| Gói / sản phẩm | Phiên bản bị ảnh hưởng | Phiên bản đã vá |
|---|---|---|
| liquidjs | < 10.26.0 | 10.26.0 |
Context.spawn() in liquidjs creates a child Context for the {% render %} tag but does not propagate the parent context's resolved ownPropertyOnly value. The new context re-derives ownPropertyOnly from opts.ownPropertyOnly (the instance-level option), silently discarding any RenderOptions.ownPropertyOnly override that was supplied to parseAndRender(). As a result, a developer who runs a Liquid instance with the backwards-compatible ownPropertyOnly:false and then locks down an untrusted render with parseAndRender(..., { ownPropertyOnly: true }) still leaks prototype-chain properties from inside any {% render %} partial. This is a distinct exploit surface from the previously identified array-filter variants (where, reject, group_by, find, find_index, has) — the underlying root cause in Context.spawn() is shared, but {% render %} is a separately reachable sink that needs no filter usage.
The bug is in Context.spawn():
// src/context/context.ts:105-114
public spawn (scope = {}) {
return new Context(scope, this.opts, {
sync: this.sync,
globals: this.globals,
strictVariables: this.strictVariables
// <-- ownPropertyOnly is missing here
}, {
renderLimit: this.renderLimit,
memoryLimit: this.memoryLimit
})
}
The constructor resolves ownPropertyOnly as:
// src/context/context.ts:47
this.ownPropertyOnly = renderOptions.ownPropertyOnly ?? opts.ownPropertyOnly
Because spawn() passes a RenderOptions object with no ownPropertyOnly, the child context falls back to opts.ownPropertyOnly (the instance-level option), throwing away any per-render override that the parent context had applied. this.opts is the raw normalized instance options object; it is not mutated to reflect render-time overrides.
The {% render %} tag at src/tags/render.ts:51-77 calls spawn() to build the partial's isolated scope:
* render (ctx: Context, emitter: Emitter): Generator<unknown, void, unknown> {
const { liquid, hash } = this
const filepath = (yield renderFilePath(this['file'], ctx, liquid)) as string
assert(filepath, () => `illegal file path "${filepath}"`)
const childCtx = ctx.spawn() // <-- ownPropertyOnly lost here
const scope = childCtx.bottom()
__assign(scope, yield hash.render(ctx))
...
const templates = (yield liquid._parsePartialFile(filepath, childCtx.sync, this['currentFile'])) as Template[]
yield liquid.renderer.renderTemplates(templates, childCtx, emitter)
}
Bạn đang dùng một trong các sản phẩm này? Quét site để biết có đang lộ phiên bản có lỗ hổng không.
Quét site miễn phíAll template variable lookups inside the partial then go through childCtx.readProperty() (src/context/context.ts:123-135), which calls readJSProperty(obj, key, this.ownPropertyOnly). With childCtx.ownPropertyOnly === false (inherited from opts), the protective check at src/context/context.ts:138-141 is skipped and prototype-chain properties are returned to the template:
export function readJSProperty (obj: Scope, key: PropertyKey, ownPropertyOnly: boolean) {
if (ownPropertyOnly && !hasOwnProperty.call(obj, key) && !(obj instanceof Drop)) return undefined
return obj[key]
}
The {% include %} tag is not affected: it does not call spawn(); it pushes onto the parent context's scope stack (src/tags/include.ts:40), so the parent's resolved ownPropertyOnly continues to apply.
Trust model / why this matters: RenderOptions.ownPropertyOnly is documented (src/liquid-options.ts:108-111) as "Same as ownPropertyOnly on LiquidOptions, but only for current render() call". It exists precisely so that developers running a non-strict instance can lock down individual untrusted renders. That contract is broken — the override is silently dropped at every partial boundary.
mkdir -p /tmp/render-poc
printf '{{ user.passwordHash }}' > /tmp/render-poc/_user.liquid
node -e "
const { Liquid } = require('./dist/liquid.node.js');
const liquid = new Liquid({ ownPropertyOnly: false, root: '/tmp/render-poc' });
class User { constructor(n){ this.name = n; } }
User.prototype.passwordHash = 'bcrypt\$secret';
const u = new User('alice');
liquid.parseAndRender(
'Direct:[{{ user.passwordHash }}] Render:[{% render \"_user.liquid\", user: user %}]',
{ user: u },
{ ownPropertyOnly: true }
).then(console.log);
"
Verified output on liquidjs 10.25.7:
Direct:[] Render:[bcrypt$secret]
The top-level expression {{ user.passwordHash }} is correctly blocked by the per-render ownPropertyOnly:true, but the same expression inside the partial loaded by {% render %} returns the prototype-chain property — proof that Context.spawn() discarded the override.
{% render %} partial — including secrets, hashes, internal state, framework-injected helpers — becomes readable from inside the partial template, even when the developer used the documented per-render lockdown.ownPropertyOnly:false for backwards compatibility (or because their data layer relies on prototype methods) and lock down untrusted-template renders with parseAndRender(..., { ownPropertyOnly:true }) are protected at the top level but silently exposed inside any partial. User-controllable template content (CMS snippets, theme partials, email templates) that uses {% render %} becomes an info-leak primitive.ownPropertyOnly:false; this is a failure of the documented mitigation (ownPropertyOnly:true per-render override), not a missing setting.spawn() root cause, but exploitable without invoking where/reject/group_by/find/find_index/has — only requires that the template uses {% render %} (a basic templating feature) and that one of the rendered values has prototype-chain properties.Propagate ownPropertyOnly (and any other security-relevant render options) inside Context.spawn():
// src/context/context.ts
public spawn (scope = {}) {
return new Context(scope, this.opts, {
sync: this.sync,
globals: this.globals,
strictVariables: this.strictVariables,
ownPropertyOnly: this.ownPropertyOnly // <-- propagate resolved per-render value
}, {
renderLimit: this.renderLimit,
memoryLimit: this.memoryLimit
})
}
Passing this.ownPropertyOnly (the resolved value, not this.opts.ownPropertyOnly) ensures any RenderOptions.ownPropertyOnly override flows into spawned child contexts. This single change closes both the {% render %} pathway documented here and the array-filter pathway tracked separately. A regression test should assert that a partial rendered via {% render %} honours parseAndRender(..., { ownPropertyOnly: true }) against an object with prototype-chain properties.