NAME
CMS_get0_type,
CMS_set1_eContentType,
CMS_get0_eContentType,
CMS_get0_content —
get and set CMS content types and
content
SYNOPSIS
#include
<openssl/cms.h>
const ASN1_OBJECT *
CMS_get0_type(const CMS_ContentInfo
*cms);
int
CMS_set1_eContentType(CMS_ContentInfo
*cms, const ASN1_OBJECT *oid);
const ASN1_OBJECT *
CMS_get0_eContentType(CMS_ContentInfo
*cms);
ASN1_OCTET_STRING **
CMS_get0_content(CMS_ContentInfo
*cms);
DESCRIPTION
CMS_get0_type()
returns the content type of the ContentInfo structure
cms. The ASN1_OBJECT value
returned can be converted to an integer NID value using
OBJ_obj2nid(3). The following content types are identified by the
following NIDs:
| SignedData | NID_pkcs7_signed |
| EnvelopedData | NID_pkcs7_enveloped |
| DigestedData | NID_pkcs7_digest |
| EncryptedData | NID_pkcs7_encrypted |
| AuthenticatedData | NID_id_smime_ct_authData |
| CompressedData | NID_id_smime_ct_compressedData |
| arbitrary data | NID_pkcs7_data |
The SignedData,
DigestedData, AuthenticatedData,
and CompressedData types contain a field
encapContentInfo to allow embedding content, and
EnvelopedData and EncryptedData
contain a field encryptedContentInfo for that purpose.
The type of the embedded content to be stored in that field can be set with
the function
CMS_set1_eContentType(),
to be called on cms structures returned from functions
such as CMS_sign(3) or
CMS_encrypt(3) with the CMS_PARTIAL flag set
and
before
the structure is finalised; otherwise the results are undefined.
CMS_set1_eContentType() copies the supplied
oid, so it should be freed up after use.
CMS_get0_eContentType()
returns the type of the embedded content.
CMS_get0_content()
returns a pointer to the storage location where the pointer to the embedded
content is stored. That means that for example after
ASN1_OCTET_STRING **pconf =
CMS_get0_content(cms);*pconf could be NULL
if there is no embedded content. Applications can access, modify or create
the embedded content in a CMS_ContentInfo structure
using this function. Applications usually will not need to modify the
embedded content as it is normally set by higher level functions.
RETURN VALUES
CMS_get0_type() and
CMS_get0_eContentType() return internal pointers to
OBJECT IDENTIFIER structures.
CMS_get0_content() returns an internal
pointer to the storage location where the pointer to the embedded content is
stored.
CMS_set1_eContentType() returns 1 for
success or 0 if an error occurred. The error can be obtained from
ERR_get_error(3).
SEE ALSO
CMS_ContentInfo_new(3), d2i_CMS_ContentInfo(3), SMIME_read_CMS(3)
STANDARDS
RFC 5652: Cryptographic Message Syntax
RFC 3274: Compressed Data Content Type for Cryptographic Message Syntax (CMS)
HISTORY
These functions first appeared in OpenSSL 0.9.8h and have been available since OpenBSD 6.7.