1.\" $OpenBSD: d2i_ASN1_OBJECT.3,v 1.12 2022/03/29 17:41:20 schwarze Exp $ 2.\" 3.\" Copyright (c) 2017, 2022 Ingo Schwarze <schwarze@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: March 29 2022 $ 18.Dt D2I_ASN1_OBJECT 3 19.Os 20.Sh NAME 21.Nm d2i_ASN1_OBJECT , 22.Nm i2d_ASN1_OBJECT 23.\" c2i_ASN1_OBJECT is intentionally undocumented because it is unused 24.\" in real-world software and was removed from the OpenSSL 1.1.1 API 25.Nd decode and encode ASN.1 object identifiers 26.Sh SYNOPSIS 27.In openssl/asn1.h 28.Ft ASN1_OBJECT * 29.Fo d2i_ASN1_OBJECT 30.Fa "ASN1_OBJECT **val_out" 31.Fa "unsigned char **der_in" 32.Fa "long length" 33.Fc 34.Ft int 35.Fo i2d_ASN1_OBJECT 36.Fa "const ASN1_OBJECT *val_in" 37.Fa "unsigned char **der_out" 38.Fc 39.Sh DESCRIPTION 40These functions decode and encode ASN.1 object identifiers. 41For details about the semantics, examples, caveats, and bugs, see 42.Xr ASN1_item_d2i 3 . 43.Pp 44The LibreSSL implementation of 45.Fn d2i_ASN1_OBJECT 46always calls 47.Xr ASN1_OBJECT_free 3 48if an existing object is passed in via 49.Fa val_out 50and it always creates a new object from scratch. 51Other implementations may attempt to reuse an existing object, 52which is fragile and prone to bugs. 53Consequently, always passing 54.Dv NULL 55for the 56.Fa val_out 57argument is recommended. 58.Pp 59The objects returned from 60.Fn d2i_ASN1_OBJECT 61and the data contained in them are always marked as dynamically 62allocated, so when they are no longer needed, 63.Xr ASN1_OBJECT_free 3 64can be called on them. 65.Sh RETURN VALUES 66.Fn d2i_ASN1_OBJECT 67returns a pointer to the new 68.Vt ASN1_OBJECT 69object or 70.Dv NULL 71if an error occurs. 72With other implementations, it might return a pointer to the reused 73.Vt ASN1_OBJECT . 74.Pp 75.Fn i2d_ASN1_OBJECT 76returns the number of bytes successfully encoded 77or a value <= 0 if an error occurs. 78.Sh SEE ALSO 79.Xr a2d_ASN1_OBJECT 3 , 80.Xr ASN1_item_d2i 3 , 81.Xr ASN1_OBJECT_new 3 , 82.Xr OBJ_nid2obj 3 83.Sh STANDARDS 84ITU-T Recommendation X.690, also known as ISO/IEC 8825-1: 85Information technology - ASN.1 encoding rules: 86Specification of Basic Encoding Rules (BER), Canonical Encoding 87Rules (CER) and Distinguished Encoding Rules (DER), 88section 8.19: Encoding of an object identifier value 89.Sh HISTORY 90.Fn d2i_ASN1_OBJECT 91and 92.Fn i2d_ASN1_OBJECT 93first appeared in SSLeay 0.5.1 and have been available since 94.Ox 2.4 . 95.Sh CAVEATS 96.Fn d2i_ASN1_OBJECT 97never sets the long and short names of the object, not even if the 98object identifier matches one that is built into the library. 99To find the names of an object identifier parsed from DER or BER 100input, call 101.Xr OBJ_obj2nid 3 102on the returned object, and then 103.Xr OBJ_nid2sn 3 104and 105.Xr OBJ_nid2ln 3 106on the result. 107