| 1 | =pod
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| 2 |
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| 3 | =head1 NAME
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| 4 |
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| 5 | SMIME_read_PKCS7_ex, SMIME_read_PKCS7 - parse S/MIME message
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| 6 |
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| 7 | =head1 SYNOPSIS
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| 8 |
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| 9 | #include <openssl/pkcs7.h>
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| 10 |
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| 11 | PKCS7 *SMIME_read_PKCS7_ex(BIO *bio, BIO **bcont, PKCS7 **p7);
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| 12 | PKCS7 *SMIME_read_PKCS7(BIO *in, BIO **bcont);
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| 13 |
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| 14 | =head1 DESCRIPTION
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| 15 |
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| 16 | SMIME_read_PKCS7() parses a message in S/MIME format.
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| 17 |
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| 18 | B<in> is a BIO to read the message from.
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| 19 |
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| 20 | If cleartext signing is used then the content is saved in
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| 21 | a memory bio which is written to B<*bcont>, otherwise
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| 22 | B<*bcont> is set to B<NULL>.
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| 23 |
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| 24 | The parsed PKCS#7 structure is returned or B<NULL> if an
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| 25 | error occurred.
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| 26 |
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| 27 | SMIME_read_PKCS7_ex() is similar to SMIME_read_PKCS7() but can optionally supply
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| 28 | a previously created I<p7> PKCS#7 object. If I<p7> is NULL then it is identical
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| 29 | to SMIME_read_PKCS7().
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| 30 | To create a I<p7> object use L<PKCS7_new_ex(3)>.
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| 31 |
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| 32 | =head1 NOTES
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| 33 |
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| 34 | If B<*bcont> is not B<NULL> then the message is clear text
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| 35 | signed. B<*bcont> can then be passed to PKCS7_verify() with
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| 36 | the B<PKCS7_DETACHED> flag set.
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| 37 |
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| 38 | Otherwise the type of the returned structure can be determined
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| 39 | using PKCS7_type_is_enveloped(), etc.
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| 40 |
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| 41 | To support future functionality if B<bcont> is not B<NULL>
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| 42 | B<*bcont> should be initialized to B<NULL>. For example:
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| 43 |
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| 44 | BIO *cont = NULL;
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| 45 | PKCS7 *p7;
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| 46 |
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| 47 | p7 = SMIME_read_PKCS7(in, &cont);
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| 48 |
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| 49 | =head1 BUGS
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| 50 |
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| 51 | The MIME parser used by SMIME_read_PKCS7() is somewhat primitive.
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| 52 | While it will handle most S/MIME messages more complex compound
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| 53 | formats may not work.
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| 54 |
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| 55 | The parser assumes that the PKCS7 structure is always base64
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| 56 | encoded and will not handle the case where it is in binary format
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| 57 | or uses quoted printable format.
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| 58 |
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| 59 | The use of a memory BIO to hold the signed content limits the size
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| 60 | of message which can be processed due to memory restraints: a
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| 61 | streaming single pass option should be available.
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| 62 |
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| 63 | =head1 RETURN VALUES
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| 64 |
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| 65 | SMIME_read_PKCS7_ex() and SMIME_read_PKCS7() return a valid B<PKCS7> structure
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| 66 | or B<NULL> if an error occurred. The error can be obtained from ERR_get_error(3).
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| 67 |
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| 68 | =head1 SEE ALSO
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| 69 |
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| 70 | L<ERR_get_error(3)>,
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| 71 | L<SMIME_read_PKCS7(3)>, L<PKCS7_sign(3)>,
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| 72 | L<PKCS7_verify(3)>, L<PKCS7_encrypt(3)>
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| 73 | L<PKCS7_decrypt(3)>
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| 74 |
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| 75 | =head1 HISTORY
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| 76 |
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| 77 | The function SMIME_read_PKCS7_ex() was added in OpenSSL 3.0.
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| 78 |
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| 79 | =head1 COPYRIGHT
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| 80 |
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| 81 | Copyright 2002-2020 The OpenSSL Project Authors. All Rights Reserved.
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| 82 |
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| 83 | Licensed under the Apache License 2.0 (the "License"). You may not use
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| 84 | this file except in compliance with the License. You can obtain a copy
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| 85 | in the file LICENSE in the source distribution or at
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| 86 | L<https://www.openssl.org/source/license.html>.
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| 87 |
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| 88 | =cut
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