--- /dev/null
+.\" $OpenBSD: SMIME_read_ASN1.3,v 1.1 2021/12/14 14:30:50 schwarze Exp $
+.\" full merge up to:
+.\" OpenSSL SMIME_read_PKCS7.pod 83cf7abf May 29 13:07:08 2018 +0100
+.\" OpenSSL SMIME_read_CMS.pod b97fdb57 Nov 11 09:33:09 2016 +0100
+.\"
+.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
+.\" Copyright (c) 2002, 2006, 2008 The OpenSSL Project. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\"
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\"
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in
+.\" the documentation and/or other materials provided with the
+.\" distribution.
+.\"
+.\" 3. All advertising materials mentioning features or use of this
+.\" software must display the following acknowledgment:
+.\" "This product includes software developed by the OpenSSL Project
+.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+.\"
+.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+.\" endorse or promote products derived from this software without
+.\" prior written permission. For written permission, please contact
+.\" openssl-core@openssl.org.
+.\"
+.\" 5. Products derived from this software may not be called "OpenSSL"
+.\" nor may "OpenSSL" appear in their names without prior written
+.\" permission of the OpenSSL Project.
+.\"
+.\" 6. Redistributions of any form whatsoever must retain the following
+.\" acknowledgment:
+.\" "This product includes software developed by the OpenSSL Project
+.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
+.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+.\" OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd $Mdocdate: December 14 2021 $
+.Dt SMIME_READ_ASN1 3
+.Os
+.Sh NAME
+.Nm SMIME_read_ASN1
+.Nd generic S/MIME message parser
+.Sh SYNOPSIS
+.In openssl/asn1.h
+.Ft ASN1_VALUE *
+.Fo SMIME_read_ASN1
+.Fa "BIO *in_bio"
+.Fa "BIO **out_bio"
+.Fa "const ASN1_ITEM *it"
+.Fc
+.Sh DESCRIPTION
+.Fn SMIME_read_ASN1
+reads a message in S/MIME format from
+.Fa in_bio .
+.Pp
+If the message uses cleartext signing, the content is saved in a memory
+.Vt BIO
+which is written to
+.Pf * Fa out_bio .
+Otherwise,
+.Pf * Fa out_bio
+is set to
+.Dv NULL .
+.Pp
+To support future functionality, if
+.Fa out_bio
+is not
+.Dv NULL ,
+.Pf * Fa out_bio
+should be initialized to
+.Dv NULL
+before calling
+.Fn SMIME_read_ASN1 .
+.Sh RETURN VALUES
+.Fn SMIME_read_ASN1
+returns a newly allocated object of type
+.Fa it
+or
+.Dv NULL
+if an error occurred.
+The error can be obtained from
+.Xr ERR_get_error 3 .
+.Sh SEE ALSO
+.Xr ASN1_item_d2i_bio 3 ,
+.Xr BIO_f_base64 3 ,
+.Xr BIO_new 3 ,
+.Xr SMIME_read_CMS 3 ,
+.Xr SMIME_read_PKCS7 3
+.Sh HISTORY
+.Fn SMIME_read_ASN1
+first appeared in OpenSSL 0.9.8h and has been available since
+.Ox 4.5 .
+.Sh BUGS
+The MIME parser used by
+.Fn SMIME_read_ASN1
+is somewhat primitive.
+While it will handle most S/MIME messages, more complex compound
+formats may not work.
+.Pp
+The parser assumes that the
+structure is always base64 encoded, and it will not handle the case
+where it is in binary format or uses quoted printable format.
+.Pp
+The use of a memory
+to hold the signed content limits the size of the message which can
+be processed due to memory restraints: a streaming single pass
+option should be available.
-.\" $OpenBSD: SMIME_read_PKCS7.3,v 1.7 2019/06/10 14:58:48 schwarze Exp $
-.\" OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400
+.\" $OpenBSD: SMIME_read_PKCS7.3,v 1.8 2021/12/14 14:30:50 schwarze Exp $
+.\" full merge up to: OpenSSL 83cf7abf May 29 13:07:08 2018 +0100
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
.\" Copyright (c) 2002, 2006 The OpenSSL Project. All rights reserved.
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd $Mdocdate: June 10 2019 $
+.Dd $Mdocdate: December 14 2021 $
.Dt SMIME_READ_PKCS7 3
.Os
.Sh NAME
.Nm SMIME_read_PKCS7
-.Nd parse S/MIME message
+.Nd extract a PKCS#7 object from an S/MIME message
.Sh SYNOPSIS
.In openssl/pkcs7.h
.Ft PKCS7 *
.Xr ERR_get_error 3 .
.Sh SEE ALSO
.Xr PKCS7_new 3 ,
+.Xr SMIME_read_ASN1 3 ,
.Xr SMIME_write_PKCS7 3
.Sh HISTORY
.Fn SMIME_read_PKCS7