Use constant-time comparison for the HMAC#59
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This PR is stale because it has been open 45 days with no activity. Remove the stale label or add a comment, or this PR will be closed in 10 days. You can always re-open if you feel this is something we should still keep working on. Tag @heynemann for more information. |
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Pull request overview
This PR hardens URL signature (HMAC/MAC) validation by switching from regular equality to a constant-time comparison to mitigate timing attacks.
Changes:
- Use a constant-time comparison function when validating URL signatures.
- Add the necessary standard-library import to support the constant-time comparison.
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| return secrets.compare_digest(url_signature, actual_signature) | ||
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| from six import text_type | ||
| import secrets |
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MACs have to be checked with a constant-time comparison function. Otherwise, they may be forged by timing attacks.