asn1: use ASN1_TIME_to_tm() to decode UTCTime and GeneralizedTime #974
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−106
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Move variable declarations for OpenSSL::ASN1 classes to the top of the file. asn1time_to_time() will need eASN1Error in the next patch.
The current logic relies on sscanf() and error checks are almost entirely missing. It also assumes that ASN1_STRING contents are NUL terminated, which is undocumented and not guaranteed for all valid ASN1_TIME objects. Switch to using ASN1_TIME_to_tm() added in OpenSSL 1.1.1. It is also supported by LibreSSL and AWS-LC. In the long term, we may want to replace ASN1_TIME_to_tm() with a hand-rolled decoder, since the function is intended for a specific use-case. It is too permissive for strict DER, yet still does not support all valid DER inputs and silently drops information such as fractional seconds. However, it handles everything that the current sscanf() code could handle.
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The current logic relies on
sscanf()and error checks are almost entirely missing. It also assumes thatASN1_STRINGcontents are NUL-terminated, which is undocumented and not guaranteed for all validASN1_TIMEobjects.Switch to using
ASN1_TIME_to_tm()added in OpenSSL 1.1.1. It is also supported by LibreSSL and AWS-LC.In the long term, we may want to replace
ASN1_TIME_to_tm()with a hand-rolled decoder, since the function is intended for a specific use-case. It is too permissive for strict DER, yet still does not support all valid DER inputs and silently drops information such as fractional seconds. However, it handles everything that the currentsscanf()code could handle.Partially resolves #725.