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proxmox-backup
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acl: add docs and adapt visibility 

document all public things, add some doc links and make some
previously-public things only available for test cases or within the
crate:

previously public, now private:
- AclTreeNode::extract_user_roles (we have extract_roles())
- AclTreeNode::extract_group_roles (same)
- AclTreeNode::delete_group_role (exists on AclTree)
- AclTreeNode::delete_user_role (same)
- AclTreeNode::insert_group_role (same)
- AclTreeNode::insert_user_role (same)
- AclTree::write_config (we have save_config())
- AclTree::load (we have config()/cached_config())

previously public, now crate-internal:
- AclTree::from_raw (only used by tests)
- split_acl_path (used by some test binaries)

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
This commit is contained in:
Fabian Grünbichler 2020-12-17 15:27:43 +01:00 committed by Dietmar Maurer
parent b532dd00c4
commit 23dc68fdea
1 changed files with 94 additions and 19 deletions
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113
src/config/acl.rs
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@ -20,10 +20,16 @@ use crate::api2::types::{Authid,Userid};
// define Privilege bitfield
constnamedbitmap! {
/// Contains a list of Privileges
/// Contains a list of privilege name to privilege value mappings.
///
/// The names are used when displaying/persisting privileges anywhere, the values are used to
/// allow easy matching of privileges as bitflags.
PRIVILEGES: u64 => {
/// Sys.Audit allows knowing about the system and its status
PRIV_SYS_AUDIT("Sys.Audit");
/// Sys.Modify allows modifying system-level configuration
PRIV_SYS_MODIFY("Sys.Modify");
/// Sys.Modify allows to poweroff/reboot/.. the system
PRIV_SYS_POWER_MANAGEMENT("Sys.PowerManagement");
/// Datastore.Audit allows knowing about a datastore,
@ -45,12 +51,17 @@ constnamedbitmap! {
/// but also requires backup ownership
PRIV_DATASTORE_PRUNE("Datastore.Prune");
/// Permissions.Modify allows modifying ACLs
PRIV_PERMISSIONS_MODIFY("Permissions.Modify");
/// Remote.Audit allows reading remote.cfg and sync.cfg entries
PRIV_REMOTE_AUDIT("Remote.Audit");
/// Remote.Modify allows modifying remote.cfg
PRIV_REMOTE_MODIFY("Remote.Modify");
/// Remote.Read allows reading data from a configured `Remote`
PRIV_REMOTE_READ("Remote.Read");
/// Sys.Console allows access to the system's console
PRIV_SYS_CONSOLE("Sys.Console");
}
}
@ -60,9 +71,10 @@ constnamedbitmap! {
/// which are limited to the 'root@pam` superuser
pub const ROLE_ADMIN: u64 = std::u64::MAX;
/// NoAccess can be used to remove privileges from specific paths
/// NoAccess can be used to remove privileges from specific (sub-)paths
pub const ROLE_NO_ACCESS: u64 = 0;
/// Audit can view configuration and status information, but not modify it.
pub const ROLE_AUDIT: u64 =
PRIV_SYS_AUDIT |
PRIV_DATASTORE_AUDIT;
@ -110,12 +122,16 @@ pub const ROLE_REMOTE_SYNC_OPERATOR: u64 =
PRIV_REMOTE_AUDIT |
PRIV_REMOTE_READ;
/// NoAccess can be used to remove privileges from specific (sub-)paths
pub const ROLE_NAME_NO_ACCESS: &str ="NoAccess";
#[api()]
#[repr(u64)]
#[derive(Serialize, Deserialize)]
/// Role
/// Enum representing roles via their [PRIVILEGES] combination.
///
/// Since privileges are implemented as bitflags, each unique combination of privileges maps to a
/// single, unique `u64` value that is used in this enum definition.
pub enum Role {
/// Administrator
Admin = ROLE_ADMIN,
@ -150,6 +166,8 @@ impl FromStr for Role {
}
lazy_static! {
/// Map of pre-defined [Roles](Role) to their associated [privileges](PRIVILEGES) combination and
/// description.
pub static ref ROLE_NAMES: HashMap<&'static str, (u64, &'static str)> = {
let mut map = HashMap::new();
@ -167,8 +185,7 @@ lazy_static! {
};
}
pub fn split_acl_path(path: &str) -> Vec<&str> {
pub(crate) fn split_acl_path(path: &str) -> Vec<&str> {
let items = path.split('/');
let mut components = vec![];
@ -181,6 +198,9 @@ pub fn split_acl_path(path: &str) -> Vec<&str> {
components
}
/// Check whether a given ACL `path` conforms to the expected schema.
///
/// Currently this just checks for the number of components for various sub-trees.
pub fn check_acl_path(path: &str) -> Result<(), Error> {
let components = split_acl_path(path);
@ -234,18 +254,29 @@ pub fn check_acl_path(path: &str) -> Result<(), Error> {
bail!("invalid acl path '{}'.", path);
}
/// Tree representing a parsed acl.cfg
pub struct AclTree {
/// Root node of the tree.
///
/// The rest of the tree is available via [find_node()](AclTree::find_node()) or an
/// [AclTreeNode]'s [children](AclTreeNode::children) member.
pub root: AclTreeNode,
}
/// Node representing ACLs for a certain ACL path.
pub struct AclTreeNode {
/// [User](crate::config::user::User) or
/// [Token](crate::config::user::ApiToken) ACLs for this node.
pub users: HashMap<Authid, HashMap<String, bool>>,
/// `Group` ACLs for this node (not yet implemented)
pub groups: HashMap<String, HashMap<String, bool>>,
/// `AclTreeNodes` representing ACL paths directly below the current one.
pub children: BTreeMap<String, AclTreeNode>,
}
impl AclTreeNode {
/// Creates a new, empty AclTreeNode.
pub fn new() -> Self {
Self {
users: HashMap::new(),
@ -254,17 +285,25 @@ impl AclTreeNode {
}
}
pub fn extract_roles(&self, auth_id: &Authid, all: bool) -> HashMap<String, bool> {
let user_roles = self.extract_user_roles(auth_id, all);
/// Returns applicable [Role] and their propagation status for a given
/// [Authid](crate::api2::types::Authid).
///
/// If the `Authid` is a [User](crate::config::user::User) that has no specific `Roles` configured on this node,
/// applicable `Group` roles will be returned instead.
///
/// If `leaf` is `false`, only those roles where the propagate flag in the ACL is set to `true`
/// are returned. Otherwise, all roles will be returned.
pub fn extract_roles(&self, auth_id: &Authid, leaf: bool) -> HashMap<String, bool> {
let user_roles = self.extract_user_roles(auth_id, leaf);
if !user_roles.is_empty() || auth_id.is_token() {
// user privs always override group privs
return user_roles
};
self.extract_group_roles(auth_id.user(), all)
self.extract_group_roles(auth_id.user(), leaf)
}
pub fn extract_user_roles(&self, auth_id: &Authid, all: bool) -> HashMap<String, bool> {
fn extract_user_roles(&self, auth_id: &Authid, leaf: bool) -> HashMap<String, bool> {
let mut map = HashMap::new();
@ -274,7 +313,7 @@ impl AclTreeNode {
};
for (role, propagate) in roles {
if *propagate || all {
if *propagate || leaf {
if role == ROLE_NAME_NO_ACCESS {
// return a map with a single role 'NoAccess'
let mut map = HashMap::new();
@ -288,7 +327,7 @@ impl AclTreeNode {
map
}
pub fn extract_group_roles(&self, _user: &Userid, all: bool) -> HashMap<String, bool> {
fn extract_group_roles(&self, _user: &Userid, leaf: bool) -> HashMap<String, bool> {
let mut map = HashMap::new();
@ -297,7 +336,7 @@ impl AclTreeNode {
if !is_member { continue; }
for (role, propagate) in roles {
if *propagate || all {
if *propagate || leaf {
if role == ROLE_NAME_NO_ACCESS {
// return a map with a single role 'NoAccess'
let mut map = HashMap::new();
@ -312,7 +351,7 @@ impl AclTreeNode {
map
}
pub fn delete_group_role(&mut self, group: &str, role: &str) {
fn delete_group_role(&mut self, group: &str, role: &str) {
let roles = match self.groups.get_mut(group) {
Some(r) => r,
None => return,
@ -320,7 +359,7 @@ impl AclTreeNode {
roles.remove(role);
}
pub fn delete_user_role(&mut self, auth_id: &Authid, role: &str) {
fn delete_user_role(&mut self, auth_id: &Authid, role: &str) {
let roles = match self.users.get_mut(auth_id) {
Some(r) => r,
None => return,
@ -328,7 +367,7 @@ impl AclTreeNode {
roles.remove(role);
}
pub fn insert_group_role(&mut self, group: String, role: String, propagate: bool) {
fn insert_group_role(&mut self, group: String, role: String, propagate: bool) {
let map = self.groups.entry(group).or_insert_with(|| HashMap::new());
if role == ROLE_NAME_NO_ACCESS {
map.clear();
@ -339,7 +378,7 @@ impl AclTreeNode {
}
}
pub fn insert_user_role(&mut self, auth_id: Authid, role: String, propagate: bool) {
fn insert_user_role(&mut self, auth_id: Authid, role: String, propagate: bool) {
let map = self.users.entry(auth_id).or_insert_with(|| HashMap::new());
if role == ROLE_NAME_NO_ACCESS {
map.clear();
@ -353,12 +392,14 @@ impl AclTreeNode {
impl AclTree {
/// Create a new, empty ACL tree with a single, empty root [node](AclTreeNode)
pub fn new() -> Self {
Self {
root: AclTreeNode::new(),
}
}
/// Iterates over the tree looking for a node matching `path`.
pub fn find_node(&mut self, path: &str) -> Option<&mut AclTreeNode> {
let path = split_acl_path(path);
return self.get_node(&path);
@ -384,6 +425,10 @@ impl AclTree {
node
}
/// Deletes the specified `role` from the `group`'s ACL on `path`.
///
/// Never fails, even if the `path` has no ACLs configured, or the `group`/`role` combination
/// does not exist on `path`.
pub fn delete_group_role(&mut self, path: &str, group: &str, role: &str) {
let path = split_acl_path(path);
let node = match self.get_node(&path) {
@ -393,6 +438,10 @@ impl AclTree {
node.delete_group_role(group, role);
}
/// Deletes the specified `role` from the `user`'s ACL on `path`.
///
/// Never fails, even if the `path` has no ACLs configured, or the `user`/`role` combination
/// does not exist on `path`.
pub fn delete_user_role(&mut self, path: &str, auth_id: &Authid, role: &str) {
let path = split_acl_path(path);
let node = match self.get_node(&path) {
@ -402,12 +451,20 @@ impl AclTree {
node.delete_user_role(auth_id, role);
}
/// Inserts the specified `role` into the `group` ACL on `path`.
///
/// The [AclTreeNode] representing `path` will be created and inserted into the tree if
/// necessary.
pub fn insert_group_role(&mut self, path: &str, group: &str, role: &str, propagate: bool) {
let path = split_acl_path(path);
let node = self.get_or_insert_node(&path);
node.insert_group_role(group.to_string(), role.to_string(), propagate);
}
/// Inserts the specified `role` into the `user` ACL on `path`.
///
/// The [AclTreeNode] representing `path` will be created and inserted into the tree if
/// necessary.
pub fn insert_user_role(&mut self, path: &str, auth_id: &Authid, role: &str, propagate: bool) {
let path = split_acl_path(path);
let node = self.get_or_insert_node(&path);
@ -498,7 +555,7 @@ impl AclTree {
Ok(())
}
pub fn write_config(&self, w: &mut dyn Write) -> Result<(), Error> {
fn write_config(&self, w: &mut dyn Write) -> Result<(), Error> {
Self::write_node_config(&self.root, "", w)
}
@ -547,7 +604,7 @@ impl AclTree {
Ok(())
}
pub fn load(filename: &Path) -> Result<(Self, [u8;32]), Error> {
fn load(filename: &Path) -> Result<(Self, [u8;32]), Error> {
let mut tree = Self::new();
let raw = match std::fs::read_to_string(filename) {
@ -575,7 +632,8 @@ impl AclTree {
Ok((tree, digest))
}
pub fn from_raw(raw: &str) -> Result<Self, Error> {
#[cfg(test)]
pub(crate) fn from_raw(raw: &str) -> Result<Self, Error> {
let mut tree = Self::new();
for (linenr, line) in raw.lines().enumerate() {
let line = line.trim();
@ -587,6 +645,14 @@ impl AclTree {
Ok(tree)
}
/// Returns a map of role name and propagation status for a given `auth_id` and `path`.
///
/// This will collect role mappings according to the following algorithm:
/// - iterate over all intermediate nodes along `path` and collect roles with `propagate` set
/// - get all (propagating and non-propagating) roles for last component of path
/// - more specific role maps replace less specific role maps
/// -- user/token is more specific than group at each level
/// -- roles lower in the tree are more specific than those higher up along the path
pub fn roles(&self, auth_id: &Authid, path: &[&str]) -> HashMap<String, bool> {
let mut node = &self.root;
@ -610,14 +676,21 @@ impl AclTree {
}
}
/// Filename where [AclTree] is stored.
pub const ACL_CFG_FILENAME: &str = "/etc/proxmox-backup/acl.cfg";
/// Path used to lock the [AclTree] when modifying.
pub const ACL_CFG_LOCKFILE: &str = "/etc/proxmox-backup/.acl.lck";
/// Reads the [AclTree] from the [default path](ACL_CFG_FILENAME).
pub fn config() -> Result<(AclTree, [u8; 32]), Error> {
let path = PathBuf::from(ACL_CFG_FILENAME);
AclTree::load(&path)
}
/// Returns a cached [AclTree] or fresh copy read directly from the [default path](ACL_CFG_FILENAME)
///
/// Since the AclTree is used for every API request's permission check, this caching mechanism
/// allows to skip reading and parsing the file again if it is unchanged.
pub fn cached_config() -> Result<Arc<AclTree>, Error> {
struct ConfigCache {
@ -663,6 +736,8 @@ pub fn cached_config() -> Result<Arc<AclTree>, Error> {
Ok(config)
}
/// Saves an [AclTree] to the [default path](ACL_CFG_FILENAME), ensuring proper ownership and
/// file permissions.
pub fn save_config(acl: &AclTree) -> Result<(), Error> {
let mut raw: Vec<u8> = Vec::new();