From cc47a3abfdbd325bb89055dfd451213698f0850e Mon Sep 17 00:00:00 2001 From: schwarze <> Date: Sat, 10 Aug 2019 23:41:22 +0000 Subject: Re-convert and re-import the CMS manual pages from OpenSSL 1.1.1 (which are still under a free license) with pod2mdoc(1) now that jsing@ has begun work to provide these APIs. Some formatting was improved and some typos were fixed, but apart from that, little was changed, so there is still much to polish. --- src/lib/libcrypto/man/CMS_decrypt.3 | 169 ++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 src/lib/libcrypto/man/CMS_decrypt.3 (limited to 'src/lib/libcrypto/man/CMS_decrypt.3') diff --git a/src/lib/libcrypto/man/CMS_decrypt.3 b/src/lib/libcrypto/man/CMS_decrypt.3 new file mode 100644 index 0000000000..de37b357a1 --- /dev/null +++ b/src/lib/libcrypto/man/CMS_decrypt.3 @@ -0,0 +1,169 @@ +.\" $OpenBSD: CMS_decrypt.3,v 1.3 2019/08/10 23:41:22 schwarze Exp $ +.\" full merge up to: OpenSSL e9b77246 Jan 20 19:58:49 2017 +0100 +.\" +.\" This file was written by Dr. Stephen Henson . +.\" Copyright (c) 2008, 2014 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: August 10 2019 $ +.Dt CMS_DECRYPT 3 +.Os +.Sh NAME +.Nm CMS_decrypt +.Nd decrypt content from a CMS envelopedData structure +.Sh SYNOPSIS +.In openssl/cms.h +.Ft int +.Fo CMS_decrypt +.Fa "CMS_ContentInfo *cms" +.Fa "EVP_PKEY *pkey" +.Fa "X509 *cert" +.Fa "BIO *dcont" +.Fa "BIO *out" +.Fa "unsigned int flags" +.Fc +.Sh DESCRIPTION +.Fn CMS_decrypt +extracts and decrypts the content from a CMS EnvelopedData structure. +.Fa pkey +is the private key of the recipient, +.Fa cert +is the recipient's certificate, +.Fa out +is a +.Vt BIO +to write the content to and +.Fa flags +is an optional set of flags. +.Pp +The +.Fa dcont +parameter is used in the rare case where the encrypted content is +detached. +It will normally be set to +.Dv NULL . +.Pp +Although the recipients certificate is not needed to decrypt the data it +is needed to locate the appropriate (of possible several) recipients in +the CMS structure. +.Pp +If +.Fa cert +is set to +.Dv NULL , +all possible recipients are tried. +This case however is problematic. +To thwart the MMA attack (Bleichenbacher's attack on PKCS #1 v1.5 RSA +padding) all recipients are tried whether they succeed or not. +If no recipient succeeds then a random symmetric key is used to decrypt +the content: this will typically output garbage and may (but is not +guaranteed to) ultimately return a padding error only. +If +.Fn CMS_decrypt +just returned an error when all recipient encrypted keys failed to +decrypt an attacker could use this in a timing attack. +If the special flag +.Dv CMS_DEBUG_DECRYPT +is set, then the above behaviour is modified and an error +.Em is +returned if no recipient encrypted key can be decrypted +.Em without +generating a random content encryption key. +Applications should use this flag with extreme caution +especially in automated gateways as it can leave them open to attack. +.Pp +It is possible to determine the correct recipient key by other means +(for example looking them up in a database) and setting them in the CMS +structure in advance using the CMS utility functions such as +.Xr CMS_set1_pkey 3 . +In this case both +.Fa cert +and +.Fa pkey +should be set to +.Dv NULL . +.Pp +To process KEKRecipientInfo types, +.Xr CMS_set1_key 3 +or +.Xr CMS_RecipientInfo_set0_key 3 +and +.Xr CMS_RecipientInfo_decrypt 3 +should be called before +.Fn CMS_decrypt +and +.Fa cert +and +.Fa pkey +set to +.Dv NULL . +.Pp +The following flags can be passed in the +.Fa flags +parameter: +.Pp +If the +.Dv CMS_TEXT +flag is set, MIME headers for type text/plain +are deleted from the content. +If the content is not of type text/plain, +then an error is returned. +.Sh RETURN VALUES +.Fn CMS_decrypt +returns either 1 for success or 0 for failure. +The error can be obtained from +.Xr ERR_get_error 3 . +.Sh SEE ALSO +.Xr CMS_encrypt 3 +.Sh HISTORY +.Fn CMS_decrypt +was added to OpenSSL 0.9.8. +.Sh BUGS +The lack of single pass processing and the need to hold all data in +memory as mentioned in +.Xr CMS_verify 3 +also applies to +.Fn CMS_decrypt . -- cgit v1.2.3-55-g6feb