source: zcrypt.c @ ae50abc

release-1.6release-1.7release-1.8release-1.9
Last change on this file since ae50abc was ae50abc, checked in by Anders Kaseorg <andersk@mit.edu>, 11 years ago
zcrypt: Don’t append a newline when decrypting. Signed-off-by: Anders Kaseorg <andersk@mit.edu> Reviewed-by: Nelson Elhage <nelhage@mit.edu>
  • Property mode set to 100644
File size: 7.4 KB
Line 
1/* This file is stolen and slightly modified code */
2
3/* zcrypt.c -- Read in a data stream from stdin & dump a decrypted/encrypted *
4 *   datastream.  Reads the string to make the key from from the first       *
5 *   parameter.  Encrypts or decrypts according to -d or -e flag.  (-e is    *
6 *   default.)  Will invoke zwrite if the -c option is provided for          *
7 *   encryption.  If a zephyr class is specified & the keyfile name omitted  *
8 *   the ~/.crypt-table will be checked for "crypt-classname" and then       *
9 *   "crypt-default" for the keyfile name.                                   */
10
11#include <stdio.h>
12#include <stdlib.h>
13#include <string.h>
14#include <sys/types.h>
15#include <sys/wait.h>
16#include "owl.h"
17
18#ifdef OWL_ENABLE_ZCRYPT
19
20#define BASE_CODE 70
21#define LAST_CODE (BASE_CODE + 15)
22#define OUTPUT_BLOCK_SIZE 16
23#include <unistd.h>
24#include <sys/types.h>
25
26#ifdef HAVE_KERBEROS_IV
27#include <kerberosIV/des.h>
28#else
29#include <openssl/des.h>
30#endif
31
32#define MAX_KEY 128
33
34#ifndef TRUE
35#define TRUE -1
36#endif
37#ifndef FALSE
38#define FALSE 0
39#endif
40
41#define ZWRITE_OPT_NOAUTH     (1<<0)
42#define ZWRITE_OPT_SIGNATURE  (1<<1)
43#define ZWRITE_OPT_IGNOREVARS (1<<2)
44#define ZWRITE_OPT_VERBOSE    (1<<3)
45#define ZWRITE_OPT_QUIET      (1<<4)
46#define ZCRYPT_OPT_MESSAGE    (1<<5)
47#define ZCRYPT_OPT_IGNOREDOT  (1<<6)
48
49typedef struct
50{
51  int flags;
52  char *signature;
53  char *message;
54} ZWRITEOPTIONS;
55
56char *GetZephyrVarKeyFile(const char *whoami, const char *class, const char *instance);
57
58#define M_NONE            0
59#define M_ZEPHYR_ENCRYPT  1
60#define M_DECRYPT         2
61#define M_ENCRYPT         3
62#define M_RANDOMIZE       4
63#define M_SETKEY          5
64
65static void owl_zcrypt_string_to_schedule(const char *keystring, des_key_schedule *schedule) {
66#ifdef HAVE_KERBEROS_IV
67  des_cblock key;
68#else
69  des_cblock _key, *key = &_key;
70#endif
71
72  des_string_to_key(keystring, key);
73  des_key_sched(key, *schedule);
74}
75
76/* The 'owl_zcrypt_decrypt' function was written by kretch for Owl.
77 * Decrypt the message in 'in' on class 'class' and instance
78 * 'instance'.  Return must be freed by caller.
79 */
80char *owl_zcrypt_decrypt(const char *in, const char *class, const char *instance)
81{
82  char *fname, keystring[MAX_KEY];
83  FILE *fkey;
84 
85  fname=GetZephyrVarKeyFile("zcrypt", class, instance);
86  if (!fname) return NULL;
87  fkey=fopen(fname, "r");
88  if (!fkey) return NULL;
89  if (!fgets(keystring, MAX_KEY-1, fkey)) {
90    fclose(fkey);
91    return NULL;
92  }
93  fclose(fkey);
94
95  return owl_zcrypt_decrypt_with_key(in, keystring);
96}
97
98char *owl_zcrypt_decrypt_with_key(const char *in, const char *keystring)
99{
100  const char *inptr, *endptr;
101  char *out;
102  des_key_schedule schedule;
103  unsigned char input[8], output[8];
104  int i, c1, c2;
105
106  out = owl_malloc(strlen(in) * 16 + 20);
107
108  strcpy(out, "");
109
110  output[0] = '\0';    /* In case no message at all                 */
111
112  owl_zcrypt_string_to_schedule(keystring, &schedule);
113
114  inptr=in;
115  endptr=in+strlen(in)-1;
116  while (inptr<endptr) {
117    for (i=0; i<8; i++) {
118      c1=(inptr[0])-BASE_CODE;
119      c2=(inptr[1])-BASE_CODE;
120      input[i]=c1 * 0x10 + c2;
121      inptr+=2;
122    }
123    des_ecb_encrypt(&input, &output, schedule, FALSE);
124    strncat(out, (const char *)output, 8);
125  }
126
127  return out;
128}
129
130char *owl_zcrypt_encrypt(const char *in, const char *class, const char *instance)
131{
132  char *fname, keystring[MAX_KEY];
133  FILE *fkey;
134
135  fname=GetZephyrVarKeyFile("zcrypt", class, instance);
136  if (!fname) return NULL;
137  fkey=fopen(fname, "r");
138  if (!fkey) return NULL;
139  if (!fgets(keystring, MAX_KEY-1, fkey)) {
140    fclose(fkey);
141    return NULL;
142  }
143  fclose(fkey);
144
145  return owl_zcrypt_encrypt_with_key(in, keystring);
146}
147
148char *owl_zcrypt_encrypt_with_key(const char *in, const char *keystring)
149{
150  des_key_schedule schedule;
151  char *out;
152  unsigned char input[8], output[8];
153  int size, length, i;
154  const char *inbuff = NULL, *inptr;
155  int num_blocks=0, last_block_size=0;
156
157  owl_zcrypt_string_to_schedule(keystring, &schedule);
158
159  /* Allocate enough space for the crypted message. For each byte of
160   * the message, the encoded cyphertext will have two bytes. Block
161   * size is 8 bytes of input, or 16 bytes of output, so make sure we
162   * have at least one block worth of space allocated. If the message
163   * is empty, no blocks are sent, but we still allocate one
164   * block. The additional 16 bytes also provide space for the null
165   * terminator, as we will never use all of it for cyphertext.
166   */
167  out = owl_malloc((strlen(in) * 2) + 16);
168
169  inbuff=in;
170  length=strlen(inbuff);
171  num_blocks=(length+7)/8;
172  last_block_size=((length+7)%8)+1;
173
174  strcpy(out, "");
175 
176  inptr=inbuff;
177  while (TRUE) {
178    /* Get 8 bytes from buffer */
179    if (num_blocks > 1) {
180      size = 8;
181      memcpy(input, inptr, size);
182      inptr+=8;
183      num_blocks--;
184    } else if (num_blocks == 1) {
185      size=last_block_size;
186      memcpy(input, inptr, size);
187      num_blocks--;
188    } else {
189      size=0;
190    }
191
192    /* Check for EOF and pad the string to 8 chars, if needed */
193    if (size == 0) break;     /* END OF INPUT: BREAK FROM while LOOP! */
194     
195    if (size<8) memset(input + size, 0, 8 - size);
196
197    /* Encrypt and output the block */
198    des_ecb_encrypt(&input, &output, schedule, TRUE);
199
200    for (i = 0; i < 8; i++) {
201      sprintf(out + strlen(out), "%c", ((output[i] & 0xf0) >> 4) + BASE_CODE);
202      sprintf(out + strlen(out), "%c", (output[i] & 0x0f)        + BASE_CODE);
203    }
204
205    if (size < 8) break;
206  }
207  return out;
208}
209
210
211#define MAX_BUFF 258
212#define MAX_SEARCH 3
213/* Find the class/instance in the .crypt-table */
214char *GetZephyrVarKeyFile(const char *whoami, const char *class, const char *instance) {
215  char *keyfile = NULL;
216  char *varname[MAX_SEARCH];
217  int length[MAX_SEARCH], i;
218  char buffer[MAX_BUFF];
219  char *filename;
220  char result[MAX_SEARCH][MAX_BUFF];
221  int numsearch = 0;
222  FILE *fsearch;
223
224  memset(varname, 0, sizeof(varname));
225
226  /* Determine names to look for in .crypt-table */
227  if (instance) {
228    varname[numsearch++] = owl_sprintf("crypt-%s-%s:", (class?class:"message"), instance);
229  }
230  if (class) {
231    varname[numsearch++] = owl_sprintf("crypt-%s:", class);
232  }
233  varname[numsearch++] = owl_strdup("crypt-default:");
234
235  /* Setup the result array, and determine string lengths */
236  for (i = 0; i < numsearch; i++) {
237    result[i][0] = '\0';
238    length[i] = strlen(varname[i]);
239  }
240
241  /* Open~/.crypt-table */
242  filename = owl_sprintf("%s/.crypt-table", getenv("HOME"));
243  fsearch = fopen(filename, "r");
244  if (fsearch) {
245    /* Scan file for a match */
246    while (!feof(fsearch)) {
247      if (!fgets(buffer, MAX_BUFF - 3, fsearch)) break;
248      for (i = 0; i < numsearch; i++) {
249        if (strncasecmp(varname[i], buffer, length[i]) == 0) {
250          int j;
251          for (j = length[i]; buffer[j] == ' '; j++)
252            ;
253          strcpy(result[i], &buffer[j]);
254          if (*result[i]) {
255            if (result[i][strlen(result[i])-1] == '\n') {
256              result[i][strlen(result[i])-1] = '\0';
257            }
258          }
259        }
260      }
261    }
262
263    /* Pick the "best" match found */
264    keyfile = NULL;
265    for (i = 0; i < numsearch; i++) {
266      if (*result[i]) {
267        keyfile = result[i];
268        break;
269      }
270    }
271
272    if (keyfile == NULL) {
273      /* printf("Could not find key table entry.\n"); */
274    } else {
275      /* Prepare result to be returned */
276      keyfile = owl_strdup(keyfile);
277    }
278   
279    fclose(fsearch);
280  } else {
281    /* printf("Could not open key table file: %s\n", filename); */
282  }
283
284  for(i = 0; i < MAX_SEARCH; i++) {
285    owl_free(varname[i]);
286  }
287
288  owl_free(filename);
289
290  return(keyfile);
291}
292
293#endif
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