Files
restic-manager/internal/auth/passwords.go
T
steve f55747a281 phase 1 foundations: api types, store, crypto, auth
Lands the bottom three layers of Phase 1:

P1-08 internal/api: protocol_version + envelope + every WS message
  shape from spec.md §6.2 (Hello, Heartbeat, Job*, Schedule*, etc).
  Wire-format tests pin the JSON shape so a rename here breaks
  tests instead of silently breaking the agent.

P1-02 + P1-03 internal/store: SQLite via modernc.org/sqlite,
  embed.FS + a tiny version table for hand-rolled migrations.
  0001_initial.sql covers every table from spec.md §5 plus
  enrollment_tokens and host_schedule_version. Typed accessors
  for users / sessions / enrollment / audit. WAL + foreign_keys
  + busy_timeout on by default.

P1-06 internal/crypto: XChaCha20-Poly1305 AEAD wrapper with
  per-message random nonce. Key file lifecycle (generate +
  refuse-to-overwrite, load with size validation). Optional
  additionalData binds ciphertext to the row that owns it.

P1-04 internal/auth (partial — passwords + tokens; sessions
  middleware lands with the HTTP handlers): argon2id following
  RFC 9106 (64 MiB / t=3 / p=4 / 32B), constant-time verify.
  HashToken stores SHA-256 of session/agent/enrollment tokens
  so a stolen DB doesn't hand over credentials.

Build floor moves to Go 1.25 (modernc.org/sqlite v1.50+ requires
it); CI + Dockerfile + README updated. Markdown lint diagnostics
on tasks.md cleared.

All packages tested. ~70 new tests pass in <1s.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-01 00:24:40 +01:00

88 lines
2.8 KiB
Go

// Package auth handles password hashing (argon2id), session
// management, CSRF tokens, and bearer-token verification for agents.
package auth
import (
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"errors"
"fmt"
"strings"
"golang.org/x/crypto/argon2"
)
// argon2id parameters following RFC 9106 §4 "second
// recommended option" (memory-constrained):
// - 64 MiB memory, 3 iterations, 4 lanes, 32-byte tag.
// These are tunable per-deployment if a beefy controller wants to
// crank them; we ship a defensible default.
const (
defaultMemoryKiB = 64 * 1024
defaultIterations = 3
defaultParallel = 4
defaultSaltLen = 16
defaultKeyLen = 32
)
// HashPassword returns an argon2id-encoded string of the form
// $argon2id$v=19$m=...,t=...,p=...$<salt>$<hash>
// safe to store in a TEXT column. The salt is freshly random per call.
func HashPassword(password string) (string, error) {
salt := make([]byte, defaultSaltLen)
if _, err := rand.Read(salt); err != nil {
return "", fmt.Errorf("auth: read salt: %w", err)
}
hash := argon2.IDKey([]byte(password), salt,
defaultIterations, defaultMemoryKiB, defaultParallel, defaultKeyLen)
return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
argon2.Version,
defaultMemoryKiB, defaultIterations, defaultParallel,
base64.RawStdEncoding.EncodeToString(salt),
base64.RawStdEncoding.EncodeToString(hash),
), nil
}
// VerifyPassword returns nil if password matches the encoded hash.
// On any decode error or mismatch the error is non-nil — callers
// should treat all non-nil returns as "invalid credentials" and not
// leak which case it was.
func VerifyPassword(encoded, password string) error {
parts := strings.Split(encoded, "$")
// "$argon2id$v=...$m=...,t=...,p=...$<salt>$<hash>" → 6 parts (leading empty)
if len(parts) != 6 || parts[1] != "argon2id" {
return errors.New("auth: unrecognised hash format")
}
var version int
if _, err := fmt.Sscanf(parts[2], "v=%d", &version); err != nil {
return fmt.Errorf("auth: parse version: %w", err)
}
if version != argon2.Version {
return fmt.Errorf("auth: unsupported argon2 version %d", version)
}
var memory, iterations uint32
var parallel uint8
if _, err := fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d",
&memory, &iterations, &parallel); err != nil {
return fmt.Errorf("auth: parse params: %w", err)
}
salt, err := base64.RawStdEncoding.DecodeString(parts[4])
if err != nil {
return fmt.Errorf("auth: decode salt: %w", err)
}
want, err := base64.RawStdEncoding.DecodeString(parts[5])
if err != nil {
return fmt.Errorf("auth: decode hash: %w", err)
}
got := argon2.IDKey([]byte(password), salt,
iterations, memory, parallel, uint32(len(want)))
if subtle.ConstantTimeCompare(got, want) != 1 {
return errors.New("auth: invalid password")
}
return nil
}