mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-04 13:23:26 +01:00
124 lines
5.0 KiB
Plaintext
124 lines
5.0 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
CMS_decrypt, CMS_decrypt_set1_pkey_and_peer,
|
|
CMS_decrypt_set1_pkey, CMS_decrypt_set1_password
|
|
- decrypt content from a CMS envelopedData structure
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/cms.h>
|
|
|
|
int CMS_decrypt(CMS_ContentInfo *cms, EVP_PKEY *pkey, X509 *cert,
|
|
BIO *dcont, BIO *out, unsigned int flags);
|
|
int CMS_decrypt_set1_pkey_and_peer(CMS_ContentInfo *cms,
|
|
EVP_PKEY *pk, X509 *cert, X509 *peer);
|
|
int CMS_decrypt_set1_pkey(CMS_ContentInfo *cms, EVP_PKEY *pk, X509 *cert);
|
|
int CMS_decrypt_set1_password(CMS_ContentInfo *cms,
|
|
unsigned char *pass, ossl_ssize_t passlen);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
CMS_decrypt() extracts the decrypted content from a CMS EnvelopedData
|
|
or AuthEnvelopedData structure.
|
|
It uses CMS_decrypt_set1_pkey() to decrypt the content
|
|
with the recipient private key I<pkey> if I<pkey> is not NULL.
|
|
In this case, it is recommended to provide the associated certificate
|
|
in I<cert> - see the NOTES below.
|
|
I<out> is a BIO to write the content to and
|
|
I<flags> is an optional set of flags.
|
|
If I<pkey> is NULL the function assumes that decryption was already done
|
|
(e.g., using CMS_decrypt_set1_pkey() or CMS_decrypt_set1_password()) and just
|
|
provides the content unless I<cert>, I<dcont>, and I<out> are NULL as well.
|
|
The I<dcont> parameter is used in the rare case where the encrypted content
|
|
is detached. It will normally be set to NULL.
|
|
|
|
CMS_decrypt_set1_pkey_and_peer() decrypts the CMS_ContentInfo structure I<cms>
|
|
using the private key I<pkey>, the corresponding certificate I<cert>, which is
|
|
recommended to be supplied but may be NULL,
|
|
and the (optional) originator certificate I<peer>.
|
|
On success, it also records in I<cms> the decryption key I<pkey>, and this
|
|
should be followed by C<CMS_decrypt(cms, NULL, NULL, dcont, out, flags)>.
|
|
This call deallocates any decryption key stored in I<cms>.
|
|
|
|
CMS_decrypt_set1_pkey() is the same as
|
|
CMS_decrypt_set1_pkey_and_peer() with I<peer> being NULL.
|
|
|
|
CMS_decrypt_set1_password() decrypts the CMS_ContentInfo structure I<cms>
|
|
using the secret I<pass> of length I<passlen>.
|
|
On success, it also records in I<cms> the decryption key used, and this
|
|
should be followed by C<CMS_decrypt(cms, NULL, NULL, dcont, out, flags)>.
|
|
This call deallocates any decryption key stored in I<cms>.
|
|
|
|
=head1 NOTES
|
|
|
|
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.
|
|
|
|
If I<cert> is set to 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 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 B<CMS_DEBUG_DECRYPT> is set
|
|
then the above behaviour is modified and an error B<is> returned if no
|
|
recipient encrypted key can be decrypted B<without> generating a random
|
|
content encryption key. Applications should use this flag with
|
|
B<extreme caution> especially in automated gateways as it can leave them
|
|
open to attack.
|
|
|
|
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 CMS_set1_pkey(),
|
|
or use CMS_decrypt_set1_password() if the recipient has a symmetric key.
|
|
In these cases both I<cert> and I<pkey> should be set to NULL.
|
|
|
|
To process KEKRecipientInfo types CMS_set1_key() or CMS_RecipientInfo_set0_key()
|
|
and CMS_RecipientInfo_decrypt() should be called before CMS_decrypt() and
|
|
I<cert> and I<pkey> set to NULL.
|
|
|
|
The following flags can be passed in the I<flags> parameter.
|
|
|
|
If the B<CMS_TEXT> flag is set MIME headers for type C<text/plain> are deleted
|
|
from the content. If the content is not of type C<text/plain> then an error is
|
|
returned.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
CMS_decrypt(), CMS_decrypt_set1_pkey_and_peer(),
|
|
CMS_decrypt_set1_pkey(), and CMS_decrypt_set1_password()
|
|
return either 1 for success or 0 for failure.
|
|
The error can be obtained from ERR_get_error(3).
|
|
|
|
=head1 BUGS
|
|
|
|
The B<set1_> part of these function names is misleading
|
|
and should better read: B<with_>.
|
|
|
|
The lack of single pass processing and the need to hold all data in memory as
|
|
mentioned in CMS_verify() also applies to CMS_decrypt().
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ERR_get_error(3)>, L<CMS_encrypt(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
CMS_decrypt_set1_pkey_and_peer() and CMS_decrypt_set1_password()
|
|
were added in OpenSSL 3.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2008-2023 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
Licensed under the Apache License 2.0 (the "License"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file LICENSE in the source distribution or at
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|