GHSA-xgxp-f695-6vrp

### Summary An authorization flaw in `repo import` allows any authenticated SSH user to clone a server-local Git repository, including another user's private repo, into a new repository they control. This breaks the private-repository confidentiality boundary and should be treated as High severity. ### Details Repo import checks authorization only for the destination repository name, not for the source remote. The destination-side authorization comes from [`pkg/ssh/cmd/cmd.go:172`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/ssh/cmd/cmd.go#L172), which calls [`pkg/backend/user.go:46`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/backend/user.go#L46). If the destination repo does not already exist, any authenticated user is granted `ReadWriteAccess` at [`pkg/backend/user.go:94`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/backend/user.go#L94). The import command then passes the user-controlled `REMOTE` into [`pkg/backend/repo.go:102`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/backend/repo.go#L102). In vulnerable `HEAD`, `git.Clone(remote, rp, copts)` is reached without validating that `remote` is actually a network remote. As a result, a user can supply a server filesystem path such as `$DATA_PATH/repos/secret.git` and cause the server to clone its own local bare repository into a new repo owned by the attacker. The relevant vulnerable flow is: - [`pkg/ssh/cmd/import.go`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/ssh/cmd/import.go) - [`pkg/ssh/cmd/cmd.go:172`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/ssh/cmd/cmd.go#L172) - [`pkg/backend/user.go:94`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/backend/user.go#L94) - [`pkg/backend/repo.go:102`](https://github.com/charmbracelet/soft-serve/blob/main/pkg/backend/repo.go#L102) ### PoC Configuration: - Default local test configuration is sufficient. - SSH must be enabled. - At least two users are needed: one owner/admin and one low-privilege authenticated user. Reproduction steps: 1. Start Soft Serve. 2. As an admin, create a private repo: ```sh soft repo create secret -p ``` 3. Create a second low-privilege user: ```sh soft user create user1 --key "$USER1_AUTHORIZED_KEY" ``` 4. Seed the private repo with secret content: ```sh git clone ssh://localhost:$SSH_PORT/secret secret echo 'top secret' > secret/SECRET.txt git -C secret add SECRET.txt git -C secret commit -m 'first' git -C secret push origin HEAD ``` 5. Confirm the low-privilege user cannot access the private repo directly: ```sh usoft repo info secret ``` Expected result: ```text Error: repository not found ``` 6. As the low-privilege user, import the server-local bare repo path into a new repo: ```sh usoft repo import stolen "$DATA_PATH/repos/secret.git" --lfs-endpoint http://example.com ``` 7. Clone the attacker-controlled imported repo and read the secret: ```sh ugit clone ssh://localhost:$SSH_PORT/stolen stolen-clone cat stolen-clone/SECRET.txt ``` Expected result: ```text top secret ``` Notes: - The `--lfs-endpoint` value is needed to avoid later LFS endpoint handling rejecting the local-path import. ### Impact This is an authorization bypass and confidentiality issue. Any authenticated SSH user on a multi-user Soft Serve instance can duplicate server-local Git repositories into new repositories they own, even when they are not a collaborator and direct access to the original private repo is denied. The primary impact is unauthorized disclosure of private source code and any secrets committed to those repositories. Impacted parties: - Operators hosting Soft Serve for multiple users or teams - Owners of private repositories on the same instance - Any deployment where untrusted authenticated users can use `repo import` Practical impact: - Theft of private source code - Disclosure of secrets committed to private repos - Exposure of unreleased or internal projects - Possible follow-on supply-chain risk if stolen code contains credentials or release material