Mounting regular files without passing them as untrusted args

[rampage644]

I'd like to propose a feature to pass files from host filesystem (just as with @somefile) but without passing its untrusted filename as untrusted argument.

For example: zvsh some.nexe @file1 @file2 @file3. Right now zvsh will create three channels (/dev/1.file1, /dev/2.file2, /dev/3.file3) and pass their untrusted paths as command line arguments.

It would be handy to somehow mark files just to mount. Like this: zvsh some.nexe @file1,<flag-for-only-mount>.

I faced with need of this feature already :) What do you think?

[mgeisler]

What does it mean to "just mount" a file? How is this different from using --zvm-image?

[rampage644]

It's exactly the same as --zvm-image. But in case of mounting tar its filename doesn't go to argument list.

[larsbutler]

I thought --zvm-image was intended for tar files. In fact, it seems that zvsh will try to treat each --zvm-image as a tar, always.

[mgeisler]

Okay... I'm still not sure I understand exactly what you mean :-) You want

$ zvsh some.nexe @foo,only-mount

to result in the tar file foo being mounted as an image and then you want what path to be passed to the nexe inside ZeroVM?

[mgeisler]

I asked Lars what you mean and he suggested that the issue could be reformulated to this:

Today,

zvsh some.nexe @file1 @file2 @file3

will result in a command line like this inside the sandbox:

some.nexe /dev/1.file1 /dev/2.file2 /dev/3.file3

The paths are translated from the host OS into the corresponding paths inside the sandbox.

It would be handy to somehow specify where the files should be mounted. Like this:

zvsh some.nexe @file1,/etc/foo

This should result in file1 being made available at /etc/foo inside the sandbox and the nexe should be started as

some.nexe /etc/foo

@rampage644 Does this make sense?

[pkit]

When we do tar mount for FS instead of channels all of that will be irrelevant.
So, let's just wait for that feature. Yaroslav actually fixed some bugs that prevented us from using tars.

[pkit]

see #36

[rampage644]

@mgeisler Almost. All i want is to be able to run zvsh some.nexe @file,<only-mount> and have nexe started as some.nexe. Just without arguments.

See? no /dev/1.file in command line. That what I want.

[rampage644]

@pkit, how would #36 address command line arguments? As for me, putting everything in tar is just a matter of implementation of some feature that only could affect, but not necessary. Am I wrong?

[larsbutler]

In that case, I wouldn't recommend using the @ syntax for this. Instead, I would add a new command line flag, similar in function to --zvm-image, something like --mount-file file,mount-point.

On 22 Apr 2014, at 17:32, Sergei Turukin notifications@github.com wrote:

@mgeisler Almost. All i want is to be able to run zvsh some.nexe @file, and have nexe started as some.nexe. Just without arguments.

See? no /dev/1.file in command line. That what I want.

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[pkit]

@rampage644 why do you need to add files to session that were not explicitly stated in the command line? What is the use case?

[rampage644]

@pkit which command line are you talking about? zvsh one? or untrusted sided?

• zvsh one. I'm not saying i want to mount files that are not stated here.
• untrusted side. Why do i ever want to pass every file as command line argument? I could easily read/stat/whatever some hard-coded file. That what i want. Or just mimic zerocloud middleware: pass /dev/input and /dev/output into untrusted side without polluting nexe's command line.

@larsbutler, totally agree. I would prefer adding new option like --mount-file for regular files as --zvm-image for tar's. But we still may have @ with simpilfied syntax.

[larsbutler]

@rampage644

I would prefer adding new option like --mount-file for regular files as --zvm-image for tar's. But we still may have @ with simpilfied syntax.

Personally, I don't think the @ syntax is simplified, but maybe it's just me. =) If you want something some short and concise, we could instead make an alias for the --mount-file flag; something like -m. So instead of this:

zvsh some.nexe @file.txt,<only-mount>

You would have this:

zvsh --mount-file file.txt some.nexe
or
zvsh -m file.txt some.nexe

What do you think about that?

[rampage644]

I think this option would simplify source code a little (or not a little?). I see no real difference in using @ or -m/--mount, so if i should have a choice, i will change the syntax.