src/util/sss_ssh.c

	sss_ssh.c revision 3194ce1c60e766e2a850949427dd99ad09944ddb
/*
    Authors:
        Jan Cholasta <jcholast@redhat.com>

    Copyright (C) 2012 Red Hat

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <arpa/inet.h>

#include "db/sysdb.h"
#include "util/util.h"
#include "util/crypto/sss_crypto.h"
#include "util/sss_ssh.h"

errno_t
sss_ssh_make_ent(TALLOC_CTX *mem_ctx,
                 struct ldb_message *msg,
                 struct sss_ssh_ent **result)
{
    TALLOC_CTX *tmp_ctx;
    struct sss_ssh_ent *res = NULL;
    errno_t ret;
    const char *name;
    struct ldb_message_element *el;
    unsigned int i;

    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) {
        return ENOMEM;
    }

    name = ldb_msg_find_attr_as_string(msg, SYSDB_NAME, NULL);
    if (!name) {
        ret = EINVAL;
        DEBUG(SSSDBG_CRIT_FAILURE, ("Host is missing name attribute\n"));
        goto done;
    }

    res = talloc_zero(tmp_ctx, struct sss_ssh_ent);
    if (!res) {
        ret = ENOMEM;
        goto done;
    }

    res->name = talloc_strdup(res, name);
    if (!res->name) {
        ret = ENOMEM;
        goto done;
    }

    el = ldb_msg_find_element(msg, SYSDB_SSH_PUBKEY);
    if (el) {
        res->num_pubkeys = el->num_values;

        res->pubkeys = talloc_array(res, struct sss_ssh_pubkey,
                                    res->num_pubkeys);
        if (!res->pubkeys) {
            ret = ENOMEM;
            goto done;
        }

        for (i = 0; i < el->num_values; i++) {
            res->pubkeys[i].data = sss_base64_decode(res->pubkeys,
                    (char *)el->values[i].data, &res->pubkeys[i].data_len);
            if (!res->pubkeys[i].data) {
                ret = ENOMEM;
                goto done;
            }
        }
    }

    el = ldb_msg_find_element(msg, SYSDB_NAME_ALIAS);
    if (el) {
        res->num_aliases = el->num_values;

        res->aliases = talloc_array(res, char *, res->num_aliases);
        if (!res->aliases) {
            ret = ENOMEM;
            goto done;
        }

        for (i = 0; i < el->num_values; i++) {
            res->aliases[i] = talloc_strdup(res->aliases,
                                            (char *)el->values[i].data);
            if (!res->aliases[i]) {
                ret = ENOMEM;
                goto done;
            }
        }
    }

    *result = talloc_steal(mem_ctx, res);
    ret = EOK;

done:
    talloc_free(tmp_ctx);

    return ret;
}

char *
sss_ssh_get_pubkey_algorithm(TALLOC_CTX *mem_ctx,
                             struct sss_ssh_pubkey *pubkey)
{
    size_t c = 0;
    uint32_t algo_len;
    char *algo;

    SAFEALIGN_COPY_UINT32(&algo_len, pubkey->data, &c);
    algo_len = ntohl(algo_len);

    algo = talloc_zero_array(mem_ctx, char, algo_len+1);
    if (!algo) {
        return NULL;
    }

    memcpy(algo, pubkey->data+c, algo_len);

    return algo;
}

char *
sss_ssh_format_pubkey(TALLOC_CTX *mem_ctx,
                      struct sss_ssh_ent *ent,
                      struct sss_ssh_pubkey *pubkey,
                      enum sss_ssh_pubkey_format format)
{
    TALLOC_CTX *tmp_ctx;
    char *blob;
    char *algo;
    char *result = NULL;

    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) {
        return NULL;
    }

    blob = sss_base64_encode(tmp_ctx, pubkey->data, pubkey->data_len);
    if (!blob) {
        goto done;
    }

    switch (format) {
    case SSS_SSH_FORMAT_RAW:
        /* base64-encoded key blob */
        result = talloc_steal(mem_ctx, blob);
        break;

    case SSS_SSH_FORMAT_OPENSSH:
        /* OpenSSH authorized_keys/known_hosts format */
        algo = sss_ssh_get_pubkey_algorithm(tmp_ctx, pubkey);
        if (!algo) {
            goto done;
        }

        result = talloc_asprintf(mem_ctx, "%s %s %s", algo, blob, ent->name);
        break;
    }

done:
    talloc_free(tmp_ctx);

    return result;
}