GHSA-cwh5-3cw7-4286

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GHSA-cwh5-3cw7-4286

Summary: tlslite-ng off-by-one error on mac checking

Details: tlslite-ng version 0.7.3 and earlier, since commit [d7b288316bca7bcdd082e6ccff5491e241305233](https://github.com/tlsfuzzer/tlslite-ng/commit/d7b288316bca7bcdd082e6ccff5491e241305233) contains a CWE-354: Improper Validation of Integrity Check Value vulnerability in TLS implementation, `tlslite/utils/constanttime.py`: `ct_check_cbc_mac_and_pad()`; line `end_pos = data_len - 1 - mac.digest_size` that can result in an attacker manipulating the TLS ciphertext which will not be detected by receiving tlslite-ng. This attack appears to be exploitable via man in the middle on a network connection. This vulnerability appears to have been fixed after commit [3674815d1b0f7484454995e2737a352e0a6a93d8](https://github.com/tlsfuzzer/tlslite-ng/pull/234/commits/3674815d1b0f7484454995e2737a352e0a6a93d8).

References: https://nvd.nist.gov/vuln/detail/CVE-2018-1000159, https://github.com/tlsfuzzer/tlslite-ng/pull/234/commits/3674815d1b0f7484454995e2737a352e0a6a93d8, https://github.com/tomato42/tlslite-ng/pull/234, https://github.com/tlsfuzzer/tlslite-ng/commit/d7b288316bca7bcdd082e6ccff5491e241305233, https://github.com/pypa/advisory-database/tree/main/vulns/tlslite-ng/PYSEC-2018-31.yaml, https://github.com/tomato42/tlslite-ng