openssl/doc/crypto/SMIME_read_CMS.pod
2008-04-08 22:27:10 +00:00

73 lines
1.9 KiB
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=pod
=head1 NAME
SMIME_read_CMS - parse S/MIME message.
=head1 SYNOPSIS
#include <openssl/cms.h>
CMS_ContentInfo *SMIME_read_CMS(BIO *in, BIO **bcont);
=head1 DESCRIPTION
SMIME_read_CMS() parses a message in S/MIME format.
B<in> is a BIO to read the message from.
If cleartext signing is used then the content is saved in
a memory bio which is written to B<*bcont>, otherwise
B<*bcont> is set to B<NULL>.
The parsed CMS_ContentInfo structure is returned or B<NULL> if an
error occurred.
=head1 NOTES
If B<*bcont> is not B<NULL> then the message is clear text
signed. B<*bcont> can then be passed to CMS_verify() with
the B<CMS_DETACHED> flag set.
Otherwise the type of the returned structure can be determined
using CMS_get0_type().
To support future functionality if B<bcont> is not B<NULL>
B<*bcont> should be initialized to B<NULL>. For example:
BIO *cont = NULL;
CMS_ContentInfo *cms;
cms = SMIME_read_CMS(in, &cont);
=head1 BUGS
The MIME parser used by SMIME_read_CMS() is somewhat primitive.
While it will handle most S/MIME messages more complex compound
formats may not work.
The parser assumes that the CMS_ContentInfo structure is always base64
encoded and will not handle the case where it is in binary format
or uses quoted printable format.
The use of a memory BIO to hold the signed content limits the size
of message which can be processed due to memory restraints: a
streaming single pass option should be available.
=head1 RETURN VALUES
SMIME_read_CMS() returns a valid B<CMS_ContentInfo> structure or B<NULL>
if an error occurred. The error can be obtained from ERR_get_error(3).
=head1 SEE ALSO
L<ERR_get_error(3)|ERR_get_error(3)>, L<CMS_type(3)|CMS_type(3)>
L<SMIME_read_CMS(3)|SMIME_read_CMS(3)>, L<CMS_sign(3)|CMS_sign(3)>,
L<CMS_verify(3)|CMS_verify(3)>, L<CMS_encrypt(3)|CMS_encrypt(3)>
L<CMS_decrypt(3)|CMS_decrypt(3)>
=head1 HISTORY
SMIME_read_CMS() was added to OpenSSL 0.9.8
=cut