crypto/evp/bio_b64.c

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