Linux Sandbox: Basic support for GPU broker.

Linux Sandbox: Basic support for GPU broker.

We add a GPU broker process to make sure we can open certain files
once the sandbox is started.

We do not need to allow open() in the GPU policy in certain configuration
anymore, which creates an effective GPU sandbox.

BUG=166111
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=173233

[jln (very slow on Chromium), 2012-12-14 09:07:52]

Jorge, this is a tentative patch to make use of the broker process for the GPU
sandbox.

I didn't test this patch on any configuration that requires /etc/drirc or
/dev/dri/card0.

Could you please test it?

[Jorge Lucangeli Obes, 2012-12-14 19:13:22]

This looks like it actually works.

https://chromiumcodereview.appspot.com/11569028/diff/1/content/common/sandbox...
File content/common/sandbox_seccomp_bpf_linux.cc (right):

https://chromiumcodereview.appspot.com/11569028/diff/1/content/common/sandbox...
content/common/sandbox_seccomp_bpf_linux.cc:1309: void
InitGpu64BrokerProcess(BrokerProcess** broker_process) {
X86_64 I guess, although it does make the name of the function ugly.

https://chromiumcodereview.appspot.com/11569028/diff/1/content/common/sandbox...
content/common/sandbox_seccomp_bpf_linux.cc:1387: // eventually start a broker
process.
'starts' to match 'Warms'.

[Markus (顧孟勤), 2012-12-14 20:23:29]

Yepp. That generally all looks OK

https://chromiumcodereview.appspot.com/11569028/diff/5001/content/common/sand...
File content/common/sandbox_seccomp_bpf_linux.cc (right):

https://chromiumcodereview.appspot.com/11569028/diff/5001/content/common/sand...
content/common/sandbox_seccomp_bpf_linux.cc:108: intptr_t
GpuOpenSIGSYS_Handler(const struct arch_seccomp_data& args,
Just a nitpick. I prefer if you didn't refer to SIGSYS here, because that's an
implementation detail that the user of the sandbox should really be oblivious
too ... and it isn't a signal handler anyway.

Refering to it as a TrapHandler or a Callback would IMHO make more sense. But as
I said, just a nitpick.

[jln (very slow on Chromium), 2012-12-14 20:30:25]

PTAL, I uploaded a new version where the broker process is
also sandboxed.

https://chromiumcodereview.appspot.com/11569028/diff/1/content/common/sandbox...
File content/common/sandbox_seccomp_bpf_linux.cc (right):

https://chromiumcodereview.appspot.com/11569028/diff/1/content/common/sandbox...
content/common/sandbox_seccomp_bpf_linux.cc:1309: void
InitGpu64BrokerProcess(BrokerProcess** broker_process) {
On 2012/12/14 19:13:22, Jorge Lucangeli Obes wrote:
> X86_64 I guess, although it does make the name of the function ugly.

Done.

https://chromiumcodereview.appspot.com/11569028/diff/1/content/common/sandbox...
content/common/sandbox_seccomp_bpf_linux.cc:1387: // eventually start a broker
process.
On 2012/12/14 19:13:22, Jorge Lucangeli Obes wrote:
> 'starts' to match 'Warms'.

Done.

[Markus (顧孟勤), 2012-12-14 22:06:11]

lgtm

[Jorge Lucangeli Obes, 2012-12-14 22:16:24]

On 2012/12/14 22:06:11, Markus (顧孟勤) wrote:
> lgtm

lgtm, the two features that require open() in the GPU process are working.

[commit-bot: I haz the power, 2012-12-14 22:44:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jln@chromium.org/11569028/8003

[commit-bot: I haz the power, 2012-12-14 22:46:57]

Change committed as 173233