CMS_GET0_TYPE(3)           Library Functions Manual           CMS_GET0_TYPE(3)

NAME
     CMS_get0_type, CMS_get_version, 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_get_version(const CMS_ContentInfo *cms, long *version);

     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_get_version() sets *version to the syntax version number of the
     ContentInfo structure cms.  The version is a number between 0 and 5 and
     is defined for all the above content types except for arbitrary data.
     For arbitrary data and unsupported content types CMS_get_version() fails
     and the content of *version is unspecified.

     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_get_version() returns 1 on success and 0 on failure.

     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.

     CMS_get_version() first appeared in OpenBSD 7.4.

Linux 6.8.2-arch2-1              July 27, 2023             Linux 6.8.2-arch2-1