openssl/crypto/evp/bio_b64.c

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2023-05-09 22:08:48 +00:00
/*
* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (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 "internal/cryptlib.h"
#include <openssl/buffer.h>
#include <openssl/evp.h>
#include "internal/bio.h"
static int b64_write(BIO *h, const char *buf, int num);
static int b64_read(BIO *h, char *buf, int size);
static int b64_puts(BIO *h, const char *str);
static long b64_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int b64_new(BIO *h);
static int b64_free(BIO *data);
static long b64_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp);
#define B64_BLOCK_SIZE 1024
#define B64_BLOCK_SIZE2 768
#define B64_NONE 0
#define B64_ENCODE 1
#define B64_DECODE 2
typedef struct b64_struct {
/*
* BIO *bio; moved to the BIO structure
*/
int buf_len;
int buf_off;
int tmp_len; /* used to find the start when decoding */
int tmp_nl; /* If true, scan until '\n' */
int encode;
int start; /* have we started decoding yet? */
int cont; /* <= 0 when finished */
EVP_ENCODE_CTX *base64;
char buf[EVP_ENCODE_LENGTH(B64_BLOCK_SIZE) + 10];
char tmp[B64_BLOCK_SIZE];
} BIO_B64_CTX;
static const BIO_METHOD methods_b64 = {
BIO_TYPE_BASE64,
"base64 encoding",
/* TODO: Convert to new style write function */
bwrite_conv,
b64_write,
/* TODO: Convert to new style read function */
bread_conv,
b64_read,
b64_puts,
NULL, /* b64_gets, */
b64_ctrl,
b64_new,
b64_free,
b64_callback_ctrl,
};
const BIO_METHOD *BIO_f_base64(void)
{
return &methods_b64;
}
static int b64_new(BIO *bi)
{
BIO_B64_CTX *ctx;
if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL) {
EVPerr(EVP_F_B64_NEW, ERR_R_MALLOC_FAILURE);
return 0;
}
ctx->cont = 1;
ctx->start = 1;
ctx->base64 = EVP_ENCODE_CTX_new();
if (ctx->base64 == NULL) {
OPENSSL_free(ctx);
return 0;
}
BIO_set_data(bi, ctx);
BIO_set_init(bi, 1);
return 1;
}
static int b64_free(BIO *a)
{
BIO_B64_CTX *ctx;
if (a == NULL)
return 0;
ctx = BIO_get_data(a);
if (ctx == NULL)
return 0;
EVP_ENCODE_CTX_free(ctx->base64);
OPENSSL_free(ctx);
BIO_set_data(a, NULL);
BIO_set_init(a, 0);
return 1;
}
static int b64_read(BIO *b, char *out, int outl)
{
int ret = 0, i, ii, j, k, x, n, num, ret_code = 0;
BIO_B64_CTX *ctx;
unsigned char *p, *q;
BIO *next;
if (out == NULL)
return 0;
ctx = (BIO_B64_CTX *)BIO_get_data(b);
next = BIO_next(b);
if ((ctx == NULL) || (next == NULL))
return 0;
BIO_clear_retry_flags(b);
if (ctx->encode != B64_DECODE) {
ctx->encode = B64_DECODE;
ctx->buf_len = 0;
ctx->buf_off = 0;
ctx->tmp_len = 0;
EVP_DecodeInit(ctx->base64);
}
/* First check if there are bytes decoded/encoded */
if (ctx->buf_len > 0) {
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
i = ctx->buf_len - ctx->buf_off;
if (i > outl)
i = outl;
OPENSSL_assert(ctx->buf_off + i < (int)sizeof(ctx->buf));
memcpy(out, &(ctx->buf[ctx->buf_off]), i);
ret = i;
out += i;
outl -= i;
ctx->buf_off += i;
if (ctx->buf_len == ctx->buf_off) {
ctx->buf_len = 0;
ctx->buf_off = 0;
}
}
/*
* At this point, we have room of outl bytes and an empty buffer, so we
* should read in some more.
*/
ret_code = 0;
while (outl > 0) {
if (ctx->cont <= 0)
break;
i = BIO_read(next, &(ctx->tmp[ctx->tmp_len]),
B64_BLOCK_SIZE - ctx->tmp_len);
if (i <= 0) {
ret_code = i;
/* Should we continue next time we are called? */
if (!BIO_should_retry(next)) {
ctx->cont = i;
/* If buffer empty break */
if (ctx->tmp_len == 0)
break;
/* Fall through and process what we have */
else
i = 0;
}
/* else we retry and add more data to buffer */
else
break;
}
i += ctx->tmp_len;
ctx->tmp_len = i;
/*
* We need to scan, a line at a time until we have a valid line if we
* are starting.
*/
if (ctx->start && (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)) {
/* ctx->start=1; */
ctx->tmp_len = 0;
} else if (ctx->start) {
q = p = (unsigned char *)ctx->tmp;
num = 0;
for (j = 0; j < i; j++) {
if (*(q++) != '\n')
continue;
/*
* due to a previous very long line, we need to keep on
* scanning for a '\n' before we even start looking for
* base64 encoded stuff.
*/
if (ctx->tmp_nl) {
p = q;
ctx->tmp_nl = 0;
continue;
}
k = EVP_DecodeUpdate(ctx->base64,
(unsigned char *)ctx->buf,
&num, p, q - p);
if ((k <= 0) && (num == 0) && (ctx->start))
EVP_DecodeInit(ctx->base64);
else {
if (p != (unsigned char *)
&(ctx->tmp[0])) {
i -= (p - (unsigned char *)
&(ctx->tmp[0]));
for (x = 0; x < i; x++)
ctx->tmp[x] = p[x];
}
EVP_DecodeInit(ctx->base64);
ctx->start = 0;
break;
}
p = q;
}
/* we fell off the end without starting */
if ((j == i) && (num == 0)) {
/*
* Is this is one long chunk?, if so, keep on reading until a
* new line.
*/
if (p == (unsigned char *)&(ctx->tmp[0])) {
/* Check buffer full */
if (i == B64_BLOCK_SIZE) {
ctx->tmp_nl = 1;
ctx->tmp_len = 0;
}
} else if (p != q) { /* finished on a '\n' */
n = q - p;
for (ii = 0; ii < n; ii++)
ctx->tmp[ii] = p[ii];
ctx->tmp_len = n;
}
/* else finished on a '\n' */
continue;
} else {
ctx->tmp_len = 0;
}
} else if ((i < B64_BLOCK_SIZE) && (ctx->cont > 0)) {
/*
* If buffer isn't full and we can retry then restart to read in
* more data.
*/
continue;
}
if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
int z, jj;
jj = i & ~3; /* process per 4 */
z = EVP_DecodeBlock((unsigned char *)ctx->buf,
(unsigned char *)ctx->tmp, jj);
if (jj > 2) {
if (ctx->tmp[jj - 1] == '=') {
z--;
if (ctx->tmp[jj - 2] == '=')
z--;
}
}
/*
* z is now number of output bytes and jj is the number consumed
*/
if (jj != i) {
memmove(ctx->tmp, &ctx->tmp[jj], i - jj);
ctx->tmp_len = i - jj;
}
ctx->buf_len = 0;
if (z > 0) {
ctx->buf_len = z;
}
i = z;
} else {
i = EVP_DecodeUpdate(ctx->base64,
(unsigned char *)ctx->buf, &ctx->buf_len,
(unsigned char *)ctx->tmp, i);
ctx->tmp_len = 0;
}
/*
* If eof or an error was signalled, then the condition
* 'ctx->cont <= 0' will prevent b64_read() from reading
* more data on subsequent calls. This assignment was
* deleted accidentally in commit 5562cfaca4f3.
*/
ctx->cont = i;
ctx->buf_off = 0;
if (i < 0) {
ret_code = 0;
ctx->buf_len = 0;
break;
}
if (ctx->buf_len <= outl)
i = ctx->buf_len;
else
i = outl;
memcpy(out, ctx->buf, i);
ret += i;
ctx->buf_off = i;
if (ctx->buf_off == ctx->buf_len) {
ctx->buf_len = 0;
ctx->buf_off = 0;
}
outl -= i;
out += i;
}
/* BIO_clear_retry_flags(b); */
BIO_copy_next_retry(b);
return ((ret == 0) ? ret_code : ret);
}
static int b64_write(BIO *b, const char *in, int inl)
{
int ret = 0;
int n;
int i;
BIO_B64_CTX *ctx;
BIO *next;
ctx = (BIO_B64_CTX *)BIO_get_data(b);
next = BIO_next(b);
if ((ctx == NULL) || (next == NULL))
return 0;
BIO_clear_retry_flags(b);
if (ctx->encode != B64_ENCODE) {
ctx->encode = B64_ENCODE;
ctx->buf_len = 0;
ctx->buf_off = 0;
ctx->tmp_len = 0;
EVP_EncodeInit(ctx->base64);
}
OPENSSL_assert(ctx->buf_off < (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
n = ctx->buf_len - ctx->buf_off;
while (n > 0) {
i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
if (i <= 0) {
BIO_copy_next_retry(b);
return i;
}
OPENSSL_assert(i <= n);
ctx->buf_off += i;
OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
n -= i;
}
/* at this point all pending data has been written */
ctx->buf_off = 0;
ctx->buf_len = 0;
if ((in == NULL) || (inl <= 0))
return 0;
while (inl > 0) {
n = (inl > B64_BLOCK_SIZE) ? B64_BLOCK_SIZE : inl;
if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
if (ctx->tmp_len > 0) {
OPENSSL_assert(ctx->tmp_len <= 3);
n = 3 - ctx->tmp_len;
/*
* There's a theoretical possibility for this
*/
if (n > inl)
n = inl;
memcpy(&(ctx->tmp[ctx->tmp_len]), in, n);
ctx->tmp_len += n;
ret += n;
if (ctx->tmp_len < 3)
break;
ctx->buf_len =
EVP_EncodeBlock((unsigned char *)ctx->buf,
(unsigned char *)ctx->tmp, ctx->tmp_len);
OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
/*
* Since we're now done using the temporary buffer, the
* length should be 0'd
*/
ctx->tmp_len = 0;
} else {
if (n < 3) {
memcpy(ctx->tmp, in, n);
ctx->tmp_len = n;
ret += n;
break;
}
n -= n % 3;
ctx->buf_len =
EVP_EncodeBlock((unsigned char *)ctx->buf,
(const unsigned char *)in, n);
OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
ret += n;
}
} else {
if (!EVP_EncodeUpdate(ctx->base64,
(unsigned char *)ctx->buf, &ctx->buf_len,
(unsigned char *)in, n))
return ((ret == 0) ? -1 : ret);
OPENSSL_assert(ctx->buf_len <= (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
ret += n;
}
inl -= n;
in += n;
ctx->buf_off = 0;
n = ctx->buf_len;
while (n > 0) {
i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
if (i <= 0) {
BIO_copy_next_retry(b);
return ((ret == 0) ? i : ret);
}
OPENSSL_assert(i <= n);
n -= i;
ctx->buf_off += i;
OPENSSL_assert(ctx->buf_off <= (int)sizeof(ctx->buf));
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
}
ctx->buf_len = 0;
ctx->buf_off = 0;
}
return ret;
}
static long b64_ctrl(BIO *b, int cmd, long num, void *ptr)
{
BIO_B64_CTX *ctx;
long ret = 1;
int i;
BIO *next;
ctx = (BIO_B64_CTX *)BIO_get_data(b);
next = BIO_next(b);
if ((ctx == NULL) || (next == NULL))
return 0;
switch (cmd) {
case BIO_CTRL_RESET:
ctx->cont = 1;
ctx->start = 1;
ctx->encode = B64_NONE;
ret = BIO_ctrl(next, cmd, num, ptr);
break;
case BIO_CTRL_EOF: /* More to read */
if (ctx->cont <= 0)
ret = 1;
else
ret = BIO_ctrl(next, cmd, num, ptr);
break;
case BIO_CTRL_WPENDING: /* More to write in buffer */
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
ret = ctx->buf_len - ctx->buf_off;
if ((ret == 0) && (ctx->encode != B64_NONE)
&& (EVP_ENCODE_CTX_num(ctx->base64) != 0))
ret = 1;
else if (ret <= 0)
ret = BIO_ctrl(next, cmd, num, ptr);
break;
case BIO_CTRL_PENDING: /* More to read in buffer */
OPENSSL_assert(ctx->buf_len >= ctx->buf_off);
ret = ctx->buf_len - ctx->buf_off;
if (ret <= 0)
ret = BIO_ctrl(next, cmd, num, ptr);
break;
case BIO_CTRL_FLUSH:
/* do a final write */
again:
while (ctx->buf_len != ctx->buf_off) {
i = b64_write(b, NULL, 0);
if (i < 0)
return i;
}
if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL) {
if (ctx->tmp_len != 0) {
ctx->buf_len = EVP_EncodeBlock((unsigned char *)ctx->buf,
(unsigned char *)ctx->tmp,
ctx->tmp_len);
ctx->buf_off = 0;
ctx->tmp_len = 0;
goto again;
}
} else if (ctx->encode != B64_NONE
&& EVP_ENCODE_CTX_num(ctx->base64) != 0) {
ctx->buf_off = 0;
EVP_EncodeFinal(ctx->base64,
(unsigned char *)ctx->buf, &(ctx->buf_len));
/* push out the bytes */
goto again;
}
/* Finally flush the underlying BIO */
ret = BIO_ctrl(next, cmd, num, ptr);
break;
case BIO_C_DO_STATE_MACHINE:
BIO_clear_retry_flags(b);
ret = BIO_ctrl(next, cmd, num, ptr);
BIO_copy_next_retry(b);
break;
case BIO_CTRL_DUP:
break;
case BIO_CTRL_INFO:
case BIO_CTRL_GET:
case BIO_CTRL_SET:
default:
ret = BIO_ctrl(next, cmd, num, ptr);
break;
}
return ret;
}
static long b64_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
{
long ret = 1;
BIO *next = BIO_next(b);
if (next == NULL)
return 0;
switch (cmd) {
default:
ret = BIO_callback_ctrl(next, cmd, fp);
break;
}
return ret;
}
static int b64_puts(BIO *b, const char *str)
{
return b64_write(b, str, strlen(str));
}