/*

 * Copyright 1995-2026 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include <errno.h>

#include "bio_local.h"

#include "internal/cryptlib.h"

static int mem_write(BIO *h, const char *buf, int num);

static int mem_read(BIO *h, char *buf, int size);

static int mem_puts(BIO *h, const char *str);

static int mem_gets(BIO *h, char *str, int size);

static long mem_ctrl(BIO *h, int cmd, long arg1, void *arg2);

static int mem_new(BIO *h);

static int secmem_new(BIO *h);

static int mem_free(BIO *data);

static int mem_buf_free(BIO *data);

static int mem_buf_sync(BIO *h);

static const BIO_METHOD mem_method = {

    BIO_TYPE_MEM,

    "memory buffer",

    bwrite_conv,

    mem_write,

    bread_conv,

    mem_read,

    mem_puts,

    mem_gets,

    mem_ctrl,

    mem_new,

    mem_free,

    NULL, /* mem_callback_ctrl */

};

static const BIO_METHOD secmem_method = {

    BIO_TYPE_MEM,

    "secure memory buffer",

    bwrite_conv,

    mem_write,

    bread_conv,

    mem_read,

    mem_puts,

    mem_gets,

    mem_ctrl,

    secmem_new,

    mem_free,

    NULL, /* mem_callback_ctrl */

};

/*

 * BIO memory stores buffer and read pointer

 * however the roles are different for read only BIOs.

 * In that case the readp just stores the original state

 * to be used for reset.

 */

typedef struct bio_buf_mem_st {

    struct buf_mem_st *buf; /* allocated buffer */

    struct buf_mem_st *readp; /* read pointer */

} BIO_BUF_MEM;

/*

 * bio->num is used to hold the value to return on 'empty', if it is 0,

 * should_retry is not set

 */

const BIO_METHOD *BIO_s_mem(void)

{

    return &mem_method;

}

const BIO_METHOD *BIO_s_secmem(void)

{

    return &secmem_method;

}

BIO *BIO_new_mem_buf(const void *buf, int len)

{

    BIO *ret;

    BUF_MEM *b;

    BIO_BUF_MEM *bb;

    size_t sz;

    if (buf == NULL) {

        ERR_raise(ERR_LIB_BIO, ERR_R_PASSED_NULL_PARAMETER);

        return NULL;

    }

    sz = (len < 0) ? strlen(buf) : (size_t)len;

    if ((ret = BIO_new(BIO_s_mem())) == NULL)

        return NULL;

    bb = (BIO_BUF_MEM *)ret->ptr;

    b = bb->buf;

    /* Cast away const and trust in the MEM_RDONLY flag. */

    b->data = (void *)buf;

    b->length = sz;

    b->max = sz;

    *bb->readp = *bb->buf;

    ret->flags |= BIO_FLAGS_MEM_RDONLY;

    /* Since this is static data retrying won't help */

    ret->num = 0;

    return ret;

}

static int mem_init(BIO *bi, unsigned long flags)

{

    BIO_BUF_MEM *bb = OPENSSL_zalloc(sizeof(*bb));

    if (bb == NULL)

        return 0;

    if ((bb->buf = BUF_MEM_new_ex(flags)) == NULL) {

        OPENSSL_free(bb);

        return 0;

    }

    if ((bb->readp = OPENSSL_zalloc(sizeof(*bb->readp))) == NULL) {

        BUF_MEM_free(bb->buf);

        OPENSSL_free(bb);

        return 0;

    }

    *bb->readp = *bb->buf;

    bi->shutdown = 1;

    bi->init = 1;

    bi->num = -1;

    bi->flags |= BIO_FLAGS_MEM_LEGACY_EOF;

    bi->ptr = (char *)bb;

    return 1;

}

static int mem_new(BIO *bi)

{

    return mem_init(bi, 0L);

}

static int secmem_new(BIO *bi)

{

    return mem_init(bi, BUF_MEM_FLAG_SECURE);

}

static int mem_free(BIO *a)

{

    BIO_BUF_MEM *bb;

    if (a == NULL)

        return 0;

    bb = (BIO_BUF_MEM *)a->ptr;

    if (!mem_buf_free(a))

        return 0;

    OPENSSL_free(bb->readp);

    OPENSSL_free(bb);

    return 1;

}

static int mem_buf_free(BIO *a)

{

    if (a == NULL)

        return 0;

    if (a->shutdown && a->init && a->ptr != NULL) {

        BIO_BUF_MEM *bb = (BIO_BUF_MEM *)a->ptr;

        BUF_MEM *b = bb->buf;

        if (a->flags & BIO_FLAGS_MEM_RDONLY)

            b->data = NULL;

        BUF_MEM_free(b);

    }

    return 1;

}

/*

 * Reallocate memory buffer if read pointer differs

 * NOT FOR RDONLY

 */

static int mem_buf_sync(BIO *b)

{

    if (b != NULL && b->init != 0 && b->ptr != NULL) {

        BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;

        if (bbm->readp->data != bbm->buf->data) {

            memmove(bbm->buf->data, bbm->readp->data, bbm->readp->length);

            bbm->buf->length = bbm->readp->length;

            bbm->readp->data = bbm->buf->data;

        }

    }

    return 0;

}

static int mem_read(BIO *b, char *out, int outl)

{

    int ret = -1;

    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;

    BUF_MEM *bm = bbm->readp;

    if (b->flags & BIO_FLAGS_MEM_RDONLY)

        bm = bbm->buf;

    BIO_clear_retry_flags(b);

    ret = (outl >= 0 && (size_t)outl > bm->length) ? (int)bm->length : outl;

    if ((out != NULL) && (ret > 0)) {

        memcpy(out, bm->data, ret);

        bm->length -= ret;

        bm->max -= ret;

        bm->data += ret;

    } else if (bm->length == 0) {

        ret = b->num;

        if (ret != 0)

            BIO_set_retry_read(b);

    }

    return ret;

}

static int mem_write(BIO *b, const char *in, int inl)

{

    int ret = -1;

    size_t blen;

    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;

    if (b->flags & BIO_FLAGS_MEM_RDONLY) {

        ERR_raise(ERR_LIB_BIO, BIO_R_WRITE_TO_READ_ONLY_BIO);

        goto end;

    }

    BIO_clear_retry_flags(b);

    if (inl <= 0)

        return 0;

    if (in == NULL) {

        ERR_raise(ERR_LIB_BIO, ERR_R_PASSED_NULL_PARAMETER);

        goto end;

    }

    blen = bbm->readp->length;

    mem_buf_sync(b);

    if (BUF_MEM_grow_clean(bbm->buf, blen + inl) == 0)

        goto end;

    memcpy(bbm->buf->data + blen, in, inl);

    *bbm->readp = *bbm->buf;

    ret = inl;

end:

    return ret;

}

static long mem_ctrl(BIO *b, int cmd, long num, void *ptr)

{

    long ret = 1;

    char **pptr;

    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)b->ptr;

    BUF_MEM *bm, *bo; /* bio_mem, bio_other */

    ossl_ssize_t off, remain;

    if (b->flags & BIO_FLAGS_MEM_RDONLY) {

        bm = bbm->buf;

        bo = bbm->readp;

    } else {

        bm = bbm->readp;

        bo = bbm->buf;

    }

    off = (bm->data == bo->data) ? 0 : bm->data - bo->data;

    remain = bm->length;

    switch (cmd) {

    case BIO_CTRL_RESET:

        bm = bbm->buf;

        if (bm->data != NULL) {

            if (!(b->flags & BIO_FLAGS_MEM_RDONLY)) {

                if (!(b->flags & BIO_FLAGS_NONCLEAR_RST)) {

                    memset(bm->data, 0, bm->max);

                    bm->length = 0;

                }

                *bbm->readp = *bbm->buf;

            } else {

                /* For read only case just reset to the start again */

                *bbm->buf = *bbm->readp;

            }

        }

        break;

    case BIO_C_FILE_SEEK:

        if (num < 0 || num > off + remain)

            return -1; /* Can't see outside of the current buffer */

        bm->data = (num != 0) ? bo->data + num : bo->data;

        bm->length = bo->length - num;

        bm->max = bo->max - num;

        off = (ossl_ssize_t)num;

        /* FALLTHRU */

    case BIO_C_FILE_TELL:

        ret = (long)off;

        if (off > LONG_MAX)

            ret = -1;

        break;

    case BIO_CTRL_EOF:

        if (b->num == 0 || (b->flags & BIO_FLAGS_MEM_LEGACY_EOF) != 0)

            ret = (long)(bm->length == 0);

        else

            ret = 0;

        break;

    case BIO_C_SET_BUF_MEM_EOF_RETURN:

        b->num = (int)num;

        b->flags &= ~BIO_FLAGS_MEM_LEGACY_EOF;

        break;

    case BIO_CTRL_INFO:

        ret = (long)bm->length;

        if (ptr != NULL) {

            pptr = (char **)ptr;

            *pptr = (char *)(bm->data);

        }

        break;

    case BIO_C_SET_BUF_MEM:

        mem_buf_free(b);

        b->shutdown = (int)num;

        bbm->buf = ptr;

        *bbm->readp = *bbm->buf;

        break;

    case BIO_C_GET_BUF_MEM_PTR:

        if (ptr != NULL) {

            if (!(b->flags & BIO_FLAGS_MEM_RDONLY))

                mem_buf_sync(b);

            bm = bbm->buf;

            pptr = (char **)ptr;

            *pptr = (char *)bm;

        }

        break;

    case BIO_CTRL_GET_CLOSE:

        ret = (long)b->shutdown;

        break;

    case BIO_CTRL_SET_CLOSE:

        b->shutdown = (int)num;

        break;

    case BIO_CTRL_WPENDING:

        ret = 0L;

        break;

    case BIO_CTRL_PENDING:

        ret = (long)bm->length;

        break;

    case BIO_CTRL_DUP:

    case BIO_CTRL_FLUSH:

        ret = 1;

        break;

    case BIO_CTRL_PUSH:

    case BIO_CTRL_POP:

    default:

        ret = 0;

        break;

    }

    return ret;

}

static int mem_gets(BIO *bp, char *buf, int size)

{

    int i, j;

    int ret = -1;

    char *p;

    BIO_BUF_MEM *bbm = (BIO_BUF_MEM *)bp->ptr;

    BUF_MEM *bm = bbm->readp;

    if (bp->flags & BIO_FLAGS_MEM_RDONLY)

        bm = bbm->buf;

    BIO_clear_retry_flags(bp);

    j = bm->length < INT_MAX ? (int)bm->length : INT_MAX;

    if ((size - 1) < j)

        j = size - 1;

    if (j <= 0) {

        *buf = '\0';

        return 0;

    }

    p = bm->data;

    for (i = 0; i < j; i++) {

        if (p[i] == '\n') {

            i++;

            break;

        }

    }

    /*

     * i is now the max num of bytes to copy, either j or up to

     * and including the first newline

     */

    i = mem_read(bp, buf, i);

    if (i > 0)

        buf[i] = '\0';

    ret = i;

    return ret;

}

static int mem_puts(BIO *bp, const char *str)

{

    int ret;

    size_t n = strlen(str);

    if (n > INT_MAX)

        return -1;

    ret = mem_write(bp, str, (int)n);

    /* memory semantics is that it will always work */

    return ret;

}