thanhnvandClaude Opus 4.8
e21a1472b1
Under CASAN_APPROVAL_STRICT=1, a high-risk approval is trusted ONLY when a REGISTERED reviewer cryptographically signs THIS exact request and their role is authorized for the action — a plain env-var CASAN_APPROVER is no longer enough. - approval-sign.sh: reviewer signs assertion "casan-approval|v1|<action>|<actor>|<input_sha256>|<approver_id>" with their key. - approval-verify.sh: gate looks up reviewer role+pubkey in reviewers.registry, enforces role→action authorization, verifies the RSA signature (fail-closed). - governance-check.sh: strict branch requires a valid signed approval; SoD still enforced; default (non-strict) env-var path UNCHANGED (baseline preserved). - reviewers.registry: role-scoped reviewer identity registry (pubkeys off-repo; production replaces with OIDC/JWT from a real IdP). - phase-h5-approval-tests.sh: 8 checks — valid/authorized approve; unsigned, wrong-role, forged-key, unregistered, replay-to-other-request, self-approval all denied; non-strict backward-compat. Baselines: run-casan4 35/35, adversarial 44/44. Lifts H5 policy-approval (C4) 2.5 -> ~3.5-4 / 5. Total suites now 6 (+8 checks = 148). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
75 lines
3.3 KiB
Bash
Executable File
75 lines
3.3 KiB
Bash
Executable File
#!/usr/bin/env bash
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set -uo pipefail
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# CASAN H5 — Signed-approval verifier (Approval-identity MVP · C4 / V20).
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#
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# Problem: high-risk approval used to trust a plain env var (CASAN_APPROVER=bob) —
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# anyone who can set the env can "approve". This binds an approval to a REGISTERED
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# reviewer's cryptographic identity: the reviewer must SIGN this exact request with
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# their private key, AND their role must be authorized for the action class.
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#
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# The signed assertion is: casan-approval|v1|<action>|<actor>|<input_sha256>|<approver_id>
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# — so a signature for one request/reviewer cannot be replayed for another.
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#
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# Usage:
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# approval-verify.sh <action> <actor> <input-file> <approver-id> <sig-file>
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# Registry (line format, no yaml dep):
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# reviewer <id> <role> <pubkey-file>
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# action <action-name|default> <comma,roles>
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# Env: CASAN_REVIEWERS_FILE (default governance/reviewers.registry)
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# CASAN_REVIEWERS_DIR (default governance/reviewers) — base dir for pubkey-file
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# Exit: 0 ok (prints "APPROVAL_OK role=<role>"), 3 deny (reason on stderr), 64 usage.
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SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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PROJECT_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
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GOV_DIR="$PROJECT_ROOT/.specify/level5/central-governance"
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REVIEWERS_FILE="${CASAN_REVIEWERS_FILE:-$GOV_DIR/reviewers.registry}"
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REVIEWERS_DIR="${CASAN_REVIEWERS_DIR:-$GOV_DIR/reviewers}"
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ACTION="${1:-}"; ACTOR="${2:-}"; INPUT_FILE="${3:-}"; APPROVER="${4:-}"; SIG_FILE="${5:-}"
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if [[ -z "$ACTION" || -z "$ACTOR" || -z "$INPUT_FILE" || -z "$APPROVER" || -z "$SIG_FILE" ]]; then
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echo "Usage: approval-verify.sh <action> <actor> <input-file> <approver-id> <sig-file>" >&2
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exit 64
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fi
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deny() { echo "APPROVAL_DENIED reason=$1 approver=$APPROVER action=$ACTION" >&2; exit 3; }
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[[ -f "$INPUT_FILE" ]] || deny "input_file_missing"
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[[ -f "$SIG_FILE" ]] || deny "signature_missing"
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[[ -f "$REVIEWERS_FILE" ]] || deny "reviewer_registry_missing"
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command -v openssl >/dev/null 2>&1 || deny "openssl_unavailable"
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hash_file() {
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if command -v sha256sum >/dev/null 2>&1; then sha256sum "$1" | awk '{print $1}'
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else shasum -a 256 "$1" | awk '{print $1}'; fi
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}
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# Reviewer lookup (first matching registered reviewer).
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REV_LINE="$(awk -v id="$APPROVER" '$1=="reviewer" && $2==id {print $3" "$4; exit}' "$REVIEWERS_FILE")"
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[[ -n "$REV_LINE" ]] || deny "approver_not_registered"
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ROLE="${REV_LINE%% *}"
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PUB_REL="${REV_LINE##* }"
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# Role authorization for this action (fallback to the "default" action policy).
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ROLES="$(awk -v a="$ACTION" '$1=="action" && $2==a {print $3; exit}' "$REVIEWERS_FILE")"
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[[ -n "$ROLES" ]] || ROLES="$(awk '$1=="action" && $2=="default" {print $3; exit}' "$REVIEWERS_FILE")"
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case ",$ROLES," in
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*",$ROLE,"*) : ;;
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*) deny "approver_role_not_authorized(role=$ROLE action=$ACTION allowed=$ROLES)" ;;
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esac
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# Resolve pubkey path (absolute or relative to reviewers dir).
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PUB="$PUB_REL"; [[ "$PUB" = /* ]] || PUB="$REVIEWERS_DIR/$PUB_REL"
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[[ -f "$PUB" ]] || deny "approver_pubkey_missing($PUB)"
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# Rebuild the exact signed assertion and verify.
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INPUT_SHA="$(hash_file "$INPUT_FILE")"
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MSG="casan-approval|v1|$ACTION|$ACTOR|$INPUT_SHA|$APPROVER"
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TMP="$(mktemp)"; trap 'rm -f "$TMP"' EXIT
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printf '%s' "$MSG" > "$TMP"
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openssl dgst -sha256 -verify "$PUB" -signature "$SIG_FILE" "$TMP" >/dev/null 2>&1 \
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|| deny "approval_signature_invalid"
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echo "APPROVAL_OK role=$ROLE approver=$APPROVER action=$ACTION"
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exit 0
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