Ramez Naam - Nexus

Rangan and Kade pulled up their development environments and linked them. Ilya linked to their environments and watched over their virtual shoulders. They thought through the plan, divided the tasks up as they turned it from a vague idea into a concrete list of things to do.

Plan complete, they set to work. It went quickly at first. The backdoors they cloned from their existing overrides, changing only the passwords. The code in the compiler was conceptually simple. But as they coded, they hit bugs, each one a frustration. They checked the clock constantly. Minutes went by as they worked. An hour. A compiler crash frustrated them for twenty minutes. The fix was trivial once they understood it. A second hour had passed. One of the back doors was leaking memory. How could that be? They'd copied the code from the back door they already had. They figured it out. This fix took longer. A third hour passed.

At hour four, the back doors were working and the Nexus compiler was adding them. Rangan forced the /obfuscate flag on, instructing the compiler to scatter the new code far and wide as seemingly disconnected, innocuous instructions in the binary, making reverse-engineering what they'd done even more difficult. Next they needed to change the workstation compiler to add the backdoor code to the Nexus compiler. Rangan got on that.

Kade turned his attention to the second phase. He wanted to be able to use the back door without the person running Nexus OS knowing. He needed support for hidden processes. ModOS had that in some form. It was simple in theory, but there were so many tendrils.

He took large chunks of ModOS code they'd never used and brought them back into Nexus OS. The back doors would connect them to a hidden super-user account. That would do most of what he wanted. Logging would be off for that account. Yes. How to hide the memory usage?

Shit. His ears were popping. They were landing. He looked out the window. Fuck. They were at SFO, the airport closest to UCSF. How long from SFO to lab? Twenty minutes? Twenty-five? Shit. Rangan was done. Kade still had to finish up.

Could he hide the memory usage? He didn't see how. He'd have to leave it in. Were there other telltales someone could find? Think, think. Logfiles. Had he gotten them all? Network traces? No easy way to hide those. He'd have to leave them in.

He glanced outside the window again. The ground was coming up. He cursed under his breath, then caught himself. Fuck. Stay quiet. Stay cool. OK. He compiled the rev of Nexus OS he had. He had time for only the most basic tests. Compiling… Compiling… Done. He put it in the stress simulator. Did it crash? Not right away. Did it leak memory? Not obviously. Could he still use the backdoors? Yes. Could he hide a process from himself… Checking… Checking. Looked like it. Would it hold up to real digging? He had no idea.

The wheels hit the ground mid-test. Fuck.

[kade]Still working. Cover for me.

[rangan]On it.

Kade went back to work. He could do this. He could finish in time.

The pressure in the cabin changed. The door was opening.

[ilya]Heads up. Focus on the real world for just a minute here.

Myers stood up. "OK, everyone out and into the car."

Kade looked out the window. There was a black SUV alongside them, a big guy in a black suit next to it. Fuck. He stood up. The code beckoned. He remembered a flag he needed to change. Shit, what file was that in? Myers walked towards him, locking eyes with him. Kade held his breath. Did he know? The ERD agent stopped.

"Come on. Let's move." Myers gestured towards the aisle and the door behind Kade.

Kade blinked. Move. Yes. Off the plane. He turned wordlessly, stepped into the aisle, went down the stairs behind Rangan. He could feel Myers right behind him. He could imagine Myers's meaty hand coming down on his shoulder, imagine the ERD agent croaking out, "You've been trying to fuck with us, haven't you?"

He nearly tripped. Myers caught him by the arm from behind. "Watch your step," he said.

Fuck. Where was his head at? Breathe. Steady. He made it into the third row of seats in the SUV. Myers closed the door on the three of them and got into the shotgun seat.

[ilya] OK. We got you covered.

Ilya started talking. "My car was at Simonyi Field. Is there going to be a way for me to get it?"

"Officer Lewis here can take you there after this is over."

"I need a ride too," Rangan said. "And I think my key was in a bag inside the hangar. Will that still be there…?" And on and on.

Kade focused on his work. Fuck. The new Nexus OS in the stress simulator had crashed after seven minutes. Shit shit shit. Look at the stack trace. What had caused the crash? All he'd done was reactivate standard ModOS code. Oh, fuck. He'd coded a crude hack to stop all logging. Something must depend on the logfiles.

Sure enough. It was a crash in accessing a logfile. OK. What to do? He created empty logfiles by hand, let the simulator run again. Another crash.

OK. Not empty logfiles. Logfiles with a bogus entry in them.

He made the mistake of looking out the window. They were on the Bayshore Freeway, right along the water, headed north into South San Francisco. Maybe halfway there. Focus, Kade, focus.

He copied a random line out of each of the parallel logfiles in his own Nexus, copied them to the right places, stepped the simulator forward. Shit, it was still past the point where it had crashed. He rewound it, added the logfiles again, put in the bogus entries, ran the stress simulator forward… A second passed. Three seconds. Ten seconds. It hadn't crashed. He was holding his breath, he realized. He let it out.

Rangan and Ilya were talking louder and louder. Had he been making noise? He glanced out the window again. The Bay was gone. Was that Potrero Hill out the window? Fuck, they were close.

He let the stress simulator keep running. He needed to copy the new code into the hidden injector in the compiler. OK, good there. To test it… run a compile using the injector. See if the file sizes were the same. Compiling. Compiling. Fuck, he hated waiting. The freeway curved. That was SoMa outside. Shit. They were almost to the exit.

The compile finished. Identical. Thank god for small miracles. Kade tossed the code over to Rangan to insert one level further upstream into the compiler's compiler. Rangan got on it. Ilya kept talking. They exited onto Duboce Avenue, then turned onto Market Street. They were in downtown San Francisco now, maybe two miles from the lab.

What did Kade need to do now? Oh yeah, the source management. He had to fake it out. He got to work convincing the source management system that these changes had always been there.

The driver turned onto 17th to cut west towards UCSF.

OK. Fake change logs. Fake histories. Fake file change dates. The car turned and turned again.

Rangan's work was done. Kade integrated it. They were on Parnassus Avenue, a few blocks from the lab now. Flashing lights ahead.

The SUV took a strange turn, came around to the lab's back entrance.

[rangan] I'll boot the machine and stall him while you copy the new files over. Cool?

Kade nodded. Shit. Stop that, he told himself.

What have I missed?

"We're here," Myers said. "The fire alarm's been set off in the building. We have twenty minutes." He hopped out and opened their door. They were at the service entrance.

[kade] I need to double-check this. Keep covering.

Ilya chatted away about lab equipment and fire safety and fire department response times. Rangan took Kade's arm, walked him to the door. There was something he'd forgotten. What was it?

There. The separate source tree for ModOS. The changes to the ModOS compiler needed to be in there. He had to fix up the file names, the histories, the dates…