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jwt.Parse silently fails if alg isn't included in JWK #959
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before I make any wild guesses, can you please provide a standalone test case that reproduces this behavior? |
I might be able to, but I want to make sure I understand the intent of the |
Not returning an error is the intended behavior. |
Here is a minimal repro of my issue: package main
import (
"os"
"fmt"
"crypto/rand"
"crypto/rsa"
"github.com/lestrrat-go/jwx/v2/jwk"
"github.com/lestrrat-go/jwx/v2/jwt"
"github.com/lestrrat-go/jwx/v2/jwa"
"github.com/lestrrat-go/jwx/v2/jwt/openid"
)
func main() {
raw, _ := rsa.GenerateKey(rand.Reader, 2048)
key, _ := jwk.FromRaw(raw)
_ = jwk.AssignKeyID(key)
//key.Set("alg", "RS256")
token, _ := openid.NewBuilder().
Subject("username").
Audience([]string{"audience"}).
Issuer("issuer").
Claim("nonce", "random").
Build()
signedToken, _ := jwt.Sign(token, jwt.WithKey(jwa.RS256, key))
keyset := jwk.NewSet()
keyset.AddKey(key)
publicKeyset, _ := jwk.PublicSetOf(keyset)
_, err := jwt.Parse([]byte(signedToken), jwt.WithKeySet(publicKeyset), jwt.WithToken(openid.New()))
if err != nil {
fmt.Fprintf(os.Stderr, err.Error())
return
}
} The parse fails. If you uncomment |
Ah, I see. tl;dr use
Though I agree that it could have been more explicit. This behavior is slightly different between using a single key and a key set for verify, because of the possible security implications. The basic premise is that this library does not allow verification to succeed unless the intended algorithm for both the JWS message and the key provided matches. If it's a single key, the user (you) are explicit in wanting to use the key with the algorithm specified in the To alleviate this problem, however, is the |
This issue is stale because it has been open 14 days with no activity. Remove stale label or comment or this will be closed in 7 days. |
This issue was closed because it has been stalled for 7 days with no activity. This does not mean your issue is rejected, but rather it is done to hide it from the view of the maintains for the time being. Feel free to reopen if you have new comments |
* Merge pull request from GHSA-rm8v-mxj3-5rmq ### Summary Decrypting AES-CBC encrypted JWE has Potential Padding Oracle Attack Vulnerability. ### Details On [v2.0.10](https://github.com/lestrrat-go/jwx/releases/tag/v2.0.10), decrypting AES-CBC encrypted JWE may return an error "failed to generate plaintext from decrypted blocks: invalid padding": https://github.com/lestrrat-go/jwx/blob/8840ffd4afc5839f591ff0e9ba9034af52b1643e/jwe/internal/aescbc/aescbc.go#L210-L213 ```go plaintext, err := unpad(buf, c.blockCipher.BlockSize()) if err != nil { return nil, fmt.Errorf(`failed to generate plaintext from decrypted blocks: %w`, err) } ``` Reporting padding error causes [Padding Oracle Attack](https://en.wikipedia.org/wiki/Padding_oracle_attack) Vulnerability. RFC 7516 JSON Web Encryption (JWE) says that we MUST NOT do this. > 11.5. Timing Attacks > To mitigate the attacks described in RFC 3218 [RFC3218], the > recipient MUST NOT distinguish between format, padding, and length > errors of encrypted keys. It is strongly recommended, in the event > of receiving an improperly formatted key, that the recipient > substitute a randomly generated CEK and proceed to the next step, to > mitigate timing attacks. In addition, the time to remove padding depends on the length of the padding. It may leak the length of the padding by Timing Attacks. https://github.com/lestrrat-go/jwx/blob/796b2a9101cf7e7cb66455e4d97f3c158ee10904/jwe/internal/aescbc/aescbc.go#L33-L66 ```go func unpad(buf []byte, n int) ([]byte, error) { lbuf := len(buf) rem := lbuf % n // First, `buf` must be a multiple of `n` if rem != 0 { return nil, fmt.Errorf("input buffer must be multiple of block size %d", n) } // Find the last byte, which is the encoded padding // i.e. 0x1 == 1 byte worth of padding last := buf[lbuf-1] // This is the number of padding bytes that we expect expected := int(last) if expected == 0 || /* we _have_ to have padding here. therefore, 0x0 is not an option */ expected > n || /* we also must make sure that we don't go over the block size (n) */ expected > lbuf /* finally, it can't be more than the buffer itself. unlikely, but could happen */ { return nil, fmt.Errorf(`invalid padding byte at the end of buffer`) } // start i = 1 because we have already established that expected == int(last) where // last = buf[lbuf-1]. // // we also don't check against lbuf-i in range, because we have established expected <= lbuf for i := 1; i < expected; i++ { if buf[lbuf-i] != last { return nil, fmt.Errorf(`invalid padding`) } } return buf[:lbuf-expected], nil } ``` To mitigate Timing Attacks, it MUST be done in constant time. ### Impact The authentication tag is verified, so it is not an immediate attack. Co-authored-by: ICHINOSE Shogo <[email protected]> * Update Changes * Bump golang.org/x/crypto from 0.9.0 to 0.10.0 (#938) * Bump golang.org/x/crypto from 0.9.0 to 0.10.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.9.0 to 0.10.0. - [Commits](golang/crypto@v0.9.0...v0.10.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * run gazelle-update-repos --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Bump github.com/lestrrat-go/jwx/v2 from 2.0.8 to 2.0.11 in /cmd/jwx (#942) Bumps [github.com/lestrrat-go/jwx/v2](https://github.com/lestrrat-go/jwx) from 2.0.8 to 2.0.11. - [Release notes](https://github.com/lestrrat-go/jwx/releases) - [Changelog](https://github.com/lestrrat-go/jwx/blob/develop/v2/Changes) - [Commits](v2.0.8...v2.0.11) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/jwx/v2 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Bump github.com/lestrrat-go/jwx/v2 from 2.0.8 to 2.0.11 in /examples (#943) Bumps [github.com/lestrrat-go/jwx/v2](https://github.com/lestrrat-go/jwx) from 2.0.8 to 2.0.11. - [Release notes](https://github.com/lestrrat-go/jwx/releases) - [Changelog](https://github.com/lestrrat-go/jwx/blob/develop/v2/Changes) - [Commits](v2.0.8...v2.0.11) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/jwx/v2 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Bump github.com/lestrrat-go/jwx/v2 in /bench/performance (#944) Bumps [github.com/lestrrat-go/jwx/v2](https://github.com/lestrrat-go/jwx) from 2.0.8 to 2.0.11. - [Release notes](https://github.com/lestrrat-go/jwx/releases) - [Changelog](https://github.com/lestrrat-go/jwx/blob/develop/v2/Changes) - [Commits](v2.0.8...v2.0.11) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/jwx/v2 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * remove unnecessarily err checks (#948) godoc says hash.Hash.Write never returns an error: https://pkg.go.dev/hash#Hash > Write (via the embedded io.Writer interface) adds more data to the running hash. > It never returns an error. So, we don't need to check errors of Write in Hmac.ComputeAuthTag. * Adam korcz fix 1 (#949) * fix panic from empty seed Signed-off-by: AdamKorcz <[email protected]> * Add test case --------- Signed-off-by: AdamKorcz <[email protected]> Co-authored-by: AdamKorcz <[email protected]> * add size check (#950) Signed-off-by: AdamKorcz <[email protected]> * Add test case to #952 (#953) * Do not ignore custom encrypt and sign options in jwt package Fixes #951 * Add test case * Update Changes --------- Co-authored-by: ItalyPaleAle <[email protected]> * Bump golang.org/x/crypto from 0.10.0 to 0.11.0 (#956) * Bump golang.org/x/crypto from 0.10.0 to 0.11.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.10.0 to 0.11.0. - [Commits](golang/crypto@v0.10.0...v0.11.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * Update bazel repos --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Bump golang.org/x/crypto from 0.11.0 to 0.12.0 (#963) * Bump golang.org/x/crypto from 0.11.0 to 0.12.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.11.0 to 0.12.0. - [Commits](golang/crypto@v0.11.0...v0.12.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * Run gazelle-update-repos --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Add documentation that explains #959 (#964) * Add documentation that explains #959 * run genoptions * Update Changes for v2.0.12 --------- Signed-off-by: dependabot[bot] <[email protected]> Signed-off-by: AdamKorcz <[email protected]> Co-authored-by: ICHINOSE Shogo <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: AdamKorcz <[email protected]> Co-authored-by: AdamKorcz <[email protected]> Co-authored-by: ItalyPaleAle <[email protected]>
* Merge pull request from GHSA-rm8v-mxj3-5rmq ### Summary Decrypting AES-CBC encrypted JWE has Potential Padding Oracle Attack Vulnerability. ### Details On [v2.0.10](https://github.com/lestrrat-go/jwx/releases/tag/v2.0.10), decrypting AES-CBC encrypted JWE may return an error "failed to generate plaintext from decrypted blocks: invalid padding": https://github.com/lestrrat-go/jwx/blob/8840ffd4afc5839f591ff0e9ba9034af52b1643e/jwe/internal/aescbc/aescbc.go#L210-L213 ```go plaintext, err := unpad(buf, c.blockCipher.BlockSize()) if err != nil { return nil, fmt.Errorf(`failed to generate plaintext from decrypted blocks: %w`, err) } ``` Reporting padding error causes [Padding Oracle Attack](https://en.wikipedia.org/wiki/Padding_oracle_attack) Vulnerability. RFC 7516 JSON Web Encryption (JWE) says that we MUST NOT do this. > 11.5. Timing Attacks > To mitigate the attacks described in RFC 3218 [RFC3218], the > recipient MUST NOT distinguish between format, padding, and length > errors of encrypted keys. It is strongly recommended, in the event > of receiving an improperly formatted key, that the recipient > substitute a randomly generated CEK and proceed to the next step, to > mitigate timing attacks. In addition, the time to remove padding depends on the length of the padding. It may leak the length of the padding by Timing Attacks. https://github.com/lestrrat-go/jwx/blob/796b2a9101cf7e7cb66455e4d97f3c158ee10904/jwe/internal/aescbc/aescbc.go#L33-L66 ```go func unpad(buf []byte, n int) ([]byte, error) { lbuf := len(buf) rem := lbuf % n // First, `buf` must be a multiple of `n` if rem != 0 { return nil, fmt.Errorf("input buffer must be multiple of block size %d", n) } // Find the last byte, which is the encoded padding // i.e. 0x1 == 1 byte worth of padding last := buf[lbuf-1] // This is the number of padding bytes that we expect expected := int(last) if expected == 0 || /* we _have_ to have padding here. therefore, 0x0 is not an option */ expected > n || /* we also must make sure that we don't go over the block size (n) */ expected > lbuf /* finally, it can't be more than the buffer itself. unlikely, but could happen */ { return nil, fmt.Errorf(`invalid padding byte at the end of buffer`) } // start i = 1 because we have already established that expected == int(last) where // last = buf[lbuf-1]. // // we also don't check against lbuf-i in range, because we have established expected <= lbuf for i := 1; i < expected; i++ { if buf[lbuf-i] != last { return nil, fmt.Errorf(`invalid padding`) } } return buf[:lbuf-expected], nil } ``` To mitigate Timing Attacks, it MUST be done in constant time. ### Impact The authentication tag is verified, so it is not an immediate attack. Co-authored-by: ICHINOSE Shogo <[email protected]> * Update Changes * Bump golang.org/x/crypto from 0.9.0 to 0.10.0 (#938) * Bump golang.org/x/crypto from 0.9.0 to 0.10.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.9.0 to 0.10.0. - [Commits](golang/crypto@v0.9.0...v0.10.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * run gazelle-update-repos --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Bump github.com/lestrrat-go/jwx/v2 from 2.0.8 to 2.0.11 in /cmd/jwx (#942) Bumps [github.com/lestrrat-go/jwx/v2](https://github.com/lestrrat-go/jwx) from 2.0.8 to 2.0.11. - [Release notes](https://github.com/lestrrat-go/jwx/releases) - [Changelog](https://github.com/lestrrat-go/jwx/blob/develop/v2/Changes) - [Commits](v2.0.8...v2.0.11) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/jwx/v2 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Bump github.com/lestrrat-go/jwx/v2 from 2.0.8 to 2.0.11 in /examples (#943) Bumps [github.com/lestrrat-go/jwx/v2](https://github.com/lestrrat-go/jwx) from 2.0.8 to 2.0.11. - [Release notes](https://github.com/lestrrat-go/jwx/releases) - [Changelog](https://github.com/lestrrat-go/jwx/blob/develop/v2/Changes) - [Commits](v2.0.8...v2.0.11) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/jwx/v2 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Bump github.com/lestrrat-go/jwx/v2 in /bench/performance (#944) Bumps [github.com/lestrrat-go/jwx/v2](https://github.com/lestrrat-go/jwx) from 2.0.8 to 2.0.11. - [Release notes](https://github.com/lestrrat-go/jwx/releases) - [Changelog](https://github.com/lestrrat-go/jwx/blob/develop/v2/Changes) - [Commits](v2.0.8...v2.0.11) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/jwx/v2 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * remove unnecessarily err checks (#948) godoc says hash.Hash.Write never returns an error: https://pkg.go.dev/hash#Hash > Write (via the embedded io.Writer interface) adds more data to the running hash. > It never returns an error. So, we don't need to check errors of Write in Hmac.ComputeAuthTag. * Adam korcz fix 1 (#949) * fix panic from empty seed Signed-off-by: AdamKorcz <[email protected]> * Add test case --------- Signed-off-by: AdamKorcz <[email protected]> Co-authored-by: AdamKorcz <[email protected]> * add size check (#950) Signed-off-by: AdamKorcz <[email protected]> * Add test case to #952 (#953) * Do not ignore custom encrypt and sign options in jwt package Fixes #951 * Add test case * Update Changes --------- Co-authored-by: ItalyPaleAle <[email protected]> * Bump golang.org/x/crypto from 0.10.0 to 0.11.0 (#956) * Bump golang.org/x/crypto from 0.10.0 to 0.11.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.10.0 to 0.11.0. - [Commits](golang/crypto@v0.10.0...v0.11.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * Update bazel repos --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Bump golang.org/x/crypto from 0.11.0 to 0.12.0 (#963) * Bump golang.org/x/crypto from 0.11.0 to 0.12.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.11.0 to 0.12.0. - [Commits](golang/crypto@v0.11.0...v0.12.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * Run gazelle-update-repos --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Add documentation that explains #959 (#964) * Add documentation that explains #959 * run genoptions * Update Changes for v2.0.12 * Add example for using raw JWT (#967) * Add example for using raw JWT * typo * autodoc updates (#968) Co-authored-by: lestrrat <[email protected]> * Update jwk iteration (#971) * autodoc updates (#972) Co-authored-by: lestrrat <[email protected]> * Bump actions/checkout from 3 to 4 (#974) Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4. - [Release notes](https://github.com/actions/checkout/releases) - [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md) - [Commits](actions/checkout@v3...v4) --- updated-dependencies: - dependency-name: actions/checkout dependency-type: direct:production update-type: version-update:semver-major ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Update HWK option documentation (#979) * Update option documentation * reinstance CacheOption * Sample implementation of jwk.Equal (#977) * Bump golang.org/x/crypto from 0.12.0 to 0.13.0 (#976) * Bump golang.org/x/crypto from 0.12.0 to 0.13.0 Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.12.0 to 0.13.0. - [Commits](golang/crypto@v0.12.0...v0.13.0) --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <[email protected]> * Run gazelle-update-repos & make tidy --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * Bump github.com/lestrrat-go/blackmagic from 1.0.1 to 1.0.2 (#983) * Bump github.com/lestrrat-go/blackmagic from 1.0.1 to 1.0.2 Bumps [github.com/lestrrat-go/blackmagic](https://github.com/lestrrat-go/blackmagic) from 1.0.1 to 1.0.2. - [Commits](lestrrat-go/blackmagic@v1.0.1...v1.0.2) --- updated-dependencies: - dependency-name: github.com/lestrrat-go/blackmagic dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <[email protected]> * Run gazelle-update-repos * Run make tidy --------- Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Daisuke Maki <[email protected]> * adapt to change in notation * Upgrade golangci-lint to 1.54.2 (#986) * Update Changes --------- Signed-off-by: dependabot[bot] <[email protected]> Signed-off-by: AdamKorcz <[email protected]> Co-authored-by: ICHINOSE Shogo <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: AdamKorcz <[email protected]> Co-authored-by: AdamKorcz <[email protected]> Co-authored-by: ItalyPaleAle <[email protected]> Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> Co-authored-by: lestrrat <[email protected]>
Describe the bug
I'm building an OIDC server with a RSA JWK key. I wasn't returning
alg: "RS256"
in the JSON. I traced the problem to jwx silently failing this check:jwx/jws/key_provider.go
Line 117 in 976a058
It returns from here without ever setting the sink:
jwx/jws/key_provider.go
Line 150 in 976a058
Note that for my server I'm generating the keys using JWX as well, and it doesn't include alg by default, which is why it was missing. Not sure if this is intended behavior. In order to fix my bug I just needed to add
key.Set("alg", "RS256")
Please attach the output of
go version
go version go1.20.4 linux/amd64
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