From d7e4f7673e6492634e70a93a7d8f84e055554b38 Mon Sep 17 00:00:00 2001 From: Marc Becker Date: Wed, 26 Feb 2025 22:02:06 +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 | 60 +++++++++++++++++++ src/shared/Core/Base64UrlConvert.cs | 39 +++++++++--- src/shared/Core/GenericHostProvider.cs | 19 +++++- 3 files changed, 107 insertions(+), 11 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..5e18ae61b --- /dev/null +++ b/src/shared/Core/Authentication/OAuth/Json/WebToken.cs @@ -0,0 +1,60 @@ +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; + + public bool IsExpired + { + get + { + return Payload.Expiry < DateTimeOffset.Now.ToUnixTimeSeconds(); + } + } + + static public bool TryCreate(string value, out WebToken jwt) + { + jwt = null; + try + { + var parts = value.Split('.'); + if (parts.Length != 3) + { + return false; + } + var header = JsonSerializer.Deserialize(Base64UrlConvert.Decode(parts[0])); + if (!"JWT".Equals(header.Type)) + { + return false; + } + var payload = JsonSerializer.Deserialize(Base64UrlConvert.Decode(parts[1])); + jwt = new WebToken(header, payload, parts[2]); + return true; + } + catch + { + return false; + } + } + } +} 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..2b0faeaf9 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 +126,20 @@ 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); + // discard credential if it's an already expired JSON Web Token + if (WebToken.TryCreate(credential.Password, out var token) && token.IsExpired) + { + // 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 @@ -150,9 +165,9 @@ private async Task GetOAuthAccessToken(Uri remoteUri, string userNa string refreshService = new UriBuilder(remoteUri) { Host = $"refresh_token.{remoteUri.Host}" } .Uri.AbsoluteUri.TrimEnd('/'); - // Try to use a refresh token if we have one + // Try to use a refresh token if we have one (unless it's an expired JSON Web Token) ICredential refreshToken = Context.CredentialStore.Get(refreshService, userName); - if (refreshToken != null) + if (refreshToken != null && !(WebToken.TryCreate(refreshToken.Password, out var token) && token.IsExpired)) { try {