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.\" ========================================================================
.\"
.IX Title "SMIME_read_CMS 3"
.TH SMIME_read_CMS 3 2019-12-20 1.0.2u OpenSSL
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
.Vb 1
\& SMIME_read_CMS \- parse S/MIME message.
.Ve
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/cms.h>
\&
\& CMS_ContentInfo *SMIME_read_CMS(BIO *in, BIO **bcont);
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
\&\fBSMIME_read_CMS()\fR parses a message in S/MIME format.
.PP
\&\fBin\fR is a BIO to read the message from.
.PP
If cleartext signing is used then the content is saved in a memory bio which is
written to \fB*bcont\fR, otherwise \fB*bcont\fR is set to NULL.
.PP
The parsed CMS_ContentInfo structure is returned or NULL if an
error occurred.
.SH NOTES
.IX Header "NOTES"
If \fB*bcont\fR is not NULL then the message is clear text signed. \fB*bcont\fR can
then be passed to \fBCMS_verify()\fR with the \fBCMS_DETACHED\fR flag set.
.PP
Otherwise the type of the returned structure can be determined
using \fBCMS_get0_type()\fR.
.PP
To support future functionality if \fBbcont\fR is not NULL \fB*bcont\fR should be
initialized to NULL. For example:
.PP
.Vb 2
\& BIO *cont = NULL;
\& CMS_ContentInfo *cms;
\&
\& cms = SMIME_read_CMS(in, &cont);
.Ve
.SH BUGS
.IX Header "BUGS"
The MIME parser used by \fBSMIME_read_CMS()\fR is somewhat primitive.  While it will
handle most S/MIME messages more complex compound formats may not work.
.PP
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.
.PP
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.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBSMIME_read_CMS()\fR returns a valid \fBCMS_ContentInfo\fR structure or \fBNULL\fR
if an error occurred. The error can be obtained from \fBERR_get_error\fR\|(3).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBERR_get_error\fR\|(3), \fBCMS_type\fR\|(3)
\&\fBSMIME_read_CMS\fR\|(3), \fBCMS_sign\fR\|(3),
\&\fBCMS_verify\fR\|(3), \fBCMS_encrypt\fR\|(3)
\&\fBCMS_decrypt\fR\|(3)
.SH HISTORY
.IX Header "HISTORY"
\&\fBSMIME_read_CMS()\fR was added to OpenSSL 0.9.8