Code fixes from audit #105
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int can be different sizes on different platforms (although 32-bit is most common). To ensure portability we can use the ‘level_t’ type which is defined as a uint32_t value. This should have no difference in function. Co-authored-by: Jean-Baptiste Bédrune
This is a safer version of memset where memory is completely cleared. This is useful for sensitive data like private keys. https://www.gnu.org/software/libc/manual/html_node/Erasing-Sensitive-Data.html Co-authored-by: Jean-Baptiste Bédrune
Detected by ASAN, buffer underflow occurs when code is capable of unbounded writing to before the buffer begins (compare to buffer overflow). This change ensures that the index is always greater than 0. Co-authored-by: Jean-Baptiste Bédrune
3noch
reviewed
Nov 13, 2019
| @@ -35,7 +35,7 @@ static inline void generate_key_pair( | |||
| check_null(out); | |||
| key_pair_t *const result = generate_key_pair_return_global(derivation_type, bip32_path); | |||
| memcpy(out, result, sizeof(*out)); | |||
| memset(result, 0, sizeof(*result)); | |||
| explicit_bzero(result, sizeof(*result)); | |||
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There are a lot of other places that we use memset(..., 0, ...). Should we replace all of them?
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It might not hurt to do that! Here I am just rewriting the ones that have some private key behind it. If the data's not sensitive, it's probably cheaper to just use memset, but maybe not something we should worry about.
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I've merged this as-is; I'll get a ticket in the backlog to investigate whether to replace the other uses of memset(..., 0, ...) with explicit_bzero.
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Assortment of changes based on audit: