openssl/doc/crypto/SMIME_read_CMS.pod
Rich Salz a528d4f0a9 Remove SSLeay history, etc., from docs
If something was "present in all versions" of SSLeay, or if it was
added to a version of SSLeay (and therefore predates OpenSSL),
remove mention of it.  Documentation history now starts with OpenSSL.

Remove mention of all history before OpenSSL 0.9.8, inclusive.

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Reviewed-by: Tim Hudson <tjh@openssl.org>
2015-10-28 17:23:51 -04:00

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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 NULL.
The parsed CMS_ContentInfo structure is returned or NULL if an
error occurred.
=head1 NOTES
If B<*bcont> is not 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 NULL B<*bcont> should be
initialized to 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)>, L<CMS_type(3)>
L<SMIME_read_CMS(3)>, L<CMS_sign(3)>,
L<CMS_verify(3)>, L<CMS_encrypt(3)>
L<CMS_decrypt(3)>
=cut