crypto/evp/bio_b64.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <errno.h>
  12 #include "internal/cryptlib.h"
  13 #include <openssl/buffer.h>
  14 #include <openssl/evp.h>
  15 #include "internal/bio.h"
  16
  17 static int b64_write(BIO *h, const char *buf, int num);
  18 static int b64_read(BIO *h, char *buf, int size);
  19 static int b64_puts(BIO *h, const char *str);
  20 static long b64_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  21 static int b64_new(BIO *h);
  22 static int b64_free(BIO *data);
  23 static long b64_callback_ctrl(BIO *h, int cmd, bio_info_cb *fp);
  24 #define B64_BLOCK_SIZE  1024
  25 #define B64_BLOCK_SIZE2 768
  26 #define B64_NONE        0
  27 #define B64_ENCODE      1
  28 #define B64_DECODE      2
  29
  30 typedef struct b64_struct {
  31     /*
  32      * BIO *bio; moved to the BIO structure
  33      */
  34     int buf_len;
  35     int buf_off;
  36     int tmp_len;                /* used to find the start when decoding */
  37     int tmp_nl;                 /* If true, scan until '\n' */
  38     int encode;
  39     int start;                  /* have we started decoding yet? */
  40     int cont;                   /* <= 0 when finished */
  41     EVP_ENCODE_CTX *base64;
  42     char buf[EVP_ENCODE_LENGTH(B64_BLOCK_SIZE) + 10];
  43     char tmp[B64_BLOCK_SIZE];
  44 } BIO_B64_CTX;
  45
  46 static const BIO_METHOD methods_b64 = {
  47     BIO_TYPE_BASE64, "base64 encoding",
  48     /* TODO: Convert to new style write function */
  49     bwrite_conv,
  50     b64_write,
  51     /* TODO: Convert to new style read function */
  52     bread_conv,
  53     b64_read,
  54     b64_puts,
  55     NULL,                       /* b64_gets, */
  56     b64_ctrl,
  57     b64_new,
  58     b64_free,
  59     b64_callback_ctrl,
  60 };
  61
  62
  63 const BIO_METHOD *BIO_f_base64(void)
  64 {
  65     return &methods_b64;
  66 }
  67
  68 static int b64_new(BIO *bi)
  69 {
  70     BIO_B64_CTX *ctx;
  71
  72     ctx = OPENSSL_zalloc(sizeof(*ctx));
  73     if (ctx == NULL)
  74         return 0;
  75
  76     ctx->cont = 1;
  77     ctx->start = 1;
  78     ctx->base64 = EVP_ENCODE_CTX_new();
  79     if (ctx->base64 == NULL) {
  80         OPENSSL_free(ctx);
  81         return 0;
  82     }
  83
  84     BIO_set_data(bi, ctx);
  85     BIO_set_init(bi, 1);
  86
  87     return 1;
  88 }
  89
  90 static int b64_free(BIO *a)
  91 {
  92     BIO_B64_CTX *ctx;
  93     if (a == NULL)
  94         return 0;
  95
  96     ctx = BIO_get_data(a);
  97     if (ctx == NULL)
  98         return 0;
  99
 100     EVP_ENCODE_CTX_free(ctx->base64);
 101     OPENSSL_free(ctx);
 102     BIO_set_data(a, NULL);
 103     BIO_set_init(a, 0);
 104
 105     return 1;
 106 }
 107
 108 static int b64_read(BIO *b, char *out, int outl)
 109 {
 110     int ret = 0, i, ii, j, k, x, n, num, ret_code = 0;
 111     BIO_B64_CTX *ctx;
 112     unsigned char *p, *q;
 113     BIO *next;
 114
 115     if (out == NULL)
 116         return (0);
 117     ctx = (BIO_B64_CTX *)BIO_get_data(b);
 118
 119     next = BIO_next(b);
 120     if ((ctx == NULL) || (next == NULL))
 121         return 0;
 122
 123     BIO_clear_retry_flags(b);
 124
 125     if (ctx->encode != B64_DECODE) {
 126         ctx->encode = B64_DECODE;
 127         ctx->buf_len = 0;
 128         ctx->buf_off = 0;
 129         ctx->tmp_len = 0;
 130         EVP_DecodeInit(ctx->base64);
 131     }
 132
 133     /* First check if there are bytes decoded/encoded */
 134     if (ctx->buf_len > 0) {
 135         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 136         i = ctx->buf_len - ctx->buf_off;
 137         if (i > outl)
 138             i = outl;
 139         OPENSSL_assert(ctx->buf_off + i < (int)sizeof(ctx->buf));
 140         memcpy(out, &(ctx->buf[ctx->buf_off]), i);
 141         ret = i;
 142         out += i;
 143         outl -= i;
 144         ctx->buf_off += i;
 145         if (ctx->buf_len == ctx->buf_off) {
 146             ctx->buf_len = 0;
 147             ctx->buf_off = 0;
 148         }
 149     }
 150
 151     /*
 152      * At this point, we have room of outl bytes and an empty buffer, so we
 153      * should read in some more.
 154      */
 155
 156     ret_code = 0;
 157     while (outl > 0) {
 158         if (ctx->cont <= 0)
 159             break;
 160
 161         i = BIO_read(next, &(ctx->tmp[ctx->tmp_len]),
 162                      B64_BLOCK_SIZE - ctx->tmp_len);
 163
 164         if (i <= 0) {
 165             ret_code = i;
 166
 167             /* Should we continue next time we are called? */
 168             if (!BIO_should_retry(next)) {
 169                 ctx->cont = i;
 170                 /* If buffer empty break */
 171                 if (ctx->tmp_len == 0)
 172                     break;
 173                 /* Fall through and process what we have */
 174                 else
 175                     i = 0;
 176             }
 177             /* else we retry and add more data to buffer */
 178             else
 179                 break;
 180         }
 181         i += ctx->tmp_len;
 182         ctx->tmp_len = i;
 183
 184         /*
 185          * We need to scan, a line at a time until we have a valid line if we
 186          * are starting.
 187          */
 188         if (ctx->start && (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)) {
 189             /* ctx->start=1; */
 190             ctx->tmp_len = 0;
 191         } else if (ctx->start) {
 192             q = p = (unsigned char *)ctx->tmp;
 193             num = 0;
 194             for (j = 0; j < i; j++) {
 195                 if (*(q++) != '\n')
 196                     continue;
 197
 198                 /*
 199                  * due to a previous very long line, we need to keep on
 200                  * scanning for a '\n' before we even start looking for
 201                  * base64 encoded stuff.
 202                  */
 203                 if (ctx->tmp_nl) {
 204                     p = q;
 205                     ctx->tmp_nl = 0;
 206                     continue;
 207                 }
 208
 209                 k = EVP_DecodeUpdate(ctx->base64,
 210                                      (unsigned char *)ctx->buf,
 211                                      &num, p, q - p);
 212                 if ((k <= 0) && (num == 0) && (ctx->start))
 213                     EVP_DecodeInit(ctx->base64);
 214                 else {
 215                     if (p != (unsigned char *)
 216                         &(ctx->tmp[0])) {
 217                         i -= (p - (unsigned char *)
 218                               &(ctx->tmp[0]));
 219                         for (x = 0; x < i; x++)
 220                             ctx->tmp[x] = p[x];
 221                     }
 222                     EVP_DecodeInit(ctx->base64);
 223                     ctx->start = 0;
 224                     break;
 225                 }
 226                 p = q;
 227             }
 228
 229             /* we fell off the end without starting */
 230             if ((j == i) && (num == 0)) {
 231                 /*
 232                  * Is this is one long chunk?, if so, keep on reading until a
 233                  * new line.
 234                  */
 235                 if (p == (unsigned char *)&(ctx->tmp[0])) {
 236                     /* Check buffer full */
 237                     if (i == B64_BLOCK_SIZE) {
 238                         ctx->tmp_nl = 1;
 239                         ctx->tmp_len = 0;
 240                     }
 241                 } else if (p != q) { /* finished on a '\n' */
 242                     n = q - p;
 243                     for (ii = 0; ii < n; ii++)
 244                         ctx->tmp[ii] = p[ii];
 245                     ctx->tmp_len = n;
 246                 }
 247                 /* else finished on a '\n' */
 248                 continue;
 249             } else {
 250                 ctx->tmp_len = 0;
 251             }
 252         } else if ((i < B64_BLOCK_SIZE) && (ctx->cont > 0)) {
 253             /*
 254              * If buffer isn't full and we can retry then restart to read in
 255              * more data.
 256              */
 257             continue;
 258         }
 259
 260         if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
 261             int z, jj;
 262
 263             jj = i & ~3;        /* process per 4 */
 264             z = EVP_DecodeBlock((unsigned char *)ctx->buf,
 265                                 (unsigned char *)ctx->tmp, jj);
 266             if (jj > 2) {
 267                 if (ctx->tmp[jj - 1] == '=') {
 268                     z--;
 269                     if (ctx->tmp[jj - 2] == '=')
 270                         z--;
 271                 }
 272             }
 273             /*
 274              * z is now number of output bytes and jj is the number consumed
 275              */
 276             if (jj != i) {
 277                 memmove(ctx->tmp, &ctx->tmp[jj], i - jj);
 278                 ctx->tmp_len = i - jj;
 279             }
 280             ctx->buf_len = 0;
 281             if (z > 0) {
 282                 ctx->buf_len = z;
 283             }
 284             i = z;
 285         } else {
 286             i = EVP_DecodeUpdate(ctx->base64,
 287                                  (unsigned char *)ctx->buf, &ctx->buf_len,
 288                                  (unsigned char *)ctx->tmp, i);
 289             ctx->tmp_len = 0;
 290         }
 291         ctx->buf_off = 0;
 292         if (i < 0) {
 293             ret_code = 0;
 294             ctx->buf_len = 0;
 295             break;
 296         }
 297
 298         if (ctx->buf_len <= outl)
 299             i = ctx->buf_len;
 300         else
 301             i = outl;
 302
 303         memcpy(out, ctx->buf, i);
 304         ret += i;
 305         ctx->buf_off = i;
 306         if (ctx->buf_off == ctx->buf_len) {
 307             ctx->buf_len = 0;
 308             ctx->buf_off = 0;
 309         }
 310         outl -= i;
 311         out += i;
 312     }
 313     /* BIO_clear_retry_flags(b); */
 314     BIO_copy_next_retry(b);
 315     return ((ret == 0) ? ret_code : ret);
 316 }
 317
 318 static int b64_write(BIO *b, const char *in, int inl)
 319 {
 320     int ret = 0;
 321     int n;
 322     int i;
 323     BIO_B64_CTX *ctx;
 324     BIO *next;
 325
 326     ctx = (BIO_B64_CTX *)BIO_get_data(b);
 327     next = BIO_next(b);
 328     if ((ctx == NULL) || (next == NULL))
 329         return 0;
 330
 331     BIO_clear_retry_flags(b);
 332
 333     if (ctx->encode != B64_ENCODE) {
 334         ctx->encode = B64_ENCODE;
 335         ctx->buf_len = 0;
 336         ctx->buf_off = 0;
 337         ctx->tmp_len = 0;
 338         EVP_EncodeInit(ctx->base64);
 339     }
 340
 341     OPENSSL_assert(ctx->buf_off < (int)sizeof(ctx->buf));
 342     OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 343     OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 344     n = ctx->buf_len - ctx->buf_off;
 345     while (n > 0) {
 346         i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
 347         if (i <= 0) {
 348             BIO_copy_next_retry(b);
 349             return (i);
 350         }
 351         OPENSSL_assert(i <= n);
 352         ctx->buf_off += i;
 353         OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
 354         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 355         n -= i;
 356     }
 357     /* at this point all pending data has been written */
 358     ctx->buf_off = 0;
 359     ctx->buf_len = 0;
 360
 361     if ((in == NULL) || (inl <= 0))
 362         return (0);
 363
 364     while (inl > 0) {
 365         n = (inl > B64_BLOCK_SIZE) ? B64_BLOCK_SIZE : inl;
 366
 367         if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
 368             if (ctx->tmp_len > 0) {
 369                 OPENSSL_assert(ctx->tmp_len <= 3);
 370                 n = 3 - ctx->tmp_len;
 371                 /*
 372                  * There's a theoretical possibility for this
 373                  */
 374                 if (n > inl)
 375                     n = inl;
 376                 memcpy(&(ctx->tmp[ctx->tmp_len]), in, n);
 377                 ctx->tmp_len += n;
 378                 ret += n;
 379                 if (ctx->tmp_len < 3)
 380                     break;
 381                 ctx->buf_len =
 382                     EVP_EncodeBlock((unsigned char *)ctx->buf,
 383                                     (unsigned char *)ctx->tmp, ctx->tmp_len);
 384                 OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 385                 OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 386                 /*
 387                  * Since we're now done using the temporary buffer, the
 388                  * length should be 0'd
 389                  */
 390                 ctx->tmp_len = 0;
 391             } else {
 392                 if (n < 3) {
 393                     memcpy(ctx->tmp, in, n);
 394                     ctx->tmp_len = n;
 395                     ret += n;
 396                     break;
 397                 }
 398                 n -= n % 3;
 399                 ctx->buf_len =
 400                     EVP_EncodeBlock((unsigned char *)ctx->buf,
 401                                     (const unsigned char *)in, n);
 402                 OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 403                 OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 404                 ret += n;
 405             }
 406         } else {
 407             if (!EVP_EncodeUpdate(ctx->base64,
 408                                  (unsigned char *)ctx->buf, &ctx->buf_len,
 409                                  (unsigned char *)in, n))
 410                 return ((ret == 0) ? -1 : ret);
 411             OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 412             OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 413             ret += n;
 414         }
 415         inl -= n;
 416         in += n;
 417
 418         ctx->buf_off = 0;
 419         n = ctx->buf_len;
 420         while (n > 0) {
 421             i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
 422             if (i <= 0) {
 423                 BIO_copy_next_retry(b);
 424                 return ((ret == 0) ? i : ret);
 425             }
 426             OPENSSL_assert(i <= n);
 427             n -= i;
 428             ctx->buf_off += i;
 429             OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
 430             OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 431         }
 432         ctx->buf_len = 0;
 433         ctx->buf_off = 0;
 434     }
 435     return (ret);
 436 }
 437
 438 static long b64_ctrl(BIO *b, int cmd, long num, void *ptr)
 439 {
 440     BIO_B64_CTX *ctx;
 441     long ret = 1;
 442     int i;
 443     BIO *next;
 444
 445     ctx = (BIO_B64_CTX *)BIO_get_data(b);
 446     next = BIO_next(b);
 447     if ((ctx == NULL) || (next == NULL))
 448         return 0;
 449
 450     switch (cmd) {
 451     case BIO_CTRL_RESET:
 452         ctx->cont = 1;
 453         ctx->start = 1;
 454         ctx->encode = B64_NONE;
 455         ret = BIO_ctrl(next, cmd, num, ptr);
 456         break;
 457     case BIO_CTRL_EOF:         /* More to read */
 458         if (ctx->cont <= 0)
 459             ret = 1;
 460         else
 461             ret = BIO_ctrl(next, cmd, num, ptr);
 462         break;
 463     case BIO_CTRL_WPENDING:    /* More to write in buffer */
 464         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 465         ret = ctx->buf_len - ctx->buf_off;
 466         if ((ret == 0) && (ctx->encode != B64_NONE)
 467             && (EVP_ENCODE_CTX_num(ctx->base64) != 0))
 468             ret = 1;
 469         else if (ret <= 0)
 470             ret = BIO_ctrl(next, cmd, num, ptr);
 471         break;
 472     case BIO_CTRL_PENDING:     /* More to read in buffer */
 473         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 474         ret = ctx->buf_len - ctx->buf_off;
 475         if (ret <= 0)
 476             ret = BIO_ctrl(next, cmd, num, ptr);
 477         break;
 478     case BIO_CTRL_FLUSH:
 479         /* do a final write */
 480  again:
 481         while (ctx->buf_len != ctx->buf_off) {
 482             i = b64_write(b, NULL, 0);
 483             if (i < 0)
 484                 return i;
 485         }
 486         if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
 487             if (ctx->tmp_len != 0) {
 488                 ctx->buf_len = EVP_EncodeBlock((unsigned char *)ctx->buf,
 489                                                (unsigned char *)ctx->tmp,
 490                                                ctx->tmp_len);
 491                 ctx->buf_off = 0;
 492                 ctx->tmp_len = 0;
 493                 goto again;
 494             }
 495         } else if (ctx->encode != B64_NONE
 496                    && EVP_ENCODE_CTX_num(ctx->base64) != 0) {
 497             ctx->buf_off = 0;
 498             EVP_EncodeFinal(ctx->base64,
 499                             (unsigned char *)ctx->buf, &(ctx->buf_len));
 500             /* push out the bytes */
 501             goto again;
 502         }
 503         /* Finally flush the underlying BIO */
 504         ret = BIO_ctrl(next, cmd, num, ptr);
 505         break;
 506
 507     case BIO_C_DO_STATE_MACHINE:
 508         BIO_clear_retry_flags(b);
 509         ret = BIO_ctrl(next, cmd, num, ptr);
 510         BIO_copy_next_retry(b);
 511         break;
 512
 513     case BIO_CTRL_DUP:
 514         break;
 515     case BIO_CTRL_INFO:
 516     case BIO_CTRL_GET:
 517     case BIO_CTRL_SET:
 518     default:
 519         ret = BIO_ctrl(next, cmd, num, ptr);
 520         break;
 521     }
 522     return ret;
 523 }
 524
 525 static long b64_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
 526 {
 527     long ret = 1;
 528     BIO *next = BIO_next(b);
 529
 530     if (next == NULL)
 531         return 0;
 532     switch (cmd) {
 533     default:
 534         ret = BIO_callback_ctrl(next, cmd, fp);
 535         break;
 536     }
 537     return (ret);
 538 }
 539
 540 static int b64_puts(BIO *b, const char *str)
 541 {
 542     return b64_write(b, str, strlen(str));
 543 }