gitlabhq/gitlab-shell

// Package authorizedkeys handles fetching and printing authorized SSH keys.
package authorizedkeys

import (
    "context"
    "fmt"
    "strconv"

    "gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/commandargs"
    "gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/readwriter"
    "gitlab.com/gitlab-org/gitlab-shell/v14/internal/config"
    "gitlab.com/gitlab-org/gitlab-shell/v14/internal/gitlabnet/authorizedkeys"
    "gitlab.com/gitlab-org/gitlab-shell/v14/internal/keyline"
)

// Command contains the configuration, arguments, and I/O interfaces.
type Command struct {
    Config     *config.Config
    Args       *commandargs.AuthorizedKeys
    ReadWriter *readwriter.ReadWriter
}

// Execute runs the command to fetch and print the authorized SSH key.
func (c *Command) Execute(ctx context.Context) (context.Context, error) {
    // Do and return nothing when the expected and actual user don't match.
    // This can happen when the user in sshd_config doesn't match the user
    // trying to login. When nothing is printed, the user will be denied access.
    if c.Args.ExpectedUser != c.Args.ActualUser {
        // TODO: Log this event once we have a consistent way to log in Go.
        // See https://gitlab.com/gitlab-org/gitlab-shell/issues/192 for more info.
        return ctx, nil
    }

    if err := c.printKeyLine(ctx); err != nil {
        return ctx, err
    }

    return ctx, nil
}

func (c *Command) printKeyLine(ctx context.Context) error {
    response, err := c.getAuthorizedKey(ctx)
    if err != nil {
        _, _ = fmt.Fprintf(c.ReadWriter.Out, "# No key was found for %s\n", c.Args.Key)
        return nil
    }

    keyLine, err := keyline.NewPublicKeyLine(strconv.FormatInt(response.ID, 10), response.Key, c.Config)
    if err != nil {
        return err
    }

    _, _ = fmt.Fprintln(c.ReadWriter.Out, keyLine.ToString())

    return nil
}

func (c *Command) getAuthorizedKey(ctx context.Context) (*authorizedkeys.Response, error) {
    client, err := authorizedkeys.NewClient(c.Config)
    if err != nil {
        return nil, err
    }

    return client.GetByKey(ctx, c.Args.Key)
}