fix: hardcode azure instance identity intermediate certificates (#6402)

This was broken for an airgapped customer!

coderd/azureidentity/azureidentity.go

@@ -1,12 +1,10 @@
 package azureidentity
 
 import (
-	"context"
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
-	"io"
+	"encoding/pem"
-	"net/http"
 	"regexp"
 
 	"go.mozilla.org/pkcs7"
@@ -23,7 +21,7 @@ type metadata struct {
 
 // Validate ensures the signature was signed by an Azure certificate.
 // It returns the associated VM ID if successful.
-func Validate(ctx context.Context, signature string, options x509.VerifyOptions) (string, error) {
+func Validate(signature string, options x509.VerifyOptions) (string, error) {
 	data, err := base64.StdEncoding.DecodeString(signature)
 	if err != nil {
 		return "", xerrors.Errorf("decode base64: %w", err)
@@ -41,24 +39,14 @@ func Validate(ctx context.Context, signature string, options x509.VerifyOptions)
 	}
 	if options.Intermediates == nil {
 		options.Intermediates = x509.NewCertPool()
-		for _, certURL := range signer.IssuingCertificateURL {
+		for _, cert := range certificates {
-			req, err := http.NewRequestWithContext(ctx, "GET", certURL, nil)
+			block, rest := pem.Decode([]byte(cert))
-			if err != nil {
+			if len(rest) != 0 {
-				return "", xerrors.Errorf("new request %q: %w", certURL, err)
+				return "", xerrors.Errorf("invalid certificate. %d bytes remain", len(rest))
 			}
-			res, err := http.DefaultClient.Do(req)
+			cert, err := x509.ParseCertificate(block.Bytes)
 			if err != nil {
-				return "", xerrors.Errorf("perform request %q: %w", certURL, err)
+				return "", xerrors.Errorf("parse certificate: %w", err)
-			}
-			data, err := io.ReadAll(res.Body)
-			if err != nil {
-				_ = res.Body.Close()
-				return "", xerrors.Errorf("read body %q: %w", certURL, err)
-			}
-			_ = res.Body.Close()
-			cert, err := x509.ParseCertificate(data)
-			if err != nil {
-				return "", xerrors.Errorf("parse certificate %q: %w", certURL, err)
 			}
 			options.Intermediates.AddCert(cert)
 		}
@@ -76,3 +64,68 @@ func Validate(ctx context.Context, signature string, options x509.VerifyOptions)
 	}
 	return metadata.VMID, nil
 }
+
+var certificates = []string{
+	`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`,
+	`-----BEGIN CERTIFICATE-----
+MIIFWjCCBEKgAwIBAgIQD6dHIsU9iMgPWJ77H51KOjANBgkqhkiG9w0BAQsFADBa
+MQswCQYDVQQGEwJJRTESMBAGA1UEChMJQmFsdGltb3JlMRMwEQYDVQQLEwpDeWJl
+clRydXN0MSIwIAYDVQQDExlCYWx0aW1vcmUgQ3liZXJUcnVzdCBSb290MB4XDTIw
+MDcyMTIzMDAwMFoXDTI0MTAwODA3MDAwMFowTzELMAkGA1UEBhMCVVMxHjAcBgNV
+BAoTFU1pY3Jvc29mdCBDb3Jwb3JhdGlvbjEgMB4GA1UEAxMXTWljcm9zb2Z0IFJT
+QSBUTFMgQ0EgMDIwggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQD0wBlZ
+qiokfAYhMdHuEvWBapTj9tFKL+NdsS4pFDi8zJVdKQfR+F039CDXtD9YOnqS7o88
++isKcgOeQNTri472mPnn8N3vPCX0bDOEVk+nkZNIBA3zApvGGg/40Thv78kAlxib
+MipsKahdbuoHByOB4ZlYotcBhf/ObUf65kCRfXMRQqOKWkZLkilPPn3zkYM5GHxe
+I4MNZ1SoKBEoHa2E/uDwBQVxadY4SRZWFxMd7ARyI4Cz1ik4N2Z6ALD3MfjAgEED
+woknyw9TGvr4PubAZdqU511zNLBoavar2OAVTl0Tddj+RAhbnX1/zypqk+ifv+d3
+CgiDa8Mbvo1u2Q8nuUBrKVUmR6EjkV/dDrIsUaU643v/Wp/uE7xLDdhC5rplK9si
+NlYohMTMKLAkjxVeWBWbQj7REickISpc+yowi3yUrO5lCgNAKrCNYw+wAfAvhFkO
+eqPm6kP41IHVXVtGNC/UogcdiKUiR/N59IfYB+o2v54GMW+ubSC3BohLFbho/oZZ
+5XyulIZK75pwTHmauCIeE5clU9ivpLwPTx9b0Vno9+ApElrFgdY0/YKZ46GfjOC9
+ta4G25VJ1WKsMmWLtzyrfgwbYopquZd724fFdpvsxfIvMG5m3VFkThOqzsOttDcU
+fyMTqM2pan4txG58uxNJ0MjR03UCEULRU+qMnwIDAQABo4IBJTCCASEwHQYDVR0O
+BBYEFP8vf+EG9DjzLe0ljZjC/g72bPz6MB8GA1UdIwQYMBaAFOWdWTCCR1jMrPoI
+VDaGezq1BE3wMA4GA1UdDwEB/wQEAwIBhjAdBgNVHSUEFjAUBggrBgEFBQcDAQYI
+KwYBBQUHAwIwEgYDVR0TAQH/BAgwBgEB/wIBADA0BggrBgEFBQcBAQQoMCYwJAYI
+KwYBBQUHMAGGGGh0dHA6Ly9vY3NwLmRpZ2ljZXJ0LmNvbTA6BgNVHR8EMzAxMC+g
+LaArhilodHRwOi8vY3JsMy5kaWdpY2VydC5jb20vT21uaXJvb3QyMDI1LmNybDAq
+BgNVHSAEIzAhMAgGBmeBDAECATAIBgZngQwBAgIwCwYJKwYBBAGCNyoBMA0GCSqG
+SIb3DQEBCwUAA4IBAQCg2d165dQ1tHS0IN83uOi4S5heLhsx+zXIOwtxnvwCWdOJ
+3wFLQaFDcgaMtN79UjMIFVIUedDZBsvalKnx+6l2tM/VH4YAyNPx+u1LFR0joPYp
+QYLbNYkedkNuhRmEBesPqj4aDz68ZDI6fJ92sj2q18QvJUJ5Qz728AvtFOat+Ajg
+K0PFqPYEAviUKr162NB1XZJxf6uyIjUlnG4UEdHfUqdhl0R84mMtrYINksTzQ2sH
+YM8fEhqICtTlcRLr/FErUaPUe9648nziSnA0qKH7rUZqP/Ifmbo+WNZSZG1BbgOh
+lk+521W+Ncih3HRbvRBE0LWYT8vWKnfjgZKxwHwJ
+-----END CERTIFICATE-----`,
+}

coderd/azureidentity/azureidentity_test.go

@@ -1,7 +1,6 @@
 package azureidentity_test
 
 import (
-	"context"
 	"crypto/x509"
 	"testing"
 	"time"
@@ -19,7 +18,7 @@ func TestValidate(t *testing.T) {
 	t.Parallel()
 	ct, err := time.Parse(time.RFC3339, "2023-02-01T00:00:00Z")
 	require.NoError(t, err)
-	vm, err := azureidentity.Validate(context.Background(), signature, x509.VerifyOptions{
+	vm, err := azureidentity.Validate(signature, x509.VerifyOptions{
 		CurrentTime: ct,
 	})
 	require.NoError(t, err)

coderd/workspaceresourceauth.go

@@ -37,7 +37,7 @@ func (api *API) postWorkspaceAuthAzureInstanceIdentity(rw http.ResponseWriter, r
 	if !httpapi.Read(ctx, rw, r, &req) {
 		return
 	}
-	instanceID, err := azureidentity.Validate(ctx, req.Signature, api.AzureCertificates)
+	instanceID, err := azureidentity.Validate(req.Signature, api.AzureCertificates)
 	if err != nil {
 		httpapi.Write(ctx, rw, http.StatusUnauthorized, codersdk.Response{
 			Message: "Invalid Azure identity.",