This file is indexed.

/usr/share/ada/adainclude/aws/aws-digest.adb is in libaws3.3.2-dev 3.3.2-2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
------------------------------------------------------------------------------
--                              Ada Web Server                              --
--                                                                          --
--                     Copyright (C) 2000-2014, AdaCore                     --
--                                                                          --
--  This library is free software;  you can redistribute it and/or modify   --
--  it under terms of the  GNU General Public License  as published by the  --
--  Free Software  Foundation;  either version 3,  or (at your  option) any --
--  later version. This library is distributed in the hope that it will be  --
--  useful, but WITHOUT ANY WARRANTY;  without even the implied warranty of --
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                    --
--                                                                          --
--  As a special exception under Section 7 of GPL version 3, you are        --
--  granted additional permissions described in the GCC Runtime Library     --
--  Exception, version 3.1, as published by the Free Software Foundation.   --
--                                                                          --
--  You should have received a copy of the GNU General Public License and   --
--  a copy of the GCC Runtime Library Exception along with this program;    --
--  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see   --
--  <http://www.gnu.org/licenses/>.                                         --
--                                                                          --
--  As a special exception, if other files instantiate generics from this   --
--  unit, or you link this unit with other files to produce an executable,  --
--  this  unit  does not  by itself cause  the resulting executable to be   --
--  covered by the GNU General Public License. This exception does not      --
--  however invalidate any other reasons why the executable file  might be  --
--  covered by the  GNU Public License.                                     --
------------------------------------------------------------------------------

pragma Ada_2012;

with Ada.Real_Time;
with Ada.Streams;
with Ada.Strings.Maps.Constants;
with Ada.Unchecked_Conversion;

with AWS.Translator;
with AWS.Utils;

package body AWS.Digest is

   use Ada;
   use Ada.Streams;
   use GNAT;

   Private_Key : MD5.Context;

   type Modular24_Bits is mod 2 ** 24;
   for Modular24_Bits'Size use 24;

   Nonce_Idx : Modular24_Bits := Modular24_Bits'Mod (Utils.Random) with Atomic;

   subtype Timestamp_String is String (1 .. 4);
   --  The timestamp string is a 24 bits Base64 encoded value

   subtype Index_String is String (1 .. 4);
   --  The Nonce string is a 24 bits Base64 encoded value

   Nonce_Expiration : constant := 300;
   --  Expiration expressed in seconds

   subtype Byte_Array_Of_Modular24 is Stream_Element_Array
     (1 .. Modular24_Bits'Size / Stream_Element_Array'Component_Size);

   subtype Byte_Array_Of_Seconds is Stream_Element_Array
     (1 .. Real_Time.Seconds_Count'Size / Stream_Element_Array'Component_Size);

   function To_Byte_Array is
      new Ada.Unchecked_Conversion
            (Real_Time.Seconds_Count, Byte_Array_Of_Seconds);

   function To_Byte_Array is
      new Ada.Unchecked_Conversion (Modular24_Bits, Byte_Array_Of_Modular24);

   function To_Modular24 is
      new Ada.Unchecked_Conversion (Byte_Array_Of_Modular24, Modular24_Bits);

   -----------------
   -- Check_Nonce --
   -----------------

   function Check_Nonce (Value : String) return Boolean is
      use Real_Time;

      subtype Timestamp_Range is
        Positive range Value'First
          .. Value'First + Timestamp_String'Length - 1;

      subtype Index_Range is
        Positive range Timestamp_Range'Last + 1
          .. Timestamp_Range'Last + Index_String'Length;

      subtype Digest_Range is
        Positive range Index_Range'Last + 1
          .. Index_Range'Last + MD5.Message_Digest'Length;

      Time_Dif      : Modular24_Bits;
      Seconds_Now   : Seconds_Count;
      TS            : Time_Span;
      Index_Nonce   : Index_String;
      Seconds_Array : Byte_Array_Of_Modular24;
      Seconds_Nonce : Modular24_Bits;
      Ctx           : MD5.Context;
      Sample        : Digest_String;

   begin
      if Value'Length /= Nonce'Length then
         return False;
      end if;

      --  Check that we have only base64 digits in the timestamp and index
      --  and hex in the digest.

      declare
         use Ada.Strings.Maps;
         Base64_Set : constant Character_Set :=
           To_Set (Character_Range'(Low => 'a', High => 'z'))
           or To_Set (Character_Range'(Low => 'A', High => 'Z'))
           or To_Set (Character_Range'(Low => '0', High => '9'))
           or To_Set ("+/");
      begin
         if not Is_Subset
           (To_Set (Value (Timestamp_Range'First .. Index_Range'Last)),
            Base64_Set)
           or else not
             Is_Subset
               (To_Set (Value (Digest_Range)), Constants.Hexadecimal_Digit_Set)
         then
            return False;
         end if;
      end;

      Split (Clock, Seconds_Now, TS);

      Seconds_Array := Translator.Base64_Decode (Value (Timestamp_Range));
      Seconds_Nonce := To_Modular24 (Seconds_Array);
      Index_Nonce := Value (Index_Range);

      Time_Dif := Modular24_Bits'Mod (Seconds_Now) - Seconds_Nonce;

      if Time_Dif > Nonce_Expiration then
         return False;
      end if;

      Ctx := Private_Key;

      MD5.Update (Ctx, To_Byte_Array (Seconds_Now - Seconds_Count (Time_Dif)));
      MD5.Update (Ctx, Index_Nonce);

      Sample := MD5.Digest (Ctx);

      return Value (Digest_Range) = Sample;
   end Check_Nonce;

   ------------
   -- Create --
   ------------

   function Create
     (Username, Realm, Password : String;
      Nonce, NC, CNonce, QOP    : String;
      Method, URI               : String) return Digest_String is
   begin
      return MD5.Digest
        (MD5.Digest (Username & ':' & Realm & ':' & Password)
           & Tail (Nonce, NC, CNonce, QOP, Method, URI));
   end Create;

   function Create
     (Username, Realm, Password : String;
      Nonce                     : String;
      Method, URI               : String) return Digest_String is
   begin
      return Create
        (Username, Realm, Password, Nonce, "", "", "", Method, URI);
   end Create;

   ------------------
   -- Create_Nonce --
   ------------------

   function Create_Nonce return Nonce is
      use Real_Time;
      Seconds_Now   : Seconds_Count;
      TS            : Time_Span;
      Timestamp_Str : Timestamp_String;
      Index_Str     : Index_String;
      Ctx           : MD5.Context;
   begin
      Split (Clock, Seconds_Now, TS);

      Ctx := Private_Key;

      Nonce_Idx := Nonce_Idx + 1;
      Index_Str := Translator.Base64_Encode (To_Byte_Array (Nonce_Idx));
      Timestamp_Str :=
        Translator.Base64_Encode
          (To_Byte_Array (Modular24_Bits'Mod (Seconds_Now)));

      MD5.Update (Ctx, To_Byte_Array (Seconds_Now));
      MD5.Update (Ctx, Index_Str);

      --  The Nonce result is composed of three parts:
      --  Five Hex Digits : timestamp to check Nonce expiration
      --  Uniq index      : to avoid generating the same Nonce twice
      --  MD5 digest      : the Nonce main MD5 data

      return Nonce (Timestamp_Str & Index_Str & MD5.Digest (Ctx));
   end Create_Nonce;

   ----------
   -- Tail --
   ----------

   function Tail
     (Nonce, NC, CNonce, QOP, Method, URI : String) return String is
   begin
      return ':' & Nonce
         & (if QOP = "" then "" else ':' & NC & ':' & CNonce & ':' & QOP & ':')
         & MD5.Digest (Method & ':' & URI);
   end Tail;

begin
   MD5.Update (Private_Key, Utils.Random_String (32));
end AWS.Digest;