1.\" $OpenBSD: SMIME_read_ASN1.3,v 1.2 2021/12/14 15:22:49 schwarze Exp $ 2.\" full merge up to: 3.\" OpenSSL SMIME_read_PKCS7.pod 83cf7abf May 29 13:07:08 2018 +0100 4.\" OpenSSL SMIME_read_CMS.pod b97fdb57 Nov 11 09:33:09 2016 +0100 5.\" 6.\" This file was written by Dr. Stephen Henson <steve@openssl.org>. 7.\" Copyright (c) 2002, 2006, 2008 The OpenSSL Project. All rights reserved. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 16.\" 2. Redistributions in binary form must reproduce the above copyright 17.\" notice, this list of conditions and the following disclaimer in 18.\" the documentation and/or other materials provided with the 19.\" distribution. 20.\" 21.\" 3. All advertising materials mentioning features or use of this 22.\" software must display the following acknowledgment: 23.\" "This product includes software developed by the OpenSSL Project 24.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 25.\" 26.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27.\" endorse or promote products derived from this software without 28.\" prior written permission. For written permission, please contact 29.\" openssl-core@openssl.org. 30.\" 31.\" 5. Products derived from this software may not be called "OpenSSL" 32.\" nor may "OpenSSL" appear in their names without prior written 33.\" permission of the OpenSSL Project. 34.\" 35.\" 6. Redistributions of any form whatsoever must retain the following 36.\" acknowledgment: 37.\" "This product includes software developed by the OpenSSL Project 38.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" 39.\" 40.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51.\" OF THE POSSIBILITY OF SUCH DAMAGE. 52.\" 53.Dd $Mdocdate: December 14 2021 $ 54.Dt SMIME_READ_ASN1 3 55.Os 56.Sh NAME 57.Nm SMIME_read_ASN1 58.Nd generic S/MIME message parser 59.Sh SYNOPSIS 60.In openssl/asn1.h 61.Ft ASN1_VALUE * 62.Fo SMIME_read_ASN1 63.Fa "BIO *in_bio" 64.Fa "BIO **out_bio" 65.Fa "const ASN1_ITEM *it" 66.Fc 67.Sh DESCRIPTION 68.Fn SMIME_read_ASN1 69reads a message in S/MIME format from 70.Fa in_bio . 71.Pp 72If the message uses cleartext signing, the content is saved in a memory 73.Vt BIO 74which is written to 75.Pf * Fa out_bio . 76Otherwise, 77.Pf * Fa out_bio 78is set to 79.Dv NULL . 80.Pp 81To support future functionality, if 82.Fa out_bio 83is not 84.Dv NULL , 85.Pf * Fa out_bio 86should be initialized to 87.Dv NULL 88before calling 89.Fn SMIME_read_ASN1 . 90.Sh RETURN VALUES 91.Fn SMIME_read_ASN1 92returns a newly allocated object of type 93.Fa it 94or 95.Dv NULL 96if an error occurred. 97The error can be obtained from 98.Xr ERR_get_error 3 . 99.Sh SEE ALSO 100.Xr ASN1_item_d2i_bio 3 , 101.Xr BIO_f_base64 3 , 102.Xr BIO_new 3 , 103.Xr SMIME_read_CMS 3 , 104.Xr SMIME_read_PKCS7 3 , 105.Xr SMIME_text 3 106.Sh HISTORY 107.Fn SMIME_read_ASN1 108first appeared in OpenSSL 0.9.8h and has been available since 109.Ox 4.5 . 110.Sh BUGS 111The MIME parser used by 112.Fn SMIME_read_ASN1 113is somewhat primitive. 114While it will handle most S/MIME messages, more complex compound 115formats may not work. 116.Pp 117The parser assumes that the 118structure is always base64 encoded, and it will not handle the case 119where it is in binary format or uses quoted printable format. 120.Pp 121The use of a memory 122to hold the signed content limits the size of the message which can 123be processed due to memory restraints: a streaming single pass 124option should be available. 125