54 lines
3.4 KiB
Markdown
54 lines
3.4 KiB
Markdown
---
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id: "bug-1952"
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status: "fixed"
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status_updated: "2026-10-10"
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status_note: ""
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component: "apiserver"
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severity: "security"
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timestamp: "2026-10-10T08:15:16Z"
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last_seen: "2026-10-10T08:15:16Z"
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occurrences: 1
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files: ["src/frontend/apiserver/controllers/users.go"]
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tags: ["apiserver", "security", "rbac"]
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related: []
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fix_commits: ["a80768f3"]
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gitea_issue: 383
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gitea_synced_status: "fixed"
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gitea_synced_hash: "d6676e7948f8"
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---
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# bug-1952: apiserver user role changes check a narrower rbac:control grant only against the target user
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## Description
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**Observed:** (source reading, `.kiro/reviews/project-gap-review-2026-10-10.md` (P0); to be confirmed by a failing test before the fix)
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Suspected (needs verification): in add/delete roles for a user, a non-`all` `rbac:control` grant is only checked against "is the target me?" (`controllers/users.go:404-412,455-462`), so such a grant could let a user give itself `cluster_admin`. Built-in roles grant `rbac:control` only with domain `all` (`config/rbac.yaml:100-102`), so this is latent.
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**Expected:** A user can never grant itself a role with more rights than it already holds.
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**Impact:** Security (latent): privilege escalation through a custom role.
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**Found by:** review: `.kiro/reviews/project-gap-review-2026-10-10.md` (P0)
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## Environment
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- OS: no /etc/os-release; Docker container; NixOS kernel; kernel Linux 6.18.33 x86_64
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- libc: glibc 2.42-47 (interpreter /nix/store/wb6rhpznjfczwlwx23zmdrrw74bayxw4-glibc-2.42-47/lib/ld-linux-x86-64.so.2)
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- Toolchain: gcc (GCC) 15.2.0, meson 1.9.1
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- Build: asan (xce.build)
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- Code: scheduler-framework @ 94472ee3-dirty
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- Deployment: any (found by source reading; the failing test that confirms it is named in Verification)
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## Reproduction
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1. Define a role with `rbac:control` scoped to `self`, assign it to a user, then add `cluster_admin` to that same user via the users API.
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- Frequency: deterministic (by code reading; confirmed by the RED test of the fix)
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- Evidence: the code sites quoted in Description; no logs kept.
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## Root cause
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`UserController.AddRolesForUser`/`DeleteRolesForUser` (`controllers/users.go`) only checked whether the target was the caller for a non-`all` `rbac:control` grant; `self` is an accepted rbac scope (`models/roles.go:78`), so a user holding only `rbac:control` scope `self` could grant itself `cluster_admin`.
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## Fix
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`canChangeUserRoles`: changing anyone's roles (the caller's included) requires an `rbac:control` grant with scope `all`, checked over all grants before deduplication; anything else gets 403. Follow-up: any `rbac:control` scope can still create roles and add permissions to a role the caller holds (`roles.go`), the same escalation by another route.
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## Verification
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- Test: `TestAddRolesForUser_SelfScopeCannotGrantItselfRoles` (`controllers/users_rbac_test.go`): RED `privilege escalation: mallory (rbac:control scope self) granted itself cluster_admin (status 200)`, GREEN after; plus `TestDeleteRolesForUser_SelfScopeRejected`, `TestUserRoleChanges_AllScopeAllowed`.
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- Suites: `xce-build.sh all asan xce.build --incremental` on the merged branch, 2026-10-10: all C suites Ok 155 / Fail 0, frontend Go unit tests ok, xceadmin tests ok; apiserver `CGO_ENABLED=0 go test ./...` (incl. middleware, router, cmd) ok
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- Live: n/a: unit/fixture-level verification only; no live deployment was run (follow-up)
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## References
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- Fix commit: `a80768f3` (on `scheduler-framework`; worker-branch original in the merge)
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- Review: `.kiro/reviews/project-gap-review-2026-10-10.md`
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