Acked-by: Igor Mammedov <[email protected]>

On Fri, Jan 7, 2011 at 5:11 PM, Jeff Layton <[email protected]> wrote:
> Based on a patch from a few years ago by Igor Mammedov. This patch
> adds the ability for cifs.upcall to establish a TGT using the
> system-default keytab.
>
> Cc: Igor Mammedov <[email protected]>
> Signed-off-by: Jeff Layton <[email protected]>
> ---
>  cifs.upcall.c |   78 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 78 insertions(+), 0 deletions(-)
>
> diff --git a/cifs.upcall.c b/cifs.upcall.c
> index 3dbcd6e..479517c 100644
> --- a/cifs.upcall.c
> +++ b/cifs.upcall.c
> @@ -54,6 +54,7 @@
>
>  #define        CIFS_DEFAULT_KRB5_DIR           "/tmp"
>  #define        CIFS_DEFAULT_KRB5_PREFIX        "krb5cc_"
> +#define CIFS_DEFAULT_KRB5_KEYTAB       "/etc/krb5.keytab"
>
>  #define        MAX_CCNAME_LEN                  PATH_MAX + 5
>
> @@ -185,6 +186,78 @@ static int krb5cc_filter(const struct dirent *dirent)
>                return 0;
>  }
>
> +static char *
> +init_cc_from_keytab(const char *keytab_name, const char *user)
> +{
> +       krb5_context context = NULL;
> +       krb5_error_code ret;
> +       krb5_creds my_creds;
> +       krb5_keytab keytab = NULL;
> +       krb5_principal me = NULL;
> +       krb5_ccache cc = NULL;
> +       char *ccname = NULL;
> +
> +       memset((char *) &my_creds, 0, sizeof(my_creds));
> +
> +       ret = krb5_init_context(&context);
> +       if (ret) {
> +               syslog(LOG_DEBUG, "krb5_init_context: %d", (int)ret);
> +               goto icfk_cleanup;
> +       }
> +
> +       ret = krb5_kt_resolve(context, keytab_name, &keytab);
> +       if (ret) {
> +               syslog(LOG_DEBUG, "krb5_kt_resolve: %d", (int)ret);
> +               goto icfk_cleanup;
> +       }
> +
> +       ret = krb5_parse_name(context, user, &me);
> +       if (ret) {
> +               syslog(LOG_DEBUG, "krb5_parse_name: %d", (int)ret);
> +               goto icfk_cleanup;
> +       }
> +
> +       ret = krb5_get_init_creds_keytab(context, &my_creds, me,
> +                       keytab, 0, NULL, NULL);
> +       if (ret) {
> +               syslog(LOG_DEBUG, "krb5_get_init_creds_keytab: %d", (int)ret);
> +               goto icfk_cleanup;
> +       }
> +
> +       ret = krb5_cc_default(context, &cc);
> +       if (ret) {
> +               syslog(LOG_DEBUG, "krb5_cc_default: %d", (int)ret);
> +               goto icfk_cleanup;
> +       }
> +
> +       ret = krb5_cc_initialize(context, cc, me);
> +       if (ret) {
> +               syslog(LOG_DEBUG, "krb5_cc_initialize: %d", (int)ret);
> +               goto icfk_cleanup;
> +       }
> +
> +       ret = krb5_cc_store_cred(context, cc, &my_creds);
> +       if (ret)
> +               syslog(LOG_DEBUG, "krb5_cc_store_cred: %d", (int)ret);
> +
> +       ccname = strdup(krb5_cc_default_name(context));
> +       if (ccname == NULL)
> +               syslog(LOG_ERR, "Unable to allocate memory");
> +icfk_cleanup:
> +       my_creds.client = 0;
> +       krb5_free_cred_contents(context, &my_creds);
> +
> +       if (me)
> +               krb5_free_principal(context, me);
> +       if (cc)
> +               krb5_cc_close(context, cc);
> +       if (keytab)
> +               krb5_kt_close(context, keytab);
> +       if (context)
> +               krb5_free_context(context);
> +       return ccname;
> +}
> +
>  /* search for a credcache that looks like a likely candidate */
>  static char *find_krb5_cc(const char *dirname, uid_t uid)
>  {
> @@ -702,6 +775,7 @@ int main(const int argc, char *const argv[])
>        struct decoded_args arg;
>        const char *oid;
>        uid_t uid;
> +       char *keytab_name = CIFS_DEFAULT_KRB5_KEYTAB;
>
>        hostbuf[0] = '\0';
>        memset(&arg, 0, sizeof(arg));
> @@ -793,6 +867,10 @@ int main(const int argc, char *const argv[])
>        }
>        ccname = find_krb5_cc(CIFS_DEFAULT_KRB5_DIR, uid);
>
> +       /* Couldn't find credcache? Try to use keytab */
> +       if (ccname == NULL && arg.username != NULL)
> +               ccname = init_cc_from_keytab(keytab_name, arg.username);
> +
>        host = arg.hostname;
>
>        // do mech specific authorization
> --
> 1.7.3.4
>
>
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