54 lines
2.7 KiB
Markdown
54 lines
2.7 KiB
Markdown
---
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id: "bug-1950"
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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: "2026-10-10T08:15:11Z"
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last_seen: "2026-10-10T08:15:11Z"
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occurrences: 1
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files: ["src/frontend/apiserver/middleware/validatehandler.go"]
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tags: ["apiserver", "security", "jwt"]
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related: []
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fix_commits: ["42dd1e7a"]
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gitea_issue: 381
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gitea_synced_status: "fixed"
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gitea_synced_hash: "edb7a297a683"
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---
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# bug-1950: apiserver JWT validation does not pin the signing algorithm
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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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The middleware's parse callback returns the key without checking `token.Method` (`middleware/validatehandler.go:102-104`), unlike the other parse path (`controllers/auth.go:186`).
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**Expected:** Only the configured HMAC algorithm is accepted.
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**Impact:** Security hardening: algorithm-confusion class of attacks is not ruled out.
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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. Present a token signed with another algorithm family; validation does not reject it on the algorithm.
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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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`isValidToken()` (`middleware/validatehandler.go`) never checked `token.Method`; `GetUsernameFromToken` accepted any HMAC variant.
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## Fix
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`controllers/auth.go`: `JWTSigningMethod` (HS256), `JWTKeyFunc`, `JWTValidMethods()`; both parse paths use them.
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## Verification
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- Test: `TestIsValidToken_PinsSigningAlgorithm` (`middleware/validatehandler_test.go`): RED `isValidToken(HS384) = true, want false`; `TestGetUsernameFromToken_PinsSigningAlgorithm`: RED; GREEN after.
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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: `42dd1e7a` (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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