keyfunc

Purpose of this package is to provide a jwt.Keyfunc for the github.com/dgrijalva/jwt-go package and its popular forks using a JSON Web Key Set (JWKs) for parsing and verifying JSON Web Tokens (JWTs).

It's common for an identity provider, such as Keycloak or Amazon Cognito (AWS) to expose a JWKs via an HTTPS endpoint. This package has the ability to consume that JWKs and produce a jwt.Keyfunc. It is important that a JWKs endpoint is using HTTPS to ensure the keys are from the correct trusted source.

This repository has the following dependencies:

jwt.Keyfunc signatures are imported from these, implemented, then exported as methods.

Supported Algorithms

It is recommended to only use this package for asymmetric signing keys. If you are using HMAC signing keys, this Go package may be unnecessary as the algorithm is symmetric, meaning the key is pre-shared. In this case a JWKs is likely not be the best solution.

Currently, this package supports JWTs signed with an alg that matches one of the following:

ES256
ES384
ES512
PS256
PS384
PS512
RS256
RS384
RS512

Additionally, the supported elliptical curve types are below:

P-256
P-384
P-521

If there are cryptographic algorithms, curve types, or something else already standardized that you'd like supported in this Go package, please open an issue or pull request.

Basic usage

For complete examples, please see the examples directory.

import "github.com/MicahParks/keyfunc"

Preconditions: Acquire the JWKs URL or JSON

A JWKs URL is not required, one can be created directly from JSON with the keyfunc.New function.

// Get the JWKs URL from an environment variable.
jwksURL := os.Getenv("JWKS_URL")

// Confirm the environment variable is not empty.
if jwksURL == "" {
	log.Fatalln("JWKS_URL environment variable must be populated.")
}

Step 1: Create the JWKs

Via HTTP:

// Create the JWKs from the resource at the given URL.
jwks, err := keyfunc.Get(jwksURL)
if err != nil {
	log.Fatalf("Failed to get the JWKs from the given URL.\nError: %s", err.Error())
}

Via JSON:

// Get the JWKs as JSON.
var jwksJSON = json.RawMessage(`{"keys":[{"kid":"zXew0UJ1h6Q4CCcd_9wxMzvcp5cEBifH0KWrCz2Kyxc","kty":"RSA","alg":"PS256","use":"sig","n":"wqS81x6fItPUdh1OWCT8p3AuLYgFlpmg61WXp6sp1pVijoyF29GOSaD9xE-vLtegX-5h0BnP7va0bwsOAPdh6SdeVslEifNGHCtID0xNFqHNWcXSt4eLfQKAPFUq0TsEO-8P1QHRq6yeG8JAFaxakkaagLFuV8Vd_21PGJFWhvJodJLhX_-Ym9L8XUpIPps_mQriMUOWDe-5DWjHnDtfV7mgaOxbBvVo3wj8V2Lmo5Li4HabT4MEzeJ6e9IdFo2kj_44Yy9osX-PMPtu8BQz_onPgf0wjrVWt349Rj6OkS8RxlNGYeuIxYZr0TOhP5F-yEPhSXDsKdVTwPf7zAAaKQ","e":"AQAB","x5c":["MIICmzCCAYMCBgF4HR7HNDANBgkqhkiG9w0BAQsFADARMQ8wDQYDVQQDDAZtYXN0ZXIwHhcNMjEwMzEwMTcwOTE5WhcNMzEwMzEwMTcxMDU5WjARMQ8wDQYDVQQDDAZtYXN0ZXIwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDCpLzXHp8i09R2HU5YJPyncC4tiAWWmaDrVZenqynWlWKOjIXb0Y5JoP3ET68u16Bf7mHQGc/u9rRvCw4A92HpJ15WyUSJ80YcK0gPTE0Woc1ZxdK3h4t9AoA8VSrROwQ77w/VAdGrrJ4bwkAVrFqSRpqAsW5XxV3/bU8YkVaG8mh0kuFf/5ib0vxdSkg+mz+ZCuIxQ5YN77kNaMecO19XuaBo7FsG9WjfCPxXYuajkuLgdptPgwTN4np70h0WjaSP/jhjL2ixf48w+27wFDP+ic+B/TCOtVa3fj1GPo6RLxHGU0Zh64jFhmvRM6E/kX7IQ+FJcOwp1VPA9/vMABopAgMBAAEwDQYJKoZIhvcNAQELBQADggEBALILq1Z4oQNJZEUt24VZcvknsWtQtvPxl3JNcBQgDR5/IMgl5VndRZ9OT56KUqrR5xRsWiCvh5Lgv4fUEzAAo9ToiPLub1SKP063zWrvfgi3YZ19bty0iXFm7l2cpQ3ejFV7WpcdLJE0lapFdPLo6QaRdgNu/1p4vbYg7zSK1fQ0OY5b3ajhAx/bhWlrN685owRbO5/r4rUOa6oo9l4Qn7jUxKUx4rcoe7zUM7qrpOPqKvn0DBp3n1/+9pOZXCjIfZGvYwP5NhzBDCkRzaXcJHlOqWzMBzyovVrzVmUilBcj+EsTYJs0gVXKzduX5zO6YWhFs23lu7AijdkxTY65YM0="],"x5t":"IYIeevIT57t8ppUejM42Bqx6f3I","x5t#S256":"TuOrBy2NcTlFSWuZ8Kh8W8AjQagb4fnfP1SlKMO8-So"},{"kid":"ebJxnm9B3QDBljB5XJWEu72qx6BawDaMAhwz4aKPkQ0","kty":"EC","alg":"ES512","use":"sig","crv":"P-521","x":"YQ95Xj8MTzcHytbU1h8YkCN2kdEQA7ThuZ1ctB9Ekiw6tlM9RwL62eQvzEt4Rz8qN69uRqgU9RzxQOkSU5xVvyo","y":"SMMuP3QnAPHtx7Go2ARsG3NBaySWBLmVvS8s2Ss7Vm_ISWenNbdjKOsY1XvtiQz5scGzWDCEUoZzgV8Ve1mLOV0"},{"kid":"TVAAet63O3xy_KK6_bxVIu7Ra3_z1wlB543Fbwi5VaU","kty":"EC","alg":"ES384","use":"sig","crv":"P-384","x":"Pik2o5as-evijFABH5p6YLXHnWw8iQ_N1ummPY1c_UgG6NO0za-gNOhTz2-tsd_w","y":"e98VSff71k19SY_mHgp3707lgQVrhfVpiGa-sGaKxOWVpxd2jWMhB0Q4RpSRuCp5"},{"kid":"arlUxX4hh56rNO-XdIPhDT7bqBMqcBwNQuP_TnZJNGs","kty":"RSA","alg":"RS512","use":"sig","n":"hhtifu8LL3ICE3BAX5l1KZv6Lni0lhlhBusSfepnpxcb4C_z2U71cQTnLY27kt8WB4bNG6e5_KMx9K3xUdd3euj9MCq8vytwEPieeHE1KXQuhJfLv017lhpK_dRMOHyc-9-50YNdgs_8KWRkrzjjuYrCiO9Iu76n5319e-SC8OPvNUglqxp2N0Sp2ltne2ZrpN8T3OEEXT62TSGmLAVopRGw5gllNVrJfmEyZJCRrBM6s5CQcz8un0FjkAAC4DI6QD-eBL0qG3_NR0hQvR1he2o4BLwjOKH45Pk_jj-eArp-DD6Xq6ABQVb5SNOSdaxl5lnmuotRoY3G5d9YSl-K3w","e":"AQAB","x5c":["MIICmzCCAYMCBgF4HSCcDzANBgkqhkiG9w0BAQsFADARMQ8wDQYDVQQDDAZtYXN0ZXIwHhcNMjEwMzEwMTcxMTE5WhcNMzEwMzEwMTcxMjU5WjARMQ8wDQYDVQQDDAZtYXN0ZXIwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCGG2J+7wsvcgITcEBfmXUpm/oueLSWGWEG6xJ96menFxvgL/PZTvVxBOctjbuS3xYHhs0bp7n8ozH0rfFR13d66P0wKry/K3AQ+J54cTUpdC6El8u/TXuWGkr91Ew4fJz737nRg12Cz/wpZGSvOOO5isKI70i7vqfnfX175ILw4+81SCWrGnY3RKnaW2d7Zmuk3xPc4QRdPrZNIaYsBWilEbDmCWU1Wsl+YTJkkJGsEzqzkJBzPy6fQWOQAALgMjpAP54EvSobf81HSFC9HWF7ajgEvCM4ofjk+T+OP54Cun4MPperoAFBVvlI05J1rGXmWea6i1Ghjcbl31hKX4rfAgMBAAEwDQYJKoZIhvcNAQELBQADggEBAB7bpwPoL02WGCCVhCsbDkq9GeFUwF01opVyFTijZlTUoTf5RcaR2qAH9/irkLjZeFeyozzC5mGvIVruBwnx/6l4PcAMxKK4YiheFVoO/dytpGMCj6ToNmKpjlXzOLAHelieWIUDtAFSYzENjIO01PyXTGYpxebpQCocJBvppj5HqARS9iNPcqBltMhxWrWmMu81tOG3Y7yd2xsIYXk6KjaoefLeN8Was4BPJ0zR6tTSEm6ZOvSRvlppqh84kz7LmWem7gGHAsY2G3tWBUmOdO/SMNMThqV62yLf7sKsuoE1w06lfmrf6D2zGwoEyz+TT6fdSkc34Yeh7+c01X6nFWU="],"x5t":"geiCPGtT_10T8xGLUK1LA0_YQEE","x5t#S256":"dLp3_QNGwMbYll5VecnR8Q9NSeFVfqJPBTa2_8qf48I"},{"kid":"tW6ae7TomE6_2jooM-sf9N_6lWg7HNtaQXrDsElBzM4","kty":"RSA","alg":"PS512","use":"sig","n":"p32N7jqKfMUB6_dKY1uZ3wizzPlBAXg9XrntfUcwNLRPfTBnshpt4uQBf3T8fexkbzhtR18oHvim-YvcWfC5eLGQmWHYiVwACa_C7oGqx51ijK2LRbUg4TKhnZX2X3Ld9xvr3HsosKh2UXn_Ay8nuvdfH-U6S7btT6a-AIFlt3BpqZP0EOl7rY-ie8nXoA13xX6BoyzYiNcugdYCU6czQcmTIJ1JLS0zohi4aTNehRt-1VMRpIMx7q7Ouq3Zhbi7RcDo-_D8FPRhWc2eEKd-h8ebFTIxEOrkguBIomjEFTf3SfYbOB_h-14v9Q2yz-NzyId3-ujRCQGC0hn-cixe2w","e":"AQAB","x5c":["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"],"x5t":"f1l1fxICz1fe9mI-sSrtc19EDhU","x5t#S256":"NUJWRA4ADpLEg_SMkSoE4FKQN0H1Tlz85L-i7puVcqQ"},{"kid":"Lx1FmayP2YBtxaqS1SKJRJGiXRKnw2ov5WmYIMG-BLE","kty":"RSA","alg":"PS384","use":"sig","n":"q7WM4SnrdzlFSo_A1DRhc-8Ho-pBsfs49kGRbw3O_OKFIUyZrzHaRuovW_QaEAyiO3HX8CNcGPcpHdmpl4DhTGEBLcd6xXtCaa65ct00Mq7ZHCRRCrKLh6lJ0rY9fP8vCV0RBigpkNoRfrqLQQN4VeVFTbGSrDaS0LzPbap0-q5FKXUR-OQmQEtOupXhKFQtbB73tL83YnG6Swl7nXsx54ulEoDzcCCYt7pjCVVp7L9fzI2_ucTdtQclAJVQZGKpsx7vabOJuiMUwuAIz56lOJyXRMePsW8UogwC4FA2A52STsYlhOPsDEW4iIExFVNqs-CGoDGhYLIavaCkZhXM0w","e":"AQAB","x5c":["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"],"x5t":"fjRYR1986VCLzbaZaw5r25UKahw","x5t#S256":"ZHNHpizlsjD3qSZh7gJQQBu8W9jBL2HR0y7-3u2Wb-g"},{"kid":"gnmAfvmlsi3kKH3VlM1AJ85P2hekQ8ON_XvJqs3xPD8","kty":"RSA","alg":"RS384","use":"sig","n":"qUNQewKl3APQcbpACMNJ2XphPpupt395z6OZvj5CW9tiRXY3J7dqi8U0bWoIhtmmc7Js6hjp-A5W_FVStuXlT1hLyjJsHeu9ZVPnfIl2MnYN83zQBKw8E4mFsVv0UXNvkVPBF_k0yXrz-ABleWLOgFGnkNU9csc3Z5aihHcwRmC_oS7PZ9Vc-l0xBCyF3YRHI-al8ppSHwFreOweF3-JP3poNAXd906_tjX2KlHSJmNqcUNiSfEluyCp02ALlRFKXUQ1HlfSupHcHySDlanfUyIzZgM9ysCvC1vfNdAuwZ44oUBMul_XPxxhzlewL2Y8PtSDLUDWGTIou8M8049D8Q","e":"AQAB","x5c":["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"],"x5t":"CmRnQVduZWtEsdOC4mauUUsSWxA","x5t#S256":"BvC0LmuM8ZIApN3TQQZWWbGO-d082Ah5d3D6vPvahGw"},{"kid":"CGt0ZWS4Lc5faiKSdi0tU0fjCAdvGROQRGU9iR7tV0A","kty":"EC","alg":"ES256","use":"sig","crv":"P-256","x":"DPW7n9yjfE6Rt-VvVmEdeu4QdW44qifocAPPDxACDDY","y":"-ejsVw8222-hg2dJWx3QV0hE4-I0Ujp7ZsWebE68JE0"},{"kid":"C65q0EKQyhpd1m4fr7SKO2He_nAxgCtAdws64d2BLt8","kty":"RSA","alg":"RS256","use":"sig","n":"ja99ybDrLvw11Z4CvNlDI-kkqJEBpSnvDf0pZF2DvBlvYmeVYL_ChqIe8E9GyHUmLMdtO_jifSgOqE5b8vILwi1kZnJR7N857uEnbWM9YTeevi_RZ-E_hr4frW2NKJ78YGvCzwLKG2GgtSjj0zuTLnSaK8fCGzqXgy6paXNhgHUSZgGwvO0YItpMlyJeqEj1wGTWz1IyA1sguF1cC7K0fojPbPoBwrhvaAeoGRPLraE0rrBsQv8iiLwnRBIez9B1j0NiUG8Iad953Y7UzaKOAw8crIEK45NIK_yxHUpxqcHLjPIcRyIyJGioRyGK7cp-_7iPLOCutQc-u46mom1_ZQ","e":"AQAB","x5c":["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"],"x5t":"5GNr3LeRXHWI4YR8-QTSsF98oTI","x5t#S256":"Dgd0_wZZqvRuf4GEISPNHREX-1ixTMIsrPeGzk0bCxs"}]}`)

// Create the JWKs from the resource at the given URL.
jwks, err := keyfunc.New(jwksJSON)
if err != nil {
	log.Fatalf("Failed to create JWKs from JSON.\nError: %s", err.Error())
}

Additional options can be passed to the keyfunc.Get function via variadic arguments. See keyfunc.Options and the additional features mentioned at the bottom of this README.md.

Step 2: Use the `keyfunc.JWKs` 's `JWKs.KeyFunc` method as the `jwt.Keyfunc` when parsing tokens

// Parse the JWT.
token, err := jwt.Parse(jwtB64, jwks.KeyFunc)
if err != nil {
	return nil, fmt.Errorf("failed to parse token: %w", err)
}

The JWKs.KeyFunc method will automatically select the key with the matching kid (if present) and return its public key as the correct Go type to its caller.

Fork support

Some packages use forks of github.com/dgrijalva/jwt-go. This package aims to support the most popular use cases of these forks.

If additional forks are required for your use case, please feel free to open an issue or PR.

Support for github.com/auth0/go-jwt-middleware

The github.com/auth0/go-jwt-middleware package requires the github.com/form3tech-oss/jwt-go fork. For this use case, use the keyfunc.JWKs 's JWKs.KeyFuncF3T method.

Example snippet

Please also see the examples directory.

// Create the middleware provider.
jwtMiddleware := jwtmiddleware.New(jwtmiddleware.Options{

	// Use the correct version of the KeyFunc method.
	ValidationKeyGetter: jwks.KeyFuncF3T,

	// Always ensure that you set your signing method to avoid tokens choosing the "none" method.
	//
	// This shouldn't matter for this keyfunc package, as the JWKs should be trusted and determines the key type,
	// but it's good practice.
	// https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/
	SigningMethod: jwt.SigningMethodRS256,
})

Test coverage

Test coverage is currently at 85.3%.

This is with current and expired JWTs, but the hard coded ones are now expired. Using non-expired JWTs would require signing JWTs during testing and would allow for additional error checking. But a bit overkill since I've already done that error checking when the JWTs were valid with no changes. A PR for this that does not introduce any dependencies is welcome though.

Additional features

A background refresh of the JWKs keys can be performed. This is possible by passing keyfunc.Options via a variadic argument to the keyfunc.Get function.
- A custom background refresh interval can be specified.
- A custom background refresh request context timeout can be specified. Defaults to one minute.
- A custom background refresh error handling function can be specified. If none is specified, errors go unhandled silently.
JWTs with a previously unseen kid can prompt an automatic refresh of the remote JWKs resource.
A custom HTTP client can be used. This is possible by passing keyfunc.Options via a variadic argument to the keyfunc.Get function.

TODO

Add HMAC support?

djsavvy/keyfunc