Files
ollama/auth/auth.go
Patrick Devine 5968989a7f server: add authorized_keys file
This change adds an "authorized_keys" file similar to sshd which can control
access to an Ollama server. The file itself is very simple and consists of
various entries for Ollama public keys.

The format is:

<key format> <public key> <name> [<endpoint>,...]

Examples:

ssh-ed25519 AAAAC3NzaC1lZDI1NT... bob /api/tags,/api/ps,/api/show,/api/generate,/api/chat

Use the "*" wildcard symbol to substitute any value, e.g.:

To grant full access to "bob":
ssh-ed25519 AAAAC3NzaC1lZDI1NT... bob *

To allow all callers to view tags (i.e. "ollama ls"):
* * * /api/tags

- The key format must be set to "ssh-ed25519" or set to the wildcard character.
- The public key must be an ssh based ed25519 (Ollama) public key or set to the wildcard
  character.
- Name can be any string you wish to associate with the public key. Note that if a public
  key is used in more than one entry in the file, the first instance of the name will be
  used and subsequent name values will be ignored.
- Endpoints is a comma separated list of Ollama Server API endpoints or the wildcard
  character. The HTTP method is not currently needed, but could be added in the future.
2025-07-29 20:50:01 -07:00

128 lines
2.7 KiB
Go

package auth
import (
"bytes"
"context"
"crypto/rand"
"encoding/base64"
"errors"
"fmt"
"io"
"log/slog"
"os"
"path/filepath"
"strings"
"golang.org/x/crypto/ssh"
)
const defaultPrivateKey = "id_ed25519"
var ErrInvalidToken = errors.New("invalid token")
func keyPath() (string, error) {
home, err := os.UserHomeDir()
if err != nil {
return "", err
}
return filepath.Join(home, ".ollama", defaultPrivateKey), nil
}
func parseToken(token string) (key, sig []byte, _ error) {
keyData, sigData, ok := strings.Cut(token, ":")
if !ok {
return nil, nil, fmt.Errorf("identity: parseToken: %w", ErrInvalidToken)
}
sig, err := base64.StdEncoding.DecodeString(sigData)
if err != nil {
return nil, nil, fmt.Errorf("identity: parseToken: base64 decoding signature: %w", err)
}
return []byte(keyData), sig, nil
}
func Authenticate(token, checkData string) (ssh.PublicKey, error) {
keyShort, sigBytes, err := parseToken(token)
if err != nil {
return nil, err
}
keyLong := append([]byte("ssh-ed25519 "), keyShort...)
pub, _, _, _, err := ssh.ParseAuthorizedKey(keyLong)
if err != nil {
return nil, err
}
if err := pub.Verify([]byte(checkData), &ssh.Signature{
Format: pub.Type(),
Blob: sigBytes,
}); err != nil {
return nil, err
}
return pub, nil
}
func GetPublicKey() (string, error) {
keyPath, err := keyPath()
if err != nil {
return "", err
}
privateKeyFile, err := os.ReadFile(keyPath)
if err != nil {
slog.Info(fmt.Sprintf("Failed to load private key: %v", err))
return "", err
}
privateKey, err := ssh.ParsePrivateKey(privateKeyFile)
if err != nil {
return "", err
}
publicKey := ssh.MarshalAuthorizedKey(privateKey.PublicKey())
return strings.TrimSpace(string(publicKey)), nil
}
func NewNonce(r io.Reader, length int) (string, error) {
nonce := make([]byte, length)
if _, err := io.ReadFull(r, nonce); err != nil {
return "", err
}
return base64.RawURLEncoding.EncodeToString(nonce), nil
}
func Sign(ctx context.Context, bts []byte) (string, error) {
keyPath, err := keyPath()
if err != nil {
return "", err
}
privateKeyFile, err := os.ReadFile(keyPath)
if err != nil {
slog.Info(fmt.Sprintf("Failed to load private key: %v", err))
return "", err
}
privateKey, err := ssh.ParsePrivateKey(privateKeyFile)
if err != nil {
return "", err
}
// get the pubkey, but remove the type
publicKey := ssh.MarshalAuthorizedKey(privateKey.PublicKey())
parts := bytes.Split(publicKey, []byte(" "))
if len(parts) < 2 {
return "", errors.New("malformed public key")
}
signedData, err := privateKey.Sign(rand.Reader, bts)
if err != nil {
return "", err
}
// signature is <pubkey>:<signature>
return fmt.Sprintf("%s:%s", bytes.TrimSpace(parts[1]), base64.StdEncoding.EncodeToString(signedData.Blob)), nil
}