1.\" $OpenBSD: CMS_uncompress.3,v 1.7 2019/11/02 15:39:46 schwarze Exp $ 2.\" full merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 3.\" 4.\" This file was written by Dr. Stephen Henson <steve@openssl.org>. 5.\" Copyright (c) 2008 The OpenSSL Project. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in 16.\" the documentation and/or other materials provided with the 17.\" distribution. 18.\" 19.\" 3. All advertising materials mentioning features or use of this 20.\" software must display the following acknowledgment: 21.\" "This product includes software developed by the OpenSSL Project 22.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 23.\" 24.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 25.\" endorse or promote products derived from this software without 26.\" prior written permission. For written permission, please contact 27.\" openssl-core@openssl.org. 28.\" 29.\" 5. Products derived from this software may not be called "OpenSSL" 30.\" nor may "OpenSSL" appear in their names without prior written 31.\" permission of the OpenSSL Project. 32.\" 33.\" 6. Redistributions of any form whatsoever must retain the following 34.\" acknowledgment: 35.\" "This product includes software developed by the OpenSSL Project 36.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" 37.\" 38.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 39.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 40.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 41.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 42.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 43.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 44.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 45.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 46.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 47.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 48.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 49.\" OF THE POSSIBILITY OF SUCH DAMAGE. 50.\" 51.Dd $Mdocdate: November 2 2019 $ 52.Dt CMS_UNCOMPRESS 3 53.Os 54.Sh NAME 55.Nm CMS_uncompress 56.Nd uncompress a CMS CompressedData structure 57.Sh SYNOPSIS 58.In openssl/cms.h 59.Ft int 60.Fo CMS_uncompress 61.Fa "CMS_ContentInfo *cms" 62.Fa "BIO *dcont" 63.Fa "BIO *out" 64.Fa "unsigned int flags" 65.Fc 66.Sh DESCRIPTION 67.Fn CMS_uncompress 68extracts and uncompresses the content of a CMS 69.Vt CompressedData 70structure 71.Fa cms 72and writes it to 73.Fa out . 74.Pp 75In the rare case where the compressed content is detached, 76pass it in via 77.Fa dcont . 78For normal use, set 79.Fa dcont 80to 81.Dv NULL . 82.Pp 83The only currently supported compression algorithm is zlib: if the 84structure indicates the use of any other algorithm, an error is returned. 85If zlib support is not compiled in, 86.Fn CMS_uncompress 87always returns an error. 88.Pp 89If the 90.Dv CMS_TEXT 91bit is set in 92.Fa flags , 93MIME headers for type text/plain are deleted from the content. 94If the content is not of type text/plain, an error is returned. 95.Sh RETURN VALUES 96.Fn CMS_uncompress 97returns 1 for success or 0 for failure. 98The error can be obtained from 99.Xr ERR_get_error 3 . 100.Sh SEE ALSO 101.Xr CMS_compress 3 , 102.Xr CMS_ContentInfo_new 3 103.Sh STANDARDS 104RFC 3274: Compressed Data Content Type for Cryptographic Message Syntax (CMS) 105.Sh HISTORY 106.Fn CMS_uncompress 107first appeared in OpenSSL 0.9.8h 108and has been available since 109.Ox 6.7 . 110.Sh BUGS 111The lack of single pass processing and the need to hold all data in 112memory as mentioned in 113.Xr CMS_verify 3 114also applies to 115.Fn CMS_uncompress . 116