crypto/bio/bss_mem.c

   1 /*
   2  * Copyright 1995-2020 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 mem_write(BIO *h, const char *buf, int num);
  16 static int mem_read(BIO *h, char *buf, int size);
  17 static int mem_puts(BIO *h, const char *str);
  18 static int mem_gets(BIO *h, char *str, int size);
  19 static long mem_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  20 static int mem_new(BIO *h);
  21 static int secmem_new(BIO *h);
  22 static int mem_free(BIO *data);
  23 static int mem_buf_free(BIO *data);
  24 static int mem_buf_sync(BIO *h);
  25
  26 static const BIO_METHOD mem_method = {
  27     BIO_TYPE_MEM,
  28     "memory buffer",
  29     /* TODO: Convert to new style write function */
  30     bwrite_conv,
  31     mem_write,
  32     /* TODO: Convert to new style read function */
  33     bread_conv,
  34     mem_read,
  35     mem_puts,
  36     mem_gets,
  37     mem_ctrl,
  38     mem_new,
  39     mem_free,
  40     NULL,                      /* mem_callback_ctrl */
  41 };
  42
  43 static const BIO_METHOD secmem_method = {
  44     BIO_TYPE_MEM,
  45     "secure memory buffer",
  46     /* TODO: Convert to new style write function */
  47     bwrite_conv,
  48     mem_write,
  49     /* TODO: Convert to new style read function */
  50     bread_conv,
  51     mem_read,
  52     mem_puts,
  53     mem_gets,
  54     mem_ctrl,
  55     secmem_new,
  56     mem_free,
  57     NULL,                      /* mem_callback_ctrl */
  58 };
  59
  60 /*
  61  * BIO memory stores buffer and read pointer
  62  * however the roles are different for read only BIOs.
  63  * In that case the readp just stores the original state
  64  * to be used for reset.
  65  */
  66 typedef struct bio_buf_mem_st {
  67     struct buf_mem_st *buf;   /* allocated buffer */
  68     struct buf_mem_st *readp; /* read pointer */
  69 } BIO_BUF_MEM;
  70
  71 /*
  72  * bio->num is used to hold the value to return on 'empty', if it is 0,
  73  * should_retry is not set
  74  */
  75
  76 const BIO_METHOD *BIO_s_mem(void)
  77 {
  78     return &mem_method;
  79 }
  80
  81 const BIO_METHOD *BIO_s_secmem(void)
  82 {
  83     return(&secmem_method);
  84 }
  85
  86 BIO *BIO_new_mem_buf(const void *buf, int len)
  87 {
  88     BIO *ret;
  89     BUF_MEM *b;
  90     BIO_BUF_MEM *bb;
  91     size_t sz;
  92
  93     if (buf == NULL) {
  94         BIOerr(BIO_F_BIO_NEW_MEM_BUF, BIO_R_NULL_PARAMETER);
  95         return NULL;
  96     }
  97     sz = (len < 0) ? strlen(buf) : (size_t)len;
  98     if ((ret = BIO_new(BIO_s_mem())) == NULL)
  99         return NULL;
 100     bb = (BIO_BUF_MEM *)ret->ptr;
 101     b = bb->buf;
 102     /* Cast away const and trust in the MEM_RDONLY flag. */
 103     b->data = (void *)buf;
 104     b->length = sz;
 105     b->max = sz;
 106     *bb->readp = *bb->buf;
 107     ret->flags |= BIO_FLAGS_MEM_RDONLY;
 108     /* Since this is static data retrying won't help */
 109     ret->num = 0;
 110     return ret;
 111 }
 112
 113 static int mem_init(BIO *bi, unsigned long flags)
 114 {
 115     BIO_BUF_MEM *bb = OPENSSL_zalloc(sizeof(*bb));
 116
 117     if (bb == NULL)
 118         return 0;
 119     if ((bb->buf = BUF_MEM_new_ex(flags)) == NULL) {
 120         OPENSSL_free(bb);
 121         return 0;
 122     }
 123     if ((bb->readp = OPENSSL_zalloc(sizeof(*bb->readp))) == NULL) {
 124         BUF_MEM_free(bb->buf);
 125         OPENSSL_free(bb);
 126         return 0;
 127     }
 128     *bb->readp = *bb->buf;
 129     bi->shutdown = 1;
 130     bi->init = 1;
 131     bi->num = -1;
 132     bi->ptr = (char *)bb;
 133     return 1;
 134 }
 135
 136 static int mem_new(BIO *bi)
 137 {
 138     return mem_init(bi, 0L);
 139 }
 140
 141 static int secmem_new(BIO *bi)
 142 {
 143     return mem_init(bi, BUF_MEM_FLAG_SECURE);
 144 }
 145
 146 static int mem_free(BIO *a)
 147 {
 148     BIO_BUF_MEM *bb;
 149
 150     if (a == NULL)
 151         return 0;
 152
 153     bb = (BIO_BUF_MEM *)a->ptr;
 154     if (!mem_buf_free(a))
 155         return 0;
 156     OPENSSL_free(bb->readp);
 157     OPENSSL_free(bb);
 158     return 1;
 159 }
 160
 161 static int mem_buf_free(BIO *a)
 162 {
 163     if (a == NULL)
 164         return 0;
 165
 166     if (a->shutdown && a->init && a->ptr != NULL) {
 167         BIO_BUF_MEM *bb = (BIO_BUF_MEM *)a->ptr;
 168         BUF_MEM *b = bb->buf;
 169
 170         if (a->flags & BIO_FLAGS_MEM_RDONLY)
 171             b->data = NULL;
 172         BUF_MEM_free(b);
 173     }
 174     return 1;
 175 }
 176
 177 /*
 178  * Reallocate memory buffer if read pointer differs
 179  * NOT FOR RDONLY
 180  */
 181 static int mem_buf_sync(BIO *b)
 182 {
 183     if (b != NULL && b->init != 0 && b->ptr != NULL) {
 184         BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
 185
 186         if (bbm->readp->data != bbm->buf->data) {
 187             memmove(bbm->buf->data, bbm->readp->data, bbm->readp->length);
 188             bbm->buf->length = bbm->readp->length;
 189             bbm->readp->data = bbm->buf->data;
 190         }
 191     }
 192     return 0;
 193 }
 194
 195 static int mem_read(BIO *b, char *out, int outl)
 196 {
 197     int ret = -1;
 198     BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
 199     BUF_MEM *bm = bbm->readp;
 200
 201     if (b->flags & BIO_FLAGS_MEM_RDONLY)
 202         bm = bbm->buf;
 203     BIO_clear_retry_flags(b);
 204     ret = (outl >= 0 && (size_t)outl > bm->length) ? (int)bm->length : outl;
 205     if ((out != NULL) && (ret > 0)) {
 206         memcpy(out, bm->data, ret);
 207         bm->length -= ret;
 208         bm->max -= ret;
 209         bm->data += ret;
 210     } else if (bm->length == 0) {
 211         ret = b->num;
 212         if (ret != 0)
 213             BIO_set_retry_read(b);
 214     }
 215     return ret;
 216 }
 217
 218 static int mem_write(BIO *b, const char *in, int inl)
 219 {
 220     int ret = -1;
 221     int blen;
 222     BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
 223
 224     if (in == NULL) {
 225         BIOerr(BIO_F_MEM_WRITE, BIO_R_NULL_PARAMETER);
 226         goto end;
 227     }
 228     if (b->flags & BIO_FLAGS_MEM_RDONLY) {
 229         BIOerr(BIO_F_MEM_WRITE, BIO_R_WRITE_TO_READ_ONLY_BIO);
 230         goto end;
 231     }
 232     BIO_clear_retry_flags(b);
 233     if (inl == 0)
 234         return 0;
 235     blen = bbm->readp->length;
 236     mem_buf_sync(b);
 237     if (BUF_MEM_grow_clean(bbm->buf, blen + inl) == 0)
 238         goto end;
 239     memcpy(bbm->buf->data + blen, in, inl);
 240     *bbm->readp = *bbm->buf;
 241     ret = inl;
 242  end:
 243     return ret;
 244 }
 245
 246 static long mem_ctrl(BIO *b, int cmd, long num, void *ptr)
 247 {
 248     long ret = 1;
 249     char **pptr;
 250     BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
 251     BUF_MEM *bm, *bo;            /* bio_mem, bio_other */
 252     long off, remain;
 253
 254     if (b->flags & BIO_FLAGS_MEM_RDONLY) {
 255         bm = bbm->buf;
 256         bo = bbm->readp;
 257     } else {
 258         bm = bbm->readp;
 259         bo = bbm->buf;
 260     }
 261     off = bm->data - bo->data;
 262     remain = bm->length;
 263
 264     switch (cmd) {
 265     case BIO_CTRL_RESET:
 266         bm = bbm->buf;
 267         if (bm->data != NULL) {
 268             if (!(b->flags & BIO_FLAGS_MEM_RDONLY)) {
 269                 if (!(b->flags & BIO_FLAGS_NONCLEAR_RST)) {
 270                     memset(bm->data, 0, bm->max);
 271                     bm->length = 0;
 272                 }
 273                 *bbm->readp = *bbm->buf;
 274             } else {
 275                 /* For read only case just reset to the start again */
 276                 *bbm->buf = *bbm->readp;
 277             }
 278         }
 279         break;
 280     case BIO_C_FILE_SEEK:
 281         if (num < 0 || num > off + remain)
 282             return -1;   /* Can't see outside of the current buffer */
 283
 284         bm->data = bo->data + num;
 285         bm->length = bo->length - num;
 286         bm->max = bo->max - num;
 287         off = num;
 288         /* FALLTHRU */
 289     case BIO_C_FILE_TELL:
 290         ret = off;
 291         break;
 292     case BIO_CTRL_EOF:
 293         ret = (long)(bm->length == 0);
 294         break;
 295     case BIO_C_SET_BUF_MEM_EOF_RETURN:
 296         b->num = (int)num;
 297         break;
 298     case BIO_CTRL_INFO:
 299         ret = (long)bm->length;
 300         if (ptr != NULL) {
 301             pptr = (char **)ptr;
 302             *pptr = (char *)&(bm->data[0]);
 303         }
 304         break;
 305     case BIO_C_SET_BUF_MEM:
 306         mem_buf_free(b);
 307         b->shutdown = (int)num;
 308         bbm->buf = ptr;
 309         *bbm->readp = *bbm->buf;
 310         break;
 311     case BIO_C_GET_BUF_MEM_PTR:
 312         if (ptr != NULL) {
 313             if (!(b->flags & BIO_FLAGS_MEM_RDONLY))
 314                 mem_buf_sync(b);
 315             bm = bbm->buf;
 316             pptr = (char **)ptr;
 317             *pptr = (char *)bm;
 318         }
 319         break;
 320     case BIO_CTRL_GET_CLOSE:
 321         ret = (long)b->shutdown;
 322         break;
 323     case BIO_CTRL_SET_CLOSE:
 324         b->shutdown = (int)num;
 325         break;
 326     case BIO_CTRL_WPENDING:
 327         ret = 0L;
 328         break;
 329     case BIO_CTRL_PENDING:
 330         ret = (long)bm->length;
 331         break;
 332     case BIO_CTRL_DUP:
 333     case BIO_CTRL_FLUSH:
 334         ret = 1;
 335         break;
 336     case BIO_CTRL_PUSH:
 337     case BIO_CTRL_POP:
 338     default:
 339         ret = 0;
 340         break;
 341     }
 342     return ret;
 343 }
 344
 345 static int mem_gets(BIO *bp, char *buf, int size)
 346 {
 347     int i, j;
 348     int ret = -1;
 349     char *p;
 350     BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)bp->ptr;
 351     BUF_MEM *bm = bbm->readp;
 352
 353     if (bp->flags & BIO_FLAGS_MEM_RDONLY)
 354         bm = bbm->buf;
 355     BIO_clear_retry_flags(bp);
 356     j = bm->length;
 357     if ((size - 1) < j)
 358         j = size - 1;
 359     if (j <= 0) {
 360         *buf = '\0';
 361         return 0;
 362     }
 363     p = bm->data;
 364     for (i = 0; i < j; i++) {
 365         if (p[i] == '\n') {
 366             i++;
 367             break;
 368         }
 369     }
 370
 371     /*
 372      * i is now the max num of bytes to copy, either j or up to
 373      * and including the first newline
 374      */
 375
 376     i = mem_read(bp, buf, i);
 377     if (i > 0)
 378         buf[i] = '\0';
 379     ret = i;
 380     return ret;
 381 }
 382
 383 static int mem_puts(BIO *bp, const char *str)
 384 {
 385     int n, ret;
 386
 387     n = strlen(str);
 388     ret = mem_write(bp, str, n);
 389     /* memory semantics is that it will always work */
 390     return ret;
 391 }