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Annotation of src/usr.bin/ssh/gss-genr.c, Revision 1.21

1.21    ! djm         1: /* $OpenBSD: gss-genr.c,v 1.20 2009/06/22 05:39:28 dtucker Exp $ */
1.1       markus      2:
                      3: /*
1.19      dtucker     4:  * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
1.1       markus      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: #ifdef GSSAPI
1.12      stevesk    28:
                     29: #include <sys/param.h>
1.11      stevesk    30:
1.20      dtucker    31: #include <stdarg.h>
1.11      stevesk    32: #include <string.h>
1.1       markus     33:
                     34: #include "xmalloc.h"
1.13      deraadt    35: #include "buffer.h"
1.1       markus     36: #include "log.h"
1.2       markus     37: #include "ssh2.h"
1.1       markus     38:
                     39: #include "ssh-gss.h"
                     40:
1.2       markus     41: extern u_char *session_id2;
                     42: extern u_int session_id2_len;
1.1       markus     43:
                     44: /* Check that the OID in a data stream matches that in the context */
                     45: int
                     46: ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
                     47: {
                     48:        return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
                     49:            ctx->oid->length == len &&
                     50:            memcmp(ctx->oid->elements, data, len) == 0);
                     51: }
                     52:
                     53: /* Set the contexts OID from a data stream */
                     54: void
                     55: ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
                     56: {
                     57:        if (ctx->oid != GSS_C_NO_OID) {
1.21    ! djm        58:                free(ctx->oid->elements);
        !            59:                free(ctx->oid);
1.1       markus     60:        }
                     61:        ctx->oid = xmalloc(sizeof(gss_OID_desc));
                     62:        ctx->oid->length = len;
                     63:        ctx->oid->elements = xmalloc(len);
                     64:        memcpy(ctx->oid->elements, data, len);
                     65: }
                     66:
                     67: /* Set the contexts OID */
                     68: void
                     69: ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
                     70: {
                     71:        ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
                     72: }
                     73:
                     74: /* All this effort to report an error ... */
                     75: void
                     76: ssh_gssapi_error(Gssctxt *ctxt)
                     77: {
1.7       djm        78:        char *s;
                     79:
                     80:        s = ssh_gssapi_last_error(ctxt, NULL, NULL);
                     81:        debug("%s", s);
1.21    ! djm        82:        free(s);
1.1       markus     83: }
                     84:
                     85: char *
1.4       djm        86: ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
                     87:     OM_uint32 *minor_status)
1.1       markus     88: {
                     89:        OM_uint32 lmin;
                     90:        gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
                     91:        OM_uint32 ctx;
                     92:        Buffer b;
                     93:        char *ret;
                     94:
                     95:        buffer_init(&b);
                     96:
                     97:        if (major_status != NULL)
                     98:                *major_status = ctxt->major;
                     99:        if (minor_status != NULL)
                    100:                *minor_status = ctxt->minor;
                    101:
                    102:        ctx = 0;
                    103:        /* The GSSAPI error */
                    104:        do {
                    105:                gss_display_status(&lmin, ctxt->major,
1.19      dtucker   106:                    GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
1.1       markus    107:
                    108:                buffer_append(&b, msg.value, msg.length);
                    109:                buffer_put_char(&b, '\n');
                    110:
                    111:                gss_release_buffer(&lmin, &msg);
                    112:        } while (ctx != 0);
                    113:
                    114:        /* The mechanism specific error */
                    115:        do {
                    116:                gss_display_status(&lmin, ctxt->minor,
1.19      dtucker   117:                    GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
1.1       markus    118:
                    119:                buffer_append(&b, msg.value, msg.length);
                    120:                buffer_put_char(&b, '\n');
                    121:
                    122:                gss_release_buffer(&lmin, &msg);
                    123:        } while (ctx != 0);
                    124:
                    125:        buffer_put_char(&b, '\0');
                    126:        ret = xmalloc(buffer_len(&b));
                    127:        buffer_get(&b, ret, buffer_len(&b));
                    128:        buffer_free(&b);
                    129:        return (ret);
                    130: }
                    131:
                    132: /*
                    133:  * Initialise our GSSAPI context. We use this opaque structure to contain all
                    134:  * of the data which both the client and server need to persist across
                    135:  * {accept,init}_sec_context calls, so that when we do it from the userauth
                    136:  * stuff life is a little easier
                    137:  */
                    138: void
                    139: ssh_gssapi_build_ctx(Gssctxt **ctx)
                    140: {
1.8       djm       141:        *ctx = xcalloc(1, sizeof (Gssctxt));
1.1       markus    142:        (*ctx)->context = GSS_C_NO_CONTEXT;
                    143:        (*ctx)->name = GSS_C_NO_NAME;
                    144:        (*ctx)->oid = GSS_C_NO_OID;
                    145:        (*ctx)->creds = GSS_C_NO_CREDENTIAL;
                    146:        (*ctx)->client = GSS_C_NO_NAME;
                    147:        (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
                    148: }
                    149:
                    150: /* Delete our context, providing it has been built correctly */
                    151: void
                    152: ssh_gssapi_delete_ctx(Gssctxt **ctx)
                    153: {
                    154:        OM_uint32 ms;
                    155:
                    156:        if ((*ctx) == NULL)
                    157:                return;
                    158:        if ((*ctx)->context != GSS_C_NO_CONTEXT)
                    159:                gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
                    160:        if ((*ctx)->name != GSS_C_NO_NAME)
                    161:                gss_release_name(&ms, &(*ctx)->name);
                    162:        if ((*ctx)->oid != GSS_C_NO_OID) {
1.21    ! djm       163:                free((*ctx)->oid->elements);
        !           164:                free((*ctx)->oid);
1.1       markus    165:                (*ctx)->oid = GSS_C_NO_OID;
                    166:        }
                    167:        if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
                    168:                gss_release_cred(&ms, &(*ctx)->creds);
                    169:        if ((*ctx)->client != GSS_C_NO_NAME)
                    170:                gss_release_name(&ms, &(*ctx)->client);
                    171:        if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
                    172:                gss_release_cred(&ms, &(*ctx)->client_creds);
                    173:
1.21    ! djm       174:        free(*ctx);
1.1       markus    175:        *ctx = NULL;
                    176: }
                    177:
                    178: /*
                    179:  * Wrapper to init_sec_context
                    180:  * Requires that the context contains:
                    181:  *     oid
                    182:  *     server name (from ssh_gssapi_import_name)
                    183:  */
                    184: OM_uint32
                    185: ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
                    186:     gss_buffer_desc* send_tok, OM_uint32 *flags)
                    187: {
                    188:        int deleg_flag = 0;
                    189:
                    190:        if (deleg_creds) {
                    191:                deleg_flag = GSS_C_DELEG_FLAG;
                    192:                debug("Delegating credentials");
                    193:        }
                    194:
                    195:        ctx->major = gss_init_sec_context(&ctx->minor,
                    196:            GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
                    197:            GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
                    198:            0, NULL, recv_tok, NULL, send_tok, flags, NULL);
                    199:
                    200:        if (GSS_ERROR(ctx->major))
                    201:                ssh_gssapi_error(ctx);
                    202:
                    203:        return (ctx->major);
                    204: }
                    205:
                    206: /* Create a service name for the given host */
                    207: OM_uint32
                    208: ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
                    209: {
                    210:        gss_buffer_desc gssbuf;
1.10      djm       211:        char *val;
1.1       markus    212:
1.10      djm       213:        xasprintf(&val, "host@%s", host);
                    214:        gssbuf.value = val;
                    215:        gssbuf.length = strlen(gssbuf.value);
1.1       markus    216:
                    217:        if ((ctx->major = gss_import_name(&ctx->minor,
                    218:            &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
                    219:                ssh_gssapi_error(ctx);
                    220:
1.21    ! djm       221:        free(gssbuf.value);
1.1       markus    222:        return (ctx->major);
                    223: }
                    224:
1.2       markus    225: OM_uint32
                    226: ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
                    227: {
                    228:        if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
                    229:            GSS_C_QOP_DEFAULT, buffer, hash)))
                    230:                ssh_gssapi_error(ctx);
1.3       djm       231:
1.2       markus    232:        return (ctx->major);
                    233: }
                    234:
                    235: void
1.3       djm       236: ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
                    237:     const char *context)
                    238: {
1.2       markus    239:        buffer_init(b);
                    240:        buffer_put_string(b, session_id2, session_id2_len);
                    241:        buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
                    242:        buffer_put_cstring(b, user);
                    243:        buffer_put_cstring(b, service);
                    244:        buffer_put_cstring(b, context);
1.14      djm       245: }
                    246:
                    247: int
1.15      djm       248: ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
1.14      djm       249: {
                    250:        gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
                    251:        OM_uint32 major, minor;
                    252:        gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
                    253:
                    254:        /* RFC 4462 says we MUST NOT do SPNEGO */
                    255:        if (oid->length == spnego_oid.length &&
                    256:            (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
1.16      djm       257:                return 0; /* false */
1.14      djm       258:
                    259:        ssh_gssapi_build_ctx(ctx);
                    260:        ssh_gssapi_set_oid(*ctx, oid);
                    261:        major = ssh_gssapi_import_name(*ctx, host);
                    262:        if (!GSS_ERROR(major)) {
                    263:                major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
                    264:                    NULL);
                    265:                gss_release_buffer(&minor, &token);
1.17      dtucker   266:                if ((*ctx)->context != GSS_C_NO_CONTEXT)
                    267:                        gss_delete_sec_context(&minor, &(*ctx)->context,
                    268:                            GSS_C_NO_BUFFER);
1.14      djm       269:        }
                    270:
                    271:        if (GSS_ERROR(major))
                    272:                ssh_gssapi_delete_ctx(ctx);
                    273:
                    274:        return (!GSS_ERROR(major));
1.1       markus    275: }
                    276:
                    277: #endif /* GSSAPI */