path: root/lib/libcrypto/man/OBJ_create.3

.\" $OpenBSD: OBJ_create.3,v 1.6 2022/01/01 02:06:07 jsg Exp $
.\" full merge up to:
.\" OpenSSL OBJ_nid2obj.pod 9b86974e Aug 17 15:21:33 2015 -0400
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.\" OpenSSL OBJ_nid2obj.pod 35fd9953 May 28 14:49:38 2019 +0200
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.Dd $Mdocdate: January 1 2022 $
.Dt OBJ_CREATE 3
.Os
.Sh NAME
.Nm OBJ_new_nid ,
.Nm OBJ_add_object ,
.Nm OBJ_create ,
.\" OBJ_create_and_add_object is a deprecated, unused alias for OBJ_create(3).
.Nm OBJ_create_objects ,
.Nm obj_cleanup_defer ,
.Nm OBJ_cleanup ,
.Nm check_defer
.Nd modify the table of ASN.1 object identifiers
.Sh SYNOPSIS
.In openssl/objects.h
.Ft int
.Fn OBJ_new_nid "int increment"
.Ft int
.Fn OBJ_add_object "const ASN1_OBJECT *object"
.Ft int
.Fo OBJ_create
.Fa "const char *oid"
.Fa "const char *sn"
.Fa "const char *ln"
.Fc
.Ft int
.Fn OBJ_create_objects "BIO *in_bio"
.Vt extern int obj_cleanup_defer ;
.Ft void
.Fn OBJ_cleanup void
.Ft void
.Fn check_defer "int nid"
.Sh DESCRIPTION
.Fn OBJ_new_nid
returns the smallest currently unassigned ASN.1 numeric
object identifier (NID) and reserves
.Fa increment
consecutive NIDs starting with it.
Passing an argument of 1 is usually recommended.
The return value can be assigned to a new object by passing it as the
.Fa nid
argument to
.Xr ASN1_OBJECT_create 3
and by passing the resulting object to
.Fn OBJ_add_object .
.Pp
.Fn OBJ_add_object
adds a copy of the
.Fa object
to the internal table of ASN.1 object identifiers for use by
.Xr OBJ_nid2obj 3
and related functions.
.Pp
.Fn OBJ_create
provides a simpler way to add a new object to the internal table.
.Fa oid
is the numerical form of the object,
.Fa sn
the short name and
.Fa ln
the long name.
A new NID is automatically assigned using
.Fn OBJ_new_nid .
.Pp
.Fn OBJ_create_objects
reads text lines of the form
.Pp
.D1 Fa oid sn ln
.Pp
from
.Fa in_bio
and calls
.Fn OBJ_create oid sn ln
for every line read.
The three fields of the input lines
are separated by one or more whitespace characters.
.Pp
For all three functions, the objects added to the internal table and
all the data contained in them is marked as not dynamically allocated.
Consequently, retrieving them with
.Xr OBJ_nid2obj 3
or a similar function and then calling
.Xr ASN1_OBJECT_free 3
on the returned pointer will have no effect.
.Pp
The global variable
.Va obj_cleanup_defer
controls the behaviour of
.Fn OBJ_cleanup
and
.Xr EVP_cleanup 3 .
.Pp
If
.Va obj_cleanup_defer
has the default value of 0,
.Fn OBJ_cleanup
resets the internal object table to its default state,
removing and freeing all objects that were added with
.Fn OBJ_add_object ,
.Fn OBJ_create ,
or
.Fn OBJ_create_objects .
Otherwise,
.Fn OBJ_cleanup
only sets
.Va obj_cleanup_defer
to 2, which defers the cleanup of the internal object table
to the next call of
.Xr EVP_cleanup 3 .
.Pp
By default,
.Xr EVP_cleanup 3
has no effect on the internal object table.
Only if
.Va obj_cleanup_defer
is 2, it resets
.Va obj_cleanup_defer
to 0 and calls
.Fn OBJ_cleanup ,
which then resets the table to its default state.
.Pp
The function
.Fn check_defer
sets
.Va obj_cleanup_defer
to 1 unless
.Fa nid
is a built-in numeric identifier, but it has no effect if
.Va obj_cleanup_defer
already differs from 0.
This function is called internally by various functions
in the EVP library, in particular by subroutines of
.Xr OpenSSL_add_all_ciphers 3
and
.Xr OpenSSL_add_all_digests 3 .
.Pp
To reliably reset the internal object table no matter what the
current state may be, an application program needs to call both
.Fn OBJ_cleanup
and
.Xr EVP_cleanup 3 ,
in this order.
The opposite order will usually not work.
.Sh RETURN VALUES
.Fn OBJ_new_nid
returns the new NID.
.Pp
.Fn OBJ_add_object
returns the NID associated with the
.Fa object
or
.Dv NID_undef
if memory allocation fails.
.Pp
.Fn OBJ_create
returns the new NID or
.Dv NID_undef
if
.Fa oid
is not a valid representation of an object identifier
or if memory allocation fails.
.Pp
.Fn OBJ_create_objects
returns the number of objects added.
.Pp
In some cases of failure of
.Fn OBJ_add_object ,
.Fn OBJ_create ,
and
.Fn OBJ_create_objects ,
the reason can be determined with
.Xr ERR_get_error 3 .
.Sh EXAMPLES
Create a new NID and initialize an object from it:
.Bd -literal -offset indent
int new_nid;
ASN1_OBJECT *obj;

new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");
obj = OBJ_nid2obj(new_nid);
.Ed
.Sh SEE ALSO
.Xr ASN1_OBJECT_new 3 ,
.Xr EVP_cleanup 3 ,
.Xr OBJ_add_sigid 3 ,
.Xr OBJ_NAME_add 3 ,
.Xr OBJ_nid2obj 3
.Sh HISTORY
.Fn OBJ_new_nid ,
.Fn OBJ_add_object ,
and
.Fn OBJ_cleanup
first appeared in SSLeay 0.8.0 and
.Fn OBJ_create
in SSLeay 0.9.0.
These functions have been available since
.Ox 2.4 .
.Pp
.Va obj_cleanup_defer
and
.Fn check_defer
first appeared in OpenSSL 1.0.0 and have been available since
.Ox 4.9 .
.Sh BUGS
.Fn OBJ_new_nid
does not reserve any return value to indicate an error.
Consequently, to avoid conflicting NID assignments and integer overflows,
care must be taken to not pass negative, zero, or large arguments to
.Fn OBJ_new_nid .
.Pp
.Fn OBJ_create_objects
does not distinguish between end of file, I/O errors, temporary
unavailability of data on a non-blocking BIO, invalid input syntax,
and memory allocation failure.
In all these cases, reading is aborted and the number of objects
that were already added is returned.