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