crypto/bio/bf_buff.c

   1 /*
   2  * Copyright 1995-2021 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 "bio_local.h"
  13 #include "internal/cryptlib.h"
  14
  15 static int buffer_write(BIO *h, const char *buf, int num);
  16 static int buffer_read(BIO *h, char *buf, int size);
  17 static int buffer_puts(BIO *h, const char *str);
  18 static int buffer_gets(BIO *h, char *str, int size);
  19 static long buffer_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  20 static int buffer_new(BIO *h);
  21 static int buffer_free(BIO *data);
  22 static long buffer_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp);
  23 #define DEFAULT_BUFFER_SIZE     4096
  24
  25 static const BIO_METHOD methods_buffer = {
  26     BIO_TYPE_BUFFER,
  27     "buffer",
  28     bwrite_conv,
  29     buffer_write,
  30     bread_conv,
  31     buffer_read,
  32     buffer_puts,
  33     buffer_gets,
  34     buffer_ctrl,
  35     buffer_new,
  36     buffer_free,
  37     buffer_callback_ctrl,
  38 };
  39
  40 const BIO_METHOD *BIO_f_buffer(void)
  41 {
  42     return &methods_buffer;
  43 }
  44
  45 static int buffer_new(BIO *bi)
  46 {
  47     BIO_F_BUFFER_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
  48
  49     if (ctx == NULL)
  50         return 0;
  51     ctx->ibuf_size = DEFAULT_BUFFER_SIZE;
  52     ctx->ibuf = OPENSSL_malloc(DEFAULT_BUFFER_SIZE);
  53     if (ctx->ibuf == NULL) {
  54         OPENSSL_free(ctx);
  55         return 0;
  56     }
  57     ctx->obuf_size = DEFAULT_BUFFER_SIZE;
  58     ctx->obuf = OPENSSL_malloc(DEFAULT_BUFFER_SIZE);
  59     if (ctx->obuf == NULL) {
  60         OPENSSL_free(ctx->ibuf);
  61         OPENSSL_free(ctx);
  62         return 0;
  63     }
  64
  65     bi->init = 1;
  66     bi->ptr = (char *)ctx;
  67     bi->flags = 0;
  68     return 1;
  69 }
  70
  71 static int buffer_free(BIO *a)
  72 {
  73     BIO_F_BUFFER_CTX *b;
  74
  75     if (a == NULL)
  76         return 0;
  77     b = (BIO_F_BUFFER_CTX *)a->ptr;
  78     OPENSSL_free(b->ibuf);
  79     OPENSSL_free(b->obuf);
  80     OPENSSL_free(a->ptr);
  81     a->ptr = NULL;
  82     a->init = 0;
  83     a->flags = 0;
  84     return 1;
  85 }
  86
  87 static int buffer_read(BIO *b, char *out, int outl)
  88 {
  89     int i, num = 0;
  90     BIO_F_BUFFER_CTX *ctx;
  91
  92     if (out == NULL)
  93         return 0;
  94     ctx = (BIO_F_BUFFER_CTX *)b->ptr;
  95
  96     if ((ctx == NULL) || (b->next_bio == NULL))
  97         return 0;
  98     num = 0;
  99     BIO_clear_retry_flags(b);
 100
 101  start:
 102     i = ctx->ibuf_len;
 103     /* If there is stuff left over, grab it */
 104     if (i != 0) {
 105         if (i > outl)
 106             i = outl;
 107         memcpy(out, &(ctx->ibuf[ctx->ibuf_off]), i);
 108         ctx->ibuf_off += i;
 109         ctx->ibuf_len -= i;
 110         num += i;
 111         if (outl == i)
 112             return num;
 113         outl -= i;
 114         out += i;
 115     }
 116
 117     /*
 118      * We may have done a partial read. try to do more. We have nothing in
 119      * the buffer. If we get an error and have read some data, just return it
 120      * and let them retry to get the error again. copy direct to parent
 121      * address space
 122      */
 123     if (outl > ctx->ibuf_size) {
 124         for (;;) {
 125             i = BIO_read(b->next_bio, out, outl);
 126             if (i <= 0) {
 127                 BIO_copy_next_retry(b);
 128                 if (i < 0)
 129                     return ((num > 0) ? num : i);
 130                 if (i == 0)
 131                     return num;
 132             }
 133             num += i;
 134             if (outl == i)
 135                 return num;
 136             out += i;
 137             outl -= i;
 138         }
 139     }
 140     /* else */
 141
 142     /* we are going to be doing some buffering */
 143     i = BIO_read(b->next_bio, ctx->ibuf, ctx->ibuf_size);
 144     if (i <= 0) {
 145         BIO_copy_next_retry(b);
 146         if (i < 0)
 147             return ((num > 0) ? num : i);
 148         if (i == 0)
 149             return num;
 150     }
 151     ctx->ibuf_off = 0;
 152     ctx->ibuf_len = i;
 153
 154     /* Lets re-read using ourselves :-) */
 155     goto start;
 156 }
 157
 158 static int buffer_write(BIO *b, const char *in, int inl)
 159 {
 160     int i, num = 0;
 161     BIO_F_BUFFER_CTX *ctx;
 162
 163     if ((in == NULL) || (inl <= 0))
 164         return 0;
 165     ctx = (BIO_F_BUFFER_CTX *)b->ptr;
 166     if ((ctx == NULL) || (b->next_bio == NULL))
 167         return 0;
 168
 169     BIO_clear_retry_flags(b);
 170  start:
 171     i = ctx->obuf_size - (ctx->obuf_len + ctx->obuf_off);
 172     /* add to buffer and return */
 173     if (i >= inl) {
 174         memcpy(&(ctx->obuf[ctx->obuf_off + ctx->obuf_len]), in, inl);
 175         ctx->obuf_len += inl;
 176         return (num + inl);
 177     }
 178     /* else */
 179     /* stuff already in buffer, so add to it first, then flush */
 180     if (ctx->obuf_len != 0) {
 181         if (i > 0) {            /* lets fill it up if we can */
 182             memcpy(&(ctx->obuf[ctx->obuf_off + ctx->obuf_len]), in, i);
 183             in += i;
 184             inl -= i;
 185             num += i;
 186             ctx->obuf_len += i;
 187         }
 188         /* we now have a full buffer needing flushing */
 189         for (;;) {
 190             i = BIO_write(b->next_bio, &(ctx->obuf[ctx->obuf_off]),
 191                           ctx->obuf_len);
 192             if (i <= 0) {
 193                 BIO_copy_next_retry(b);
 194
 195                 if (i < 0)
 196                     return ((num > 0) ? num : i);
 197                 if (i == 0)
 198                     return num;
 199             }
 200             ctx->obuf_off += i;
 201             ctx->obuf_len -= i;
 202             if (ctx->obuf_len == 0)
 203                 break;
 204         }
 205     }
 206     /*
 207      * we only get here if the buffer has been flushed and we still have
 208      * stuff to write
 209      */
 210     ctx->obuf_off = 0;
 211
 212     /* we now have inl bytes to write */
 213     while (inl >= ctx->obuf_size) {
 214         i = BIO_write(b->next_bio, in, inl);
 215         if (i <= 0) {
 216             BIO_copy_next_retry(b);
 217             if (i < 0)
 218                 return ((num > 0) ? num : i);
 219             if (i == 0)
 220                 return num;
 221         }
 222         num += i;
 223         in += i;
 224         inl -= i;
 225         if (inl == 0)
 226             return num;
 227     }
 228
 229     /*
 230      * copy the rest into the buffer since we have only a small amount left
 231      */
 232     goto start;
 233 }
 234
 235 static long buffer_ctrl(BIO *b, int cmd, long num, void *ptr)
 236 {
 237     BIO *dbio;
 238     BIO_F_BUFFER_CTX *ctx;
 239     long ret = 1;
 240     char *p1, *p2;
 241     int r, i, *ip;
 242     int ibs, obs;
 243
 244     ctx = (BIO_F_BUFFER_CTX *)b->ptr;
 245
 246     switch (cmd) {
 247     case BIO_CTRL_RESET:
 248         ctx->ibuf_off = 0;
 249         ctx->ibuf_len = 0;
 250         ctx->obuf_off = 0;
 251         ctx->obuf_len = 0;
 252         if (b->next_bio == NULL)
 253             return 0;
 254         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 255         break;
 256     case BIO_CTRL_EOF:
 257         if (ctx->ibuf_len > 0)
 258             return 0;
 259         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 260         break;
 261     case BIO_CTRL_INFO:
 262         ret = (long)ctx->obuf_len;
 263         break;
 264     case BIO_C_GET_BUFF_NUM_LINES:
 265         ret = 0;
 266         p1 = ctx->ibuf;
 267         for (i = 0; i < ctx->ibuf_len; i++) {
 268             if (p1[ctx->ibuf_off + i] == '\n')
 269                 ret++;
 270         }
 271         break;
 272     case BIO_CTRL_WPENDING:
 273         ret = (long)ctx->obuf_len;
 274         if (ret == 0) {
 275             if (b->next_bio == NULL)
 276                 return 0;
 277             ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 278         }
 279         break;
 280     case BIO_CTRL_PENDING:
 281         ret = (long)ctx->ibuf_len;
 282         if (ret == 0) {
 283             if (b->next_bio == NULL)
 284                 return 0;
 285             ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 286         }
 287         break;
 288     case BIO_C_SET_BUFF_READ_DATA:
 289         if (num > ctx->ibuf_size) {
 290             if (num <= 0)
 291                 return 0;
 292             p1 = OPENSSL_malloc((size_t)num);
 293             if (p1 == NULL)
 294                 return 0;
 295             OPENSSL_free(ctx->ibuf);
 296             ctx->ibuf = p1;
 297         }
 298         ctx->ibuf_off = 0;
 299         ctx->ibuf_len = (int)num;
 300         memcpy(ctx->ibuf, ptr, (int)num);
 301         ret = 1;
 302         break;
 303     case BIO_C_SET_BUFF_SIZE:
 304         if (ptr != NULL) {
 305             ip = (int *)ptr;
 306             if (*ip == 0) {
 307                 ibs = (int)num;
 308                 obs = ctx->obuf_size;
 309             } else {            /* if (*ip == 1) */
 310
 311                 ibs = ctx->ibuf_size;
 312                 obs = (int)num;
 313             }
 314         } else {
 315             ibs = (int)num;
 316             obs = (int)num;
 317         }
 318         p1 = ctx->ibuf;
 319         p2 = ctx->obuf;
 320         if ((ibs > DEFAULT_BUFFER_SIZE) && (ibs != ctx->ibuf_size)) {
 321             if (num <= 0)
 322                 return 0;
 323             p1 = OPENSSL_malloc((size_t)num);
 324             if (p1 == NULL)
 325                 return 0;
 326         }
 327         if ((obs > DEFAULT_BUFFER_SIZE) && (obs != ctx->obuf_size)) {
 328             p2 = OPENSSL_malloc((size_t)num);
 329             if (p2 == NULL) {
 330                 if (p1 != ctx->ibuf)
 331                     OPENSSL_free(p1);
 332                 return 0;
 333             }
 334         }
 335         if (ctx->ibuf != p1) {
 336             OPENSSL_free(ctx->ibuf);
 337             ctx->ibuf = p1;
 338             ctx->ibuf_off = 0;
 339             ctx->ibuf_len = 0;
 340             ctx->ibuf_size = ibs;
 341         }
 342         if (ctx->obuf != p2) {
 343             OPENSSL_free(ctx->obuf);
 344             ctx->obuf = p2;
 345             ctx->obuf_off = 0;
 346             ctx->obuf_len = 0;
 347             ctx->obuf_size = obs;
 348         }
 349         break;
 350     case BIO_C_DO_STATE_MACHINE:
 351         if (b->next_bio == NULL)
 352             return 0;
 353         BIO_clear_retry_flags(b);
 354         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 355         BIO_copy_next_retry(b);
 356         break;
 357
 358     case BIO_CTRL_FLUSH:
 359         if (b->next_bio == NULL)
 360             return 0;
 361         if (ctx->obuf_len <= 0) {
 362             ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 363             break;
 364         }
 365
 366         for (;;) {
 367             BIO_clear_retry_flags(b);
 368             if (ctx->obuf_len > 0) {
 369                 r = BIO_write(b->next_bio,
 370                               &(ctx->obuf[ctx->obuf_off]), ctx->obuf_len);
 371                 BIO_copy_next_retry(b);
 372                 if (r <= 0)
 373                     return (long)r;
 374                 ctx->obuf_off += r;
 375                 ctx->obuf_len -= r;
 376             } else {
 377                 ctx->obuf_len = 0;
 378                 ctx->obuf_off = 0;
 379                 break;
 380             }
 381         }
 382         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 383         break;
 384     case BIO_CTRL_DUP:
 385         dbio = (BIO *)ptr;
 386         if (!BIO_set_read_buffer_size(dbio, ctx->ibuf_size) ||
 387             !BIO_set_write_buffer_size(dbio, ctx->obuf_size))
 388             ret = 0;
 389         break;
 390     case BIO_CTRL_PEEK:
 391         /* Ensure there's stuff in the input buffer */
 392         {
 393             char fake_buf[1];
 394             (void)buffer_read(b, fake_buf, 0);
 395         }
 396         if (num > ctx->ibuf_len)
 397             num = ctx->ibuf_len;
 398         memcpy(ptr, &(ctx->ibuf[ctx->ibuf_off]), num);
 399         ret = num;
 400         break;
 401     default:
 402         if (b->next_bio == NULL)
 403             return 0;
 404         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 405         break;
 406     }
 407     return ret;
 408 }
 409
 410 static long buffer_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
 411 {
 412     if (b->next_bio == NULL)
 413         return 0;
 414     return BIO_callback_ctrl(b->next_bio, cmd, fp);
 415 }
 416
 417 static int buffer_gets(BIO *b, char *buf, int size)
 418 {
 419     BIO_F_BUFFER_CTX *ctx;
 420     int num = 0, i, flag;
 421     char *p;
 422
 423     ctx = (BIO_F_BUFFER_CTX *)b->ptr;
 424     size--;                     /* reserve space for a '\0' */
 425     BIO_clear_retry_flags(b);
 426
 427     for (;;) {
 428         if (ctx->ibuf_len > 0) {
 429             p = &(ctx->ibuf[ctx->ibuf_off]);
 430             flag = 0;
 431             for (i = 0; (i < ctx->ibuf_len) && (i < size); i++) {
 432                 *(buf++) = p[i];
 433                 if (p[i] == '\n') {
 434                     flag = 1;
 435                     i++;
 436                     break;
 437                 }
 438             }
 439             num += i;
 440             size -= i;
 441             ctx->ibuf_len -= i;
 442             ctx->ibuf_off += i;
 443             if (flag || size == 0) {
 444                 *buf = '\0';
 445                 return num;
 446             }
 447         } else {                /* read another chunk */
 448
 449             i = BIO_read(b->next_bio, ctx->ibuf, ctx->ibuf_size);
 450             if (i <= 0) {
 451                 BIO_copy_next_retry(b);
 452                 *buf = '\0';
 453                 if (i < 0)
 454                     return ((num > 0) ? num : i);
 455                 if (i == 0)
 456                     return num;
 457             }
 458             ctx->ibuf_len = i;
 459             ctx->ibuf_off = 0;
 460         }
 461     }
 462 }
 463
 464 static int buffer_puts(BIO *b, const char *str)
 465 {
 466     return buffer_write(b, str, strlen(str));
 467 }