correctly handle non-byte-aligned BIT STRING length #135
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XAMPPRocky
reviewed
Aug 3, 2023
src/ber/de.rs
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| // TODO: | ||
| // Using `saturating_sub` here ensures that the `flip1` test passes, | ||
| // but returning an error on an overflow is probably more correct, | ||
| // at least for DER. | ||
| // Need to consult the spec... | ||
| let bit_length = string.len().saturating_sub(bits as usize); | ||
| string.truncate(bit_length); |
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I'd switch this to checked_sub and then return an error, I'm pretty sure the spec doesn't cover what you should do here
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I've taken a look at X.690 again:
The only way that we can get an overflow here is if string.len() == 0 && bits > 0, meaning the BIT STRING was empty but the unused bits octet was non-zero.
Thus clause 8.6.2.3 applies, and the right thing to do is error.
Will do this now...
|
Thank you for your PR, and congrats on your first contribution! 🎉 |
Merged
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Fixes #134