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Annotation of src/usr.bin/ssh/gss-genr.c, Revision 1.1.4.2

1.1.4.2 ! brad        1: /*     $OpenBSD: gss-genr.c,v 1.3 2003/11/21 11:57:03 djm Exp $        */
1.1       markus      2:
                      3: /*
                      4:  * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
                      5:  *
                      6:  * Redistribution and use in source and binary forms, with or without
                      7:  * modification, are permitted provided that the following conditions
                      8:  * are met:
                      9:  * 1. Redistributions of source code must retain the above copyright
                     10:  *    notice, this list of conditions and the following disclaimer.
                     11:  * 2. Redistributions in binary form must reproduce the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer in the
                     13:  *    documentation and/or other materials provided with the distribution.
                     14:  *
                     15:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
                     16:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     17:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     18:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
                     19:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
                     20:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
                     21:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
                     22:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     23:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
                     24:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                     25:  */
                     26:
                     27: #include "includes.h"
                     28:
                     29: #ifdef GSSAPI
                     30:
                     31: #include "xmalloc.h"
                     32: #include "bufaux.h"
                     33: #include "compat.h"
                     34: #include "log.h"
                     35: #include "monitor_wrap.h"
1.1.4.2 ! brad       36: #include "ssh2.h"
1.1       markus     37:
                     38: #include "ssh-gss.h"
                     39:
1.1.4.2 ! brad       40: extern u_char *session_id2;
        !            41: extern u_int session_id2_len;
1.1       markus     42:
                     43: /* Check that the OID in a data stream matches that in the context */
                     44: int
                     45: ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
                     46: {
                     47:        return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
                     48:            ctx->oid->length == len &&
                     49:            memcmp(ctx->oid->elements, data, len) == 0);
                     50: }
                     51:
                     52: /* Set the contexts OID from a data stream */
                     53: void
                     54: ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
                     55: {
                     56:        if (ctx->oid != GSS_C_NO_OID) {
                     57:                xfree(ctx->oid->elements);
                     58:                xfree(ctx->oid);
                     59:        }
                     60:        ctx->oid = xmalloc(sizeof(gss_OID_desc));
                     61:        ctx->oid->length = len;
                     62:        ctx->oid->elements = xmalloc(len);
                     63:        memcpy(ctx->oid->elements, data, len);
                     64: }
                     65:
                     66: /* Set the contexts OID */
                     67: void
                     68: ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
                     69: {
                     70:        ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
                     71: }
                     72:
                     73: /* All this effort to report an error ... */
                     74: void
                     75: ssh_gssapi_error(Gssctxt *ctxt)
                     76: {
                     77:        debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
                     78: }
                     79:
                     80: char *
                     81: ssh_gssapi_last_error(Gssctxt *ctxt,
                     82:                      OM_uint32 *major_status, OM_uint32 *minor_status)
                     83: {
                     84:        OM_uint32 lmin;
                     85:        gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
                     86:        OM_uint32 ctx;
                     87:        Buffer b;
                     88:        char *ret;
                     89:
                     90:        buffer_init(&b);
                     91:
                     92:        if (major_status != NULL)
                     93:                *major_status = ctxt->major;
                     94:        if (minor_status != NULL)
                     95:                *minor_status = ctxt->minor;
                     96:
                     97:        ctx = 0;
                     98:        /* The GSSAPI error */
                     99:        do {
                    100:                gss_display_status(&lmin, ctxt->major,
                    101:                    GSS_C_GSS_CODE, GSS_C_NULL_OID, &ctx, &msg);
                    102:
                    103:                buffer_append(&b, msg.value, msg.length);
                    104:                buffer_put_char(&b, '\n');
                    105:
                    106:                gss_release_buffer(&lmin, &msg);
                    107:        } while (ctx != 0);
                    108:
                    109:        /* The mechanism specific error */
                    110:        do {
                    111:                gss_display_status(&lmin, ctxt->minor,
                    112:                    GSS_C_MECH_CODE, GSS_C_NULL_OID, &ctx, &msg);
                    113:
                    114:                buffer_append(&b, msg.value, msg.length);
                    115:                buffer_put_char(&b, '\n');
                    116:
                    117:                gss_release_buffer(&lmin, &msg);
                    118:        } while (ctx != 0);
                    119:
                    120:        buffer_put_char(&b, '\0');
                    121:        ret = xmalloc(buffer_len(&b));
                    122:        buffer_get(&b, ret, buffer_len(&b));
                    123:        buffer_free(&b);
                    124:        return (ret);
                    125: }
                    126:
                    127: /*
                    128:  * Initialise our GSSAPI context. We use this opaque structure to contain all
                    129:  * of the data which both the client and server need to persist across
                    130:  * {accept,init}_sec_context calls, so that when we do it from the userauth
                    131:  * stuff life is a little easier
                    132:  */
                    133: void
                    134: ssh_gssapi_build_ctx(Gssctxt **ctx)
                    135: {
                    136:        *ctx = xmalloc(sizeof (Gssctxt));
                    137:        (*ctx)->major = 0;
                    138:        (*ctx)->minor = 0;
                    139:        (*ctx)->context = GSS_C_NO_CONTEXT;
                    140:        (*ctx)->name = GSS_C_NO_NAME;
                    141:        (*ctx)->oid = GSS_C_NO_OID;
                    142:        (*ctx)->creds = GSS_C_NO_CREDENTIAL;
                    143:        (*ctx)->client = GSS_C_NO_NAME;
                    144:        (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
                    145: }
                    146:
                    147: /* Delete our context, providing it has been built correctly */
                    148: void
                    149: ssh_gssapi_delete_ctx(Gssctxt **ctx)
                    150: {
                    151:        OM_uint32 ms;
                    152:
                    153:        if ((*ctx) == NULL)
                    154:                return;
                    155:        if ((*ctx)->context != GSS_C_NO_CONTEXT)
                    156:                gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
                    157:        if ((*ctx)->name != GSS_C_NO_NAME)
                    158:                gss_release_name(&ms, &(*ctx)->name);
                    159:        if ((*ctx)->oid != GSS_C_NO_OID) {
                    160:                xfree((*ctx)->oid->elements);
                    161:                xfree((*ctx)->oid);
                    162:                (*ctx)->oid = GSS_C_NO_OID;
                    163:        }
                    164:        if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
                    165:                gss_release_cred(&ms, &(*ctx)->creds);
                    166:        if ((*ctx)->client != GSS_C_NO_NAME)
                    167:                gss_release_name(&ms, &(*ctx)->client);
                    168:        if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
                    169:                gss_release_cred(&ms, &(*ctx)->client_creds);
                    170:
                    171:        xfree(*ctx);
                    172:        *ctx = NULL;
                    173: }
                    174:
                    175: /*
                    176:  * Wrapper to init_sec_context
                    177:  * Requires that the context contains:
                    178:  *     oid
                    179:  *     server name (from ssh_gssapi_import_name)
                    180:  */
                    181: OM_uint32
                    182: ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
                    183:     gss_buffer_desc* send_tok, OM_uint32 *flags)
                    184: {
                    185:        int deleg_flag = 0;
                    186:
                    187:        if (deleg_creds) {
                    188:                deleg_flag = GSS_C_DELEG_FLAG;
                    189:                debug("Delegating credentials");
                    190:        }
                    191:
                    192:        ctx->major = gss_init_sec_context(&ctx->minor,
                    193:            GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
                    194:            GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
                    195:            0, NULL, recv_tok, NULL, send_tok, flags, NULL);
                    196:
                    197:        if (GSS_ERROR(ctx->major))
                    198:                ssh_gssapi_error(ctx);
                    199:
                    200:        return (ctx->major);
                    201: }
                    202:
                    203: /* Create a service name for the given host */
                    204: OM_uint32
                    205: ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
                    206: {
                    207:        gss_buffer_desc gssbuf;
                    208:
                    209:        gssbuf.length = sizeof("host@") + strlen(host);
                    210:        gssbuf.value = xmalloc(gssbuf.length);
                    211:        snprintf(gssbuf.value, gssbuf.length, "host@%s", host);
                    212:
                    213:        if ((ctx->major = gss_import_name(&ctx->minor,
                    214:            &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
                    215:                ssh_gssapi_error(ctx);
                    216:
                    217:        xfree(gssbuf.value);
                    218:        return (ctx->major);
                    219: }
                    220:
                    221: /* Acquire credentials for a server running on the current host.
                    222:  * Requires that the context structure contains a valid OID
                    223:  */
                    224:
                    225: /* Returns a GSSAPI error code */
                    226: OM_uint32
                    227: ssh_gssapi_acquire_cred(Gssctxt *ctx)
                    228: {
                    229:        OM_uint32 status;
                    230:        char lname[MAXHOSTNAMELEN];
                    231:        gss_OID_set oidset;
                    232:
                    233:        gss_create_empty_oid_set(&status, &oidset);
                    234:        gss_add_oid_set_member(&status, ctx->oid, &oidset);
                    235:
                    236:        if (gethostname(lname, MAXHOSTNAMELEN))
                    237:                return (-1);
                    238:
                    239:        if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
                    240:                return (ctx->major);
                    241:
                    242:        if ((ctx->major = gss_acquire_cred(&ctx->minor,
                    243:            ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
                    244:                ssh_gssapi_error(ctx);
                    245:
                    246:        gss_release_oid_set(&status, &oidset);
                    247:        return (ctx->major);
1.1.4.2 ! brad      248: }
        !           249:
        !           250: OM_uint32
        !           251: ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
        !           252: {
        !           253:        if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
        !           254:            GSS_C_QOP_DEFAULT, buffer, hash)))
        !           255:                ssh_gssapi_error(ctx);
        !           256:
        !           257:        return (ctx->major);
        !           258: }
        !           259:
        !           260: void
        !           261: ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
        !           262:     const char *context)
        !           263: {
        !           264:        buffer_init(b);
        !           265:        buffer_put_string(b, session_id2, session_id2_len);
        !           266:        buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
        !           267:        buffer_put_cstring(b, user);
        !           268:        buffer_put_cstring(b, service);
        !           269:        buffer_put_cstring(b, context);
1.1       markus    270: }
                    271:
                    272: OM_uint32
                    273: ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
                    274:        if (*ctx)
                    275:                ssh_gssapi_delete_ctx(ctx);
                    276:        ssh_gssapi_build_ctx(ctx);
                    277:        ssh_gssapi_set_oid(*ctx, oid);
                    278:        return (ssh_gssapi_acquire_cred(*ctx));
                    279: }
                    280:
                    281: #endif /* GSSAPI */