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Unnamed repository; edit this file to name it for gitweb.

Sumit Bose

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author	Simo Sorce <ssorce@redhat.com>	2009-12-10 15:48:16 -0500
committer	Stephen Gallagher <sgallagh@redhat.com>	2009-12-10 17:20:27 -0500
commit	781b66f3f87d11ae320a4c4a861f2599ca6edff6 (patch)
tree	84e9c624059691c4e35742dcab88e4c544147619 /common/collection
parent	17980ab09ad29695e68bda67dbbd6cc3a8269f49 (diff)

Fix for #322, update from old database versions.

Diffstat (limited to 'common/collection')

0 files changed, 0 insertions, 0 deletions

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/*
    Authors:
        Sumit Bose <sbose@redhat.com>

    Copyright (C) 2009-2010 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 <stdio.h>
#include <errno.h>
#include <talloc.h>

#include "config.h"

#include "util/util.h"
#include "util/sss_krb5.h"

char *
sss_krb5_get_primary(TALLOC_CTX *mem_ctx,
                     const char *pattern,
                     const char *hostname)
{
    char *primary;
    char *dot;
    char *c;
    char *shortname;

    if (strcmp(pattern, "%S$") == 0) {
        shortname = talloc_strdup(mem_ctx, hostname);
        if (!shortname) return NULL;

        dot = strchr(shortname, '.');
        if (dot) {
            *dot = '\0';
        }

        for (c=shortname; *c != '\0'; ++c) {
            *c = toupper(*c);
        }

        primary = talloc_asprintf(mem_ctx, "%s$", shortname);
        talloc_free(shortname);
        return primary;
    }

    return talloc_asprintf(mem_ctx, pattern, hostname);
}

errno_t select_principal_from_keytab(TALLOC_CTX *mem_ctx,
                                     const char *hostname,
                                     const char *desired_realm,
                                     const char *keytab_name,
                                     char **_principal,
                                     char **_primary,
                                     char **_realm)
{
    krb5_error_code kerr = 0;
    krb5_context krb_ctx = NULL;
    krb5_keytab keytab = NULL;
    krb5_principal client_princ = NULL;
    TALLOC_CTX *tmp_ctx;
    char *primary = NULL;
    char *realm = NULL;
    int i = 0;
    errno_t ret;
    char *principal_string;
    const char *realm_name;
    int realm_len;

    /**
     * The %s conversion is passed as-is, the %S conversion is translated to
     * "short host name"
     *
     * Priority of lookup:
     * - our.hostname@REALM or host/our.hostname@REALM depending on the input
     * - SHORT.HOSTNAME$@REALM (AD domain)
     * - host/our.hostname@REALM
     * - foobar$@REALM (AD domain)
     * - host/foobar@REALM
     * - host/foo@BAR
     * - pick the first principal in the keytab
     */
    const char *primary_patterns[] = {"%s", "%S$", "host/%s", "*$", "host/*",
                                      "host/*", NULL};
    const char *realm_patterns[] =   {"%s", "%s",  "%s",      "%s", "%s",
                                      NULL,     NULL};

    DEBUG(SSSDBG_FUNC_DATA,
          "trying to select the most appropriate principal from keytab\n");
    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) {
        DEBUG(SSSDBG_CRIT_FAILURE, "talloc_new failed\n");
        return ENOMEM;
    }

    kerr = krb5_init_context(&krb_ctx);
    if (kerr) {
        DEBUG(SSSDBG_OP_FAILURE, "Failed to init kerberos context\n");
        ret = EFAULT;
        goto done;
    }

    if (keytab_name != NULL) {
        kerr = krb5_kt_resolve(krb_ctx, keytab_name, &keytab);
    } else {
        kerr = krb5_kt_default(krb_ctx, &keytab);
    }
    if (kerr) {
        DEBUG(SSSDBG_FATAL_FAILURE,
              "Failed to read keytab [%s]: %s\n",
               KEYTAB_CLEAN_NAME,
               sss_krb5_get_error_message(krb_ctx, kerr));
        ret = EFAULT;
        goto done;
    }

    if (!desired_realm) {
        desired_realm = "*";
    }
    if (!hostname) {
        hostname = "*";
    }

    do {
        if (primary_patterns[i]) {
            primary = sss_krb5_get_primary(tmp_ctx,
                                           primary_patterns[i],
                                           hostname);
            if (primary == NULL) {
                ret = ENOMEM;
                goto done;
            }
        } else {
            primary = NULL;
        }
        if (realm_patterns[i]) {
            realm = talloc_asprintf(tmp_ctx, realm_patterns[i], desired_realm);
            if (realm == NULL) {
                ret = ENOMEM;
                goto done;
            }
        } else {
            realm = NULL;
        }

        kerr = find_principal_in_keytab(krb_ctx, keytab, primary, realm,
                                        &client_princ);
        talloc_zfree(primary);
        talloc_zfree(realm);
        if (kerr == 0) {
            break;
        }
        if (client_princ != NULL) {
            krb5_free_principal(krb_ctx, client_princ);
            client_princ = NULL;
        }
        i++;
    } while(primary_patterns[i-1] != NULL || realm_patterns[i-1] != NULL);

    if (kerr == 0) {
        if (_principal) {
            kerr = krb5_unparse_name(krb_ctx, client_princ, &principal_string);
            if (kerr) {
                DEBUG(SSSDBG_CRIT_FAILURE, "krb5_unparse_name failed\n");
                ret = EFAULT;
                goto done;
            }

            *_principal = talloc_strdup(mem_ctx, principal_string);
            free(principal_string);
            if (!*_principal) {
                DEBUG(SSSDBG_CRIT_FAILURE, "talloc_strdup failed\n");
                ret = ENOMEM;
                goto done;
            }
            DEBUG(SSSDBG_FUNC_DATA, "Selected principal: %s\n", *_principal);
        }

        if (_primary) {
            kerr = sss_krb5_unparse_name_flags(krb_ctx, client_princ,
                                               KRB5_PRINCIPAL_UNPARSE_NO_REALM,
                                               &principal_string);
            if (kerr) {
                DEBUG(SSSDBG_CRIT_FAILURE, "krb5_unparse_name failed\n");
                ret = EFAULT;
                goto done;
            }

            *_primary = talloc_strdup(mem_ctx, principal_string);
            free(principal_string);
            if (!*_primary) {
                DEBUG(SSSDBG_CRIT_FAILURE, "talloc_strdup failed\n");
                if (_principal) talloc_zfree(*_principal);
                ret = ENOMEM;
                goto done;
            }
            DEBUG(SSSDBG_FUNC_DATA, "Selected primary: %s\n", *_primary);
        }

        if (_realm) {
            sss_krb5_princ_realm(krb_ctx, client_princ,
                                 &realm_name,
                                 &realm_len);
            if (realm_len == 0) {
                DEBUG(SSSDBG_CRIT_FAILURE, "sss_krb5_princ_realm failed.\n");
                if (_principal) talloc_zfree(*_principal);
                if (_primary) talloc_zfree(*_primary);
                ret = EINVAL;
                goto done;
            }

            *_realm = talloc_asprintf(mem_ctx, "%.*s",
                                      realm_len, realm_name);
            if (!*_realm) {
                DEBUG(SSSDBG_CRIT_FAILURE, "talloc_asprintf failed\n");
                if (_principal) talloc_zfree(*_principal);
                if (_primary) talloc_zfree(*_primary);
                ret = ENOMEM;
                goto done;
            }
            DEBUG(SSSDBG_FUNC_DATA, "Selected realm: %s\n", *_realm);
        }

        ret = EOK;
    } else {
        DEBUG(SSSDBG_MINOR_FAILURE, "No suitable principal found in keytab\n");
        ret = ENOENT;
    }

done:
    if (ret != EOK) {
        DEBUG(SSSDBG_FATAL_FAILURE, "Failed to read keytab [%s]: %s\n",
               KEYTAB_CLEAN_NAME, strerror(ret));
        sss_log(SSS_LOG_ERR, "Failed to read keytab [%s]: %s\n",
                KEYTAB_CLEAN_NAME, strerror(ret));
    }
    if (keytab) krb5_kt_close(krb_ctx, keytab);
    if (krb_ctx) krb5_free_context(krb_ctx);
    if (client_princ != NULL) {
        krb5_free_principal(krb_ctx, client_princ);
        client_princ = NULL;
    }
    talloc_free(tmp_ctx);
    return ret;
}

enum matching_mode {MODE_NORMAL, MODE_PREFIX, MODE_POSTFIX};
/**
 * We only have primary and instances stored separately, we need to
 * join them to one string and compare that string.
 *
 * @param ctx kerberos context
 * @param principal principal we want to match
 * @param pattern_primary primary part of the principal we want to
 *        perform matching against. It is possible to use * wildcard
 *        at the beginning or at the end of the string. If NULL, it
 *        will act as "*"
 * @param pattern_realm realm part of the principal we want to perform
 *        the matching against. If NULL, it will act as "*"
 */
static bool match_principal(krb5_context ctx,
                     krb5_principal principal,
                     const char *pattern_primary,
                     const char *pattern_realm)
{
    char *primary = NULL;
    char *primary_str = NULL;
    int primary_str_len = 0;
    int tmp_len;
    int len_diff;
    const char *realm_name;
    int realm_len;

    enum matching_mode mode = MODE_NORMAL;
    TALLOC_CTX *tmp_ctx;
    bool ret = false;

    sss_krb5_princ_realm(ctx, principal, &realm_name, &realm_len);
    if (realm_len == 0) {
        DEBUG(SSSDBG_MINOR_FAILURE, "sss_krb5_princ_realm failed.\n");
        return false;
    }

    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) {
        DEBUG(SSSDBG_CRIT_FAILURE, "talloc_new failed\n");
        return false;
    }

    if (pattern_primary) {
        tmp_len = strlen(pattern_primary);
        if (pattern_primary[tmp_len-1] == '*') {
            mode = MODE_PREFIX;
            primary_str = talloc_strdup(tmp_ctx, pattern_primary);
            primary_str[tmp_len-1] = '\0';
            primary_str_len = tmp_len-1;
        } else if (pattern_primary[0] == '*') {
            mode = MODE_POSTFIX;
            primary_str = talloc_strdup(tmp_ctx, pattern_primary+1);
            primary_str_len = tmp_len-1;
        }

        sss_krb5_unparse_name_flags(ctx, principal, KRB5_PRINCIPAL_UNPARSE_NO_REALM,
                                    &primary);

        len_diff = strlen(primary)-primary_str_len;

        if ((mode == MODE_NORMAL &&
                strcmp(primary, pattern_primary) != 0) ||
            (mode == MODE_PREFIX &&
                strncmp(primary, primary_str, primary_str_len) != 0) ||
            (mode == MODE_POSTFIX &&
                strcmp(primary+len_diff, primary_str) != 0)) {
            goto done;
        }
    }

    if (!pattern_realm || (realm_len == strlen(pattern_realm) &&
        strncmp(realm_name, pattern_realm, realm_len) == 0)) {
        DEBUG(SSSDBG_TRACE_LIBS,
              "Principal matched to the sample (%s@%s).\n", pattern_primary,
                                                                pattern_realm);
        ret = true;
    }

done:
    free(primary);
    talloc_free(tmp_ctx);
    return ret;
}

krb5_error_code find_principal_in_keytab(krb5_context ctx,
                                         krb5_keytab keytab,
                                         const char *pattern_primary,
                                         const char *pattern_realm,
                                         krb5_principal *princ)
{
    krb5_error_code kerr;
    krb5_error_code kt_err;
    krb5_error_code kerr_d;
    krb5_kt_cursor cursor;
    krb5_keytab_entry entry;
    bool principal_found = false;

    memset(&cursor, 0, sizeof(cursor));
    kerr = krb5_kt_start_seq_get(ctx, keytab, &cursor);
    if (kerr != 0) {
        DEBUG(SSSDBG_CRIT_FAILURE, "krb5_kt_start_seq_get failed.\n");
        return kerr;
    }

    DEBUG(SSSDBG_TRACE_ALL,
          "Trying to find principal %s@%s in keytab.\n", pattern_primary, pattern_realm);
    memset(&entry, 0, sizeof(entry));
    while ((kt_err = krb5_kt_next_entry(ctx, keytab, &entry, &cursor)) == 0) {
        principal_found = match_principal(ctx, entry.principal, pattern_primary, pattern_realm);
        if (principal_found) {
            break;
        }

        kerr = sss_krb5_free_keytab_entry_contents(ctx, &entry);
        if (kerr != 0) {
            DEBUG(SSSDBG_CRIT_FAILURE, "Failed to free keytab entry.\n");
        }
        memset(&entry, 0, sizeof(entry));
    }

    /* Close the keytab here.  Even though we're using cursors, the file
     * handle is stored in the krb5_keytab structure, and it gets
     * overwritten by other keytab calls, creating a leak. */
    kerr = krb5_kt_end_seq_get(ctx, keytab, &cursor);
    if (kerr != 0) {
        DEBUG(SSSDBG_CRIT_FAILURE, "krb5_kt_end_seq_get failed.\n");
        goto done;
    }

    if (!principal_found) {
        kerr = KRB5_KT_NOTFOUND;
        DEBUG(SSSDBG_TRACE_FUNC,
              "No principal matching %s@%s found in keytab.\n",
               pattern_primary, pattern_realm);
        goto done;
    }

    /* check if we got any errors from krb5_kt_next_entry */
    if (kt_err != 0 && kt_err != KRB5_KT_END) {
        DEBUG(SSSDBG_CRIT_FAILURE, "Error while reading keytab.\n");
        goto done;
    }

    kerr = krb5_copy_principal(ctx, entry.principal, princ);
    if (kerr != 0) {
        DEBUG(SSSDBG_CRIT_FAILURE, "krb5_copy_principal failed.\n");
        goto done;
    }

    kerr = 0;

done:
    kerr_d = sss_krb5_free_keytab_entry_contents(ctx, &entry);
    if (kerr_d != 0) {
        DEBUG(SSSDBG_CRIT_FAILURE, "Failed to free keytab entry.\n");
    }

    return kerr;
}

const char *KRB5_CALLCONV sss_krb5_get_error_message(krb5_context ctx,
                                               krb5_error_code ec)
{
#ifdef HAVE_KRB5_GET_ERROR_MESSAGE
    return krb5_get_error_message(ctx, ec);
#else
    int ret;
    char *s = NULL;
    int size = sizeof("Kerberos error [XXXXXXXXXXXX]");

    s = malloc(sizeof(char) * (size));
    if (s == NULL) {
        return NULL;
    }

    ret = snprintf(s, size, "Kerberos error [%12d]", ec);

    if (ret < 0 || ret >= size) {
        free(s);
        return NULL;
    }

    return s;
#endif
}

void KRB5_CALLCONV sss_krb5_free_error_message(krb5_context ctx, const char *s)
{


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