| 1 | = Windows Code Signing |
| 2 | |
| 3 | This is how we do automated code signing of Windows binaries using a !YubiKey. We started with: |
| 4 | |
| 5 | * Enterprise Contract with Sectigo, https://www.sectigo.com |
| 6 | * !YubiKey 5 FIPS |
| 7 | * !YubiKey Smart Card Minidriver (Windows) from https://www.yubico.com/support/download/smart-card-drivers-tools/ |
| 8 | * yubio-piv-tool from https://developers.yubico.com/yubico-piv-tool/ |
| 9 | * signtool from Microsoft Visual Studio |
| 10 | * scsigntool from https://www.mgtek.com/smartcard |
| 11 | |
| 12 | Outline: |
| 13 | |
| 14 | * Used !YubiKey Authenticator application from Windows Store to set PIN, PUK, and Management Key |
| 15 | * Install !YubiKey Smart Card Minidriver |
| 16 | * Install yubio-piv-tool |
| 17 | * Get email invitation to submit code signing CSR to Sectigo initiated by corporate IT |
| 18 | * Submit CSR and !YubiKey attestation |
| 19 | * Get email from Sectigo with link to certificate |
| 20 | * Install certificate on !YubiKey |
| 21 | * Sign code |
| 22 | |
| 23 | == Submit CSR |
| 24 | |
| 25 | The code signing slot is the Authentication slot `9A`. |
| 26 | |
| 27 | === Create key in slot |
| 28 | |
| 29 | `yubico-piv-tool --slot=$SLOT --action=generate --touch-policy=never --algorithm=$ALGORITHM --key --output=public.key` |
| 30 | |
| 31 | === Use public key to create CSR |
| 32 | |
| 33 | `yubico-piv-tool --slot=$SLOT --action=verify-pin --action=request-certificate --subject='/CN=Sectigo/' --input=public.key --output=csr.txt` |
| 34 | |
| 35 | Upload `csr.txt` for the CSR |
| 36 | |
| 37 | === !YubiKey attestation |
| 38 | |
| 39 | ==== Get attestation |
| 40 | |
| 41 | `yubico-piv-tool --slot=$SLOT --action=attest --output=attest.crt` |
| 42 | |
| 43 | ==== Get !YubiKey's intermediate certificates |
| 44 | |
| 45 | `yubico-piv-tool --action=read-certificate --slot=f9 --output=intermediateCA.crt` |
| 46 | |
| 47 | ==== Combine and encode in base64 |
| 48 | {{{ |
| 49 | cat attest.crt intermediateCA.crt > attestation.pem |
| 50 | base64 < attestation.pem > attestation.pem.b64 |
| 51 | }}} |
| 52 | |
| 53 | |
| 54 | Attestation is in `attestation.pem.b64`. Copy the contents and paste in the Key Attestation field. Make sure `YubiKey` is the HSM type. |
| 55 | |
| 56 | == Install Certificate |
| 57 | |
| 58 | Use "Certificate only, PEM encoded" certificate. Downloads as `$CERT_BASE_cert.cer`. |
| 59 | |
| 60 | === Install in Windows User Certificate manager |
| 61 | |
| 62 | Open `$CERT_BASE_cert.cer` in file explorer, then click on `Install Certificate...`. Choose `Current User`. Place in `Personal` Certificate Store. |
| 63 | |
| 64 | === Install on !YubiKey |
| 65 | |
| 66 | `yubico-piv-tool --action=import-certificate --slot=$SLOT --key --pin-policy=once --touch-policy=never --input=$CERT_BASE_cert.cer` |
| 67 | |
| 68 | == Install intermediate certificates onto !YubiKey |
| 69 | |
| 70 | Use "Root/Intermediate(s) only, PEM encoded" certificates. Downloads as `CERT_BASE_interm.cer`. |
| 71 | |
| 72 | {{{ |
| 73 | interm=$CERT_BASE_interm.cer |
| 74 | let slot=$((0x82)) |
| 75 | let max_slot=$((0x95)) |
| 76 | while openssl x509 -out cert.pem |
| 77 | do |
| 78 | if [ $slot -ge $max_slot ] |
| 79 | then |
| 80 | echo "too many intermediate certificates" |
| 81 | exit 1 |
| 82 | fi |
| 83 | hex_slot=$(printf "%x" $slot) |
| 84 | echo "Import slot $hex_slot: $(openssl x509 -in cert.pem -noout -subject | sed 's/.*CN = //')" |
| 85 | yubico-piv-tool --action=import-certificate --slot=$hex_slot --key --input=cert.pem |
| 86 | slot=$((slot + 1)) |
| 87 | done < $interm |
| 88 | }}} |
| 89 | |
| 90 | == Sign Code |
| 91 | |
| 92 | Microsoft's `signtool` doesn't have a way to provide the PIN needed use the private key. So use MGTEK's `scsigntool` to wrap signtool. In our case: |
| 93 | {{{ |
| 94 | scsigntool.exe -pin CODESIGN sign /v /a /sha1 CERT_SHA /fd sha256 /t http://timestamp.sectigo.com/authenticode /d "Application Name" app-installer.exe |
| 95 | }}} |