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Refactor DNS-01 Challenge processing #71

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merged 2 commits into from
Mar 2, 2020
Merged

Refactor DNS-01 Challenge processing #71

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396bde7
Refactor DNS-01 Challenge processing
shibayan Mar 2, 2020
488e11b
Remove dead code
shibayan Mar 2, 2020
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6 changes: 3 additions & 3 deletions KeyVault.Acmebot/Contracts/ISharedFunctions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,15 +23,15 @@ public interface ISharedFunctions

Task Dns01Precondition(string[] hostNames);

Task<AcmeChallengeResult> Dns01Authorization((string, string) input);
Task<IList<AcmeChallengeResult>> Dns01Authorization(string[] authorizationUrls);

[RetryOptions("00:00:10", 6, HandlerType = typeof(RetryStrategy), HandlerMethodName = nameof(RetryStrategy.RetriableException))]
Task CheckDnsChallenge(AcmeChallengeResult challenge);
Task CheckDnsChallenge(IList<AcmeChallengeResult> challengeResults);

[RetryOptions("00:00:05", 12, HandlerType = typeof(RetryStrategy), HandlerMethodName = nameof(RetryStrategy.RetriableException))]
Task CheckIsReady(OrderDetails orderDetails);

Task AnswerChallenges(IList<AcmeChallengeResult> challenges);
Task AnswerChallenges(IList<AcmeChallengeResult> challengeResults);

Task FinalizeOrder((string[], OrderDetails) input);
}
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12 changes: 12 additions & 0 deletions KeyVault.Acmebot/Internal/AzureSdkExtensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -45,5 +45,17 @@ public static async Task<IList<CertificateItem>> GetAllCertificatesAsync(this IK

return certificates;
}

public static async Task<RecordSet> GetOrDefaultAsync(this IRecordSetsOperations operations, string resourceGroupName, string zoneName, string relativeRecordSetName, RecordType recordType)
{
try
{
return await operations.GetAsync(resourceGroupName, zoneName, relativeRecordSetName, RecordType.TXT);
}
catch
{
return null;
}
}
}
}
154 changes: 61 additions & 93 deletions KeyVault.Acmebot/SharedFunctions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -41,8 +41,6 @@ public SharedFunctions(IHttpClientFactory httpClientFactory, LookupClient lookup
_dnsManagementClient = dnsManagementClient;
}

private const string InstanceIdKey = "InstanceId";

private readonly IHttpClientFactory _httpClientFactory;
private readonly LookupClient _lookupClient;
private readonly IAcmeProtocolClientFactory _acmeProtocolClientFactory;
Expand All @@ -63,22 +61,14 @@ public async Task IssueCertificate([OrchestrationTrigger] IDurableOrchestrationC
// 新しく ACME Order を作成する
var orderDetails = await activity.Order(dnsNames);

// 複数の Authorizations を処理する
var challenges = new List<AcmeChallengeResult>();

foreach (var authorization in orderDetails.Payload.Authorizations)
{
// ACME Challenge を実行
var result = await activity.Dns01Authorization((authorization, context.ParentInstanceId ?? context.InstanceId));
// ACME Challenge を実行
var challengeResults = await activity.Dns01Authorization(orderDetails.Payload.Authorizations);

// Azure DNS で正しくレコードが引けるか確認
await activity.CheckDnsChallenge(result);

challenges.Add(result);
}
// Azure DNS で正しくレコードが引けるか確認
await activity.CheckDnsChallenge(challengeResults);

// ACME Answer を実行
await activity.AnswerChallenges(challenges);
await activity.AnswerChallenges(challengeResults);

// Order のステータスが ready になるまで 60 秒待機
await activity.CheckIsReady(orderDetails);
Expand Down Expand Up @@ -135,106 +125,84 @@ public async Task Dns01Precondition([ActivityTrigger] string[] hostNames)
}

[FunctionName(nameof(Dns01Authorization))]
public async Task<AcmeChallengeResult> Dns01Authorization([ActivityTrigger] (string, string) input)
public async Task<IList<AcmeChallengeResult>> Dns01Authorization([ActivityTrigger] string[] authorizationUrls)
{
var (authzUrl, instanceId) = input;

var acmeProtocolClient = await _acmeProtocolClientFactory.CreateClientAsync();

var authz = await acmeProtocolClient.GetAuthorizationDetailsAsync(authzUrl);
var challengeResults = new List<AcmeChallengeResult>();

// DNS-01 Challenge の情報を拾う
var challenge = authz.Challenges.First(x => x.Type == "dns-01");
foreach (var authorizationUrl in authorizationUrls)
{
// Authorization の詳細を取得
var authorization = await acmeProtocolClient.GetAuthorizationDetailsAsync(authorizationUrl);

var challengeValidationDetails = AuthorizationDecoder.ResolveChallengeForDns01(authz, challenge, acmeProtocolClient.Signer);
// DNS-01 Challenge の情報を拾う
var challenge = authorization.Challenges.First(x => x.Type == "dns-01");

// Azure DNS の TXT レコードを書き換え
var zones = await _dnsManagementClient.Zones.ListAllAsync();
var challengeValidationDetails = AuthorizationDecoder.ResolveChallengeForDns01(authorization, challenge, acmeProtocolClient.Signer);

var zone = zones.Where(x => challengeValidationDetails.DnsRecordName.EndsWith($".{x.Name}", StringComparison.OrdinalIgnoreCase))
.OrderByDescending(x => x.Name.Length)
.First();
// Challenge の情報を保存する
challengeResults.Add(new AcmeChallengeResult
{
Url = challenge.Url,
DnsRecordName = challengeValidationDetails.DnsRecordName,
DnsRecordValue = challengeValidationDetails.DnsRecordValue
});
}

var resourceGroup = ExtractResourceGroup(zone.Id);
// Azure DNS zone の一覧を取得する
var zones = await _dnsManagementClient.Zones.ListAllAsync();

// Challenge の詳細から Azure DNS 向けにレコード名を作成
var acmeDnsRecordName = challengeValidationDetails.DnsRecordName.Replace($".{zone.Name}", "", StringComparison.OrdinalIgnoreCase);
// DNS-01 の検証レコード名毎に Azure DNS に TXT レコードを作成
foreach (var lookup in challengeResults.ToLookup(x => x.DnsRecordName))
{
var dnsRecordName = lookup.Key;

RecordSet recordSet;
var zone = zones.Where(x => dnsRecordName.EndsWith($".{x.Name}", StringComparison.OrdinalIgnoreCase))
.OrderByDescending(x => x.Name.Length)
.First();

try
{
recordSet = await _dnsManagementClient.RecordSets.GetAsync(resourceGroup, zone.Name, acmeDnsRecordName, RecordType.TXT);
}
catch
{
recordSet = null;
}
var resourceGroup = ExtractResourceGroup(zone.Id);

if (recordSet != null)
{
if (recordSet.Metadata == null || !recordSet.Metadata.TryGetValue(InstanceIdKey, out var dnsInstanceId) || dnsInstanceId != instanceId)
{
recordSet.Metadata = new Dictionary<string, string>
{
{ InstanceIdKey, instanceId }
};
// Challenge の詳細から Azure DNS 向けにレコード名を作成
var acmeDnsRecordName = dnsRecordName.Replace($".{zone.Name}", "", StringComparison.OrdinalIgnoreCase);

recordSet.TxtRecords.Clear();
}
// 既存の TXT レコードがあれば取得する
var recordSet = await _dnsManagementClient.RecordSets.GetOrDefaultAsync(resourceGroup, zone.Name, acmeDnsRecordName, RecordType.TXT) ?? new RecordSet();

// TXT レコードに TTL と値をセットする
recordSet.TTL = 60;
recordSet.TxtRecords = lookup.Select(x => new TxtRecord(new[] { x.DnsRecordValue })).ToArray();

// 既存の TXT レコードに値を追加する
recordSet.TxtRecords.Add(new TxtRecord(new[] { challengeValidationDetails.DnsRecordValue }));
}
else
{
// 新しく TXT レコードを作成する
recordSet = new RecordSet
{
TTL = 60,
Metadata = new Dictionary<string, string>
{
{ InstanceIdKey, instanceId }
},
TxtRecords = new[]
{
new TxtRecord(new[] { challengeValidationDetails.DnsRecordValue })
}
};
await _dnsManagementClient.RecordSets.CreateOrUpdateAsync(resourceGroup, zone.Name, acmeDnsRecordName, RecordType.TXT, recordSet);
}

await _dnsManagementClient.RecordSets.CreateOrUpdateAsync(resourceGroup, zone.Name, acmeDnsRecordName, RecordType.TXT, recordSet);

return new AcmeChallengeResult
{
Url = challenge.Url,
DnsRecordName = challengeValidationDetails.DnsRecordName,
DnsRecordValue = challengeValidationDetails.DnsRecordValue
};
return challengeResults;
}

[FunctionName(nameof(CheckDnsChallenge))]
public async Task CheckDnsChallenge([ActivityTrigger] AcmeChallengeResult challenge)
public async Task CheckDnsChallenge([ActivityTrigger] IList<AcmeChallengeResult> challengeResults)
{
// 実際に ACME の TXT レコードを引いて確認する
var queryResult = await _lookupClient.QueryAsync(challenge.DnsRecordName, QueryType.TXT);
foreach (var challengeResult in challengeResults)
{
// 実際に ACME の TXT レコードを引いて確認する
var queryResult = await _lookupClient.QueryAsync(challengeResult.DnsRecordName, QueryType.TXT);

var txtRecords = queryResult.Answers
.OfType<DnsClient.Protocol.TxtRecord>()
.ToArray();
var txtRecords = queryResult.Answers
.OfType<DnsClient.Protocol.TxtRecord>()
.ToArray();

// レコードが存在しなかった場合はエラー
if (txtRecords.Length == 0)
{
throw new RetriableActivityException($"{challenge.DnsRecordName} did not resolve.");
}
// レコードが存在しなかった場合はエラー
if (txtRecords.Length == 0)
{
throw new RetriableActivityException($"{challengeResult.DnsRecordName} did not resolve.");
}

// レコードに今回のチャレンジが含まれていない場合もエラー
if (!txtRecords.Any(x => x.Text.Contains(challenge.DnsRecordValue)))
{
throw new RetriableActivityException($"{challenge.DnsRecordName} value is not correct.");
// レコードに今回のチャレンジが含まれていない場合もエラー
if (!txtRecords.Any(x => x.Text.Contains(challengeResult.DnsRecordValue)))
{
throw new RetriableActivityException($"{challengeResult.DnsRecordName} value is not correct.");
}
}
}

Expand All @@ -259,14 +227,14 @@ public async Task CheckIsReady([ActivityTrigger] OrderDetails orderDetails)
}

[FunctionName(nameof(AnswerChallenges))]
public async Task AnswerChallenges([ActivityTrigger] IList<AcmeChallengeResult> challenges)
public async Task AnswerChallenges([ActivityTrigger] IList<AcmeChallengeResult> challengeResults)
{
var acmeProtocolClient = await _acmeProtocolClientFactory.CreateClientAsync();

// Answer の準備が出来たことを通知
foreach (var challenge in challenges)
foreach (var challengeResult in challengeResults)
{
await acmeProtocolClient.AnswerChallengeAsync(challenge.Url);
await acmeProtocolClient.AnswerChallengeAsync(challengeResult.Url);
}
}

Expand Down