ci: zizmor security hardening (#133)

* ci: pass ref context through env in release tag step

zizmor flagged the "Resolve target tag" step in release.yml for
template-injection: github.event_name / github.ref / github.ref_name
were interpolated directly into the shell script. On a tag push the tag
name is attacker-influenceable, so a crafted tag could inject commands.

Move all three context values into the step env and reference them as
shell variables instead. Verified with zizmor 1.16.3: template-injection
findings on release.yml drop from 2 to 0.

* ci: accept release.yml build caches via zizmor config

The release pipeline restores Swatinem/rust-cache and actions/setup-node
caches as a deliberate optimisation. zizmor flags all eight under
cache-poisoning because release.yml publishes to crates.io / PyPI / npm.
The caches are maintainer-controlled and the restore speedup is kept on
purpose, so accept the finding via a zizmor config ignore for release.yml
rather than running cache-free release builds. (Six of the eight are
actions/setup-node, reported at Low confidence.)

Adds .github/zizmor.yml; release.yml now reports 0 high findings.

* ci: drop persisted checkout credentials on read-only jobs

zizmor's artipacked audit flags every actions/checkout that keeps the
default persisted credential: the token is written to the runner's
.git/config, where it can leak if a later step packs .git into an
uploaded artifact, or be read by another step in the same job.

Set persist-credentials: false on the 20 checkouts whose jobs never push
or authenticate to git (build/test/clippy/msrv/coverage/supply-chain/
fuzz/python/wasm/node in ci.yml, plus bench.yml, codeql.yml, the seven
release.yml build/publish jobs, and sync-metadata.yml). The publish and
release jobs authenticate to crates.io / npm / PyPI / the GitHub API with
their own tokens, not persisted git credentials, so this is safe.

sync-about.yml genuinely pushes the indicator-count fix-up to the PR
branch, so it keeps its credential and is accepted via .github/zizmor.yml.
zizmor artipacked for the repo drops to 0 (0 high, 0 medium remaining).

.github/workflows/bench.yml

@@ -49,6 +49,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
 

.github/workflows/ci.yml

@@ -40,6 +40,8 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -88,6 +90,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Set up Node
         id: setup_node
@@ -175,6 +179,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -253,6 +259,8 @@ jobs:
             packages: "-p wickra-node"
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust ${{ matrix.toolchain }}
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -276,6 +284,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -315,6 +325,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: cargo-deny
         uses: EmbarkStudios/cargo-deny-action@bb137d7af7e4fb67e5f82a49c4fce4fad40782fe # v2.0.20
@@ -331,6 +343,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install nightly Rust
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -387,6 +401,8 @@ jobs:
         python-version: ["3.9", "3.11", "3.12", "3.13"]
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -461,6 +477,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust toolchain (with wasm target)
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
@@ -507,6 +525,8 @@ jobs:
         node-version: ["18", "20"]
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27

.github/workflows/codeql.yml

@@ -41,6 +41,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@03e4368ac7daa2bd82b3e85262f3bf87ee112f57 # v3.36.0

.github/workflows/release.yml

@@ -46,6 +46,8 @@ jobs:
     environment: release
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
       - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable branch, 2026-03-27
       - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         continue-on-error: true # cache is an optimisation; never block on a stuck/slow restore
@@ -156,6 +158,8 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
       - name: Set up Python
         id: setup_python
         continue-on-error: true
@@ -194,6 +198,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
       - name: Sync root README into bindings/python so it ships in the sdist
         run: cp README.md bindings/python/README.md
       - uses: PyO3/maturin-action@e83996d129638aa358a18fbd1dfb82f0b0fb5d3b # v1.51.0
@@ -244,6 +250,8 @@ jobs:
     runs-on: ${{ matrix.host }}
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Set up Node
         id: setup_node
@@ -303,6 +311,8 @@ jobs:
       id-token: write
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Set up Node
         id: setup_node
@@ -470,6 +480,8 @@ jobs:
       id-token: write
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Set up Node
         id: setup_node
@@ -570,13 +582,22 @@ jobs:
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
+          persist-credentials: false
           fetch-depth: 0
 
       - name: Resolve target tag
         id: tag
+        # Pass the (potentially attacker-influenceable on a tag push) ref context
+        # through the environment instead of interpolating it into the shell
+        # script, so a crafted tag name cannot inject commands (zizmor:
+        # template-injection).
+        env:
+          EVENT_NAME: ${{ github.event_name }}
+          REF: ${{ github.ref }}
+          REF_NAME: ${{ github.ref_name }}
         run: |
-          if [ "${{ github.event_name }}" = "push" ] && [[ "${{ github.ref }}" == refs/tags/* ]]; then
-            tag="${{ github.ref_name }}"
+          if [ "$EVENT_NAME" = "push" ] && [[ "$REF" == refs/tags/* ]]; then
+            tag="$REF_NAME"
           else
             # workflow_dispatch / non-tag push: attach to the latest v* tag.
             tag=$(git tag --list 'v*' --sort=-v:refname | head -n1)

.github/workflows/sync-metadata.yml

@@ -15,6 +15,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
       - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         with:
           python-version: "3.12"