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47257438 AC |
1 | ------------------------------------------------------------------------------ |
2 | -- -- | |
fed1bd44 | 3 | -- GNAT LIBRARY COMPONENTS -- |
47257438 | 4 | -- -- |
36e76408 | 5 | -- G N A T . S E C U R E _ H A S H E S -- |
47257438 AC |
6 | -- -- |
7 | -- B o d y -- | |
8 | -- -- | |
4b490c1e | 9 | -- Copyright (C) 2009-2020, Free Software Foundation, Inc. -- |
47257438 AC |
10 | -- -- |
11 | -- GNAT is free software; you can redistribute it and/or modify it under -- | |
12 | -- terms of the GNU General Public License as published by the Free Soft- -- | |
13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- | |
14 | -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- | |
15 | -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
16 | -- or FITNESS FOR A PARTICULAR PURPOSE. -- | |
17 | -- -- | |
18 | -- As a special exception under Section 7 of GPL version 3, you are granted -- | |
19 | -- additional permissions described in the GCC Runtime Library Exception, -- | |
20 | -- version 3.1, as published by the Free Software Foundation. -- | |
21 | -- -- | |
22 | -- You should have received a copy of the GNU General Public License and -- | |
23 | -- a copy of the GCC Runtime Library Exception along with this program; -- | |
24 | -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- | |
25 | -- <http://www.gnu.org/licenses/>. -- | |
26 | -- -- | |
27 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
28 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- | |
29 | -- -- | |
30 | ------------------------------------------------------------------------------ | |
31 | ||
32 | with System; use System; | |
33 | with Interfaces; use Interfaces; | |
34 | ||
36e76408 | 35 | package body GNAT.Secure_Hashes is |
47257438 | 36 | |
47257438 | 37 | Hex_Digit : constant array (Stream_Element range 0 .. 15) of Character := |
2546734c | 38 | "0123456789abcdef"; |
47257438 AC |
39 | |
40 | type Fill_Buffer_Access is | |
41 | access procedure | |
42 | (M : in out Message_State; | |
43 | S : String; | |
44 | First : Natural; | |
45 | Last : out Natural); | |
eaf18088 AC |
46 | -- A procedure to transfer data from S, starting at First, into M's block |
47 | -- buffer until either the block buffer is full or all data from S has been | |
48 | -- consumed. | |
47257438 AC |
49 | |
50 | procedure Fill_Buffer_Copy | |
51 | (M : in out Message_State; | |
52 | S : String; | |
53 | First : Natural; | |
54 | Last : out Natural); | |
55 | -- Transfer procedure which just copies data from S to M | |
56 | ||
57 | procedure Fill_Buffer_Swap | |
58 | (M : in out Message_State; | |
59 | S : String; | |
60 | First : Natural; | |
61 | Last : out Natural); | |
eaf18088 AC |
62 | -- Transfer procedure which swaps bytes from S when copying into M. S must |
63 | -- have even length. Note that the swapping is performed considering pairs | |
64 | -- starting at S'First, even if S'First /= First (that is, if | |
65 | -- First = S'First then the first copied byte is always S (S'First + 1), | |
66 | -- and if First = S'First + 1 then the first copied byte is always | |
67 | -- S (S'First). | |
47257438 AC |
68 | |
69 | procedure To_String (SEA : Stream_Element_Array; S : out String); | |
70 | -- Return the hexadecimal representation of SEA | |
71 | ||
72 | ---------------------- | |
73 | -- Fill_Buffer_Copy -- | |
74 | ---------------------- | |
75 | ||
76 | procedure Fill_Buffer_Copy | |
77 | (M : in out Message_State; | |
78 | S : String; | |
79 | First : Natural; | |
80 | Last : out Natural) | |
81 | is | |
82 | Buf_String : String (M.Buffer'Range); | |
83 | for Buf_String'Address use M.Buffer'Address; | |
84 | pragma Import (Ada, Buf_String); | |
9cf032ef | 85 | |
47257438 | 86 | Length : constant Natural := |
9cf032ef RD |
87 | Natural'Min (M.Block_Length - M.Last, S'Last - First + 1); |
88 | ||
47257438 AC |
89 | begin |
90 | pragma Assert (Length > 0); | |
91 | ||
92 | Buf_String (M.Last + 1 .. M.Last + Length) := | |
9fe2f33e | 93 | S (First .. First + Length - 1); |
47257438 AC |
94 | M.Last := M.Last + Length; |
95 | Last := First + Length - 1; | |
96 | end Fill_Buffer_Copy; | |
97 | ||
98 | ---------------------- | |
99 | -- Fill_Buffer_Swap -- | |
100 | ---------------------- | |
101 | ||
102 | procedure Fill_Buffer_Swap | |
103 | (M : in out Message_State; | |
104 | S : String; | |
105 | First : Natural; | |
106 | Last : out Natural) | |
107 | is | |
eaf18088 | 108 | pragma Assert (S'Length mod 2 = 0); |
47257438 AC |
109 | Length : constant Natural := |
110 | Natural'Min (M.Block_Length - M.Last, S'Last - First + 1); | |
111 | begin | |
112 | Last := First; | |
113 | while Last - First < Length loop | |
114 | M.Buffer (M.Last + 1 + Last - First) := | |
eaf18088 AC |
115 | (if (Last - S'First) mod 2 = 0 |
116 | then S (Last + 1) | |
117 | else S (Last - 1)); | |
47257438 AC |
118 | Last := Last + 1; |
119 | end loop; | |
120 | M.Last := M.Last + Length; | |
121 | Last := First + Length - 1; | |
122 | end Fill_Buffer_Swap; | |
123 | ||
124 | --------------- | |
125 | -- To_String -- | |
126 | --------------- | |
127 | ||
128 | procedure To_String (SEA : Stream_Element_Array; S : out String) is | |
129 | pragma Assert (S'Length = 2 * SEA'Length); | |
130 | begin | |
131 | for J in SEA'Range loop | |
132 | declare | |
133 | S_J : constant Natural := 1 + Natural (J - SEA'First) * 2; | |
134 | begin | |
135 | S (S_J) := Hex_Digit (SEA (J) / 16); | |
136 | S (S_J + 1) := Hex_Digit (SEA (J) mod 16); | |
137 | end; | |
138 | end loop; | |
139 | end To_String; | |
140 | ||
141 | ------- | |
142 | -- H -- | |
143 | ------- | |
144 | ||
145 | package body H is | |
146 | ||
147 | procedure Update | |
148 | (C : in out Context; | |
149 | S : String; | |
150 | Fill_Buffer : Fill_Buffer_Access); | |
151 | -- Internal common routine for all Update procedures | |
152 | ||
153 | procedure Final | |
154 | (C : Context; | |
155 | Hash_Bits : out Ada.Streams.Stream_Element_Array); | |
156 | -- Perform final hashing operations (data padding) and extract the | |
157 | -- (possibly truncated) state of C into Hash_Bits. | |
158 | ||
159 | ------------ | |
160 | -- Digest -- | |
161 | ------------ | |
162 | ||
163 | function Digest (C : Context) return Message_Digest is | |
164 | Hash_Bits : Stream_Element_Array | |
165 | (1 .. Stream_Element_Offset (Hash_Length)); | |
166 | begin | |
167 | Final (C, Hash_Bits); | |
168 | return MD : Message_Digest do | |
169 | To_String (Hash_Bits, MD); | |
170 | end return; | |
171 | end Digest; | |
172 | ||
47257438 AC |
173 | function Digest (S : String) return Message_Digest is |
174 | C : Context; | |
175 | begin | |
176 | Update (C, S); | |
177 | return Digest (C); | |
178 | end Digest; | |
179 | ||
47257438 AC |
180 | function Digest (A : Stream_Element_Array) return Message_Digest is |
181 | C : Context; | |
182 | begin | |
183 | Update (C, A); | |
184 | return Digest (C); | |
185 | end Digest; | |
186 | ||
59a9c170 PO |
187 | function Digest (C : Context) return Binary_Message_Digest is |
188 | Hash_Bits : Stream_Element_Array | |
189 | (1 .. Stream_Element_Offset (Hash_Length)); | |
190 | begin | |
191 | Final (C, Hash_Bits); | |
192 | return Hash_Bits; | |
193 | end Digest; | |
194 | ||
195 | function Digest (S : String) return Binary_Message_Digest is | |
196 | C : Context; | |
197 | begin | |
198 | Update (C, S); | |
199 | return Digest (C); | |
200 | end Digest; | |
201 | ||
202 | function Digest | |
203 | (A : Stream_Element_Array) return Binary_Message_Digest | |
204 | is | |
205 | C : Context; | |
206 | begin | |
207 | Update (C, A); | |
208 | return Digest (C); | |
209 | end Digest; | |
210 | ||
47257438 AC |
211 | ----------- |
212 | -- Final -- | |
213 | ----------- | |
214 | ||
061bc17d AC |
215 | -- Once a complete message has been processed, it is padded with one 1 |
216 | -- bit followed by enough 0 bits so that the last block is 2 * Word'Size | |
217 | -- bits short of being completed. The last 2 * Word'Size bits are set to | |
218 | -- the message size in bits (excluding padding). | |
47257438 AC |
219 | |
220 | procedure Final | |
4ff2b6dc AC |
221 | (C : Context; |
222 | Hash_Bits : out Stream_Element_Array) | |
47257438 AC |
223 | is |
224 | FC : Context := C; | |
225 | ||
226 | Zeroes : Natural; | |
227 | -- Number of 0 bytes in padding | |
228 | ||
229 | Message_Length : Unsigned_64 := FC.M_State.Length; | |
230 | -- Message length in bytes | |
231 | ||
232 | Size_Length : constant Natural := | |
233 | 2 * Hash_State.Word'Size / 8; | |
234 | -- Length in bytes of the size representation | |
235 | ||
236 | begin | |
237 | Zeroes := (Block_Length - 1 - Size_Length - FC.M_State.Last) | |
238 | mod FC.M_State.Block_Length; | |
239 | declare | |
240 | Pad : String (1 .. 1 + Zeroes + Size_Length) := | |
241 | (1 => Character'Val (128), others => ASCII.NUL); | |
9cf032ef RD |
242 | |
243 | Index : Natural; | |
47257438 | 244 | First_Index : Natural; |
9cf032ef | 245 | |
47257438 | 246 | begin |
9cf032ef RD |
247 | First_Index := (if Hash_Bit_Order = Low_Order_First |
248 | then Pad'Last - Size_Length + 1 | |
249 | else Pad'Last); | |
47257438 AC |
250 | |
251 | Index := First_Index; | |
252 | while Message_Length > 0 loop | |
253 | if Index = First_Index then | |
9cf032ef | 254 | |
47257438 | 255 | -- Message_Length is in bytes, but we need to store it as |
60aa5228 | 256 | -- a bit count. |
47257438 AC |
257 | |
258 | Pad (Index) := Character'Val | |
259 | (Shift_Left (Message_Length and 16#1f#, 3)); | |
260 | Message_Length := Shift_Right (Message_Length, 5); | |
9cf032ef | 261 | |
47257438 AC |
262 | else |
263 | Pad (Index) := Character'Val (Message_Length and 16#ff#); | |
264 | Message_Length := Shift_Right (Message_Length, 8); | |
265 | end if; | |
9cf032ef | 266 | |
47257438 AC |
267 | Index := Index + |
268 | (if Hash_Bit_Order = Low_Order_First then 1 else -1); | |
269 | end loop; | |
270 | ||
271 | Update (FC, Pad); | |
272 | end; | |
273 | ||
274 | pragma Assert (FC.M_State.Last = 0); | |
275 | ||
276 | Hash_State.To_Hash (FC.H_State, Hash_Bits); | |
4ff2b6dc AC |
277 | |
278 | -- HMAC case: hash outer pad | |
279 | ||
280 | if C.KL /= 0 then | |
281 | declare | |
282 | Outer_C : Context; | |
283 | Opad : Stream_Element_Array := | |
284 | (1 .. Stream_Element_Offset (Block_Length) => 16#5c#); | |
285 | ||
286 | begin | |
287 | for J in C.Key'Range loop | |
288 | Opad (J) := Opad (J) xor C.Key (J); | |
289 | end loop; | |
290 | ||
291 | Update (Outer_C, Opad); | |
292 | Update (Outer_C, Hash_Bits); | |
293 | ||
294 | Final (Outer_C, Hash_Bits); | |
295 | end; | |
296 | end if; | |
47257438 AC |
297 | end Final; |
298 | ||
4ff2b6dc AC |
299 | -------------------------- |
300 | -- HMAC_Initial_Context -- | |
301 | -------------------------- | |
302 | ||
303 | function HMAC_Initial_Context (Key : String) return Context is | |
304 | begin | |
305 | if Key'Length = 0 then | |
306 | raise Constraint_Error with "null key"; | |
307 | end if; | |
308 | ||
309 | return C : Context (KL => (if Key'Length <= Key_Length'Last | |
310 | then Key'Length | |
311 | else Stream_Element_Offset (Hash_Length))) | |
312 | do | |
313 | -- Set Key (if longer than block length, first hash it) | |
314 | ||
315 | if C.KL = Key'Length then | |
316 | declare | |
317 | SK : String (1 .. Key'Length); | |
318 | for SK'Address use C.Key'Address; | |
319 | pragma Import (Ada, SK); | |
320 | begin | |
321 | SK := Key; | |
322 | end; | |
323 | ||
324 | else | |
325 | C.Key := Digest (Key); | |
326 | end if; | |
327 | ||
328 | -- Hash inner pad | |
329 | ||
330 | declare | |
331 | Ipad : Stream_Element_Array := | |
332 | (1 .. Stream_Element_Offset (Block_Length) => 16#36#); | |
333 | ||
334 | begin | |
335 | for J in C.Key'Range loop | |
336 | Ipad (J) := Ipad (J) xor C.Key (J); | |
337 | end loop; | |
338 | ||
339 | Update (C, Ipad); | |
340 | end; | |
341 | end return; | |
342 | end HMAC_Initial_Context; | |
343 | ||
0e77949e AC |
344 | ---------- |
345 | -- Read -- | |
346 | ---------- | |
347 | ||
348 | procedure Read | |
349 | (Stream : in out Hash_Stream; | |
350 | Item : out Stream_Element_Array; | |
351 | Last : out Stream_Element_Offset) | |
352 | is | |
353 | pragma Unreferenced (Stream, Item, Last); | |
354 | begin | |
355 | raise Program_Error with "Hash_Stream is write-only"; | |
356 | end Read; | |
357 | ||
47257438 AC |
358 | ------------ |
359 | -- Update -- | |
360 | ------------ | |
361 | ||
362 | procedure Update | |
363 | (C : in out Context; | |
364 | S : String; | |
365 | Fill_Buffer : Fill_Buffer_Access) | |
366 | is | |
4ff2b6dc | 367 | Last : Natural; |
9cf032ef | 368 | |
47257438 AC |
369 | begin |
370 | C.M_State.Length := C.M_State.Length + S'Length; | |
371 | ||
4ff2b6dc | 372 | Last := S'First - 1; |
47257438 AC |
373 | while Last < S'Last loop |
374 | Fill_Buffer (C.M_State, S, Last + 1, Last); | |
375 | ||
376 | if C.M_State.Last = Block_Length then | |
377 | Transform (C.H_State, C.M_State); | |
378 | C.M_State.Last := 0; | |
379 | end if; | |
380 | end loop; | |
47257438 AC |
381 | end Update; |
382 | ||
383 | ------------ | |
384 | -- Update -- | |
385 | ------------ | |
386 | ||
387 | procedure Update (C : in out Context; Input : String) is | |
388 | begin | |
389 | Update (C, Input, Fill_Buffer_Copy'Access); | |
390 | end Update; | |
391 | ||
392 | ------------ | |
393 | -- Update -- | |
394 | ------------ | |
395 | ||
396 | procedure Update (C : in out Context; Input : Stream_Element_Array) is | |
397 | S : String (1 .. Input'Length); | |
398 | for S'Address use Input'Address; | |
399 | pragma Import (Ada, S); | |
400 | begin | |
401 | Update (C, S, Fill_Buffer_Copy'Access); | |
402 | end Update; | |
403 | ||
404 | ----------------- | |
405 | -- Wide_Update -- | |
406 | ----------------- | |
407 | ||
408 | procedure Wide_Update (C : in out Context; Input : Wide_String) is | |
409 | S : String (1 .. 2 * Input'Length); | |
410 | for S'Address use Input'Address; | |
411 | pragma Import (Ada, S); | |
412 | begin | |
413 | Update | |
414 | (C, S, | |
415 | (if System.Default_Bit_Order /= Low_Order_First | |
9cf032ef RD |
416 | then Fill_Buffer_Swap'Access |
417 | else Fill_Buffer_Copy'Access)); | |
47257438 AC |
418 | end Wide_Update; |
419 | ||
420 | ----------------- | |
421 | -- Wide_Digest -- | |
422 | ----------------- | |
423 | ||
424 | function Wide_Digest (W : Wide_String) return Message_Digest is | |
425 | C : Context; | |
426 | begin | |
427 | Wide_Update (C, W); | |
428 | return Digest (C); | |
429 | end Wide_Digest; | |
430 | ||
59a9c170 PO |
431 | function Wide_Digest (W : Wide_String) return Binary_Message_Digest is |
432 | C : Context; | |
433 | begin | |
434 | Wide_Update (C, W); | |
435 | return Digest (C); | |
436 | end Wide_Digest; | |
437 | ||
0e77949e AC |
438 | ----------- |
439 | -- Write -- | |
440 | ----------- | |
441 | ||
442 | procedure Write | |
443 | (Stream : in out Hash_Stream; | |
444 | Item : Stream_Element_Array) | |
445 | is | |
446 | begin | |
447 | Update (Stream.C.all, Item); | |
448 | end Write; | |
449 | ||
47257438 AC |
450 | end H; |
451 | ||
452 | ------------------------- | |
453 | -- Hash_Function_State -- | |
454 | ------------------------- | |
455 | ||
456 | package body Hash_Function_State is | |
457 | ||
458 | ------------- | |
459 | -- To_Hash -- | |
460 | ------------- | |
461 | ||
462 | procedure To_Hash (H : State; H_Bits : out Stream_Element_Array) is | |
463 | Hash_Words : constant Natural := H'Size / Word'Size; | |
9cf032ef RD |
464 | Result : State (1 .. Hash_Words) := |
465 | H (H'Last - Hash_Words + 1 .. H'Last); | |
47257438 AC |
466 | |
467 | R_SEA : Stream_Element_Array (1 .. Result'Size / 8); | |
468 | for R_SEA'Address use Result'Address; | |
469 | pragma Import (Ada, R_SEA); | |
9cf032ef | 470 | |
47257438 AC |
471 | begin |
472 | if System.Default_Bit_Order /= Hash_Bit_Order then | |
473 | for J in Result'Range loop | |
474 | Swap (Result (J)'Address); | |
475 | end loop; | |
476 | end if; | |
477 | ||
478 | -- Return truncated hash | |
479 | ||
480 | pragma Assert (H_Bits'Length <= R_SEA'Length); | |
481 | H_Bits := R_SEA (R_SEA'First .. R_SEA'First + H_Bits'Length - 1); | |
482 | end To_Hash; | |
483 | ||
484 | end Hash_Function_State; | |
485 | ||
36e76408 | 486 | end GNAT.Secure_Hashes; |