path: root/lib/libcrypto/man/ASN1_STRING_length.3

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.Dd $Mdocdate: April 25 2018 $
.Dt ASN1_STRING_LENGTH 3
.Os
.Sh NAME
.Nm ASN1_STRING_cmp ,
.Nm ASN1_STRING_data ,
.Nm ASN1_STRING_dup ,
.Nm ASN1_STRING_get0_data ,
.Nm ASN1_STRING_length ,
.Nm ASN1_STRING_length_set ,
.Nm ASN1_STRING_set ,
.Nm ASN1_STRING_to_UTF8 ,
.Nm ASN1_STRING_type
.Nd ASN1_STRING utility functions
.Sh SYNOPSIS
.In openssl/asn1.h
.Ft int
.Fo ASN1_STRING_cmp
.Fa "const ASN1_STRING *a"
.Fa "const ASN1_STRING *b"
.Fc
.Ft unsigned char *
.Fo ASN1_STRING_data
.Fa "ASN1_STRING *x"
.Fc
.Ft ASN1_STRING *
.Fo ASN1_STRING_dup
.Fa "const ASN1_STRING *a"
.Fc
.Ft const unsigned char *
.Fo ASN1_STRING_get0_data
.Fa "const ASN1_STRING *x"
.Fc
.Ft int
.Fo ASN1_STRING_length
.Fa "const ASN1_STRING *x"
.Fc
.Ft void
.Fo ASN1_STRING_length_set
.Fa "ASN1_STRING *x"
.Fa "int len"
.Fc
.Ft int
.Fo ASN1_STRING_set
.Fa "ASN1_STRING *str"
.Fa "const void *data"
.Fa "int len"
.Fc
.Ft int
.Fo ASN1_STRING_to_UTF8
.Fa "unsigned char **out"
.Fa "ASN1_STRING *in"
.Fc
.Ft int
.Fo ASN1_STRING_type
.Fa "const ASN1_STRING *x"
.Fc
.Sh DESCRIPTION
These functions manipulate
.Vt ASN1_STRING
structures.
.Pp
.Fn ASN1_STRING_cmp
compares the type, the length, and the content of
.Fa a
and
.Fa b .
.Pp
.Fn ASN1_STRING_data
is similar to
.Fn ASN1_STRING_get0_data
except that the returned value is not constant.
This function is deprecated.
Applications should use
.Fn ASN1_STRING_get0_data
instead.
.Pp
.Fn ASN1_STRING_dup
copies
.Fa a .
.Pp
.Fn ASN1_STRING_get0_data
returns an internal pointer to the data of
.Fa x .
It should not be freed or modified in any way.
.Pp
.Fn ASN1_STRING_length
returns the length attribute of
.Fa x ,
measured in bytes.
.Pp
.Fn ASN1_STRING_length_set
sets the length attribute of
.Fa x
to
.Fa len .
It may put
.Fa x
into an inconsistent internal state.
.Pp
.Fn ASN1_STRING_set
sets the length attribute of
.Fa str
to
.Fa len
and copies that number of bytes from
.Fa data
into
.Fa str .
If
.Fa len
is -1, then
.Fn strlen data
is used instead of
.Fa len .
If
.Fa data
is
.Dv NULL ,
the content of
.Fa str
remains uninitialized; that is not considered an error unless
.Fa len
is negative.
.Pp
.Fn ASN1_STRING_to_UTF8
converts the string
.Fa in
to UTF-8 format.
The converted data is copied into a newly allocated buffer
.Pf * Fa out .
The buffer
.Pf * Fa out
should be freed using
.Xr free 3 .
.Pp
.Fn ASN1_STRING_type
returns the type of
.Fa x .
.Pp
Almost all ASN.1 types are represented as
.Vt ASN1_STRING
structures.
Other types such as
.Vt ASN1_OCTET_STRING
are simply typedefed to
.Vt ASN1_STRING
and the functions call the
.Vt ASN1_STRING
equivalents.
.Vt ASN1_STRING
is also used for some CHOICE types which consist entirely of primitive
string types such as
.Vt DirectoryString
and
.Vt Time .
.Pp
These functions should
.Em not
be used to examine or modify
.Vt ASN1_INTEGER
or
.Vt ASN1_ENUMERATED
types: the relevant INTEGER or ENUMERATED utility functions should
be used instead.
.Pp
In general it cannot be assumed that the data returned by
.Fn ASN1_STRING_get0_data
and
.Fn ASN1_STRING_data
is NUL terminated, and it may contain embedded NUL characters.
The format of the data depends on the string type:
for example for an
.Vt IA5String
the data contains ASCII characters, for a
.Vt BMPString
two bytes per character in big endian format, and for a
.Vt UTF8String
UTF-8 characters.
.Pp
Similar care should be taken to ensure the data is in the correct format
when calling
.Fn ASN1_STRING_set .
.Sh RETURN VALUES
.Fn ASN1_STRING_cmp
returns 0 if the type, the length, and the content of
.Fa a
and
.Fa b
agree, or a non-zero value otherwise.
In contrast to
.Xr strcmp 3 ,
the sign of the return value does not indicate lexicographical ordering.
.Pp
.Fn ASN1_STRING_data
and
.Fn ASN1_STRING_get0_data
return an internal pointer to the data of
.Fa x .
.Pp
.Fn ASN1_STRING_dup
returns a pointer to a newly allocated
.Vt ASN1_STRING
structure or
.Dv NULL
if an error occurred.
.Pp
.Fn ASN1_STRING_length
returns a number of bytes.
.Pp
.Fn ASN1_STRING_set
returns 1 on success or 0 on failure.
.Pp
.Fn ASN1_STRING_to_UTF8
returns the number of bytes in the output buffer
.Pf * Fa out ,
or a negative number if an error occurred.
.Pp
.Fn ASN1_STRING_type
returns an integer constant, for example
.Dv V_ASN1_OCTET_STRING .
.Sh SEE ALSO
.Xr ERR_get_error 3
.Sh HISTORY
.Fn ASN1_STRING_cmp ,
.Fn ASN1_STRING_dup ,
and
.Fn ASN1_STRING_set
first appeared in SSLeay 0.6.5.
.Fn ASN1_STRING_data
and
.Fn ASN1_STRING_type
first appeared in SSLeay 0.8.0.
.Fn ASN1_STRING_length
first appeared in SSLeay 0.9.0.
All these functions have been available since
.Ox 2.4 .
.Pp
.Fn ASN1_STRING_length_set
first appeared in OpenSSL 0.9.5 and has been available since
.Ox 2.7 .
.Pp
.Fn ASN1_STRING_to_UTF8
first appeared in OpenSSL 0.9.6 and has been available since
.Ox 2.9 .
.Pp
.Fn ASN1_STRING_get0_data
first appeared in OpenSSL 1.1.0 and has been available since
.Ox 6.3 .