Files
netbird/client/internal/ipcauth/identity.go
Theodor S. Midtlien 0137876618 Clean up comments
2026-07-24 14:57:21 +02:00

90 lines
2.9 KiB
Go

// Package ipcauth provides the kernel-authenticated identity of a local IPC
// (gRPC) caller and the transport credentials that surface it into the gRPC
// context, so the daemon can authorize each RPC by caller identity.
//
// On Unix the identity is read from the kernel via SO_PEERCRED (Linux) or
// LOCAL_PEERCRED (Darwin/FreeBSD). On Windows it is derived from the named-pipe
// client token. Platforms without a peer-identity primitive get no credentials
// and therefore no enforcement.
package ipcauth
import (
"context"
"fmt"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/peer"
)
// sidLocalSystem is the well-known Windows SID for the LocalSystem account.
const sidLocalSystem = "S-1-5-18"
// Identity is the kernel-authenticated identity of a local IPC caller. The zero
// value is not a valid identity.
type Identity struct {
// UID and GID are the caller's Unix user ID and primary group ID.
// Zero on Windows, where SID is authoritative instead.
UID uint32
GID uint32
// SID is the caller's Windows security identifier (empty on Unix).
SID string
// Groups holds the caller's Windows group SIDs, captured from the client
// token at handshake (empty on Unix, where supplementary group membership is
// resolved on demand via NSS/getent by the authorizer).
Groups []string
// Elevated reports whether the Windows client token is elevated (run as
// administrator). Always false on Unix, where privilege is uid==0.
Elevated bool
}
// IsWindows reports whether this identity is a Windows principal (SID-based)
// rather than a Unix uid/gid principal.
func (i Identity) IsWindows() bool {
return i.SID != ""
}
// IsPrivileged reports whether the caller is the platform's administrative
// principal.
func (i Identity) IsPrivileged() bool {
if i.IsWindows() {
return i.Elevated || i.SID == sidLocalSystem
}
return i.UID == 0
}
// String renders the identity for audit logs.
func (i Identity) String() string {
if i.IsWindows() {
return fmt.Sprintf("sid=%s elevated=%t", i.SID, i.Elevated)
}
return fmt.Sprintf("uid=%d gid=%d", i.UID, i.GID)
}
// AuthInfo carries the peer Identity as a gRPC credentials.AuthInfo so the
// interceptor can retrieve it from the request context via IdentityFromContext.
type AuthInfo struct {
credentials.CommonAuthInfo
Identity Identity
}
// AuthType identifies the authentication scheme.
func (AuthInfo) AuthType() string { return "netbird-ipc-peercred" }
// IdentityFromContext extracts the caller's kernel-authenticated identity from
// the gRPC peer context. The second return value is false when no IPC transport
// credentials were negotiated, callers MUST fail closed in that case.
func IdentityFromContext(ctx context.Context) (Identity, bool) {
p, ok := peer.FromContext(ctx)
if !ok {
return Identity{}, false
}
info, ok := p.AuthInfo.(AuthInfo)
if !ok {
return Identity{}, false
}
return info.Identity, true
}