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
15static int mem_write(BIO *h, const char *buf, int num);
16static int mem_read(BIO *h, char *buf, int size);
17static int mem_puts(BIO *h, const char *str);
18static int mem_gets(BIO *h, char *str, int size);
19static long mem_ctrl(BIO *h, int cmd, long arg1, void *arg2);
20static int mem_new(BIO *h);
21static int secmem_new(BIO *h);
22static int mem_free(BIO *data);
23static int mem_buf_free(BIO *data);
24static int mem_buf_sync(BIO *h);
25
26static const BIO_METHOD mem_method = {
27    BIO_TYPE_MEM,
28    "memory buffer",
29    bwrite_conv,
30    mem_write,
31    bread_conv,
32    mem_read,
33    mem_puts,
34    mem_gets,
35    mem_ctrl,
36    mem_new,
37    mem_free,
38    NULL,                      /* mem_callback_ctrl */
39};
40
41static const BIO_METHOD secmem_method = {
42    BIO_TYPE_MEM,
43    "secure memory buffer",
44    bwrite_conv,
45    mem_write,
46    bread_conv,
47    mem_read,
48    mem_puts,
49    mem_gets,
50    mem_ctrl,
51    secmem_new,
52    mem_free,
53    NULL,                      /* mem_callback_ctrl */
54};
55
56/*
57 * BIO memory stores buffer and read pointer
58 * however the roles are different for read only BIOs.
59 * In that case the readp just stores the original state
60 * to be used for reset.
61 */
62typedef struct bio_buf_mem_st {
63    struct buf_mem_st *buf;   /* allocated buffer */
64    struct buf_mem_st *readp; /* read pointer */
65} BIO_BUF_MEM;
66
67/*
68 * bio->num is used to hold the value to return on 'empty', if it is 0,
69 * should_retry is not set
70 */
71
72const BIO_METHOD *BIO_s_mem(void)
73{
74    return &mem_method;
75}
76
77const BIO_METHOD *BIO_s_secmem(void)
78{
79    return(&secmem_method);
80}
81
82BIO *BIO_new_mem_buf(const void *buf, int len)
83{
84    BIO *ret;
85    BUF_MEM *b;
86    BIO_BUF_MEM *bb;
87    size_t sz;
88
89    if (buf == NULL) {
90        ERR_raise(ERR_LIB_BIO, ERR_R_PASSED_NULL_PARAMETER);
91        return NULL;
92    }
93    sz = (len < 0) ? strlen(buf) : (size_t)len;
94    if ((ret = BIO_new(BIO_s_mem())) == NULL)
95        return NULL;
96    bb = (BIO_BUF_MEM *)ret->ptr;
97    b = bb->buf;
98    /* Cast away const and trust in the MEM_RDONLY flag. */
99    b->data = (void *)buf;
100    b->length = sz;
101    b->max = sz;
102    *bb->readp = *bb->buf;
103    ret->flags |= BIO_FLAGS_MEM_RDONLY;
104    /* Since this is static data retrying won't help */
105    ret->num = 0;
106    return ret;
107}
108
109static int mem_init(BIO *bi, unsigned long flags)
110{
111    BIO_BUF_MEM *bb = OPENSSL_zalloc(sizeof(*bb));
112
113    if (bb == NULL)
114        return 0;
115    if ((bb->buf = BUF_MEM_new_ex(flags)) == NULL) {
116        OPENSSL_free(bb);
117        return 0;
118    }
119    if ((bb->readp = OPENSSL_zalloc(sizeof(*bb->readp))) == NULL) {
120        BUF_MEM_free(bb->buf);
121        OPENSSL_free(bb);
122        return 0;
123    }
124    *bb->readp = *bb->buf;
125    bi->shutdown = 1;
126    bi->init = 1;
127    bi->num = -1;
128    bi->ptr = (char *)bb;
129    return 1;
130}
131
132static int mem_new(BIO *bi)
133{
134    return mem_init(bi, 0L);
135}
136
137static int secmem_new(BIO *bi)
138{
139    return mem_init(bi, BUF_MEM_FLAG_SECURE);
140}
141
142static int mem_free(BIO *a)
143{
144    BIO_BUF_MEM *bb;
145
146    if (a == NULL)
147        return 0;
148
149    bb = (BIO_BUF_MEM *)a->ptr;
150    if (!mem_buf_free(a))
151        return 0;
152    OPENSSL_free(bb->readp);
153    OPENSSL_free(bb);
154    return 1;
155}
156
157static int mem_buf_free(BIO *a)
158{
159    if (a == NULL)
160        return 0;
161
162    if (a->shutdown && a->init && a->ptr != NULL) {
163        BIO_BUF_MEM *bb = (BIO_BUF_MEM *)a->ptr;
164        BUF_MEM *b = bb->buf;
165
166        if (a->flags & BIO_FLAGS_MEM_RDONLY)
167            b->data = NULL;
168        BUF_MEM_free(b);
169    }
170    return 1;
171}
172
173/*
174 * Reallocate memory buffer if read pointer differs
175 * NOT FOR RDONLY
176 */
177static int mem_buf_sync(BIO *b)
178{
179    if (b != NULL && b->init != 0 && b->ptr != NULL) {
180        BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
181
182        if (bbm->readp->data != bbm->buf->data) {
183            memmove(bbm->buf->data, bbm->readp->data, bbm->readp->length);
184            bbm->buf->length = bbm->readp->length;
185            bbm->readp->data = bbm->buf->data;
186        }
187    }
188    return 0;
189}
190
191static int mem_read(BIO *b, char *out, int outl)
192{
193    int ret = -1;
194    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
195    BUF_MEM *bm = bbm->readp;
196
197    if (b->flags & BIO_FLAGS_MEM_RDONLY)
198        bm = bbm->buf;
199    BIO_clear_retry_flags(b);
200    ret = (outl >= 0 && (size_t)outl > bm->length) ? (int)bm->length : outl;
201    if ((out != NULL) && (ret > 0)) {
202        memcpy(out, bm->data, ret);
203        bm->length -= ret;
204        bm->max -= ret;
205        bm->data += ret;
206    } else if (bm->length == 0) {
207        ret = b->num;
208        if (ret != 0)
209            BIO_set_retry_read(b);
210    }
211    return ret;
212}
213
214static int mem_write(BIO *b, const char *in, int inl)
215{
216    int ret = -1;
217    int blen;
218    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
219
220    if (b->flags & BIO_FLAGS_MEM_RDONLY) {
221        ERR_raise(ERR_LIB_BIO, BIO_R_WRITE_TO_READ_ONLY_BIO);
222        goto end;
223    }
224    BIO_clear_retry_flags(b);
225    if (inl == 0)
226        return 0;
227    if (in == NULL) {
228        ERR_raise(ERR_LIB_BIO, ERR_R_PASSED_NULL_PARAMETER);
229        goto end;
230    }
231    blen = bbm->readp->length;
232    mem_buf_sync(b);
233    if (BUF_MEM_grow_clean(bbm->buf, blen + inl) == 0)
234        goto end;
235    memcpy(bbm->buf->data + blen, in, inl);
236    *bbm->readp = *bbm->buf;
237    ret = inl;
238 end:
239    return ret;
240}
241
242static long mem_ctrl(BIO *b, int cmd, long num, void *ptr)
243{
244    long ret = 1;
245    char **pptr;
246    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;
247    BUF_MEM *bm, *bo;            /* bio_mem, bio_other */
248    long off, remain;
249
250    if (b->flags & BIO_FLAGS_MEM_RDONLY) {
251        bm = bbm->buf;
252        bo = bbm->readp;
253    } else {
254        bm = bbm->readp;
255        bo = bbm->buf;
256    }
257    off = (bm->data == bo->data) ? 0 : bm->data - bo->data;
258    remain = bm->length;
259
260    switch (cmd) {
261    case BIO_CTRL_RESET:
262        bm = bbm->buf;
263        if (bm->data != NULL) {
264            if (!(b->flags & BIO_FLAGS_MEM_RDONLY)) {
265                if (!(b->flags & BIO_FLAGS_NONCLEAR_RST)) {
266                    memset(bm->data, 0, bm->max);
267                    bm->length = 0;
268                }
269                *bbm->readp = *bbm->buf;
270            } else {
271                /* For read only case just reset to the start again */
272                *bbm->buf = *bbm->readp;
273            }
274        }
275        break;
276    case BIO_C_FILE_SEEK:
277        if (num < 0 || num > off + remain)
278            return -1;   /* Can't see outside of the current buffer */
279
280        bm->data = (num != 0) ? bo->data + num : bo->data;
281        bm->length = bo->length - num;
282        bm->max = bo->max - num;
283        off = num;
284        /* FALLTHRU */
285    case BIO_C_FILE_TELL:
286        ret = off;
287        break;
288    case BIO_CTRL_EOF:
289        ret = (long)(bm->length == 0);
290        break;
291    case BIO_C_SET_BUF_MEM_EOF_RETURN:
292        b->num = (int)num;
293        break;
294    case BIO_CTRL_INFO:
295        ret = (long)bm->length;
296        if (ptr != NULL) {
297            pptr = (char **)ptr;
298            *pptr = (char *)(bm->data);
299        }
300        break;
301    case BIO_C_SET_BUF_MEM:
302        mem_buf_free(b);
303        b->shutdown = (int)num;
304        bbm->buf = ptr;
305        *bbm->readp = *bbm->buf;
306        break;
307    case BIO_C_GET_BUF_MEM_PTR:
308        if (ptr != NULL) {
309            if (!(b->flags & BIO_FLAGS_MEM_RDONLY))
310                mem_buf_sync(b);
311            bm = bbm->buf;
312            pptr = (char **)ptr;
313            *pptr = (char *)bm;
314        }
315        break;
316    case BIO_CTRL_GET_CLOSE:
317        ret = (long)b->shutdown;
318        break;
319    case BIO_CTRL_SET_CLOSE:
320        b->shutdown = (int)num;
321        break;
322    case BIO_CTRL_WPENDING:
323        ret = 0L;
324        break;
325    case BIO_CTRL_PENDING:
326        ret = (long)bm->length;
327        break;
328    case BIO_CTRL_DUP:
329    case BIO_CTRL_FLUSH:
330        ret = 1;
331        break;
332    case BIO_CTRL_PUSH:
333    case BIO_CTRL_POP:
334    default:
335        ret = 0;
336        break;
337    }
338    return ret;
339}
340
341static int mem_gets(BIO *bp, char *buf, int size)
342{
343    int i, j;
344    int ret = -1;
345    char *p;
346    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)bp->ptr;
347    BUF_MEM *bm = bbm->readp;
348
349    if (bp->flags & BIO_FLAGS_MEM_RDONLY)
350        bm = bbm->buf;
351    BIO_clear_retry_flags(bp);
352    j = bm->length;
353    if ((size - 1) < j)
354        j = size - 1;
355    if (j <= 0) {
356        *buf = '\0';
357        return 0;
358    }
359    p = bm->data;
360    for (i = 0; i < j; i++) {
361        if (p[i] == '\n') {
362            i++;
363            break;
364        }
365    }
366
367    /*
368     * i is now the max num of bytes to copy, either j or up to
369     * and including the first newline
370     */
371
372    i = mem_read(bp, buf, i);
373    if (i > 0)
374        buf[i] = '\0';
375    ret = i;
376    return ret;
377}
378
379static int mem_puts(BIO *bp, const char *str)
380{
381    int n, ret;
382
383    n = strlen(str);
384    ret = mem_write(bp, str, n);
385    /* memory semantics is that it will always work */
386    return ret;
387}
388