.\" $OpenBSD: X509_ATTRIBUTE_set1_object.3,v 1.3 2021/11/26 13:48:21 jsg Exp $ .\" .\" Copyright (c) 2021 Ingo Schwarze .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .Dd $Mdocdate: November 26 2021 $ .Dt X509_ATTRIBUTE_SET1_OBJECT 3 .Os .Sh NAME .Nm X509_ATTRIBUTE_set1_object , .Nm X509_ATTRIBUTE_set1_data , .Nm X509_ATTRIBUTE_create_by_OBJ , .Nm X509_ATTRIBUTE_create_by_NID , .Nm X509_ATTRIBUTE_create_by_txt .\" In the following line, "X.501" and "Attribute" are not typos. .\" The "Attribute" type is defined in X.501, not in X.509. .\" The type is called "Attribute" with capital "A", not "attribute". .Nd modify an X.501 Attribute .Sh SYNOPSIS .In openssl/x509.h .Ft int .Fo X509_ATTRIBUTE_set1_object .Fa "X509_ATTRIBUTE *attr" .Fa "const ASN1_OBJECT *obj" .Fc .Ft int .Fo X509_ATTRIBUTE_set1_data .Fa "X509_ATTRIBUTE *attr" .Fa "int type" .Fa "const void *data" .Fa "int len" .Fc .Ft X509_ATTRIBUTE * .Fo X509_ATTRIBUTE_create_by_OBJ .Fa "X509_ATTRIBUTE **pattr" .Fa "const ASN1_OBJECT *obj" .Fa "int type" .Fa "const void *data" .Fa "int len" .Fc .Ft X509_ATTRIBUTE * .Fo X509_ATTRIBUTE_create_by_NID .Fa "X509_ATTRIBUTE **pattr" .Fa "int nid" .Fa "int type" .Fa "const void *data" .Fa "int len" .Fc .Ft X509_ATTRIBUTE * .Fo X509_ATTRIBUTE_create_by_txt .Fa "X509_ATTRIBUTE **pattr" .Fa "const char *name" .Fa "int type" .Fa "const unsigned char *data" .Fa "int len" .Fc .Sh DESCRIPTION .Fn X509_ATTRIBUTE_set1_object sets the type of .Fa attr to .Fa obj . If .Fa obj is dynamically allocated, a deep copy is created. If the type of .Fa attr was already set, the old type is freed as far as it was dynamically allocated. After calling this function, .Fa attr may be in an inconsistent state because its values may not agree with the new attribute type. .Pp .Fn X509_ATTRIBUTE_set1_data sets .Fa attr to be multi-valued and initializes its set of values to contain a single new ASN.1 ANY object representing the .Fa data . .Pp The interpretation of the .Fa data depends on the values of the .Fa type and .Fa len arguments; there are four different cases. .Pp If the .Fa type argument has the bit .Dv MBSTRING_FLAG set, .Fa data is expected to point to a multibyte character string that is .Fa len bytes long and uses the encoding specified by the .Fa type argument, and it is expected that an attribute type was already assigned to .Fa attr , for example by calling .Fn X509_ATTRIBUTE_set1_object before calling .Fn X509_ATTRIBUTE_set1_data . In this case, an appropriate ASN.1 multibyte string type is chosen and a new object of that type is allocated and populated to represent the .Fa data by calling .Xr ASN1_STRING_set_by_NID 3 . The type of that new ASN.1 string object is subsequently used instead of the .Fa type argument. .Pp If the .Fa type argument does not have the bit .Dv MBSTRING_FLAG set and the .Fa len argument is not \-1, the .Fa type argument is expected to be one of the types documented in .Xr ASN1_STRING_new 3 and .Fa data is expected to point to a buffer of .Fa len bytes. In this case, a new object is allocated with .Xr ASN1_STRING_type_new 3 and populated with .Xr ASN1_STRING_set 3 . .Pp If the .Fa type argument does not have the bit .Dv MBSTRING_FLAG set and the .Fa len argument is \-1, .Fa data is expected to point to an object of the given .Fa type rather than to a buffer. In this case, a deep copy of the existing object into the new ASN.1 ANY object is performed with .Xr ASN1_TYPE_set1 3 . .Pp If the .Fa type argument is 0, the .Fa data and .Fa len arguments are ignored and the set of values is left empty instead of adding a single ASN.1 ANY object to it. This violates section 8.2 of the X.501 standard, which requires every attribute to contain at least one value, but some attribute types used by the library use empty sets of values anyway. .Pp .Fn X509_ATTRIBUTE_create_by_OBJ sets the type of .Pf ** Fa attr to .Fa obj using .Fn X509_ATTRIBUTE_set1_object and copies the .Fa data into it using .Fn X509_ATTRIBUTE_set1_data . If .Fa attr or .Pf * Fa attr is .Dv NULL , a new .Vt X509_ATTRIBUTE object is allocated, populated, and returned. .Pp .Fn X509_ATTRIBUTE_create_by_NID is a wrapper around .Fn X509_ATTRIBUTE_create_by_OBJ that obtains the required .Fa obj argument by calling .Xr OBJ_nid2obj 3 on the .Fa nid argument. .Pp .Fn X509_ATTRIBUTE_create_by_txt is a similar wrapper that obtains .Fa obj by calling .Xr OBJ_txt2obj 3 with the arguments .Fa name and 0, which means that long names, short names, and numerical OID strings are all acceptable. .Sh RETURN VALUES .Fn X509_ATTRIBUTE_set1_object returns 1 if successful or 0 if .Fa attr or .Fa obj is .Dv NULL or if memory allocation fails. .Pp .Fn X509_ATTRIBUTE_set1_data returns 1 if successful or 0 if .Fa attr is .Dv NULL or if .Xr ASN1_STRING_set_by_NID 3 , .Xr ASN1_STRING_set 3 , .Xr ASN1_TYPE_set1 3 , or memory allocation fails. .Pp .Fn X509_ATTRIBUTE_create_by_OBJ , .Fn X509_ATTRIBUTE_create_by_NID , and .Fn X509_ATTRIBUTE_create_by_txt return a pointer to the changed or new object or .Dv NULL if obtaining .Fa obj , allocating memory, or copying fails. .Sh SEE ALSO .Xr ASN1_OBJECT_new 3 , .Xr ASN1_STRING_new 3 , .Xr ASN1_STRING_set 3 , .Xr ASN1_STRING_set_by_NID 3 , .Xr ASN1_TYPE_new 3 , .Xr OBJ_nid2obj 3 , .Xr X509_ATTRIBUTE_get0_object 3 , .Xr X509_ATTRIBUTE_new 3 .Sh HISTORY These functions first appeared in OpenSSL 0.9.5 and have been available since .Ox 2.7 . .Sh BUGS If .Fa attr already contains one or more values, .Fn X509_ATTRIBUTE_set1_data , .Fn X509_ATTRIBUTE_create_by_OBJ , .Fn X509_ATTRIBUTE_create_by_NID , and .Fn X509_ATTRIBUTE_create_by_txt silently overwrite the pointers to the old values and leak the memory used for them.