bvandeusen
ff4d443269
Shared primitives for /api/* auth: mint a url-safe opaque token, hash it for storage, verify a bcrypt password hash. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
41 lines
1.4 KiB
Go
41 lines
1.4 KiB
Go
package auth
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"golang.org/x/crypto/bcrypt"
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)
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// sessionTokenBytes is the raw entropy per session token. 32 bytes of
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// crypto/rand gives ~256 bits; after base64 url-safe encoding the cookie
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// value is 43 chars with no padding.
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const sessionTokenBytes = 32
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// MintSessionToken returns a freshly-generated, url-safe opaque token.
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// The token is what the client carries; the DB only ever sees its sha256.
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func MintSessionToken() (string, error) {
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b := make([]byte, sessionTokenBytes)
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if _, err := rand.Read(b); err != nil {
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return "", err
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}
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return base64.RawURLEncoding.EncodeToString(b), nil
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}
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// HashSessionToken is the single source of truth for mapping a raw token to
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// the `sessions.token_hash` column. sha256 is fine here — we're not guarding
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// against offline brute force (the token has 256 bits of entropy); we only
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// want "leaked DB row can't be replayed without also having the raw token."
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func HashSessionToken(token string) []byte {
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sum := sha256.Sum256([]byte(token))
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return sum[:]
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}
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// VerifyPassword is the canonical bcrypt comparison. Returns false on a
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// malformed hash so callers don't need to distinguish "hash invalid" from
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// "password wrong" — both are auth failures from the client's perspective.
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func VerifyPassword(hash, plaintext string) bool {
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return bcrypt.CompareHashAndPassword([]byte(hash), []byte(plaintext)) == nil
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}
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