.\" $OpenBSD: CMS_compress.3,v 1.7 2019/11/02 15:39:46 schwarze Exp $ .\" full merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2019 Ingo Schwarze .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .\" The original file was written by Dr. Stephen Henson . .\" Copyright (c) 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: November 2 2019 $ .Dt CMS_COMPRESS 3 .Os .Sh NAME .Nm CMS_compress .Nd create a CMS CompressedData structure .Sh SYNOPSIS .In openssl/cms.h .Ft CMS_ContentInfo * .Fo CMS_compress .Fa "BIO *in" .Fa "int comp_nid" .Fa "unsigned int flags" .Fc .Sh DESCRIPTION .Fn CMS_compress creates and returns a CMS .Vt CompressedData structure. .Pp .Fa comp_nid is the compression algorithm to use or .Dv NID_undef to use the default algorithm. Currently, the default algorithm .Dv NID_zlib_compression is the only supported algorithm. If zlib support is not compiled in, .Fn CMS_compress always returns an error. .Pp .Fa in provides the content to be compressed. .Pp Any of the following flags (OR'ed together) can be passed in the .Fa flags parameter: .Bl -tag -width Ds .It Dv CMS_TEXT Prepend MIME headers for type text/plain to the data. .It Dv CMS_BINARY Do not translate the supplied content into MIME canonical format, even though that is required by the S/MIME specifications. This option should be used if the supplied data is in binary format. Otherwise, the translation will corrupt it. If .Dv CMS_BINARY is set, .Dv CMS_TEXT is ignored. .It Dv CMS_STREAM Return a partial .Vt CMS_ContentInfo structure suitable for streaming I/O: no data is read from .Fa in . Several functions including .Xr SMIME_write_CMS 3 , .Xr i2d_CMS_bio_stream 3 , or .Xr PEM_write_bio_CMS_stream 3 can be used to finalize the structure. Alternatively, finalization can be performed by obtaining the streaming ASN1 .Vt BIO directly using .Xr BIO_new_CMS 3 . Outputting the contents of the .Vt CMS_ContentInfo structure via a function that does not properly finalize it will give unpredictable results. .It Dv CMS_DETACHED Do not include the compressed data in the .Vt CMS_ContentInfo structure. This is rarely used in practice and is not supported by .Xr SMIME_write_CMS 3 . .El .Pp Additional compression parameters such as the zlib compression level cannot currently be set. .Sh RETURN VALUES .Fn CMS_compress returns either a .Vt CMS_ContentInfo structure or .Dv NULL if an error occurred. The error can be obtained from .Xr ERR_get_error 3 . .Sh SEE ALSO .Xr CMS_ContentInfo_new 3 , .Xr CMS_uncompress 3 .Sh STANDARDS RFC 3274: Compressed Data Content Type for Cryptographic Message Syntax (CMS) .Sh HISTORY .Fn CMS_compress first appeared in OpenSSL 0.9.8h and has been available since .Ox 6.7 . .Pp The .Dv CMS_STREAM flag first appeared in OpenSSL 1.0.0.