NAME
ASN1_TYPE_new,
ASN1_TYPE_free,
ASN1_TYPE_get,
ASN1_TYPE_set,
ASN1_TYPE_set1,
ASN1_TYPE_set_octetstring,
ASN1_TYPE_get_octetstring,
ASN1_TYPE_set_int_octetstring,
ASN1_TYPE_get_int_octetstring,
ASN1_TYPE_cmp —
ASN.1 objects of arbitrary
type
SYNOPSIS
#include
<openssl/asn1.h>
ASN1_TYPE *
ASN1_TYPE_new(void);
void
ASN1_TYPE_free(ASN1_TYPE
*a);
int
ASN1_TYPE_get(const ASN1_TYPE
*a);
void
ASN1_TYPE_set(ASN1_TYPE *a,
int type, void *value);
int
ASN1_TYPE_set1(ASN1_TYPE *a,
int type, const void
*value);
int
ASN1_TYPE_set_octetstring(ASN1_TYPE
*a, const unsigned char *data,
int len);
int
ASN1_TYPE_get_octetstring(const
ASN1_TYPE *a, unsigned char *buffer,
int buflen);
int
ASN1_TYPE_set_int_octetstring(ASN1_TYPE
*a, long num, const unsigned
char *data, int len);
int
ASN1_TYPE_get_int_octetstring(const
ASN1_TYPE *a, long *num,
unsigned char *buffer, int
buflen);
int
ASN1_TYPE_cmp(const ASN1_TYPE
*a, const ASN1_TYPE *b);
DESCRIPTION
The ASN1_TYPE data type and the
V_ASN1_ANY type identifier constant represent the
ASN.1 ANY type. An ASN1_TYPE object can store an ASN.1
value of arbitrary type, including constructed types such as a SEQUENCE. It
also remembers internally which type it currently holds.
ASN1_TYPE_new()
allocates and initializes an empty ASN1_TYPE object of
type V_ASN1_UNDEF.
ASN1_TYPE_free()
frees a including the value stored in it, if any. If
a is a NULL pointer, no action
occurs.
ASN1_TYPE_get()
returns the type currently held by a, represented by
one of the V_ASN1_* constants defined in
<openssl/asn1.h>.
ASN1_TYPE_set()
frees the value contained in a, if any, and sets the
value and type now held in
a. This function uses the pointer
value internally so it must not be
freed up after the call.
ASN1_TYPE_set1()
sets the type held by a to type
and its value to a copy of value. If copying succeeds,
the previous value that was contained in a is freed.
If copying fails, a remains unchanged.
The type and meaning of the
value argument of
ASN1_TYPE_set()
and ASN1_TYPE_set1() is determined by the
type argument. If type is
V_ASN1_NULL, value is ignored.
If type is V_ASN1_BOOLEAN,
then the boolean is set to TRUE if value is not
NULL. If type is
V_ASN1_OBJECT, then value is
an ASN1_OBJECT structure. Otherwise
type is an ASN1_STRING
structure. If type corresponds to a primitive type or
a string type, then the contents of the ASN1_STRING
contains the content octets of the type. If type
corresponds to a constructed type or a tagged type
(V_ASN1_SEQUENCE,
V_ASN1_SET, or
V_ASN1_OTHER), then the
ASN1_STRING contains the entire ASN.1 encoding
verbatim, including tag and length octets.
ASN1_TYPE_set_octetstring()
allocates a new ASN1_OCTET_STRING object, copies
len bytes of data into it using
ASN1_STRING_set(3), and replaces the value of
a with it by calling
ASN1_TYPE_set() with a type of
V_ASN1_OCTET_STRING.
ASN1_TYPE_get_octetstring()
copies the contents of the ASN1_OCTET_STRING object
contained in a, but not more than
buflen bytes, into the buffer
provided by the caller.
ASN1_TYPE_set_int_octetstring()
frees the value contained in a, if any, sets its type
to V_ASN1_SEQUENCE, and sets its value to a
two-element ASN.1 sequence consisting of an ASN.1 INTEGER object with the
value num and an ASN.1 OCTET STRING object containing
a copy of the len bytes pointed to by
data.
ASN1_TYPE_get_int_octetstring()
copies the integer value from the first element of the ASN.1 sequence
a to *num unless
num is a NULL pointer and
copies the octet string value from the second element, but not more than
buflen bytes, into the buffer
provided by the caller unless buffer is a
NULL pointer.
ASN1_TYPE_cmp()
checks that a and b hold the
same type, the same value, and are encoded in the same way.
If the types agree and the values have the
same meaning but are encoded differently, they are considered different. For
example, a boolean value is represented using a single content octet. Under
BER, any non-zero octet represents the TRUE value, but
ASN1_TYPE_cmp()
will only report a match if the content octet is the same.
If either or both of the arguments passed to
ASN1_TYPE_cmp()
is NULL, the result is a mismatch. Technically, if
both arguments are NULL, the two types could be
absent OPTIONAL fields and so should match, however passing
NULL values could also indicate a programming error
(for example an unparsable type which returns NULL)
for types which do not match. So applications should
handle the case of two absent values separately.
RETURN VALUES
ASN1_TYPE_new() returns the new
ASN1_TYPE object or NULL if an
error occurs.
ASN1_TYPE_get() returns the type currently
held by a or 0 if an error occurs. The latter can
happen if a does not contain a value even though its
type is not V_ASN1_NULL. For example, it will always
happen for empty objects newly constructed with
ASN1_TYPE_new().
ASN1_TYPE_set1(),
ASN1_TYPE_set_octetstring(), and
ASN1_TYPE_set_int_octetstring() return 1 on success
or 0 on failure.
ASN1_TYPE_get_octetstring() returns the
number of data bytes contained in the
ASN1_OCTET_STRING object contained in
a or -1 if a is not of the type
V_ASN1_OCTET_STRING or does not contain any object.
If the return value is greater than the buflen
argument, the content was truncated when copied to the
buffer.
ASN1_TYPE_get_int_octetstring() returns
the number of data bytes contained in the
ASN1_OCTET_STRING object that is the second element of
the ASN.1 sequence a or -1 if a
is not of the type V_ASN1_SEQUENCE or if decoding
fails. If the return value is greater than the buflen
argument, the content was truncated when copied to the
buffer.
ASN1_TYPE_cmp() returns 0 for a match or
non-zero for a mismatch.
SEE ALSO
ASN1_generate_nconf(3), ASN1_get_object(3), ASN1_item_free(3), ASN1_OBJECT_new(3), ASN1_parse_dump(3), ASN1_put_object(3), ASN1_STRING_dup(3), ASN1_STRING_new(3), crypto(3), d2i_ASN1_NULL(3), d2i_ASN1_SEQUENCE_ANY(3), d2i_ASN1_TYPE(3), OBJ_dup(3)
HISTORY
ASN1_TYPE_new() and
ASN1_TYPE_free() first appeared in SSLeay 0.5.1,
ASN1_TYPE_get() and
ASN1_TYPE_set() in SSLeay 0.8.0, and
ASN1_TYPE_set_octetstring(),
ASN1_TYPE_get_octetstring(),
ASN1_TYPE_set_int_octetstring(), and
ASN1_TYPE_get_int_octetstring() in SSLeay 0.9.0.
These functions have been available since OpenBSD
2.4.
ASN1_TYPE_set1() first appeared in OpenSSL
0.9.8h and has been available since OpenBSD 4.5.
ASN1_TYPE_cmp() first appeared in OpenSSL
0.9.8zd, 1.0.0p, and 1.0.1k and has been available since
OpenBSD 4.9.