feat: avoid Instantiation of banker on pure packages

[Villaquiranm]

Related to #2192

• Trigger a panic if a p/ attempts to create a banker, but allow interaction with an already instantiated banker from r/.

Don't really know if this is the right approach. If you have another idea of how to implement this security check please let me know :)

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

Attention: Patch coverage is 28.57143% with 5 lines in your changes missing coverage. Please review.

Project coverage is 63.40%. Comparing base (a2e5c3d) to head (53369df).
Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
gnovm/stdlibs/std/native.go	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2248      +/-   ##
==========================================
- Coverage   63.40%   63.40%   -0.01%     
==========================================
  Files         565      565              
  Lines       79454    79461       +7     
==========================================
+ Hits        50375    50379       +4     
- Misses      25688    25690       +2     
- Partials     3391     3392       +1     

Flag	Coverage Δ
contribs/gnodev	60.57% <ø> (+0.62%)	⬆️
contribs/gnofaucet	15.77% <ø> (+0.94%)	⬆️
gno.land	67.37% <ø> (ø)
gnovm	67.87% <28.57%> (-0.01%)	⬇️
misc/genstd	79.72% <ø> (ø)
tm2	62.47% <ø> (+0.13%)	⬆️

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[thehowl]

This will not work in a real life scenario, as CurrentRealm() skips frames of pure packages. (If you want a good side-task, change NewCodeRealm to work only with PkgPath's that match the rules of gnolang.IsRealmPath)

I suggest:

• Having a function like assertCallerIsRealm.
• This should get the frame of the function where this is called (I think m.Frames[m.NumFrames()-2]).
• Then call LastPackage and make sure its PkgPath matches that of gnolang.IsRealmPath.

Thanks!

[Villaquiranm]

This will not work in a real life scenario, as CurrentRealm() skips frames of pure packages. (If you want a good side-task, change NewCodeRealm to work only with PkgPath's that match the rules of gnolang.IsRealmPath)

I suggest:

• Having a function like assertCallerIsRealm.
• This should get the frame of the function where this is called (I think m.Frames[m.NumFrames()-2]).
• Then call LastPackage and make sure its PkgPath matches that of gnolang.IsRealmPath.

Thanks!

Hello thanks a lot for your review and for the great guidance :)
I hope I got the general idea of what you wanted me to do, I got a few questions though

• I put this code on assertCallerIsRealm function should I make some extra verifications ? I don't really know why m.NumFrames()-2.

frame := m.Frames[m.NumFrames()-2]
if !frame.LastPackage.IsRealm() {
	m.Panic(typedString("caller is not a realm"))
}

• When you said a side task for NewCodeRealm this is what you meant ? It is okay to add another function on sdt tests ?
  e7ade2c

[thehowl]

Okay, generally looks good.

To justify why len(m.Frames)-2, I suggest you dump the machine in the point you use it (in the native function), just for your own reference. len(frames)-1 will be the frame of assertCallerIsRealm, len(frames)-2 is the frame of its caller, ie. GetBanker. We can then use LastPackage to determine which package called it.

[thehowl]

Apologies, revert the changes in tests/files/extern and remove that dir from the fmt rule.

gno fmt doesn't understand the imports in that dir and it shouldn't, so let's just skip it.

[Villaquiranm]

Apologies, revert the changes in tests/files/extern and remove that dir from the fmt rule.

gno fmt doesn't understand the imports in that dir and it shouldn't, so let's just skip it.

No worries :)
fixed on 53369df