[Toybox] toybox.cp usage for preserving SMACK attributes

[Rob Landley]

On 8/1/23 18:11, Lokesh Chandra Kumar wrote:
> Hello all, 
> 
> I am currently using toybox (version 0.8.6) to copy files in an embedded device,
> but the cp seems to be not preserving SMACK attributes for intermediate
> directories while doing the copy.

Alas SMACK support hasn't been properly regression tested since the Tizen guys
wandered off about 5 years ago. I don't have a test environment for it. (Can you
maybe suggest a distro I can run in kvm to test it?)

In theory we're preserving the xattrs so the security context should marshall
along. I admit some of the newer code (ala tar) has specifically thought about
selinux rather than using the generic lib/lsm.h wrapper functions just because
nobody'd asked about smack in so long.

> This is the command I run, 
> 
> cp -a --preserve=all --parents <abs path to source file or folder> <destination
> directory>
> 
> What I see is that the final file has the correct SMACK attributes, but the
> intermediate folders have their SMACK labels reset to "System". Is this a known
> issue and is there a suitable patch that I could use to prevent this issue ?

Ah, that's a known issue:

  https://github.com/landley/toybox/blob/0.8.10/toys/posix/cp.c#L273

Hmmm, I'll take another stab at it...

Rob