crypto/evp/bio_b64.c

   1 /*
   2  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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,
  48     "base64 encoding",
  49     /* TODO: Convert to new style write function */
  50     bwrite_conv,
  51     b64_write,
  52     /* TODO: Convert to new style read function */
  53     bread_conv,
  54     b64_read,
  55     b64_puts,
  56     NULL,                       /* b64_gets, */
  57     b64_ctrl,
  58     b64_new,
  59     b64_free,
  60     b64_callback_ctrl,
  61 };
  62
  63
  64 const BIO_METHOD *BIO_f_base64(void)
  65 {
  66     return &methods_b64;
  67 }
  68
  69 static int b64_new(BIO *bi)
  70 {
  71     BIO_B64_CTX *ctx;
  72
  73     if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL) {
  74         EVPerr(EVP_F_B64_NEW, ERR_R_MALLOC_FAILURE);
  75         return 0;
  76     }
  77
  78     ctx->cont = 1;
  79     ctx->start = 1;
  80     ctx->base64 = EVP_ENCODE_CTX_new();
  81     if (ctx->base64 == NULL) {
  82         OPENSSL_free(ctx);
  83         return 0;
  84     }
  85
  86     BIO_set_data(bi, ctx);
  87     BIO_set_init(bi, 1);
  88
  89     return 1;
  90 }
  91
  92 static int b64_free(BIO *a)
  93 {
  94     BIO_B64_CTX *ctx;
  95     if (a == NULL)
  96         return 0;
  97
  98     ctx = BIO_get_data(a);
  99     if (ctx == NULL)
 100         return 0;
 101
 102     EVP_ENCODE_CTX_free(ctx->base64);
 103     OPENSSL_free(ctx);
 104     BIO_set_data(a, NULL);
 105     BIO_set_init(a, 0);
 106
 107     return 1;
 108 }
 109
 110 static int b64_read(BIO *b, char *out, int outl)
 111 {
 112     int ret = 0, i, ii, j, k, x, n, num, ret_code = 0;
 113     BIO_B64_CTX *ctx;
 114     unsigned char *p, *q;
 115     BIO *next;
 116
 117     if (out == NULL)
 118         return 0;
 119     ctx = (BIO_B64_CTX *)BIO_get_data(b);
 120
 121     next = BIO_next(b);
 122     if ((ctx == NULL) || (next == NULL))
 123         return 0;
 124
 125     BIO_clear_retry_flags(b);
 126
 127     if (ctx->encode != B64_DECODE) {
 128         ctx->encode = B64_DECODE;
 129         ctx->buf_len = 0;
 130         ctx->buf_off = 0;
 131         ctx->tmp_len = 0;
 132         EVP_DecodeInit(ctx->base64);
 133     }
 134
 135     /* First check if there are bytes decoded/encoded */
 136     if (ctx->buf_len > 0) {
 137         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 138         i = ctx->buf_len - ctx->buf_off;
 139         if (i > outl)
 140             i = outl;
 141         OPENSSL_assert(ctx->buf_off + i < (int)sizeof(ctx->buf));
 142         memcpy(out, &(ctx->buf[ctx->buf_off]), i);
 143         ret = i;
 144         out += i;
 145         outl -= i;
 146         ctx->buf_off += i;
 147         if (ctx->buf_len == ctx->buf_off) {
 148             ctx->buf_len = 0;
 149             ctx->buf_off = 0;
 150         }
 151     }
 152
 153     /*
 154      * At this point, we have room of outl bytes and an empty buffer, so we
 155      * should read in some more.
 156      */
 157
 158     ret_code = 0;
 159     while (outl > 0) {
 160         if (ctx->cont <= 0)
 161             break;
 162
 163         i = BIO_read(next, &(ctx->tmp[ctx->tmp_len]),
 164                      B64_BLOCK_SIZE - ctx->tmp_len);
 165
 166         if (i <= 0) {
 167             ret_code = i;
 168
 169             /* Should we continue next time we are called? */
 170             if (!BIO_should_retry(next)) {
 171                 ctx->cont = i;
 172                 /* If buffer empty break */
 173                 if (ctx->tmp_len == 0)
 174                     break;
 175                 /* Fall through and process what we have */
 176                 else
 177                     i = 0;
 178             }
 179             /* else we retry and add more data to buffer */
 180             else
 181                 break;
 182         }
 183         i += ctx->tmp_len;
 184         ctx->tmp_len = i;
 185
 186         /*
 187          * We need to scan, a line at a time until we have a valid line if we
 188          * are starting.
 189          */
 190         if (ctx->start && (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)) {
 191             /* ctx->start=1; */
 192             ctx->tmp_len = 0;
 193         } else if (ctx->start) {
 194             q = p = (unsigned char *)ctx->tmp;
 195             num = 0;
 196             for (j = 0; j < i; j++) {
 197                 if (*(q++) != '\n')
 198                     continue;
 199
 200                 /*
 201                  * due to a previous very long line, we need to keep on
 202                  * scanning for a '\n' before we even start looking for
 203                  * base64 encoded stuff.
 204                  */
 205                 if (ctx->tmp_nl) {
 206                     p = q;
 207                     ctx->tmp_nl = 0;
 208                     continue;
 209                 }
 210
 211                 k = EVP_DecodeUpdate(ctx->base64,
 212                                      (unsigned char *)ctx->buf,
 213                                      &num, p, q - p);
 214                 if ((k <= 0) && (num == 0) && (ctx->start))
 215                     EVP_DecodeInit(ctx->base64);
 216                 else {
 217                     if (p != (unsigned char *)
 218                         &(ctx->tmp[0])) {
 219                         i -= (p - (unsigned char *)
 220                               &(ctx->tmp[0]));
 221                         for (x = 0; x < i; x++)
 222                             ctx->tmp[x] = p[x];
 223                     }
 224                     EVP_DecodeInit(ctx->base64);
 225                     ctx->start = 0;
 226                     break;
 227                 }
 228                 p = q;
 229             }
 230
 231             /* we fell off the end without starting */
 232             if ((j == i) && (num == 0)) {
 233                 /*
 234                  * Is this is one long chunk?, if so, keep on reading until a
 235                  * new line.
 236                  */
 237                 if (p == (unsigned char *)&(ctx->tmp[0])) {
 238                     /* Check buffer full */
 239                     if (i == B64_BLOCK_SIZE) {
 240                         ctx->tmp_nl = 1;
 241                         ctx->tmp_len = 0;
 242                     }
 243                 } else if (p != q) { /* finished on a '\n' */
 244                     n = q - p;
 245                     for (ii = 0; ii < n; ii++)
 246                         ctx->tmp[ii] = p[ii];
 247                     ctx->tmp_len = n;
 248                 }
 249                 /* else finished on a '\n' */
 250                 continue;
 251             } else {
 252                 ctx->tmp_len = 0;
 253             }
 254         } else if ((i < B64_BLOCK_SIZE) && (ctx->cont > 0)) {
 255             /*
 256              * If buffer isn't full and we can retry then restart to read in
 257              * more data.
 258              */
 259             continue;
 260         }
 261
 262         if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
 263             int z, jj;
 264
 265             jj = i & ~3;        /* process per 4 */
 266             z = EVP_DecodeBlock((unsigned char *)ctx->buf,
 267                                 (unsigned char *)ctx->tmp, jj);
 268             if (jj > 2) {
 269                 if (ctx->tmp[jj - 1] == '=') {
 270                     z--;
 271                     if (ctx->tmp[jj - 2] == '=')
 272                         z--;
 273                 }
 274             }
 275             /*
 276              * z is now number of output bytes and jj is the number consumed
 277              */
 278             if (jj != i) {
 279                 memmove(ctx->tmp, &ctx->tmp[jj], i - jj);
 280                 ctx->tmp_len = i - jj;
 281             }
 282             ctx->buf_len = 0;
 283             if (z > 0) {
 284                 ctx->buf_len = z;
 285             }
 286             i = z;
 287         } else {
 288             i = EVP_DecodeUpdate(ctx->base64,
 289                                  (unsigned char *)ctx->buf, &ctx->buf_len,
 290                                  (unsigned char *)ctx->tmp, i);
 291             ctx->tmp_len = 0;
 292         }
 293         /*
 294          * If eof or an error was signalled, then the condition
 295          * 'ctx->cont <= 0' will prevent b64_read() from reading
 296          * more data on subsequent calls. This assignment was
 297          * deleted accidentally in commit 5562cfaca4f3.
 298          */
 299         ctx->cont = i;
 300
 301         ctx->buf_off = 0;
 302         if (i < 0) {
 303             ret_code = 0;
 304             ctx->buf_len = 0;
 305             break;
 306         }
 307
 308         if (ctx->buf_len <= outl)
 309             i = ctx->buf_len;
 310         else
 311             i = outl;
 312
 313         memcpy(out, ctx->buf, i);
 314         ret += i;
 315         ctx->buf_off = i;
 316         if (ctx->buf_off == ctx->buf_len) {
 317             ctx->buf_len = 0;
 318             ctx->buf_off = 0;
 319         }
 320         outl -= i;
 321         out += i;
 322     }
 323     /* BIO_clear_retry_flags(b); */
 324     BIO_copy_next_retry(b);
 325     return ((ret == 0) ? ret_code : ret);
 326 }
 327
 328 static int b64_write(BIO *b, const char *in, int inl)
 329 {
 330     int ret = 0;
 331     int n;
 332     int i;
 333     BIO_B64_CTX *ctx;
 334     BIO *next;
 335
 336     ctx = (BIO_B64_CTX *)BIO_get_data(b);
 337     next = BIO_next(b);
 338     if ((ctx == NULL) || (next == NULL))
 339         return 0;
 340
 341     BIO_clear_retry_flags(b);
 342
 343     if (ctx->encode != B64_ENCODE) {
 344         ctx->encode = B64_ENCODE;
 345         ctx->buf_len = 0;
 346         ctx->buf_off = 0;
 347         ctx->tmp_len = 0;
 348         EVP_EncodeInit(ctx->base64);
 349     }
 350
 351     OPENSSL_assert(ctx->buf_off < (int)sizeof(ctx->buf));
 352     OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 353     OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 354     n = ctx->buf_len - ctx->buf_off;
 355     while (n > 0) {
 356         i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
 357         if (i <= 0) {
 358             BIO_copy_next_retry(b);
 359             return i;
 360         }
 361         OPENSSL_assert(i <= n);
 362         ctx->buf_off += i;
 363         OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
 364         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 365         n -= i;
 366     }
 367     /* at this point all pending data has been written */
 368     ctx->buf_off = 0;
 369     ctx->buf_len = 0;
 370
 371     if ((in == NULL) || (inl <= 0))
 372         return 0;
 373
 374     while (inl > 0) {
 375         n = (inl > B64_BLOCK_SIZE) ? B64_BLOCK_SIZE : inl;
 376
 377         if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
 378             if (ctx->tmp_len > 0) {
 379                 OPENSSL_assert(ctx->tmp_len <= 3);
 380                 n = 3 - ctx->tmp_len;
 381                 /*
 382                  * There's a theoretical possibility for this
 383                  */
 384                 if (n > inl)
 385                     n = inl;
 386                 memcpy(&(ctx->tmp[ctx->tmp_len]), in, n);
 387                 ctx->tmp_len += n;
 388                 ret += n;
 389                 if (ctx->tmp_len < 3)
 390                     break;
 391                 ctx->buf_len =
 392                     EVP_EncodeBlock((unsigned char *)ctx->buf,
 393                                     (unsigned char *)ctx->tmp, ctx->tmp_len);
 394                 OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 395                 OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 396                 /*
 397                  * Since we're now done using the temporary buffer, the
 398                  * length should be 0'd
 399                  */
 400                 ctx->tmp_len = 0;
 401             } else {
 402                 if (n < 3) {
 403                     memcpy(ctx->tmp, in, n);
 404                     ctx->tmp_len = n;
 405                     ret += n;
 406                     break;
 407                 }
 408                 n -= n % 3;
 409                 ctx->buf_len =
 410                     EVP_EncodeBlock((unsigned char *)ctx->buf,
 411                                     (const unsigned char *)in, n);
 412                 OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 413                 OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 414                 ret += n;
 415             }
 416         } else {
 417             if (!EVP_EncodeUpdate(ctx->base64,
 418                                  (unsigned char *)ctx->buf, &ctx->buf_len,
 419                                  (unsigned char *)in, n))
 420                 return ((ret == 0) ? -1 : ret);
 421             OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
 422             OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 423             ret += n;
 424         }
 425         inl -= n;
 426         in += n;
 427
 428         ctx->buf_off = 0;
 429         n = ctx->buf_len;
 430         while (n > 0) {
 431             i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
 432             if (i <= 0) {
 433                 BIO_copy_next_retry(b);
 434                 return ((ret == 0) ? i : ret);
 435             }
 436             OPENSSL_assert(i <= n);
 437             n -= i;
 438             ctx->buf_off += i;
 439             OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
 440             OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 441         }
 442         ctx->buf_len = 0;
 443         ctx->buf_off = 0;
 444     }
 445     return ret;
 446 }
 447
 448 static long b64_ctrl(BIO *b, int cmd, long num, void *ptr)
 449 {
 450     BIO_B64_CTX *ctx;
 451     long ret = 1;
 452     int i;
 453     BIO *next;
 454
 455     ctx = (BIO_B64_CTX *)BIO_get_data(b);
 456     next = BIO_next(b);
 457     if ((ctx == NULL) || (next == NULL))
 458         return 0;
 459
 460     switch (cmd) {
 461     case BIO_CTRL_RESET:
 462         ctx->cont = 1;
 463         ctx->start = 1;
 464         ctx->encode = B64_NONE;
 465         ret = BIO_ctrl(next, cmd, num, ptr);
 466         break;
 467     case BIO_CTRL_EOF:         /* More to read */
 468         if (ctx->cont <= 0)
 469             ret = 1;
 470         else
 471             ret = BIO_ctrl(next, cmd, num, ptr);
 472         break;
 473     case BIO_CTRL_WPENDING:    /* More to write in buffer */
 474         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 475         ret = ctx->buf_len - ctx->buf_off;
 476         if ((ret == 0) && (ctx->encode != B64_NONE)
 477             && (EVP_ENCODE_CTX_num(ctx->base64) != 0))
 478             ret = 1;
 479         else if (ret <= 0)
 480             ret = BIO_ctrl(next, cmd, num, ptr);
 481         break;
 482     case BIO_CTRL_PENDING:     /* More to read in buffer */
 483         OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
 484         ret = ctx->buf_len - ctx->buf_off;
 485         if (ret <= 0)
 486             ret = BIO_ctrl(next, cmd, num, ptr);
 487         break;
 488     case BIO_CTRL_FLUSH:
 489         /* do a final write */
 490  again:
 491         while (ctx->buf_len != ctx->buf_off) {
 492             i = b64_write(b, NULL, 0);
 493             if (i < 0)
 494                 return i;
 495         }
 496         if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
 497             if (ctx->tmp_len != 0) {
 498                 ctx->buf_len = EVP_EncodeBlock((unsigned char *)ctx->buf,
 499                                                (unsigned char *)ctx->tmp,
 500                                                ctx->tmp_len);
 501                 ctx->buf_off = 0;
 502                 ctx->tmp_len = 0;
 503                 goto again;
 504             }
 505         } else if (ctx->encode != B64_NONE
 506                    && EVP_ENCODE_CTX_num(ctx->base64) != 0) {
 507             ctx->buf_off = 0;
 508             EVP_EncodeFinal(ctx->base64,
 509                             (unsigned char *)ctx->buf, &(ctx->buf_len));
 510             /* push out the bytes */
 511             goto again;
 512         }
 513         /* Finally flush the underlying BIO */
 514         ret = BIO_ctrl(next, cmd, num, ptr);
 515         break;
 516
 517     case BIO_C_DO_STATE_MACHINE:
 518         BIO_clear_retry_flags(b);
 519         ret = BIO_ctrl(next, cmd, num, ptr);
 520         BIO_copy_next_retry(b);
 521         break;
 522
 523     case BIO_CTRL_DUP:
 524         break;
 525     case BIO_CTRL_INFO:
 526     case BIO_CTRL_GET:
 527     case BIO_CTRL_SET:
 528     default:
 529         ret = BIO_ctrl(next, cmd, num, ptr);
 530         break;
 531     }
 532     return ret;
 533 }
 534
 535 static long b64_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
 536 {
 537     long ret = 1;
 538     BIO *next = BIO_next(b);
 539
 540     if (next == NULL)
 541         return 0;
 542     switch (cmd) {
 543     default:
 544         ret = BIO_callback_ctrl(next, cmd, fp);
 545         break;
 546     }
 547     return ret;
 548 }
 549
 550 static int b64_puts(BIO *b, const char *str)
 551 {
 552     return b64_write(b, str, strlen(str));
 553 }