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0edcbacca9
Commit 8bfb7506d2 updated
`BIO_f_base64(3)` to improve the documentation of the
`BIO_FLAGS_BASE64_NO_NL` flag. In particular, the updated text
states that when this flag is used, all newlines in the input are
ignored. This is incorrect, as the following program proves:
```c
unsigned char *in_buf =
"IlRoZSBxdWljayBicm93biBmb3gganVt\ncHMgb3ZlciBhIGxhenkgZG9nLiI=\n";
int main(int argc, char **argv) {
BIO *b64 = BIO_new(BIO_f_base64());
if (b64 == NULL) return 1;
BIO_set_flags(b64, BIO_get_flags(b64) | BIO_FLAGS_BASE64_NO_NL);
int in_len = strlen(in_buf);
BIO *in = BIO_new_mem_buf(in_buf, in_len);
if (in == NULL) return 2;
in = BIO_push(b64, in);
unsigned char *out_buf = calloc(in_len, sizeof(unsigned char));
if (out_buf == NULL) return 3;
size_t out_len;
int r = BIO_read_ex(in, out_buf, in_len, &out_len);
printf("rv = %d\n", r);
printf("decoded = %s\n", out_buf);
return 0;
}
```
Update the text of `BIO_f_base64(3)` to clarify that when the flag
is set, the data must be all on one line (with or without a trailing
newline character).
Signed-off-by: Fraser Tweedale <ftweedal@redhat.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18568)
104 lines
2.7 KiB
Plaintext
104 lines
2.7 KiB
Plaintext
=pod
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=head1 NAME
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BIO_f_base64 - base64 BIO filter
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=head1 SYNOPSIS
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=for openssl multiple includes
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#include <openssl/bio.h>
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#include <openssl/evp.h>
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const BIO_METHOD *BIO_f_base64(void);
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=head1 DESCRIPTION
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BIO_f_base64() returns the base64 BIO method. This is a filter
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BIO that base64 encodes any data written through it and decodes
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any data read through it.
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Base64 BIOs do not support BIO_gets() or BIO_puts().
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For writing, output is by default divided to lines of length 64
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characters and there is always a newline at the end of output.
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For reading, first line should be at most 1024
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characters long. If it is longer then it is ignored completely.
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Other input lines can be of any length. There must be a newline
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at the end of input.
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This behavior can be changed with BIO_FLAGS_BASE64_NO_NL flag.
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BIO_flush() on a base64 BIO that is being written through is
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used to signal that no more data is to be encoded: this is used
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to flush the final block through the BIO.
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The flag BIO_FLAGS_BASE64_NO_NL can be set with BIO_set_flags().
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For writing, it causes all data to be written on one line without
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newline at the end.
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For reading, it expects the data to be all on one line (with or
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without a trailing newline).
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=head1 NOTES
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Because of the format of base64 encoding the end of the encoded
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block cannot always be reliably determined.
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=head1 RETURN VALUES
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BIO_f_base64() returns the base64 BIO method.
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=head1 EXAMPLES
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Base64 encode the string "Hello World\n" and write the result
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to standard output:
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BIO *bio, *b64;
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char message[] = "Hello World \n";
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b64 = BIO_new(BIO_f_base64());
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bio = BIO_new_fp(stdout, BIO_NOCLOSE);
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BIO_push(b64, bio);
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BIO_write(b64, message, strlen(message));
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BIO_flush(b64);
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BIO_free_all(b64);
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Read Base64 encoded data from standard input and write the decoded
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data to standard output:
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BIO *bio, *b64, *bio_out;
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char inbuf[512];
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int inlen;
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b64 = BIO_new(BIO_f_base64());
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bio = BIO_new_fp(stdin, BIO_NOCLOSE);
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bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
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BIO_push(b64, bio);
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while ((inlen = BIO_read(b64, inbuf, 512)) > 0)
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BIO_write(bio_out, inbuf, inlen);
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BIO_flush(bio_out);
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BIO_free_all(b64);
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=head1 BUGS
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The ambiguity of EOF in base64 encoded data can cause additional
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data following the base64 encoded block to be misinterpreted.
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There should be some way of specifying a test that the BIO can perform
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to reliably determine EOF (for example a MIME boundary).
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=head1 COPYRIGHT
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Copyright 2000-2022 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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