Re: [PATCH 1/2] http.c: prompt for SSL client certificate password

> If an SSL client certificate is enabled (via http.sslcert or
> GIT_SSL_CERT), prompt for the certificate password rather than
> defaulting to OpenSSL's password prompt.  This causes the prompt to only
> appear once each run.  Previously, OpenSSL prompted the user *many*
> times, causing git to be unusable over HTTPS with client-side
> certificates.
>
> Note that the password is stored in memory in the clear while the
> program is running.  This may be a security problem if git crashes and
> core dumps.
>
> The user is always prompted, even if the certificate is not encrypted.
> This should be fine; unencrypted certificates are rare and a security
> risk anyway.
>
> Signed-off-by: Mark Lodato <lodatom@gmail.com>
> ---
>
> See http://osdir.com/ml/git/2009-02/msg03402.html for a discussion of
> this topic and an example showing how horrible the current password
> prompts are.
>
> The next patch adds an option to disable this feature.  I split it into
> two commits in case the configuration option is not wanted.
>
> I did not create any tests because the existing http.sslcert option has
> no tests to begin with.
>
> I would really like to use git over HTTPS with client certs, but the
> current situation is just unusable.  So, I'm hoping this gets included
> in git.git at some point.  I would be happy to hear any comments people
> have about this patch series.  Thanks!
>
>
>  http.c |   40 +++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 39 insertions(+), 1 deletions(-)
>
> diff --git a/http.c b/http.c
> index 2e3d649..1fc3444 100644
> --- a/http.c
> +++ b/http.c
> @@ -26,6 +26,8 @@ static long curl_low_speed_time = -1;
>  static int curl_ftp_no_epsv;
>  static const char *curl_http_proxy;
>  static char *user_name, *user_pass;
> +static char *ssl_cert_password;
> +static int ssl_cert_password_required;
>
>  static struct curl_slist *pragma_header;
>
> @@ -167,6 +169,22 @@ static void init_curl_http_auth(CURL *result)
>        }
>  }
>
> +static int has_cert_password(void)
> +{
> +       if (ssl_cert_password != NULL)
> +               return 1;
> +       if (ssl_cert == NULL || ssl_cert_password_required != 1)
> +               return 0;
> +       /* Only prompt the user once. */
> +       ssl_cert_password_required = -1;
> +       ssl_cert_password = getpass("Certificate Password: ");
> +       if (ssl_cert_password != NULL) {
> +               ssl_cert_password = xstrdup(ssl_cert_password);
> +               return 1;
> +       } else
> +               return 0;
> +}
> +
>  static CURL *get_curl_handle(void)
>  {
>        CURL *result = curl_easy_init();
> @@ -189,6 +207,16 @@ static CURL *get_curl_handle(void)
>
>        if (ssl_cert != NULL)
>                curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
> +       if (has_cert_password())
> +               curl_easy_setopt(result,
> +#if LIBCURL_VERSION_NUM >= 0x071700
> +                                CURLOPT_KEYPASSWD,
> +#elif LIBCURL_VERSION_NUM >= 0x070903
> +                                CURLOPT_SSLKEYPASSWD,
> +#else
> +                                CURLOPT_SSLCERTPASSWD,
> +#endif
> +                                ssl_cert_password);
>  #if LIBCURL_VERSION_NUM >= 0x070902
>        if (ssl_key != NULL)
>                curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
> @@ -329,8 +357,11 @@ void http_init(struct remote *remote)
>        if (getenv("GIT_CURL_FTP_NO_EPSV"))
>                curl_ftp_no_epsv = 1;
>
> -       if (remote && remote->url && remote->url[0])
> +       if (remote && remote->url && remote->url[0]) {
>                http_auth_init(remote->url[0]);
> +               if (!prefixcmp(remote->url[0], "https://"))
> +                       ssl_cert_password_required = 1;
> +       }
>
>  #ifndef NO_CURL_EASY_DUPHANDLE
>        curl_default = get_curl_handle();
> @@ -370,6 +401,13 @@ void http_cleanup(void)
>                free((void *)curl_http_proxy);
>                curl_http_proxy = NULL;
>        }
> +
> +       if (ssl_cert_password != NULL) {
> +               memset(ssl_cert_password, 0, strlen(ssl_cert_password));
> +               free(ssl_cert_password);
> +               ssl_cert_password = NULL;
> +       }
> +       ssl_cert_password_required = 0;
>  }
>
>  struct active_request_slot *get_active_slot(void)
> --
> 1.6.3.1
>
>