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Remotely Compromising Android and iOS via a bug in Broadcom's WI-FI Chipsets

(blog.exodusintel.com)
387 points pedro84 | 5 comments | 26 Jul 17 19:51 UTC | HN request time: 0.734s | source
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thomastjeffery ◴[26 Jul 17 23:00 UTC] No.14861166[source]▶
Why does Broadcom insist on proprietary drivers?

How could it possibly be detrimental for Broadcom to have free software drivers?

This article is a poignant example that it is detrimental for them to continue to keep their drivers proprietary.

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azernik ◴[27 Jul 17 17:27 UTC] No.14867469[source]▶
The bugs in question here are not in the drivers (the bits that run in the OS kernel on the CPU). They are in the firmware (code that runs on a little ARM core on the WiFi chip itself - also called the microcode in the biz).

The driver is indeed "protected" for IP-lawyer reasons; they'll have it out under license to every Tom, Dick, and Jane looking to build a device with their chipset. The firmware, on the other hand, is very closely held, because that's where the chip's functionality lives. A WiFi chipset implements a fantastically complicated protocol, and no one wants to bake that into hardware that can't be updated as bugs are found; so they build relatively simple hardware, and slap a microcontroller right on the die that runs all the complicated logic.

This means that the microcode is as sensitive as The hardware specs on earlier generations of hardware; a competitor with a copy of that source can make a (perhaps better and improved) knockoff if they're not too worried about legal implications like, say, several dozen Chinese knockoff shops.

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thomastjeffery ◴[27 Jul 17 17:33 UTC] No.14867534[source]▶

    echo $original_comment | sed 's/driver/firmware/g'
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1. azernik ◴[27 Jul 17 17:42 UTC] No.14867621[source]▶
In which case this is your answer; they're worried about knockoffs, because without the firmware logic their devices are simple commodities, ie don't really have strong differentiators from the competition.
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2. thomastjeffery ◴[27 Jul 17 18:43 UTC] No.14868177[source]▶
Is their firmware really noticeably better or have more features than competing chipsets?
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3. azernik ◴[27 Jul 17 19:02 UTC] No.14868330[source]▶
Yes. 802.11ac, for example, takes both a faster transceiver and a bunch of firmware support, and time to market with this features was a big driver of sales. And that was an ongoing process - ac is actually a set of features, and it's taking years for all of them to be implemented.

Similarly, cheaper chips often don't support optional performance-enhancing features at layers 2 and 3 (link and MAC) that boost performance without any hardware investment.

4. nucleardog ◴[27 Jul 17 22:37 UTC] No.14870318[source]▶
The other hugely important side of this is that a lot of these devices have the ability to transmit on frequencies which they may not be licensed for, or may not be licensed for in all markets.

The easiest example being b/g channel 13. You're permitted to use it for WiFi in most of the world, but not North America. Keeping the firmware proprietary and "secure" is likely an important part of their FCC/IC certifications.

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5. zero_intp ◴[30 Jul 17 18:59 UTC] No.14887299[source]▶
It is required(1). The FCC requires locking down the ability to transmit into regulated frequencies.

1. https://apps.fcc.gov/eas/comments/GetPublishedDocument.html?...