mbedtls/ChangeLog.d/fix_ccm_add_length_check.txt
Fredrik Strupe 5e940c6068 Fix additional data length field check for CCM
The CCM specification (NIST SP 800-38C) mandates that the formatting of
the additional data length l(a) changes when it is greater _or equal_ to
2^16 - 2^8 (>= 0xFF00). Since such lengths are not supported in mbed TLS,
the operation should fail in such cases.

This commit fixes an off-by-one error which allowed encryption/decryption
to be executed when l(a) was equal to 0xFF00, resulting in an
incorrect/non-standard length format being used.

Fixes #3719.

Signed-off-by: Fredrik Strupe <fredrik.strupe@silabs.com>
2020-10-08 12:09:44 +02:00

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Bugfix
* Fix an off-by-one error in the additional data length check for
CCM, which allowed encryption with a non-standard length field.
Fixes #3719.