From c8a7e32ed11614197dd2205b804386c1661b20c3 Mon Sep 17 00:00:00 2001 From: Marc Becker Date: Tue, 25 Feb 2025 17:03:50 +0100 Subject: [PATCH] fix(generic): check expiry in JWT password values add minimal JWT data class for content decoding and extraction add decode support to Base64Url converter override GenericHostProvider credential query to check for JWT content add expiry check for JWT refresh token --- .../Authentication/OAuth/Json/WebToken.cs | 57 +++++++++++++++++++ src/shared/Core/Base64UrlConvert.cs | 39 ++++++++++--- src/shared/Core/GenericHostProvider.cs | 16 +++++- 3 files changed, 102 insertions(+), 10 deletions(-) create mode 100644 src/shared/Core/Authentication/OAuth/Json/WebToken.cs diff --git a/src/shared/Core/Authentication/OAuth/Json/WebToken.cs b/src/shared/Core/Authentication/OAuth/Json/WebToken.cs new file mode 100644 index 000000000..727ef033c --- /dev/null +++ b/src/shared/Core/Authentication/OAuth/Json/WebToken.cs @@ -0,0 +1,57 @@ +using System; +using System.Text.Json; +using System.Text.Json.Serialization; + +namespace GitCredentialManager.Authentication.Oauth.Json +{ + public class WebToken(WebToken.TokenHeader header, WebToken.TokenPayload payload, string signature) + { + public class TokenHeader + { + [JsonRequired] + [JsonInclude] + [JsonPropertyName("typ")] + public string Type { get; private set; } + } + public class TokenPayload + { + [JsonRequired] + [JsonInclude] + [JsonPropertyName("exp")] + public long Expiry { get; private set; } + } + public TokenHeader Header { get; } = header; + public TokenPayload Payload { get; } = payload; + public string Signature { get; } = signature; + + static public WebToken TryCreate(string value) + { + try + { + var parts = value.Split('.'); + if (parts.Length != 3) + { + return null; + } + var header = JsonSerializer.Deserialize(Base64UrlConvert.Decode(parts[0])); + if (!"JWT".Equals(header.Type)) + { + return null; + } + var payload = JsonSerializer.Deserialize(Base64UrlConvert.Decode(parts[1])); + return new WebToken(header, payload, parts[2]); + } + catch + { + return null; + } + } + + static public bool IsExpiredToken(string value) + { + var token = TryCreate(value); + return token != null && token.Payload.Expiry < DateTimeOffset.Now.ToUnixTimeSeconds(); + + } + } +} diff --git a/src/shared/Core/Base64UrlConvert.cs b/src/shared/Core/Base64UrlConvert.cs index 7b2fce035..3a0f299f8 100644 --- a/src/shared/Core/Base64UrlConvert.cs +++ b/src/shared/Core/Base64UrlConvert.cs @@ -4,22 +4,43 @@ namespace GitCredentialManager { public static class Base64UrlConvert { + + // The base64url format is the same as regular base64 format except: + // 1. character 62 is "-" (minus) not "+" (plus) + // 2. character 63 is "_" (underscore) not "/" (slash) + // 3. padding is optional + private const char base64PadCharacter = '='; + private const char base64Character62 = '+'; + private const char base64Character63 = '/'; + private const char base64UrlCharacter62 = '-'; + private const char base64UrlCharacter63 = '_'; + public static string Encode(byte[] data, bool includePadding = true) { - const char base64PadCharacter = '='; - const char base64Character62 = '+'; - const char base64Character63 = '/'; - const char base64UrlCharacter62 = '-'; - const char base64UrlCharacter63 = '_'; - - // The base64url format is the same as regular base64 format except: - // 1. character 62 is "-" (minus) not "+" (plus) - // 2. character 63 is "_" (underscore) not "/" (slash) string base64Url = Convert.ToBase64String(data) .Replace(base64Character62, base64UrlCharacter62) .Replace(base64Character63, base64UrlCharacter63); return includePadding ? base64Url : base64Url.TrimEnd(base64PadCharacter); } + + public static byte[] Decode(string data) + { + string base64 = data + .Replace(base64UrlCharacter62, base64Character62) + .Replace(base64UrlCharacter63, base64Character63); + + switch (base64.Length % 4) + { + case 2: + base64 += base64PadCharacter; + goto case 3; + case 3: + base64 += base64PadCharacter; + break; + } + + return Convert.FromBase64String(base64); + } } } diff --git a/src/shared/Core/GenericHostProvider.cs b/src/shared/Core/GenericHostProvider.cs index 9f087ca5b..d1d7d0ce1 100644 --- a/src/shared/Core/GenericHostProvider.cs +++ b/src/shared/Core/GenericHostProvider.cs @@ -5,6 +5,7 @@ using System.Threading; using System.Threading.Tasks; using GitCredentialManager.Authentication; +using GitCredentialManager.Authentication.Oauth.Json; using GitCredentialManager.Authentication.OAuth; namespace GitCredentialManager @@ -125,6 +126,19 @@ public override async Task GenerateCredentialAsync(InputArguments i return await _basicAuth.GetCredentialsAsync(uri.AbsoluteUri, input.UserName); } + public override async Task GetCredentialAsync(InputArguments input) + { + var credential = await base.GetCredentialAsync(input); + if (WebToken.IsExpiredToken(credential.Password)) + { + // No existing credential was found, create a new one + Context.Trace.WriteLine("Refreshing expired JWT credential..."); + credential = await GenerateCredentialAsync(input); + Context.Trace.WriteLine("Credential created."); + } + return credential; + } + private async Task GetOAuthAccessToken(Uri remoteUri, string userName, GenericOAuthConfig config, ITrace2 trace2) { // TODO: Determined user info from a webcall? ID token? Need OIDC support @@ -152,7 +166,7 @@ private async Task GetOAuthAccessToken(Uri remoteUri, string userNa // Try to use a refresh token if we have one ICredential refreshToken = Context.CredentialStore.Get(refreshService, userName); - if (refreshToken != null) + if (refreshToken != null && !WebToken.IsExpiredToken(refreshToken.Password)) { try {