open-vault/vault/acl.go

131 lines
3.4 KiB
Go

package vault
import (
"github.com/armon/go-radix"
"github.com/hashicorp/vault/logical"
)
// ACL is used to wrap a set of policies to provide
// an efficient interface for access control.
type ACL struct {
// exactRules contains the path policies that are exact
exactRules *radix.Tree
// globRules contains the path policies that glob
globRules *radix.Tree
// root is enabled if the "root" named policy is present.
root bool
}
// New is used to construct a policy based ACL from a set of policies.
func NewACL(policies []*Policy) (*ACL, error) {
// Initialize
a := &ACL{
exactRules: radix.New(),
globRules: radix.New(),
root: false,
}
// Inject each policy
for _, policy := range policies {
// Ignore a nil policy object
if policy == nil {
continue
}
// Check if this is root
if policy.Name == "root" {
a.root = true
}
for _, pc := range policy.Paths {
// Check which tree to use
tree := a.exactRules
if pc.Glob {
tree = a.globRules
}
// Check for an existing policy
raw, ok := tree.Get(pc.Prefix)
if !ok {
tree.Insert(pc.Prefix, pc.CapabilitiesBitmap)
continue
}
existing := raw.(uint32)
switch {
case existing&DenyCapabilityInt > 0:
// If we are explicitly denied in the existing capability set,
// don't save anything else
case pc.CapabilitiesBitmap&DenyCapabilityInt > 0:
// If this new policy explicitly denies, only save the deny value
tree.Insert(pc.Prefix, DenyCapabilityInt)
default:
// Insert the capabilities in this new policy into the existing
// value; since it's a pointer we can just modify the
// underlying data
tree.Insert(pc.Prefix, existing|pc.CapabilitiesBitmap)
}
}
}
return a, nil
}
// AllowOperation is used to check if the given operation is permitted. The
// first bool indicates if an op is allowed, the second whether sudo priviliges
// exist for that op and path.
func (a *ACL) AllowOperation(op logical.Operation, path string) (allowed bool, sudo bool) {
// Fast-path root
if a.root {
return true, true
}
// Help is always allowed
if op == logical.HelpOperation {
return true, false
}
// Find an exact matching rule, look for glob if no match
var capabilities uint32
raw, ok := a.exactRules.Get(path)
if ok {
capabilities = raw.(uint32)
goto CHECK
}
// Find a glob rule, default deny if no match
_, raw, ok = a.globRules.LongestPrefix(path)
if !ok {
return false, false
} else {
capabilities = raw.(uint32)
}
CHECK:
// Check if the minimum permissions are met
// If "deny" has been explicitly set, only deny will be in the map, so we
// only need to check for the existence of other values
sudo = capabilities&SudoCapabilityInt > 0
switch op {
case logical.ReadOperation:
allowed = capabilities&ReadCapabilityInt > 0
case logical.ListOperation:
allowed = capabilities&ListCapabilityInt > 0
case logical.UpdateOperation:
allowed = capabilities&UpdateCapabilityInt > 0
case logical.DeleteOperation:
allowed = capabilities&DeleteCapabilityInt > 0
case logical.CreateOperation:
allowed = capabilities&CreateCapabilityInt > 0
// These three re-use UpdateCapabilityInt since that's the most appropraite capability/operation mapping
case logical.RevokeOperation, logical.RenewOperation, logical.RollbackOperation:
allowed = capabilities&UpdateCapabilityInt > 0
default:
return false, false
}
return
}