| 1 | package main |
| 2 | |
| 3 | // 🤖 A minimal SES v2 sender for the email anchor's sign-in codes (issue |
| 4 | // #1091) — one SigV4-signed POST to the SendEmail API, riding the same |
| 5 | // hand-rolled signer the S3 store uses (sigv4.go). No SDK: the whole mailer |
| 6 | // is readable in one sitting, and home's dependency set stays boring. |
| 7 | // |
| 8 | // Deliverability (SPF/DKIM, sandbox exit, bounce handling) is SES-console |
| 9 | // and DNS work, deliberately outside this file — see issue #1091's ops list. |
| 10 | |
| 11 | import ( |
| 12 | "bytes" |
| 13 | "crypto/sha256" |
| 14 | "encoding/hex" |
| 15 | "encoding/json" |
| 16 | "errors" |
| 17 | "fmt" |
| 18 | "io" |
| 19 | "net/http" |
| 20 | "os" |
| 21 | "time" |
| 22 | ) |
| 23 | |
| 24 | // sesMailer sends through SES v2 in one region from one address. endpoint is |
| 25 | // overridable for tests (a fake SES httptest server); empty means the real |
| 26 | // regional endpoint. |
| 27 | type sesMailer struct { |
| 28 | region string |
| 29 | from string |
| 30 | accessKey string |
| 31 | secretKey string |
| 32 | endpoint string |
| 33 | } |
| 34 | |
| 35 | func newSESMailer(region, from string) (*sesMailer, error) { |
| 36 | access, secret := os.Getenv("AWS_ACCESS_KEY_ID"), os.Getenv("AWS_SECRET_ACCESS_KEY") |
| 37 | if access == "" || secret == "" { |
| 38 | return nil, errors.New("email anchor: AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY must be set") |
| 39 | } |
| 40 | return &sesMailer{region: region, from: from, accessKey: access, secretKey: secret}, nil |
| 41 | } |
| 42 | |
| 43 | // send delivers one plain-text email. The recipient address is used for this |
| 44 | // send and then dropped — nothing here persists it (the blind-index rule). |
| 45 | func (m *sesMailer) send(to, subject, text string) error { |
| 46 | body, err := json.Marshal(map[string]any{ |
| 47 | "FromEmailAddress": m.from, |
| 48 | "Destination": map[string]any{"ToAddresses": []string{to}}, |
| 49 | "Content": map[string]any{ |
| 50 | "Simple": map[string]any{ |
| 51 | "Subject": map[string]any{"Data": subject, "Charset": "UTF-8"}, |
| 52 | "Body": map[string]any{ |
| 53 | "Text": map[string]any{"Data": text, "Charset": "UTF-8"}, |
| 54 | }, |
| 55 | }, |
| 56 | }, |
| 57 | }) |
| 58 | if err != nil { |
| 59 | return err |
| 60 | } |
| 61 | endpoint := m.endpoint |
| 62 | if endpoint == "" { |
| 63 | endpoint = "https://email." + m.region + ".amazonaws.com" |
| 64 | } |
| 65 | req, err := http.NewRequest("POST", endpoint+"/v2/email/outbound-emails", bytes.NewReader(body)) |
| 66 | if err != nil { |
| 67 | return err |
| 68 | } |
| 69 | now := time.Now() |
| 70 | digest := sha256.Sum256(body) |
| 71 | req.Header.Set("Content-Type", "application/json") |
| 72 | req.Header.Set("X-Amz-Date", now.UTC().Format("20060102T150405Z")) |
| 73 | req.Header.Set("X-Amz-Content-Sha256", hex.EncodeToString(digest[:])) |
| 74 | awsSignV4(req, m.accessKey, m.secretKey, m.region, "ses", now) |
| 75 | resp, err := oidcHTTP.Do(req) |
| 76 | if err != nil { |
| 77 | return err |
| 78 | } |
| 79 | defer resp.Body.Close() |
| 80 | if resp.StatusCode/100 != 2 { |
| 81 | b, _ := io.ReadAll(io.LimitReader(resp.Body, 512)) |
| 82 | return fmt.Errorf("ses: %s: %s", resp.Status, b) |
| 83 | } |
| 84 | return nil |
| 85 | } |
| 86 | |
amadan