?}, {0x8adb10, 0x4000158960}, 0x40000f89a0, {0x4, 0x8, 0x0, 0x516c0008}, {0x8ab220, 0x4000171380}, ...)
        /home/ubuntu/retro-aim-server/server/oscar/router.go:72 +0x138 fp=0x4000115ac0 sp=0x4000115a30 pc=0x6a0998
github.com/mk6i/retro-aim-server/server/oscar.dispatchIncomingMessages({0x8adb10, 0x4000158960}, 0x40000f89a0, 0x4000158870, {0x8ab640, 0x4000026268}, 0x4000012760, {0x8aaf60, 0x40000756b0},
 {{0x40000100b9, ...}, ...})
        /home/ubuntu/retro-aim-server/server/oscar/connection.go:90 +0x2b8 fp=0x4000115d00 sp=0x4000115ac0 pc=0x69fe78