_ Git - BearSSL/blob - tools/files.c

   1 /*
   2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <stdint.h>
  29 #include <errno.h>
  30
  31 #include "brssl.h"
  32
  33 /* see brssl.h */
  34 unsigned char *
  35 read_file(const char *fname, size_t *len)
  36 {
  37         bvector vbuf = VEC_INIT;
  38         FILE *f;
  39
  40         *len = 0;
  41         f = fopen(fname, "rb");
  42         if (f == NULL) {
  43                 fprintf(stderr,
  44                         "ERROR: could not open file '%s' for reading\n", fname);
  45                 return NULL;
  46         }
  47         for (;;) {
  48                 unsigned char tmp[1024];
  49                 size_t rlen;
  50
  51                 rlen = fread(tmp, 1, sizeof tmp, f);
  52                 if (rlen == 0) {
  53                         unsigned char *buf;
  54
  55                         if (ferror(f)) {
  56                                 fprintf(stderr,
  57                                         "ERROR: read error on file '%s'\n",
  58                                         fname);
  59                                 fclose(f);
  60                                 return NULL;
  61                         }
  62                         buf = VEC_TOARRAY(vbuf);
  63                         *len = VEC_LEN(vbuf);
  64                         VEC_CLEAR(vbuf);
  65                         fclose(f);
  66                         return buf;
  67                 }
  68                 VEC_ADDMANY(vbuf, tmp, rlen);
  69         }
  70 }
  71
  72 /* see brssl.h */
  73 int
  74 write_file(const char *fname, const void *data, size_t len)
  75 {
  76         FILE *f;
  77         const unsigned char *buf;
  78
  79         f = fopen(fname, "wb");
  80         if (f == NULL) {
  81                 fprintf(stderr,
  82                         "ERROR: could not open file '%s' for reading\n", fname);
  83                 return -1;
  84         }
  85         buf = data;
  86         while (len > 0) {
  87                 size_t wlen;
  88
  89                 wlen = fwrite(buf, 1, len, f);
  90                 if (wlen == 0) {
  91                         fprintf(stderr,
  92                                 "ERROR: could not write all bytes to '%s'\n",
  93                                 fname);
  94                         fclose(f);
  95                         return -1;
  96                 }
  97                 buf += wlen;
  98                 len -= wlen;
  99         }
 100         if (ferror(f)) {
 101                 fprintf(stderr, "ERROR: write error on file '%s'\n", fname);
 102                 fclose(f);
 103                 return -1;
 104         }
 105         fclose(f);
 106         return 0;
 107 }
 108
 109 /* see brssl.h */
 110 int
 111 looks_like_DER(const unsigned char *buf, size_t len)
 112 {
 113         int fb;
 114         size_t dlen;
 115
 116         if (len < 2) {
 117                 return 0;
 118         }
 119         if (*buf ++ != 0x30) {
 120                 return 0;
 121         }
 122         fb = *buf ++;
 123         len -= 2;
 124         if (fb < 0x80) {
 125                 return (size_t)fb == len;
 126         } else if (fb == 0x80) {
 127                 return 0;
 128         } else {
 129                 fb -= 0x80;
 130                 if (len < (size_t)fb + 2) {
 131                         return 0;
 132                 }
 133                 len -= (size_t)fb;
 134                 dlen = 0;
 135                 while (fb -- > 0) {
 136                         if (dlen > (len >> 8)) {
 137                                 return 0;
 138                         }
 139                         dlen = (dlen << 8) + (size_t)*buf ++;
 140                 }
 141                 return dlen == len;
 142         }
 143 }
 144
 145 static void
 146 vblob_append(void *cc, const void *data, size_t len)
 147 {
 148         bvector *bv;
 149
 150         bv = cc;
 151         VEC_ADDMANY(*bv, data, len);
 152 }
 153
 154 /* see brssl.h */
 155 void
 156 free_pem_object_contents(pem_object *po)
 157 {
 158         if (po != NULL) {
 159                 xfree(po->name);
 160                 xfree(po->data);
 161         }
 162 }
 163
 164 /* see brssl.h */
 165 pem_object *
 166 decode_pem(const void *src, size_t len, size_t *num)
 167 {
 168         VECTOR(pem_object) pem_list = VEC_INIT;
 169         br_pem_decoder_context pc;
 170         pem_object po, *pos;
 171         const unsigned char *buf;
 172         bvector bv = VEC_INIT;
 173         int inobj;
 174         int extra_nl;
 175
 176         *num = 0;
 177         br_pem_decoder_init(&pc);
 178         buf = src;
 179         inobj = 0;
 180         po.name = NULL;
 181         po.data = NULL;
 182         po.data_len = 0;
 183         extra_nl = 1;
 184         while (len > 0) {
 185                 size_t tlen;
 186
 187                 tlen = br_pem_decoder_push(&pc, buf, len);
 188                 buf += tlen;
 189                 len -= tlen;
 190                 switch (br_pem_decoder_event(&pc)) {
 191
 192                 case BR_PEM_BEGIN_OBJ:
 193                         po.name = xstrdup(br_pem_decoder_name(&pc));
 194                         br_pem_decoder_setdest(&pc, vblob_append, &bv);
 195                         inobj = 1;
 196                         break;
 197
 198                 case BR_PEM_END_OBJ:
 199                         if (inobj) {
 200                                 po.data = VEC_TOARRAY(bv);
 201                                 po.data_len = VEC_LEN(bv);
 202                                 VEC_ADD(pem_list, po);
 203                                 VEC_CLEAR(bv);
 204                                 po.name = NULL;
 205                                 po.data = NULL;
 206                                 po.data_len = 0;
 207                                 inobj = 0;
 208                         }
 209                         break;
 210
 211                 case BR_PEM_ERROR:
 212                         xfree(po.name);
 213                         VEC_CLEAR(bv);
 214                         fprintf(stderr,
 215                                 "ERROR: invalid PEM encoding\n");
 216                         VEC_CLEAREXT(pem_list, &free_pem_object_contents);
 217                         return NULL;
 218                 }
 219
 220                 /*
 221                  * We add an extra newline at the end, in order to
 222                  * support PEM files that lack the newline on their last
 223                  * line (this is somwehat invalid, but PEM format is not
 224                  * standardised and such files do exist in the wild, so
 225                  * we'd better accept them).
 226                  */
 227                 if (len == 0 && extra_nl) {
 228                         extra_nl = 0;
 229                         buf = (const unsigned char *)"\n";
 230                         len = 1;
 231                 }
 232         }
 233         if (inobj) {
 234                 fprintf(stderr, "ERROR: unfinished PEM object\n");
 235                 xfree(po.name);
 236                 VEC_CLEAR(bv);
 237                 VEC_CLEAREXT(pem_list, &free_pem_object_contents);
 238                 return NULL;
 239         }
 240
 241         *num = VEC_LEN(pem_list);
 242         VEC_ADD(pem_list, po);
 243         pos = VEC_TOARRAY(pem_list);
 244         VEC_CLEAR(pem_list);
 245         return pos;
 246 }
 247
 248 /* see brssl.h */
 249 br_x509_certificate *
 250 read_certificates(const char *fname, size_t *num)
 251 {
 252         VECTOR(br_x509_certificate) cert_list = VEC_INIT;
 253         unsigned char *buf;
 254         size_t len;
 255         pem_object *pos;
 256         size_t u, num_pos;
 257         br_x509_certificate *xcs;
 258         br_x509_certificate dummy;
 259
 260         *num = 0;
 261
 262         /*
 263          * TODO: reading the whole file is crude; we could parse them
 264          * in a streamed fashion. But it does not matter much in practice.
 265          */
 266         buf = read_file(fname, &len);
 267         if (buf == NULL) {
 268                 return NULL;
 269         }
 270
 271         /*
 272          * Check for a DER-encoded certificate.
 273          */
 274         if (looks_like_DER(buf, len)) {
 275                 xcs = xmalloc(2 * sizeof *xcs);
 276                 xcs[0].data = buf;
 277                 xcs[0].data_len = len;
 278                 xcs[1].data = NULL;
 279                 xcs[1].data_len = 0;
 280                 *num = 1;
 281                 return xcs;
 282         }
 283
 284         pos = decode_pem(buf, len, &num_pos);
 285         xfree(buf);
 286         if (pos == NULL) {
 287                 return NULL;
 288         }
 289         for (u = 0; u < num_pos; u ++) {
 290                 if (eqstr(pos[u].name, "CERTIFICATE")
 291                         || eqstr(pos[u].name, "X509 CERTIFICATE"))
 292                 {
 293                         br_x509_certificate xc;
 294
 295                         xc.data = pos[u].data;
 296                         xc.data_len = pos[u].data_len;
 297                         pos[u].data = NULL;
 298                         VEC_ADD(cert_list, xc);
 299                 }
 300         }
 301         for (u = 0; u < num_pos; u ++) {
 302                 free_pem_object_contents(&pos[u]);
 303         }
 304         xfree(pos);
 305
 306         if (VEC_LEN(cert_list) == 0) {
 307                 fprintf(stderr, "ERROR: no certificate in file '%s'\n", fname);
 308                 return NULL;
 309         }
 310         *num = VEC_LEN(cert_list);
 311         dummy.data = NULL;
 312         dummy.data_len = 0;
 313         VEC_ADD(cert_list, dummy);
 314         xcs = VEC_TOARRAY(cert_list);
 315         VEC_CLEAR(cert_list);
 316         return xcs;
 317 }
 318
 319 /* see brssl.h */
 320 void
 321 free_certificates(br_x509_certificate *certs, size_t num)
 322 {
 323         size_t u;
 324
 325         for (u = 0; u < num; u ++) {
 326                 xfree(certs[u].data);
 327         }
 328         xfree(certs);
 329 }