I just added a -checkbase64 switch to mhfixmsg(1): The -checkbase64 switch enables a check of the encoding validity in base64-encoded MIME parts. The check looks for a non-encoded text footer appended to a base64-encoded part. Per RFC 2045 §6.8, the occurrence of a "=" character signifies the end of base-64 encoded content. If none is found, a heuristic is used: specifically, two consecutive invalid base64 characters signify the beginning of a plain text footer. If a text footer is found and this switch is enabled, mhfixmsg separates the base64-encoded and non-encoded content and places them in a pair of subparts to a newly constructed multipart/mixed part. That multipart/mixed part replaces the original base64-encoded part in the MIME structure of the message.
It takes care of the particular issue reported by Anthony. It is enabled by default in mhfixmsg. I didn't modify the base64 decoder to conform to RFC 2045. David -- nmh-workers https://lists.nongnu.org/mailman/listinfo/nmh-workers
