/* $OpenBSD: bf_buff.c,v 1.29 2025/05/10 05:54:38 tb Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <errno.h>
#include <stdio.h>
#include <string.h>

#include <openssl/bio.h>

#include "bio_local.h"
#include "err_local.h"

static int buffer_write(BIO *h, const char *buf, int num);
static int buffer_read(BIO *h, char *buf, int size);
static int buffer_puts(BIO *h, const char *str);
static int buffer_gets(BIO *h, char *str, int size);
static long buffer_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int buffer_new(BIO *h);
static int buffer_free(BIO *data);
static long buffer_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp);
#define DEFAULT_BUFFER_SIZE     4096

static const BIO_METHOD methods_buffer = {
        .type = BIO_TYPE_BUFFER,
        .name = "buffer",
        .bwrite = buffer_write,
        .bread = buffer_read,
        .bputs = buffer_puts,
        .bgets = buffer_gets,
        .ctrl = buffer_ctrl,
        .create = buffer_new,
        .destroy = buffer_free,
        .callback_ctrl = buffer_callback_ctrl
};

const BIO_METHOD *
BIO_f_buffer(void)
{
        return (&methods_buffer);
}
LCRYPTO_ALIAS(BIO_f_buffer);

static int
buffer_new(BIO *bi)
{
        BIO_F_BUFFER_CTX *ctx;

        ctx = malloc(sizeof(BIO_F_BUFFER_CTX));
        if (ctx == NULL)
                return (0);
        ctx->ibuf = malloc(DEFAULT_BUFFER_SIZE);
        if (ctx->ibuf == NULL) {
                free(ctx);
                return (0);
        }
        ctx->obuf = malloc(DEFAULT_BUFFER_SIZE);
        if (ctx->obuf == NULL) {
                free(ctx->ibuf);
                free(ctx);
                return (0);
        }
        ctx->ibuf_size = DEFAULT_BUFFER_SIZE;
        ctx->obuf_size = DEFAULT_BUFFER_SIZE;
        ctx->ibuf_len = 0;
        ctx->ibuf_off = 0;
        ctx->obuf_len = 0;
        ctx->obuf_off = 0;

        bi->init = 1;
        bi->ptr = (char *)ctx;
        bi->flags = 0;
        return (1);
}

static int
buffer_free(BIO *a)
{
        BIO_F_BUFFER_CTX *b;

        if (a == NULL)
                return (0);
        b = (BIO_F_BUFFER_CTX *)a->ptr;
        free(b->ibuf);
        free(b->obuf);
        free(a->ptr);
        a->ptr = NULL;
        a->init = 0;
        a->flags = 0;
        return (1);
}

static int
buffer_read(BIO *b, char *out, int outl)
{
        int i, num = 0;
        BIO_F_BUFFER_CTX *ctx;

        if (out == NULL)
                return (0);
        ctx = (BIO_F_BUFFER_CTX *)b->ptr;

        if ((ctx == NULL) || (b->next_bio == NULL))
                return (0);
        num = 0;
        BIO_clear_retry_flags(b);

start:
        i = ctx->ibuf_len;
        /* If there is stuff left over, grab it */
        if (i != 0) {
                if (i > outl)
                        i = outl;
                memcpy(out, &(ctx->ibuf[ctx->ibuf_off]), i);
                ctx->ibuf_off += i;
                ctx->ibuf_len -= i;
                num += i;
                if (outl == i)
                        return (num);
                outl -= i;
                out += i;
        }

        /* We may have done a partial read. try to do more.
         * We have nothing in the buffer.
         * If we get an error and have read some data, just return it
         * and let them retry to get the error again.
         * copy direct to parent address space */
        if (outl > ctx->ibuf_size) {
                for (;;) {
                        i = BIO_read(b->next_bio, out, outl);
                        if (i <= 0) {
                                BIO_copy_next_retry(b);
                                if (i < 0)
                                        return ((num > 0) ? num : i);
                                if (i == 0)
                                        return (num);
                        }
                        num += i;
                        if (outl == i)
                                return (num);
                        out += i;
                        outl -= i;
                }
        }
        /* else */

        /* we are going to be doing some buffering */
        i = BIO_read(b->next_bio, ctx->ibuf, ctx->ibuf_size);
        if (i <= 0) {
                BIO_copy_next_retry(b);
                if (i < 0)
                        return ((num > 0) ? num : i);
                if (i == 0)
                        return (num);
        }
        ctx->ibuf_off = 0;
        ctx->ibuf_len = i;

        /* Lets re-read using ourselves :-) */
        goto start;
}

static int
buffer_write(BIO *b, const char *in, int inl)
{
        int i, num = 0;
        BIO_F_BUFFER_CTX *ctx;

        if ((in == NULL) || (inl <= 0))
                return (0);
        ctx = (BIO_F_BUFFER_CTX *)b->ptr;
        if ((ctx == NULL) || (b->next_bio == NULL))
                return (0);

        BIO_clear_retry_flags(b);
start:
        i = ctx->obuf_size - (ctx->obuf_len + ctx->obuf_off);
        /* add to buffer and return */
        if (i >= inl) {
                memcpy(&(ctx->obuf[ctx->obuf_off + ctx->obuf_len]), in, inl);
                ctx->obuf_len += inl;
                return (num + inl);
        }
        /* else */
        /* stuff already in buffer, so add to it first, then flush */
        if (ctx->obuf_len != 0) {
                if (i > 0) /* lets fill it up if we can */
                {
                        memcpy(&(ctx->obuf[ctx->obuf_off + ctx->obuf_len]), in, i);
                        in += i;
                        inl -= i;
                        num += i;
                        ctx->obuf_len += i;
                }
                /* we now have a full buffer needing flushing */
                for (;;) {
                        i = BIO_write(b->next_bio, &(ctx->obuf[ctx->obuf_off]),
                            ctx->obuf_len);
                        if (i <= 0) {
                                BIO_copy_next_retry(b);

                                if (i < 0)
                                        return ((num > 0) ? num : i);
                                if (i == 0)
                                        return (num);
                        }
                        ctx->obuf_off += i;
                        ctx->obuf_len -= i;
                        if (ctx->obuf_len == 0)
                                break;
                }
        }
        /* we only get here if the buffer has been flushed and we
         * still have stuff to write */
        ctx->obuf_off = 0;

        /* we now have inl bytes to write */
        while (inl >= ctx->obuf_size) {
                i = BIO_write(b->next_bio, in, inl);
                if (i <= 0) {
                        BIO_copy_next_retry(b);
                        if (i < 0)
                                return ((num > 0) ? num : i);
                        if (i == 0)
                                return (num);
                }
                num += i;
                in += i;
                inl -= i;
                if (inl == 0)
                        return (num);
        }

        /* copy the rest into the buffer since we have only a small
         * amount left */
        goto start;
}

static long
buffer_ctrl(BIO *b, int cmd, long num, void *ptr)
{
        BIO *dbio;
        BIO_F_BUFFER_CTX *ctx;
        long ret = 1;
        char *p1, *p2;
        int r, i, *ip;
        int ibs, obs;

        ctx = (BIO_F_BUFFER_CTX *)b->ptr;

        switch (cmd) {
        case BIO_CTRL_RESET:
                ctx->ibuf_off = 0;
                ctx->ibuf_len = 0;
                ctx->obuf_off = 0;
                ctx->obuf_len = 0;
                if (b->next_bio == NULL)
                        return (0);
                ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                break;
        case BIO_CTRL_INFO:
                ret = (long)ctx->obuf_len;
                break;
        case BIO_C_GET_BUFF_NUM_LINES:
                ret = 0;
                p1 = ctx->ibuf;
                for (i = 0; i < ctx->ibuf_len; i++) {
                        if (p1[ctx->ibuf_off + i] == '\n')
                                ret++;
                }
                break;
        case BIO_CTRL_WPENDING:
                ret = (long)ctx->obuf_len;
                if (ret == 0) {
                        if (b->next_bio == NULL)
                                return (0);
                        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                }
                break;
        case BIO_CTRL_PENDING:
                ret = (long)ctx->ibuf_len;
                if (ret == 0) {
                        if (b->next_bio == NULL)
                                return (0);
                        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                }
                break;
        case BIO_C_SET_BUFF_READ_DATA:
                if (num > ctx->ibuf_size) {
                        p1 = malloc(num);
                        if (p1 == NULL)
                                goto malloc_error;
                        free(ctx->ibuf);
                        ctx->ibuf = p1;
                }
                ctx->ibuf_off = 0;
                ctx->ibuf_len = (int)num;
                memcpy(ctx->ibuf, ptr, num);
                ret = 1;
                break;
        case BIO_C_SET_BUFF_SIZE:
                if (ptr != NULL) {
                        ip = (int *)ptr;
                        if (*ip == 0) {
                                ibs = (int)num;
                                obs = ctx->obuf_size;
                        }
                        else /* if (*ip == 1) */
                        {
                                ibs = ctx->ibuf_size;
                                obs = (int)num;
                        }
                } else {
                        ibs = (int)num;
                        obs = (int)num;
                }
                p1 = ctx->ibuf;
                p2 = ctx->obuf;
                if ((ibs > DEFAULT_BUFFER_SIZE) && (ibs != ctx->ibuf_size)) {
                        p1 = malloc(num);
                        if (p1 == NULL)
                                goto malloc_error;
                }
                if ((obs > DEFAULT_BUFFER_SIZE) && (obs != ctx->obuf_size)) {
                        p2 = malloc(num);
                        if (p2 == NULL) {
                                if (p1 != ctx->ibuf)
                                        free(p1);
                                goto malloc_error;
                        }
                }
                if (ctx->ibuf != p1) {
                        free(ctx->ibuf);
                        ctx->ibuf = p1;
                        ctx->ibuf_off = 0;
                        ctx->ibuf_len = 0;
                        ctx->ibuf_size = ibs;
                }
                if (ctx->obuf != p2) {
                        free(ctx->obuf);
                        ctx->obuf = p2;
                        ctx->obuf_off = 0;
                        ctx->obuf_len = 0;
                        ctx->obuf_size = obs;
                }
                break;
        case BIO_C_DO_STATE_MACHINE:
                if (b->next_bio == NULL)
                        return (0);
                BIO_clear_retry_flags(b);
                ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                BIO_copy_next_retry(b);
                break;

        case BIO_CTRL_FLUSH:
                if (b->next_bio == NULL)
                        return (0);
                if (ctx->obuf_len <= 0) {
                        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                        break;
                }

                for (;;) {
                        BIO_clear_retry_flags(b);
                        if (ctx->obuf_len > 0) {
                                r = BIO_write(b->next_bio,
                                    &(ctx->obuf[ctx->obuf_off]),
                                    ctx->obuf_len);
                                BIO_copy_next_retry(b);
                                if (r <= 0)
                                        return ((long)r);
                                ctx->obuf_off += r;
                                ctx->obuf_len -= r;
                        } else {
                                ctx->obuf_len = 0;
                                ctx->obuf_off = 0;
                                break;
                        }
                }
                ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                break;
        case BIO_CTRL_DUP:
                dbio = (BIO *)ptr;
                if (!BIO_set_read_buffer_size(dbio, ctx->ibuf_size) ||
                    !BIO_set_write_buffer_size(dbio, ctx->obuf_size))
                        ret = 0;
                break;
        default:
                if (b->next_bio == NULL)
                        return (0);
                ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
                break;
        }
        return (ret);
malloc_error:
        BIOerror(ERR_R_MALLOC_FAILURE);
        return (0);
}

static long
buffer_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
{
        long ret = 1;

        if (b->next_bio == NULL)
                return (0);
        switch (cmd) {
        default:
                ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
                break;
        }
        return (ret);
}

static int
buffer_gets(BIO *b, char *buf, int size)
{
        BIO_F_BUFFER_CTX *ctx;
        int num = 0, i, flag;
        char *p;

        ctx = (BIO_F_BUFFER_CTX *)b->ptr;
        size--; /* reserve space for a '\0' */
        BIO_clear_retry_flags(b);

        for (;;) {
                if (ctx->ibuf_len > 0) {
                        p = &(ctx->ibuf[ctx->ibuf_off]);
                        flag = 0;
                        for (i = 0; (i < ctx->ibuf_len) && (i < size); i++) {
                                *(buf++) = p[i];
                                if (p[i] == '\n') {
                                        flag = 1;
                                        i++;
                                        break;
                                }
                        }
                        num += i;
                        size -= i;
                        ctx->ibuf_len -= i;
                        ctx->ibuf_off += i;
                        if (flag || size == 0) {
                                *buf = '\0';
                                return (num);
                        }
                }
                else    /* read another chunk */
                {
                        i = BIO_read(b->next_bio, ctx->ibuf, ctx->ibuf_size);
                        if (i <= 0) {
                                BIO_copy_next_retry(b);
                                *buf = '\0';
                                if (i < 0)
                                        return ((num > 0) ? num : i);
                                if (i == 0)
                                        return (num);
                        }
                        ctx->ibuf_len = i;
                        ctx->ibuf_off = 0;
                }
        }
}

static int
buffer_puts(BIO *b, const char *str)
{
        return (buffer_write(b, str, strlen(str)));
}