92 lines
2.5 KiB
Markdown
92 lines
2.5 KiB
Markdown
# Authentication in Golang
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## Use header
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Use the http header or the body, but avoid using cookies to transport tokens etc
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(because of CSRF)
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## Implementation
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```
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# create password/user
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update_password(password):
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generate salt
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db.store(hash(salt + password))
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#login
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get_token(userId, password):
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if not hash(salt + password) == db.get(salted_hash_of_password): # use timing-attack resistant compare here
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return FAILED
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generate selector
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db.store(selector)
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generate salt
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generate auth_token
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db.store(salt, hash(salt+auth_token))
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return selector:auth_token
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#authenticate
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validate_token(selector, auth_token):
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if not hash(salt+auth_token) == db.get(salt, salted_hash_of_auth_token WHERE selector): # use timing-attack resistant compare here
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return UNKNOWN_TOKEN
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return AUTHENTICATED
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```
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idea: replace selector with userId?
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## JWT
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```json
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{
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"userId": "id",
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"userRole": "role",
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"expiryTime": "now+10min"
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}
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```
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We use JWT with a lifespan of 10min and an in-memory db to blacklist revoked
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tokens. So if for e.g. a user changes it's password, we would add the userId and
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the time of the change to the blacklist, filtering out all tokens that have been
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issued before.
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After a server restart, all tokens will become invalid as well, since we can not
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be sure which ones were 'on the blacklist'. This could be mitigated by making
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the blacklist persistent during restarts.
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If a token has expired (either by a server restart or after 10min), a new token
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is requested with a 'long lived' refresh-token (lifetime of ~1 week) that is
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stored in a database.
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### Pros:
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- less DB lookups in general
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### Cons:
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- timestamps of blacklisting could become a problem (maybe add 1 second or use
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timestamp returned by n-th node when it has received the update).
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- increased load on db + service since we need to issue new jwt for everybody.
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## SSL/TLS
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```bash
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openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout keyFile.key -out certFile.crt
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```
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## CRIME/BREACH http compression attack
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While we do not use a CSRF token, headers sent to the `/api` still contain
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private data.
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If you are using http/1.1 or lower and have compression enabled on your proxy,
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you would be .
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## CRSF
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We check for a http header like this `X-YOURSITE-CSRF-PROTECTION=1`. This should
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be enough, according to
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[cheatsheetseries.owasp.org](https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Request_Forgery_Prevention_Cheat_Sheet.html#custom-request-headers)
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## XSS
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We rely on Vue.js's ability to escape user-input in templates.
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