TritonDataCenter / node-asn1

Contains parsers and serializers for ASN.1 (currently BER only)
MIT License
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reader.js is not reading the TAG correctly #50

Open jtgrant65 opened 2 years ago

jtgrant65 commented 2 years ago

I am writing a lambda function in aws using node.js to ssh to an ec2 instance. I want to use public key private key pairs so I don't have to embed a password in the code. I'm using simple-ssh as a wrapper library to ssh2 which in turn calls asn1 reader.js to parse the private key to verify its validity. There appears to be a problem with indexing through the first 8 bytes of the key which manifests itself in the method readString. The first 8 bytes are as follows: 30 82 04 bd 02 01 00 30. By the time readSting is called, the offset variable is 7 which causes the code to read the 8th byte which is 0x30. readString compares this value with the TAG value which is 0x02 and throws an error stating that the key is invalid because 0x30 doesn't match 0x02. If I load my private key into this website https://lapo.it/asn1js/ it can parse the key without fail. I also found some javascript code that also is consistent with how the first 8 bytes are indexed and successfully parses the key. I think that the offsets are being handled incorrectly in the code.