path: root/src/lib/krb5/krb/ser_ctx.c

/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/krb/ser_ctx.c - Serialize krb5_context structure */
/*
 * Copyright 1995, 2007, 2008 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

#include "k5-int.h"
#include "int-proto.h"

krb5_error_code profile_ser_size(krb5_context, profile_t, size_t *);
krb5_error_code profile_ser_externalize(krb5_context, profile_t,
                                        krb5_octet **, size_t *);
krb5_error_code profile_ser_internalize(krb5_context, profile_t *,
                                        krb5_octet **, size_t *);

static krb5_error_code size_oscontext(krb5_os_context os_ctx, size_t *sizep);
static krb5_error_code externalize_oscontext(krb5_os_context os_ctx,
                                             krb5_octet **buffer,
                                             size_t *lenremain);
static krb5_error_code internalize_oscontext(krb5_os_context *argp,
                                             krb5_octet **buffer,
                                             size_t *lenremain);

static inline unsigned int
etypes_len(krb5_enctype *list)
{
    return (list == NULL) ? 0 : k5_count_etypes(list);
}

krb5_error_code
k5_size_context(krb5_context context, size_t *sizep)
{
    krb5_error_code     kret;
    size_t              required;

    /*
     * The KRB5 context itself requires:
     *  krb5_int32                      for KV5M_CONTEXT
     *  krb5_int32                      for sizeof(default_realm)
     *  strlen(default_realm)           for default_realm.
     *  krb5_int32                      for n_tgs_etypes*sizeof(krb5_int32)
     *  nktypes*sizeof(krb5_int32)      for tgs_etypes.
     *  krb5_int32                      for clockskew
     *  krb5_int32                      for kdc_default_options
     *  krb5_int32                      for library_options
     *  krb5_int32                      for profile_secure
     *  krb5_int32                      for fcc_default_format
     *    <>                            for os_context
     *    <>                            for profile
     *  krb5_int32                      for trailer.
     */
    kret = EINVAL;
    if (context != NULL) {
        /* Calculate base length */
        required = (9 * sizeof(krb5_int32) +
                    (etypes_len(context->tgs_etypes) * sizeof(krb5_int32)));

        if (context->default_realm)
            required += strlen(context->default_realm);

        /* Calculate size required by os_context, if appropriate */
        kret = size_oscontext(&context->os_context, &required);

        /* Calculate size required by profile, if appropriate */
        if (!kret && context->profile)
            kret = profile_ser_size(NULL, context->profile, &required);
    }
    if (!kret)
        *sizep += required;
    return(kret);
}

krb5_error_code
k5_externalize_context(krb5_context context,
                       krb5_octet **buffer, size_t *lenremain)
{
    krb5_error_code     kret;
    size_t              required;
    krb5_octet          *bp;
    size_t              remain;
    unsigned int        i;

    required = 0;
    bp = *buffer;
    remain = *lenremain;
    if (!context)
        return (EINVAL);
    if (context->magic != KV5M_CONTEXT)
        return (KV5M_CONTEXT);

    if ((kret = k5_size_context(context, &required)))
        return (kret);

    if (required > remain)
        return (ENOMEM);

    /* First write our magic number */
    kret = krb5_ser_pack_int32(KV5M_CONTEXT, &bp, &remain);
    if (kret)
        return (kret);

    /* Now sizeof default realm */
    kret = krb5_ser_pack_int32((context->default_realm) ?
                               (krb5_int32) strlen(context->default_realm) : 0,
                               &bp, &remain);
    if (kret)
        return (kret);

    /* Now default_realm bytes */
    if (context->default_realm) {
        kret = krb5_ser_pack_bytes((krb5_octet *) context->default_realm,
                                   strlen(context->default_realm),
                                   &bp, &remain);
        if (kret)
            return (kret);
    }

    /* Now number of default ktypes */
    kret = krb5_ser_pack_int32(etypes_len(context->tgs_etypes), &bp, &remain);
    if (kret)
        return (kret);

    /* Now serialize ktypes */
    if (context->tgs_etypes) {
        for (i = 0; context->tgs_etypes[i]; i++) {
            kret = krb5_ser_pack_int32(context->tgs_etypes[i], &bp, &remain);
            if (kret)
                return (kret);
        }
    }

    /* Now allowable clockskew */
    kret = krb5_ser_pack_int32((krb5_int32) context->clockskew,
                               &bp, &remain);
    if (kret)
        return (kret);

    /* Now kdc_default_options */
    kret = krb5_ser_pack_int32((krb5_int32) context->kdc_default_options,
                               &bp, &remain);
    if (kret)
        return (kret);

    /* Now library_options */
    kret = krb5_ser_pack_int32((krb5_int32) context->library_options,
                               &bp, &remain);
    if (kret)
        return (kret);

    /* Now profile_secure */
    kret = krb5_ser_pack_int32((krb5_int32) context->profile_secure,
                               &bp, &remain);
    if (kret)
        return (kret);

    /* Now fcc_default_format */
    kret = krb5_ser_pack_int32((krb5_int32) context->fcc_default_format,
                               &bp, &remain);
    if (kret)
        return (kret);

    /* Now handle os_context, if appropriate */
    kret = externalize_oscontext(&context->os_context, &bp, &remain);
    if (kret)
        return (kret);

    /* Finally, handle profile, if appropriate */
    if (context->profile != NULL) {
        kret = profile_ser_externalize(NULL, context->profile, &bp, &remain);
        if (kret)
            return (kret);
    }

    /*
     * If we were successful, write trailer then update the pointer and
     * remaining length;
     */
    kret = krb5_ser_pack_int32(KV5M_CONTEXT, &bp, &remain);
    if (kret)
        return (kret);

    *buffer = bp;
    *lenremain = remain;

    return (0);
}

krb5_error_code
k5_internalize_context(krb5_context *argp,
                       krb5_octet **buffer, size_t *lenremain)
{
    krb5_error_code     kret;
    krb5_context        context;
    krb5_int32          ibuf;
    krb5_octet          *bp;
    size_t              remain;
    unsigned int        i, count;

    bp = *buffer;
    remain = *lenremain;

    /* Read our magic number */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        return (EINVAL);

    if (ibuf != KV5M_CONTEXT)
        return (EINVAL);

    /* Get memory for the context */
    context = (krb5_context) calloc(1, sizeof(struct _krb5_context));
    if (!context)
        return (ENOMEM);

    /* Get the size of the default realm */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;

    if (ibuf) {
        context->default_realm = (char *) malloc((size_t) ibuf+1);
        if (!context->default_realm) {
            kret = ENOMEM;
            goto cleanup;
        }

        kret = krb5_ser_unpack_bytes((krb5_octet *) context->default_realm,
                                     (size_t) ibuf, &bp, &remain);
        if (kret)
            goto cleanup;

        context->default_realm[ibuf] = '\0';
    }

    /* Get the tgs_etypes */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;
    count = ibuf;
    if (count > 0) {
        context->tgs_etypes = calloc(count + 1, sizeof(krb5_enctype));
        if (!context->tgs_etypes) {
            kret = ENOMEM;
            goto cleanup;
        }
        for (i = 0; i < count; i++) {
            if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
                goto cleanup;
            context->tgs_etypes[i] = ibuf;
        }
        context->tgs_etypes[count] = 0;
    } else
        context->tgs_etypes = NULL;

    /* Allowable clockskew */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;
    context->clockskew = (krb5_deltat) ibuf;

    /* kdc_default_options */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;
    context->kdc_default_options = (krb5_flags) ibuf;

    /* library_options */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;
    context->library_options = (krb5_flags) ibuf;

    /* profile_secure */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;
    context->profile_secure = (krb5_boolean) ibuf;

    /* fcc_default_format */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;
    context->fcc_default_format = (int) ibuf;

    /* Attempt to read in the os_context.  It's an array now, but
       we still treat it in most places as a separate object with
       a pointer.  */
    {
        krb5_os_context osp = 0;
        kret = internalize_oscontext(&osp, &bp, &remain);
        if (kret && (kret != EINVAL) && (kret != ENOENT))
            goto cleanup;
        /* Put the newly allocated data into the krb5_context
           structure where we're really keeping it these days.  */
        if (osp)
            context->os_context = *osp;
        free(osp);
    }

    /* Attempt to read in the profile */
    kret = profile_ser_internalize(NULL, &context->profile, &bp, &remain);
    if (kret && (kret != EINVAL) && (kret != ENOENT))
        goto cleanup;

    /* Finally, find the trailer */
    if ((kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain)))
        goto cleanup;

    if (ibuf != KV5M_CONTEXT) {
        kret = EINVAL;
        goto cleanup;
    }

    context->magic = KV5M_CONTEXT;
    *buffer = bp;
    *lenremain = remain;
    *argp = context;

    return 0;

cleanup:
    if (context)
        krb5_free_context(context);
    return(kret);
}

krb5_error_code
size_oscontext(krb5_os_context os_ctx, size_t *sizep)
{
    /*
     * We need five 32-bit integers:
     *  two for header and trailer
     *  one each for time_offset, usec_offset and os_flags
     */
    *sizep += (5*sizeof(krb5_int32));
    return(0);
}

krb5_error_code
externalize_oscontext(krb5_os_context os_ctx,
                      krb5_octet **buffer, size_t *lenremain)
{
    krb5_error_code     kret;
    size_t              required;
    krb5_octet          *bp;
    size_t              remain;

    required = 0;
    bp = *buffer;
    remain = *lenremain;
    kret = EINVAL;
    if (os_ctx != NULL) {
        kret = ENOMEM;
        if (!size_oscontext(os_ctx, &required) && required <= remain) {
            (void) krb5_ser_pack_int32(KV5M_OS_CONTEXT, &bp, &remain);
            (void) krb5_ser_pack_int32(os_ctx->time_offset, &bp, &remain);
            (void) krb5_ser_pack_int32(os_ctx->usec_offset, &bp, &remain);
            (void) krb5_ser_pack_int32(os_ctx->os_flags, &bp, &remain);
            (void) krb5_ser_pack_int32(KV5M_OS_CONTEXT, &bp, &remain);

            /* Handle any other OS context here */
            kret = 0;
            if (!kret) {
                *buffer = bp;
                *lenremain = remain;
            }
        }
    }
    return(kret);
}

static krb5_error_code
internalize_oscontext(krb5_os_context *argp,
                      krb5_octet **buffer, size_t *lenremain)
{
    krb5_error_code     kret;
    krb5_os_context     os_ctx;
    krb5_int32          ibuf;
    krb5_octet          *bp;
    size_t              remain;

    bp = *buffer;
    remain = *lenremain;
    kret = EINVAL;
    os_ctx = (krb5_os_context) NULL;
    /* Read our magic number */
    if (krb5_ser_unpack_int32(&ibuf, &bp, &remain))
        ibuf = 0;
    if (ibuf == KV5M_OS_CONTEXT) {
        kret = ENOMEM;

        /* Get memory for the context */
        if ((os_ctx = (krb5_os_context)
             calloc(1, sizeof(struct _krb5_os_context))) &&
            (remain >= 4*sizeof(krb5_int32))) {
            os_ctx->magic = KV5M_OS_CONTEXT;

            /* Read out our context */
            (void) krb5_ser_unpack_int32(&os_ctx->time_offset, &bp, &remain);
            (void) krb5_ser_unpack_int32(&os_ctx->usec_offset, &bp, &remain);
            (void) krb5_ser_unpack_int32(&os_ctx->os_flags, &bp, &remain);
            (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);

            if (ibuf == KV5M_OS_CONTEXT) {
                os_ctx->magic = KV5M_OS_CONTEXT;
                kret = 0;
                *buffer = bp;
                *lenremain = remain;
            } else
                kret = EINVAL;
        }
    }
    if (!kret) {
        *argp = os_ctx;
    }
    else {
        if (os_ctx)
            free(os_ctx);
    }
    return(kret);
}