pnpm vulnerable to no-script global cache poisoning via overrides / `ignore-scripts` evasion

The package manager pnpm prior to version 9.15.0 seems to mishandle overrides and global cache: Overrides from one workspace leak into npm metadata saved in global cache; npm metadata from global cache affects other workspaces; and installs by default don't revalidate the data (including on first lockfile generation). This can make workspace A (even running with `ignore-scripts=true`) posion global cache and execute scripts in workspace B. Users generally expect `ignore-scripts` to be sufficient to prevent immediate code execution on install (e.g. when the tree is just repacked/bundled without executing it). Here, that expectation is broken. Global state integrity is lost via operations that one would expect to be secure, enabling subsequently running arbitrary code execution on installs. Version 9.15.0 fixes the issue. As a work-around, use separate cache and store dirs in each workspace.

The package manager pnpm prior to version 9.15.0 seems to mishandle overrides and global cache: Overrides from one workspace leak into npm metadata saved in global cache; npm metadata from global cache affects other workspaces; and installs by default don't revalidate the data (including on first lockfile generation). This can make workspace A (even running with `ignore-scripts=true`) posion global cache and execute scripts in workspace B. Users generally expect `ignore-scripts` to be sufficient to prevent immediate code execution on install (e.g. when the tree is just repacked/bundled without executing it). Here, that expectation is broken. Global state integrity is lost via operations that one would expect to be secure, enabling subsequently running arbitrary code execution on installs. Version 9.15.0 fixes the issue. As a work-around, use separate cache and store dirs in each workspace.

The package manager pnpm prior to version 9.15.0 seems to mishandle overrides and global cache: Overrides from one workspace leak into npm metadata saved in global cache; npm metadata from global cache affects other workspaces; and installs by default don't revalidate the data (including on first lockfile generation). This can make workspace A (even running with `ignore-scripts=true`) posion global cache and execute scripts in workspace B. Users generally expect `ignore-scripts` to be sufficient to prevent immediate code execution on install (e.g. when the tree is just repacked/bundled without executing it). Here, that expectation is broken. Global state integrity is lost via operations that one would expect to be secure, enabling subsequently running arbitrary code execution on installs. Version 9.15.0 fixes the issue. As a work-around, use separate cache and store dirs in each workspace.

### Summary pnpm seems to mishandle overrides and global cache: 1. Overrides from one workspace leak into npm metadata saved in global cache 2. npm metadata from global cache affects other workspaces 3. installs by default don't revalidate the data (including on first lockfile generation) This can make workspace A (even running with `ignore-scripts=true`) posion global cache and execute scripts in workspace B Users generally expect `ignore-scripts` to be sufficient to prevent immediate code execution on install (e.g. when the tree is just repacked/bundled without executing it). Here, that expectation is broken ### Details See PoC. In it, overrides from a single run of A get leaked into e.g. `~/Library/Caches/pnpm/metadata/registry.npmjs.org/rimraf.json` and persistently affect all other projects using the cache ### PoC Postinstall code used in PoC is benign and can be inspected in <https://www.npmjs.com/package/ponyhooves?activeTab=code>, it's just a `console.log` 1. Remove store and cache On mac: `rm -rf ~/Library/Caches/pnpm ~/Library/pnpm/store` This step is not required in general, but we'll be using a popular package for PoC that's likely cached 2. Create `A/package.json`: ```json { "name": "A", "pnpm": { "overrides": { "rimraf>glob": "npm:ponyhooves@1" } }, "dependencies": { "rimraf": "6.0.1" } } ``` Install it with `pnpm i --ignore-scripts` (the flag is not required, but the point of the demo is to show that it doesn't help) 4. Create `B/package.json`: ```json { "name": "B", "dependencies": { "rimraf": "6.0.1" } } ``` Install it with `pnpm i` Result: ```console Packages: +3 +++ Progress: resolved 3, reused 3, downloaded 0, added 3, done node_modules/.pnpm/[email protected]/node_modules/ponyhooves: Running postinstall script, done in 51ms dependencies: + rimraf 6.0.1 Done in 1.4s ``` Also, that code got leaked into another project and it's lockfile now! ### Impact Global state integrity is lost via operations that one would expect to be secure, enabling subsequently running arbitrary code execution on installs As a work-around, use separate cache and store dirs in each workspace