fix: use io.ReadFull for salt generation#19
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dhui merged 1 commit intodhui:masterfrom Sep 21, 2025
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Switch salt generation to io.ReadFull to reject short reads and prevent zero-padded, low-entropy salts when the RNG is swapped. Add a short-EOF RNG test to verify failure. Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
dhui
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Sep 21, 2025
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Thanks for the find and fix @thevilledev !
EDIT: also thanks for adding a test to prevent a regression!
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Motivation
Salt generation used
io.Reader.Readand ignored short reads, allowing zero-padded, low-entropy salts when the RNG is swapped.Changes
Switch salt generation to use
io.ReadFull. Performance impact should be negligible.Prevents CWE-331 "Insufficient Entropy". Fails fast on RNG anomalies.
Testing
Add a short-EOF RNG test to verify failure. All tests pass.
Backwards Compatibility
No API changes. Credential creation will now error if the RNG short-reads instead of silently proceeding.