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[FIXED] Make sure to use byte slice to receive proper copy #59

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merged 1 commit into from
Oct 23, 2023

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derekcollison
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@derekcollison derekcollison commented Oct 21, 2023

Empty public key was being used.

Huge thanks for the report from @tinou98!

Signed-off-by: Derek Collison [email protected]

…ublic key is being used.

Signed-off-by: Derek Collison <[email protected]>
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Pull Request Test Coverage Report for Build 6598807631

  • 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
  • No unchanged relevant lines lost coverage.
  • Overall coverage increased (+0.4%) to 80.115%

Totals Coverage Status
Change from base Build 6225067835: 0.4%
Covered Lines: 419
Relevant Lines: 523

💛 - Coveralls

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@philpennock philpennock left a comment

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I don't think this is needed. I think it's fine to apply as a comprehension change, but I think the logic before was correct.

Notably, the prior state was that the input was an array, not a slice, and that the [:] did not force a capacity limit and thus a reallocation.

https://go.dev/play/p/c3N6VcA-L1Q

See that test code, and how using y := x[:] before copying into y also updates x.

So I don't think there's a security issue here. But it's good to be clear, so approving the changes.

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@aricart aricart left a comment

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LGTM

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Okay, so the actual problem is caused by missing that Go is pass-by-value and when you're passing in an array, you get a copy of the array, so the passing in of the slice over the array results in the called function getting a new slice value over the same array, and being able to modify the caller.

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Please update the title before merge, because "Make sure to use byte slice to receive proper copy" is ... the opposite of true? You're using a byte slice so that you're not getting a copy of the underlaying data and can instead modify the original.

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The title I believe is correct, we would copy the byte array on the stack, so when we copied it into that copy, it was lost. Using the slice we do get the data correctly when we return.

@derekcollison derekcollison merged commit d2e442e into main Oct 23, 2023
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@derekcollison derekcollison deleted the empty branch December 28, 2023 17:35
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4 participants