xref: /freebsd/crypto/openssl/doc/man3/SMIME_read_CMS.pod (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1=pod
2
3=head1 NAME
4
5SMIME_read_CMS - parse S/MIME message
6
7=head1 SYNOPSIS
8
9 #include <openssl/cms.h>
10
11 CMS_ContentInfo *SMIME_read_CMS(BIO *in, BIO **bcont);
12
13=head1 DESCRIPTION
14
15SMIME_read_CMS() parses a message in S/MIME format.
16
17B<in> is a BIO to read the message from.
18
19If cleartext signing is used then the content is saved in a memory bio which is
20written to B<*bcont>, otherwise B<*bcont> is set to NULL.
21
22The parsed CMS_ContentInfo structure is returned or NULL if an
23error occurred.
24
25=head1 NOTES
26
27If B<*bcont> is not NULL then the message is clear text signed. B<*bcont> can
28then be passed to CMS_verify() with the B<CMS_DETACHED> flag set.
29
30Otherwise the type of the returned structure can be determined
31using CMS_get0_type().
32
33To support future functionality if B<bcont> is not NULL B<*bcont> should be
34initialized to NULL. For example:
35
36 BIO *cont = NULL;
37 CMS_ContentInfo *cms;
38
39 cms = SMIME_read_CMS(in, &cont);
40
41=head1 BUGS
42
43The MIME parser used by SMIME_read_CMS() is somewhat primitive.  While it will
44handle most S/MIME messages more complex compound formats may not work.
45
46The parser assumes that the CMS_ContentInfo structure is always base64 encoded
47and will not handle the case where it is in binary format or uses quoted
48printable format.
49
50The use of a memory BIO to hold the signed content limits the size of message
51which can be processed due to memory restraints: a streaming single pass option
52should be available.
53
54=head1 RETURN VALUES
55
56SMIME_read_CMS() returns a valid B<CMS_ContentInfo> structure or B<NULL>
57if an error occurred. The error can be obtained from ERR_get_error(3).
58
59=head1 SEE ALSO
60
61L<ERR_get_error(3)>, L<CMS_type(3)>,
62L<SMIME_read_CMS(3)>, L<CMS_sign(3)>,
63L<CMS_verify(3)>, L<CMS_encrypt(3)>,
64L<CMS_decrypt(3)>
65
66=head1 COPYRIGHT
67
68Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved.
69
70Licensed under the OpenSSL license (the "License").  You may not use
71this file except in compliance with the License.  You can obtain a copy
72in the file LICENSE in the source distribution or at
73L<https://www.openssl.org/source/license.html>.
74
75=cut
76