summaryrefslogtreecommitdiff
path: root/gnu/packages/patches/mit-krb5-CVE-2015-2695-pt1.patch
blob: 0f5603e228576bc9364f7323a161b1b7c2db413b (about) (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
Copied from Debian.

From b813d5811432faed844a2dfd3daecde914978f2c Mon Sep 17 00:00:00 2001
From: Nicolas Williams <nico@twosigma.com>
Date: Mon, 14 Sep 2015 12:27:52 -0400
Subject: Fix SPNEGO context aliasing bugs [CVE-2015-2695]

The SPNEGO mechanism currently replaces its context handle with the
mechanism context handle upon establishment, under the assumption that
most GSS functions are only called after context establishment.  This
assumption is incorrect, and can lead to aliasing violations for some
programs.  Maintain the SPNEGO context structure after context
establishment and refer to it in all GSS methods.  Add initiate and
opened flags to the SPNEGO context structure for use in
gss_inquire_context() prior to context establishment.

CVE-2015-2695:

In MIT krb5 1.5 and later, applications which call
gss_inquire_context() on a partially-established SPNEGO context can
cause the GSS-API library to read from a pointer using the wrong type,
generally causing a process crash.  This bug may go unnoticed, because
the most common SPNEGO authentication scenario establishes the context
after just one call to gss_accept_sec_context().  Java server
applications using the native JGSS provider are vulnerable to this
bug.  A carefully crafted SPNEGO packet might allow the
gss_inquire_context() call to succeed with attacker-determined
results, but applications should not make access control decisions
based on gss_inquire_context() results prior to context establishment.

    CVSSv2 Vector: AV:N/AC:M/Au:N/C:N/I:N/A:C/E:POC/RL:OF/RC:C

[ghudson@mit.edu: several bugfixes, style changes, and edge-case
behavior changes; commit message and CVE description]

ticket: 8244
target_version: 1.14
tags: pullup

(cherry picked from commit b51b33f2bc5d1497ddf5bd107f791c101695000d)
Patch-Category: upstream
---
 src/lib/gssapi/spnego/gssapiP_spnego.h |   2 +
 src/lib/gssapi/spnego/spnego_mech.c    | 254 ++++++++++++++++++++++++---------
 2 files changed, 192 insertions(+), 64 deletions(-)

diff --git a/src/lib/gssapi/spnego/gssapiP_spnego.h b/src/lib/gssapi/spnego/gssapiP_spnego.h
index bc23f56..8e05736 100644
--- a/src/lib/gssapi/spnego/gssapiP_spnego.h
+++ b/src/lib/gssapi/spnego/gssapiP_spnego.h
@@ -102,6 +102,8 @@ typedef struct {
 	int firstpass;
 	int mech_complete;
 	int nego_done;
+	int initiate;
+	int opened;
 	OM_uint32 ctx_flags;
 	gss_name_t internal_name;
 	gss_OID actual_mech;
diff --git a/src/lib/gssapi/spnego/spnego_mech.c b/src/lib/gssapi/spnego/spnego_mech.c
index 6e39c37..a1072b0 100644
--- a/src/lib/gssapi/spnego/spnego_mech.c
+++ b/src/lib/gssapi/spnego/spnego_mech.c
@@ -104,7 +104,7 @@ static OM_uint32 get_negotiable_mechs(OM_uint32 *, spnego_gss_cred_id_t,
 				      gss_cred_usage_t, gss_OID_set *);
 static void release_spnego_ctx(spnego_gss_ctx_id_t *);
 static void check_spnego_options(spnego_gss_ctx_id_t);
-static spnego_gss_ctx_id_t create_spnego_ctx(void);
+static spnego_gss_ctx_id_t create_spnego_ctx(int);
 static int put_mech_set(gss_OID_set mechSet, gss_buffer_t buf);
 static int put_input_token(unsigned char **, gss_buffer_t, unsigned int);
 static int put_mech_oid(unsigned char **, gss_OID_const, unsigned int);
@@ -442,7 +442,7 @@ check_spnego_options(spnego_gss_ctx_id_t spnego_ctx)
 }
 
 static spnego_gss_ctx_id_t
-create_spnego_ctx(void)
+create_spnego_ctx(int initiate)
 {
 	spnego_gss_ctx_id_t spnego_ctx = NULL;
 	spnego_ctx = (spnego_gss_ctx_id_t)
@@ -465,6 +465,8 @@ create_spnego_ctx(void)
 	spnego_ctx->mic_rcvd = 0;
 	spnego_ctx->mech_complete = 0;
 	spnego_ctx->nego_done = 0;
+	spnego_ctx->opened = 0;
+	spnego_ctx->initiate = initiate;
 	spnego_ctx->internal_name = GSS_C_NO_NAME;
 	spnego_ctx->actual_mech = GSS_C_NO_OID;
 
@@ -630,7 +632,7 @@ init_ctx_new(OM_uint32 *minor_status,
 	OM_uint32 ret;
 	spnego_gss_ctx_id_t sc = NULL;
 
-	sc = create_spnego_ctx();
+	sc = create_spnego_ctx(1);
 	if (sc == NULL)
 		return GSS_S_FAILURE;
 
@@ -647,10 +649,7 @@ init_ctx_new(OM_uint32 *minor_status,
 		ret = GSS_S_FAILURE;
 		goto cleanup;
 	}
-	/*
-	 * The actual context is not yet determined, set the output
-	 * context handle to refer to the spnego context itself.
-	 */
+
 	sc->ctx_handle = GSS_C_NO_CONTEXT;
 	*ctx = (gss_ctx_id_t)sc;
 	sc = NULL;
@@ -1091,16 +1090,11 @@ cleanup:
 	}
 	gss_release_buffer(&tmpmin, &mechtok_out);
 	if (ret == GSS_S_COMPLETE) {
-		/*
-		 * Now, switch the output context to refer to the
-		 * negotiated mechanism's context.
-		 */
-		*context_handle = (gss_ctx_id_t)spnego_ctx->ctx_handle;
+		spnego_ctx->opened = 1;
 		if (actual_mech != NULL)
 			*actual_mech = spnego_ctx->actual_mech;
 		if (ret_flags != NULL)
 			*ret_flags = spnego_ctx->ctx_flags;
-		release_spnego_ctx(&spnego_ctx);
 	} else if (ret != GSS_S_CONTINUE_NEEDED) {
 		if (spnego_ctx != NULL) {
 			gss_delete_sec_context(&tmpmin,
@@ -1344,7 +1338,7 @@ acc_ctx_hints(OM_uint32 *minor_status,
 	if (ret != GSS_S_COMPLETE)
 		goto cleanup;
 
-	sc = create_spnego_ctx();
+	sc = create_spnego_ctx(0);
 	if (sc == NULL) {
 		ret = GSS_S_FAILURE;
 		goto cleanup;
@@ -1426,7 +1420,7 @@ acc_ctx_new(OM_uint32 *minor_status,
 		gss_release_buffer(&tmpmin, &sc->DER_mechTypes);
 		assert(mech_wanted != GSS_C_NO_OID);
 	} else
-		sc = create_spnego_ctx();
+		sc = create_spnego_ctx(0);
 	if (sc == NULL) {
 		ret = GSS_S_FAILURE;
 		*return_token = NO_TOKEN_SEND;
@@ -1809,13 +1803,12 @@ cleanup:
 			ret = GSS_S_FAILURE;
 	}
 	if (ret == GSS_S_COMPLETE) {
-		*context_handle = (gss_ctx_id_t)sc->ctx_handle;
+		sc->opened = 1;
 		if (sc->internal_name != GSS_C_NO_NAME &&
 		    src_name != NULL) {
 			*src_name = sc->internal_name;
 			sc->internal_name = GSS_C_NO_NAME;
 		}
-		release_spnego_ctx(&sc);
 	} else if (ret != GSS_S_CONTINUE_NEEDED) {
 		if (sc != NULL) {
 			gss_delete_sec_context(&tmpmin, &sc->ctx_handle,
@@ -2128,8 +2121,13 @@ spnego_gss_unwrap(
 		gss_qop_t *qop_state)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_unwrap(minor_status,
-			context_handle,
+			sc->ctx_handle,
 			input_message_buffer,
 			output_message_buffer,
 			conf_state,
@@ -2149,8 +2147,13 @@ spnego_gss_wrap(
 		gss_buffer_t output_message_buffer)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_wrap(minor_status,
-		    context_handle,
+		    sc->ctx_handle,
 		    conf_req_flag,
 		    qop_req,
 		    input_message_buffer,
@@ -2167,8 +2170,14 @@ spnego_gss_process_context_token(
 				const gss_buffer_t token_buffer)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	/* SPNEGO doesn't have its own context tokens. */
+	if (!sc->opened)
+		return (GSS_S_DEFECTIVE_TOKEN);
+
 	ret = gss_process_context_token(minor_status,
-					context_handle,
+					sc->ctx_handle,
 					token_buffer);
 
 	return (ret);
@@ -2192,19 +2201,9 @@ spnego_gss_delete_sec_context(
 	if (*ctx == NULL)
 		return (GSS_S_COMPLETE);
 
-	/*
-	 * If this is still an SPNEGO mech, release it locally.
-	 */
-	if ((*ctx)->magic_num == SPNEGO_MAGIC_ID) {
-		(void) gss_delete_sec_context(minor_status,
-				    &(*ctx)->ctx_handle,
-				    output_token);
-		(void) release_spnego_ctx(ctx);
-	} else {
-		ret = gss_delete_sec_context(minor_status,
-				    context_handle,
-				    output_token);
-	}
+	(void) gss_delete_sec_context(minor_status, &(*ctx)->ctx_handle,
+				      output_token);
+	(void) release_spnego_ctx(ctx);
 
 	return (ret);
 }
@@ -2216,8 +2215,13 @@ spnego_gss_context_time(
 			OM_uint32	*time_rec)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_context_time(minor_status,
-			    context_handle,
+			    sc->ctx_handle,
 			    time_rec);
 	return (ret);
 }
@@ -2229,9 +2233,20 @@ spnego_gss_export_sec_context(
 			    gss_buffer_t interprocess_token)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = *(spnego_gss_ctx_id_t *)context_handle;
+
+	/* We don't currently support exporting partially established
+	 * contexts. */
+	if (!sc->opened)
+		return GSS_S_UNAVAILABLE;
+
 	ret = gss_export_sec_context(minor_status,
-				    context_handle,
+				    &sc->ctx_handle,
 				    interprocess_token);
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT) {
+		release_spnego_ctx(&sc);
+		*context_handle = GSS_C_NO_CONTEXT;
+	}
 	return (ret);
 }
 
@@ -2241,11 +2256,12 @@ spnego_gss_import_sec_context(
 	const gss_buffer_t	interprocess_token,
 	gss_ctx_id_t		*context_handle)
 {
-	OM_uint32 ret;
-	ret = gss_import_sec_context(minor_status,
-				    interprocess_token,
-				    context_handle);
-	return (ret);
+	/*
+	 * Until we implement partial context exports, there are no SPNEGO
+	 * exported context tokens, only tokens for underlying mechs.  So just
+	 * return an error for now.
+	 */
+	return GSS_S_UNAVAILABLE;
 }
 #endif /* LEAN_CLIENT */
 
@@ -2262,16 +2278,48 @@ spnego_gss_inquire_context(
 			int		*opened)
 {
 	OM_uint32 ret = GSS_S_COMPLETE;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (src_name != NULL)
+		*src_name = GSS_C_NO_NAME;
+	if (targ_name != NULL)
+		*targ_name = GSS_C_NO_NAME;
+	if (lifetime_rec != NULL)
+		*lifetime_rec = 0;
+	if (mech_type != NULL)
+		*mech_type = (gss_OID)gss_mech_spnego;
+	if (ctx_flags != NULL)
+		*ctx_flags = 0;
+	if (locally_initiated != NULL)
+		*locally_initiated = sc->initiate;
+	if (opened != NULL)
+		*opened = sc->opened;
+
+	if (sc->ctx_handle != GSS_C_NO_CONTEXT) {
+		ret = gss_inquire_context(minor_status, sc->ctx_handle,
+					  src_name, targ_name, lifetime_rec,
+					  mech_type, ctx_flags, NULL, NULL);
+	}
 
-	ret = gss_inquire_context(minor_status,
-				context_handle,
-				src_name,
-				targ_name,
-				lifetime_rec,
-				mech_type,
-				ctx_flags,
-				locally_initiated,
-				opened);
+	if (!sc->opened) {
+		/*
+		 * We are still doing SPNEGO negotiation, so report SPNEGO as
+		 * the OID.  After negotiation is complete we will report the
+		 * underlying mechanism OID.
+		 */
+		if (mech_type != NULL)
+			*mech_type = (gss_OID)gss_mech_spnego;
+
+		/*
+		 * Remove flags we don't support with partially-established
+		 * contexts.  (Change this to keep GSS_C_TRANS_FLAG if we add
+		 * support for exporting partial SPNEGO contexts.)
+		 */
+		if (ctx_flags != NULL) {
+			*ctx_flags &= ~GSS_C_PROT_READY_FLAG;
+			*ctx_flags &= ~GSS_C_TRANS_FLAG;
+		}
+	}
 
 	return (ret);
 }
@@ -2286,8 +2334,13 @@ spnego_gss_wrap_size_limit(
 	OM_uint32	*max_input_size)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_wrap_size_limit(minor_status,
-				context_handle,
+				sc->ctx_handle,
 				conf_req_flag,
 				qop_req,
 				req_output_size,
@@ -2304,8 +2357,13 @@ spnego_gss_get_mic(
 		gss_buffer_t message_token)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_get_mic(minor_status,
-		    context_handle,
+		    sc->ctx_handle,
 		    qop_req,
 		    message_buffer,
 		    message_token);
@@ -2321,8 +2379,13 @@ spnego_gss_verify_mic(
 		gss_qop_t *qop_state)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_verify_mic(minor_status,
-			    context_handle,
+			    sc->ctx_handle,
 			    msg_buffer,
 			    token_buffer,
 			    qop_state);
@@ -2337,8 +2400,14 @@ spnego_gss_inquire_sec_context_by_oid(
 		gss_buffer_set_t *data_set)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	/* There are no SPNEGO-specific OIDs for this function. */
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_UNAVAILABLE);
+
 	ret = gss_inquire_sec_context_by_oid(minor_status,
-			    context_handle,
+			    sc->ctx_handle,
 			    desired_object,
 			    data_set);
 	return (ret);
@@ -2407,8 +2476,15 @@ spnego_gss_set_sec_context_option(
 		const gss_buffer_t value)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)*context_handle;
+
+	/* There are no SPNEGO-specific OIDs for this function, and we cannot
+	 * construct an empty SPNEGO context with it. */
+	if (sc == NULL || sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_UNAVAILABLE);
+
 	ret = gss_set_sec_context_option(minor_status,
-			    context_handle,
+			    &sc->ctx_handle,
 			    desired_object,
 			    value);
 	return (ret);
@@ -2425,8 +2501,13 @@ spnego_gss_wrap_aead(OM_uint32 *minor_status,
 		     gss_buffer_t output_message_buffer)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_wrap_aead(minor_status,
-			    context_handle,
+			    sc->ctx_handle,
 			    conf_req_flag,
 			    qop_req,
 			    input_assoc_buffer,
@@ -2447,8 +2528,13 @@ spnego_gss_unwrap_aead(OM_uint32 *minor_status,
 		       gss_qop_t *qop_state)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_unwrap_aead(minor_status,
-			      context_handle,
+			      sc->ctx_handle,
 			      input_message_buffer,
 			      input_assoc_buffer,
 			      output_payload_buffer,
@@ -2467,8 +2553,13 @@ spnego_gss_wrap_iov(OM_uint32 *minor_status,
 		    int iov_count)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_wrap_iov(minor_status,
-			   context_handle,
+			   sc->ctx_handle,
 			   conf_req_flag,
 			   qop_req,
 			   conf_state,
@@ -2486,8 +2577,13 @@ spnego_gss_unwrap_iov(OM_uint32 *minor_status,
 		      int iov_count)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_unwrap_iov(minor_status,
-			     context_handle,
+			     sc->ctx_handle,
 			     conf_state,
 			     qop_state,
 			     iov,
@@ -2505,8 +2601,13 @@ spnego_gss_wrap_iov_length(OM_uint32 *minor_status,
 			   int iov_count)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_wrap_iov_length(minor_status,
-				  context_handle,
+				  sc->ctx_handle,
 				  conf_req_flag,
 				  qop_req,
 				  conf_state,
@@ -2523,8 +2624,13 @@ spnego_gss_complete_auth_token(
 		gss_buffer_t input_message_buffer)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_UNAVAILABLE);
+
 	ret = gss_complete_auth_token(minor_status,
-				      context_handle,
+				      sc->ctx_handle,
 				      input_message_buffer);
 	return (ret);
 }
@@ -2776,8 +2882,13 @@ spnego_gss_pseudo_random(OM_uint32 *minor_status,
 			 gss_buffer_t prf_out)
 {
 	OM_uint32 ret;
+	spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context;
+
+	if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+		return (GSS_S_NO_CONTEXT);
+
 	ret = gss_pseudo_random(minor_status,
-				context,
+				sc->ctx_handle,
 				prf_key,
 				prf_in,
 				desired_output_len,
@@ -2918,7 +3029,12 @@ spnego_gss_get_mic_iov(OM_uint32 *minor_status, gss_ctx_id_t context_handle,
 		       gss_qop_t qop_req, gss_iov_buffer_desc *iov,
 		       int iov_count)
 {
-    return gss_get_mic_iov(minor_status, context_handle, qop_req, iov,
+    spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+    if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+	    return (GSS_S_NO_CONTEXT);
+
+    return gss_get_mic_iov(minor_status, sc->ctx_handle, qop_req, iov,
 			   iov_count);
 }
 
@@ -2927,7 +3043,12 @@ spnego_gss_verify_mic_iov(OM_uint32 *minor_status, gss_ctx_id_t context_handle,
 			  gss_qop_t *qop_state, gss_iov_buffer_desc *iov,
 			  int iov_count)
 {
-    return gss_verify_mic_iov(minor_status, context_handle, qop_state, iov,
+    spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+    if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+	    return (GSS_S_NO_CONTEXT);
+
+    return gss_verify_mic_iov(minor_status, sc->ctx_handle, qop_state, iov,
 			      iov_count);
 }
 
@@ -2936,7 +3057,12 @@ spnego_gss_get_mic_iov_length(OM_uint32 *minor_status,
 			      gss_ctx_id_t context_handle, gss_qop_t qop_req,
 			      gss_iov_buffer_desc *iov, int iov_count)
 {
-    return gss_get_mic_iov_length(minor_status, context_handle, qop_req, iov,
+    spnego_gss_ctx_id_t sc = (spnego_gss_ctx_id_t)context_handle;
+
+    if (sc->ctx_handle == GSS_C_NO_CONTEXT)
+	    return (GSS_S_NO_CONTEXT);
+
+    return gss_get_mic_iov_length(minor_status, sc->ctx_handle, qop_req, iov,
 				  iov_count);
 }