-
Notifications
You must be signed in to change notification settings - Fork 1
/
Copy pathsession-continuation-spec.lyx
1973 lines (1458 loc) · 37.6 KB
/
session-continuation-spec.lyx
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
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#LyX 2.0 created this file. For more info see http://www.lyx.org/
\lyxformat 413
\begin_document
\begin_header
\textclass docbook
\use_default_options true
\maintain_unincluded_children false
\begin_local_layout
Format 31
InsetLayout Flex:PI_Strict
LyXType Custom
HTMLTag div
LabelString PI_Strict
End
InsetLayout Flex:PI
LyXType Custom
HTMLTag div
LabelString PI
End
InsetLayout Flex:PI_SymRefs
LyXType Custom
HTMLTag div
LabelString PI_SymRefs
End
InsetLayout Flex:PI_SortRefs
LyXType Custom
HTMLTag div
LabelString PI_SortRefs
End
InsetLayout Flex:PI_TOC
LyXType Custom
HTMLTag div
LabelString PI_TOC
End
InsetLayout Flex:PI_TOCIndent
LyXType Custom
HTMLTag div
LabelString PI_TOCIndent
End
InsetLayout Flex:PI_TOCDepth
LyXType Custom
HTMLTag div
LabelString PI_TOCDepth
End
InsetLayout Flex:PI_TOCNarrow
LyXType Custom
HTMLTag div
LabelString PI_TOCNarrow
End
InsetLayout Flex:PI_TOCCompact
LyXType Custom
HTMLTag div
LabelString PI_TOCCompact
End
InsetLayout Flex:PI_TOCAppendix
LyXType Custom
HTMLTag div
LabelString PI_TOCAppendix
End
InsetLayout Flex:DocName
LyXType Custom
HTMLTag div
LabelString DocName
End
InsetLayout Flex:IntendedStatus
LyXType Custom
HTMLTag div
LabelString IntendedStatus
End
InsetLayout Flex:RFCNumber
LyXType Custom
HTMLTag div
LabelString RFCNumber
End
InsetLayout Flex:IPR
LyXType Custom
HTMLTag div
LabelString IPR
End
InsetLayout Flex:IETFArea
LyXType Custom
HTMLTag div
LabelString IETFArea
End
InsetLayout Flex:IETFWorkingGroup
LyXType Custom
HTMLTag div
LabelString IETFWorkingGroup
End
InsetLayout Flex:XML2RFCKeyword
LyXType Custom
HTMLTag div
LabelString XML2RFCKeyword
End
InsetLayout Flex:TitleAbbrev
LyXType Custom
HTMLTag div
LabelString TitleAbbrev
End
InsetLayout Flex:AuthorRole
LyXType Custom
HTMLTag div
LabelString AuthRole
End
InsetLayout Flex:AuthorInitials
LyXType Custom
HTMLTag div
LabelString AuthInitials
End
InsetLayout Flex:AuthorSurname
LyXType Custom
HTMLTag div
LabelString AuthSurname
End
InsetLayout Flex:AuthorOrg
LyXType Custom
HTMLTag div
LabelString AuthOrg
End
InsetLayout Flex:AuthorOrgAbbrev
LyXType Custom
HTMLTag div
LabelString AuthOrgAbbrev
End
InsetLayout Flex:AuthorEmailAddr
LyXType Custom
HTMLTag div
LabelString AuthEmailAddr
End
InsetLayout Flex:AuthorAddrStreet
LyXType Custom
HTMLTag div
LabelString AuthAddrStreet
End
InsetLayout Flex:AuthorAddrCity
LyXType Custom
HTMLTag div
LabelString AuthAddrCity
End
InsetLayout Flex:AuthorAddrRegion
LyXType Custom
HTMLTag div
LabelString AuthAddrRegion
End
InsetLayout Flex:AuthorAddrCode
LyXType Custom
HTMLTag div
LabelString AuthAddrCode
End
InsetLayout Flex:AuthorAddrCountry
LyXType Custom
HTMLTag div
LabelString AuthAddrCountry
End
InsetLayout Flex:EntityXRef
LyXType Custom
HTMLTag div
LabelString EntityXRef
End
InsetLayout Flex:BibXML
LyXType Custom
HTMLTag div
LabelString BibXML
End
InsetLayout Flex:EmbeddedBibXML
LyXType Custom
HTMLTag div
LabelString EmbeddedBibXML
End
\end_local_layout
\language english
\language_package default
\inputencoding auto
\fontencoding global
\font_roman cmr
\font_sans cmss
\font_typewriter cmtt
\font_default_family ttdefault
\use_non_tex_fonts false
\font_sc false
\font_osf false
\font_sf_scale 100
\font_tt_scale 100
\graphics default
\default_output_format default
\output_sync 0
\bibtex_command default
\index_command default
\paperfontsize default
\spacing single
\use_hyperref false
\papersize default
\use_geometry false
\use_amsmath 1
\use_esint 1
\use_mhchem 1
\use_mathdots 1
\cite_engine basic
\use_bibtopic false
\use_indices false
\paperorientation portrait
\suppress_date false
\use_refstyle 0
\index Index
\shortcut idx
\color #008000
\end_index
\secnumdepth 3
\tocdepth 3
\paragraph_separation indent
\paragraph_indentation default
\quotes_language english
\papercolumns 1
\papersides 1
\paperpagestyle default
\tracking_changes false
\output_changes false
\html_math_output 0
\html_css_as_file 0
\html_be_strict false
\end_header
\begin_body
\begin_layout Title
Hypertext Transport Protocol (HTTP) Session Continuation Protocol
\end_layout
\begin_layout Standard
\begin_inset Flex DocName
status open
\begin_layout Plain Layout
draft-williams-websec-session-continue-proto-00
\end_layout
\end_inset
\begin_inset Flex IPR
status open
\begin_layout Plain Layout
trust200902
\end_layout
\end_inset
\begin_inset Flex IntendedStatus
status open
\begin_layout Plain Layout
std
\end_layout
\end_inset
\begin_inset Flex TitleAbbrev
status open
\begin_layout Plain Layout
HTTP Session Problem
\end_layout
\end_inset
\begin_inset Flex IETFArea
status open
\begin_layout Plain Layout
Security Area
\end_layout
\end_inset
\begin_inset Flex XML2RFCKeyword
status open
\begin_layout Plain Layout
Internet-Draft
\end_layout
\end_inset
\begin_inset Flex PI
status open
\begin_layout Plain Layout
tocindent="no"
\end_layout
\end_inset
\begin_inset Flex PI
status open
\begin_layout Plain Layout
comments="yes"
\end_layout
\end_inset
\begin_inset Flex PI
status open
\begin_layout Plain Layout
inline="yes"
\end_layout
\end_inset
\end_layout
\begin_layout Author
Nicolas Williams
\begin_inset Flex AuthorOrg
status open
\begin_layout Plain Layout
Cryptonector, LLC
\end_layout
\end_inset
\begin_inset Flex AuthorOrgAbbrev
status open
\begin_layout Plain Layout
Cryptonector
\end_layout
\end_inset
\begin_inset Flex AuthorEmailAddr
status open
\begin_layout Plain Layout
\end_layout
\end_inset
\end_layout
\begin_layout Abstract
One of the most often talked about problems in web security is
\begin_inset Quotes eld
\end_inset
cookies
\begin_inset Quotes erd
\end_inset
.
Web cookies are a method of associating requests with
\begin_inset Quotes eld
\end_inset
sessions
\begin_inset Quotes erd
\end_inset
that may have been authenticated somehow.
Cookies are a form of bearer token that leave much to be desired.
This document proposes a session
\begin_inset Quotes eld
\end_inset
continuation
\begin_inset Quotes erd
\end_inset
protocol for HyperText Transport Protocol (HTTP).
\end_layout
\begin_layout Standard
\begin_inset CommandInset toc
LatexCommand tableofcontents
\end_inset
\end_layout
\begin_layout Section
\begin_inset CommandInset label
LatexCommand label
name "sec:Introduction"
\end_inset
Introduction
\end_layout
\begin_layout Standard
The motivation for this protocol is described in
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
I-D.williams-websec-session-continue-prob
\end_layout
\end_inset
.
\end_layout
\begin_layout Standard
We define a protocol for cryptographic
\begin_inset Quotes eld
\end_inset
session continuation
\begin_inset Quotes erd
\end_inset
for HyperText Transport Protocol (HTTP)
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
RFC2616
\end_layout
\end_inset
.
Session continuation is the act of binding an HTTP request to a
\begin_inset Quotes eld
\end_inset
session
\begin_inset Quotes erd
\end_inset
.
A
\begin_inset Quotes eld
\end_inset
session
\begin_inset Quotes erd
\end_inset
consists of all the HTTP requests by a given user (possibly an authenticated
user, or possibly an anonymous user).
This protocol is a cryptographic protocol that aims to meet all the requirement
s given in
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
I-D.williams-websec-session-continue-prob
\end_layout
\end_inset
.
\end_layout
\begin_layout Standard
The protocol consists of:
\end_layout
\begin_layout Itemize
a request header carrying a keyed Message Authentication Code (MAC) that
proves possession of a shared session key (shared between the user and
the server);
\end_layout
\begin_layout Itemize
a response header advertising a default session scope to clients;
\end_layout
\begin_layout Itemize
a session identification in the form of a URI;
\end_layout
\begin_layout Itemize
an optional facility for server-side statelessness by storing state on the
client-side, encrypted in a secret key known to the server;
\end_layout
\begin_layout Itemize
a request header for requesting the establishment of a session;
\end_layout
\begin_layout Itemize
a response header for indicating the establishment of a session, and including
a session URI and any optional state to be repeated by the client.
\end_layout
\begin_layout Subsection
Conventions used in this document
\end_layout
\begin_layout Standard
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are
to be interpreted as described in
\begin_inset Flex EntityXRef
status open
\begin_layout Plain Layout
RFC2119
\end_layout
\end_inset
.
\end_layout
\begin_layout Section
Session Keying
\end_layout
\begin_layout Standard
There are two methods for keying an HTTP session:
\end_layout
\begin_layout Itemize
session keys are output by HTTP authentication;
\end_layout
\begin_layout Itemize
or session keys are asserted by the client or the server;
\end_layout
\begin_layout Standard
For the key assertion method TLS with confidentiality protection is clearly
REQUIRED for security.
We've considered the possibility of using Diffie-Hellman key agreement
or RSA key transport, but as that would duplicate functionality that is
in TLS we consider that out of scope for the time being.
\end_layout
\begin_layout Standard
In either case a single session key is produced, and that is the only key
utilized.
Having a single key helps reduce session state size and protocol complexity,
but we must (and do) distinguish key usage by prefixing a purpose indicator
to the MAC input.
\end_layout
\begin_layout Standard
When keys are output by HTTP authentication there may be a key length mismatch.
In this case a Key Derivation Function (KDF)
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
RFC5869
\end_layout
\end_inset
is applied to generate the session key.
\end_layout
\begin_layout RevisionRemark
We could also use the TLS extractor to generate keys, but that would be
an unnecessary complication and would provide very little additional value.
Channel binding is achieved per-RFCs 5056 and 5929.
\end_layout
\begin_layout RevisionRemark
Should we have distinct session keys for request and response MACs? Probably,
but it increases state size.
Better to add a direction indicator to the MAC plaintext.
\end_layout
\begin_layout Subsection
Mixing HTTP and HTTPS
\end_layout
\begin_layout Standard
We expect that many sites will continue to mix HTTP and HTTPS for various
reasons.
To make this possible the MAC input will include a marker indicating HTTP
or HTTPS.
\end_layout
\begin_layout Subsection
Authenticated Session Keying
\end_layout
\begin_layout Standard
When an HTTP client uses HTTP authentication, and the authentication mechanism
used can establish a session key, then the client SHOULD request session
initiation using a shared session key output by the HTTP authentication
mechanism.
The client MUST send the session initiation header concurrently with the
last HTTP authentication message.
\end_layout
\begin_layout Subsubsection
HTTP/Negotiate Session Keying
\end_layout
\begin_layout RevisionRemark
Write text explaining how to use the GSS PRF to exchange keys when using
HTTP/Negotiate
\end_layout
\begin_layout Subsubsection
Digest
\end_layout
\begin_layout RevisionRemark
Digest could output a session key.
Do we want to bother? (Basic certainly can't, or we'd not want it to anyways.)
\end_layout
\begin_layout Subsection
Unauthenticated Session Keying
\end_layout
\begin_layout Standard
Sessions for unauthenticated users may appear to make little sense at first.
This is useful, for example, and just as web cookies are, for tracking
\begin_inset Quotes eld
\end_inset
shopping carts
\begin_inset Quotes erd
\end_inset
when a user is window shopping, so to speak.
\end_layout
\begin_layout Standard
For unauthenticated session initiation the client merely requests the creation
of a session with an asserted session key, for lack of a better choice.
\end_layout
\begin_layout Section
Session Initiation
\end_layout
\begin_layout Standard
Sessions are always initiated by the client by including a Session-Init
header in the client's request carrying the client's proposal for a session.
\end_layout
\begin_layout Standard
Servers that support sessions will respond by creating a session and returning
a session ID URI.
\end_layout
\begin_layout Standard
The Session-Init proposal header's value consists of a comma-separated list
of proposal parameters:
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
session-param = token "=" ( token | quoted-string )
\end_layout
\begin_layout Plain Layout
Session-Init = 1#session-param
\end_layout
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption
\begin_layout Plain Layout
Session-Init request header
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Standard
The following session parameters are defined:
\end_layout
\begin_layout Description
Key-Method The type of keying:
\begin_inset Quotes eld
\end_inset
auth
\begin_inset Quotes erd
\end_inset
(key will be output by HTTP authentication),
\begin_inset Quotes eld
\end_inset
c-assert
\begin_inset Quotes erd
\end_inset
(key is asserted in this Session-Init) or
\begin_inset Quotes eld
\end_inset
s-assert
\begin_inset Quotes erd
\end_inset
(the server is expected to assert a key).
In the
\begin_inset Quotes eld
\end_inset
auth
\begin_inset Quotes erd
\end_inset
case the Session-Init MUST also carry a nonce and a MAC.
This session-param MUST be present.
\end_layout
\begin_layout Description
Key The key that the client asserts, if the client asserts a key (Key-Method=c-a
ssert).
This may also be included when Key-Method is
\begin_inset Quotes eld
\end_inset
auth
\begin_inset Quotes erd
\end_inset
in case the server's implementation of HTTP authentication does not output
a key, but only when using HTTPS.
\end_layout
\begin_layout Description
Key-Length The length of the master session key, as a count of key bits,
in base-10.
The value MUST NOT be less than 96 or larger than 256.
If absent the key length SHALL be 128 bits.
\end_layout
\begin_layout Description
MAC-Algs The MAC algorithms supported by the client.
This document defines only
\begin_inset Quotes eld
\end_inset
HMAC-SHA-1
\begin_inset Quotes erd
\end_inset
(HMAC with SHA-1),
\begin_inset Quotes eld
\end_inset
HMAC-SHA-1-96
\begin_inset Quotes erd
\end_inset
(HMAC with SHA-1 and truncation to 96 bits),
\begin_inset Quotes eld
\end_inset
HMAC-SHA256
\begin_inset Quotes erd
\end_inset
(HMAC with SHA256), and
\begin_inset Quotes eld
\end_inset
HMAC-SHA256-128
\begin_inset Quotes erd
\end_inset
(HMAC with SHA256 and truncation to 128 bits).
All of these use HMAC
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
RFC2104
\end_layout
\end_inset
.
Clients and servers MUST support HMAC-SHA-1-96 and HMAC-SHA256-128.
If absent the default value is
\begin_inset Quotes eld
\end_inset
HMAC-SHA256-128
\begin_inset Quotes erd
\end_inset
.
\end_layout
\begin_layout Description
KDF-Algs A list of KDF algorithms.
This is needed only when Key-Method is
\begin_inset Quotes eld
\end_inset
auth
\begin_inset Quotes erd
\end_inset
.
The following are specified here:
\begin_inset Quotes eld
\end_inset
HKDF-SHA-1
\begin_inset Quotes erd
\end_inset
(HKDF
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
RFC5869
\end_layout
\end_inset
with SHA-1) and
\begin_inset Quotes eld
\end_inset
HKDF-SHA256
\begin_inset Quotes erd
\end_inset
(HKDF with SHA256).
Clients and servers MUST support HKDF-SHA256.
If absent and Key-Method is
\begin_inset Quotes eld
\end_inset
auth
\begin_inset Quotes erd
\end_inset
then the default value is HKDF-SHA256.
\end_layout
\begin_layout Description
Channel-Binding-Types A comma-separated list of channel binding
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
RFC5056
\end_layout
\end_inset
types.
Clients and servers MUST support 'tls-server-end-point'
\begin_inset Flex EntityXRef
status collapsed
\begin_layout Plain Layout
RFC5929
\end_layout
\end_inset
when using HTTPS.
(Note the need to use quoted-string when the list has more than one item.)
If absent the default is 'tls-server-end-point'.
\end_layout
\begin_layout Description
Nonce A 128-bit nonce, base64-encoded.
This session-param MUST be present.
\end_layout
\begin_layout Description
Previous-Session-URI The URI of a previous session.
See
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Unauthenticated-to-Authenticated"
\end_inset
.
\end_layout
\begin_layout Description
Previous-Session-State The session state for the previous session, if any.
See
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Unauthenticated-to-Authenticated"
\end_inset
.
\end_layout
\begin_layout Description
Unprotected-Allowed If present the value MUST be
\begin_inset Quotes eld
\end_inset
true
\begin_inset Quotes erd
\end_inset
, and indicates that HTTP and HTTPS are both allowed for this session.
Otherwise only HTTPS is allowed for this session.
\end_layout
\begin_layout Standard
The server responds with a Session-Assign header:
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\begin_inset listings
inline false
status open
\begin_layout Plain Layout