GHSA-hgfg-j9pg-43xw: Medium severity go/github.com/siyuan-note/siyuan/kernel vulnerability

Summary

/api/system/getConf serves Conf.UILayout to publish readers after passing it through FilterConfByPublishIgnore, whose only function is to filter that layout. The layout is written exclusively by setUILayout, which is administrator-gated, so what readers receive is the administrator's own live workspace state, re-saved on every tab open, close and focus change.

The filter that is supposed to protect it, filterLayoutItemByPublishIgnore, has four separate defects. Together they mean a single unauthenticated POST with no arguments returns the titles and identifiers of the administrator's open password-protected documents, the titles of documents in locked or closed notebooks, their recent search terms and the paths those searches were scoped to, and the paths of private assets they have open.

This report concerns FilterConfByPublishIgnore and its layout walker. It is distinct from the previously reported getConf issues, which concern configuration fields surviving HideConfSecret's blocklist. Restructuring the secret-masking path would not affect this, because UILayout is not a secret to be stripped. It is a field intended to be served and filtered.

Details

Route and writer asymmetry. kernel/api/router.go:70 registers POST /api/system/getConf with model.CheckAuth only, so it is reachable by the publish RoleReader token and anonymously when Publish.Auth.Enable is false. The corresponding writer, setUILayout at kernel/api/router.go:67, carries CheckAuth, CheckAdminRole and CheckReadonly. Only an administrator can write this state, and any reader can read it.

The filter exists and is intended to work. HideConfSecret never touches UILayout (zero matches on both refs). Instead the reader branch runs:

go if model.IsReadOnlyRoleContext(c) { publishIgnore := model.GetInvisiblePublishAccess(publishAccess) maskedConf = model.FilterConfByPublishIgnore(publishIgnore, maskedConf) }

FilterConfByPublishIgnore does exactly one thing, which is filter UILayout. The intent that readers must not see the administrator's private tabs is therefore already established in the code. The four defects below are failures of that filter, not an argument that it should exist.

filterLayoutItemByPublishIgnore is byte-identical at eef105683 and v3.7.4-alpha.1 and has not changed since 3facc37df (#16041).

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Defect 1: the password tier is not checked. GetPathPasswordByPublishAccess and CheckPublishAuthCookie appear zero times in the walker. Of the five access levels defined in publishAccess.ts, only the protected level is {visible: true, password: ...}. A password-protected document therefore never matches the invisible list, and there is no password check to catch it afterwards. Its tab survives intact, carrying title (the document title), docIcon, notebookId, rootId and blockId.

To be precise about scope: the forbidden level sets visible: false, so forbidden documents are correctly filtered. The leak is specific to the password tier.

This is the same class of defect as the recently fixed tag-label filter, on a different function that the tag fix does not touch.

Defect 2: fail-open on an unresolvable document. The walker does:

go bt := treenode.GetBlockTree(rootId) if bt == nil { return }

and the tab is retained. Compare CheckBlockIdAccessableByPublishAccess, which fails closed on the same condition. A rootId is unresolvable when its notebook is a locked encrypted notebook or a closed notebook, which are precisely the notebooks a reader must not learn about. Their tab titles pass through.

This survives the recent change that appends encrypted boxes to the invisible and disable ignore lists, because that change only takes effect once bt resolves. The nil branch returns before any ignore list is consulted.

Defect 3: non-editor tabs are never inspected. The walker examines one key, children["rootId"]. Editor tabs and Backlink/Graph tabs carry it. Other tab types do not, and pass through entirely unexamined:

- Asset{path, page} discloses the path of a private PDF or other asset the administrator has open. - Outline{blockId} discloses a block identifier. - Search{config} discloses k (the search text), r (replace text), name, hPath (a human-readable list of paths) and idPath (the notebook and document identifiers the search was scoped to). - Custom{customModelData} discloses arbitrary plugin state.

The Search case is the sharpest, because it discloses what the administrator was looking for and where, in their own words. Search text frequently contains the exact terms a private document is about.

Defect 4: the docks are not filtered. IUiLayout is {layout, left, right, bottom, hideDock} and the walker enters only ["layout"]. Dock entries carry type, size and localized titles, so this is low value on its own, noted for completeness rather than as part of the impact claim.

Proof of Concept

Precondition: publish mode enabled (default port 6808), anonymous when Publish.Auth.Enable is false, otherwise any publish reader account. An administrator with the desktop client open, having at some point opened a password-protected document, a document in a locked or closed notebook, an asset, and run a search.

POST http://127.0.0.1:6808/api/system/getConf {}

→ 200. conf.uiLayout.layout contains, for the administrator's session: - Editor tabs for password-protected documents, with title, docIcon, notebookId, rootId and blockId intact - Editor tabs whose rootId does not resolve, retained with their titles, corresponding to locked encrypted or closed notebooks - Asset tabs carrying private asset paths - Search tabs carrying the search text, replace text, hPath and idPath

No arguments and no authentication are required. Repeating the request after the administrator opens or closes a tab returns updated state, since setUILayout persists on every such event.

Impact

An anonymous reader in publish mode, or any publish RoleReader, receives a live view of the administrator's working session. The disclosed material includes the titles and identifiers of documents the administrator protected with a publish password, the titles of documents in notebooks that are locked or closed and therefore should not be known to exist, the administrator's search terms together with the human-readable paths those searches covered, and the filesystem paths of private assets.

Titles and search terms are author-written free text and routinely describe the subject matter of the documents they refer to. Because the layout is re-persisted on every tab event, repeated polling yields a running record of what the administrator is working on. Confidentiality only, with no integrity or availability impact.

Suggested fix

Four changes, corresponding to the four defects:

1. Replace the invisible-only check with checkBlockTreeAccessableByPublishAccess, so the password tier is honoured. 2. Make the bt == nil branch fail closed, matching CheckBlockIdAccessableByPublishAccess. 3. Drop or scrub Asset, Outline, Search and Custom instances rather than passing through anything without a rootId. 4. Walk left, right and bottom in addition to layout.

The simpler and more robust option is to stop serving the administrator's layout to readers at all, and return a minimal default layout instead. Readers have no legitimate use for the administrator's tab arrangement, and a filter that must correctly classify every present and future tab type is a standing source of this class of defect. Defect 3 in particular will recur every time a new tab type is added.