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Split ber.3 into logical parts. Further tweaking will be done in tree. 

Discussed with and ok jmc@, schwarze@, claudio@
OPENBSD_6_6
rob 5 years ago
parent
afee62df16
commit
b43f7ed0ff
7 changed files with 769 additions and 456 deletions
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  1. +4
    -2
      src/lib/libutil/Makefile
  2. +0
    -454
      src/lib/libutil/ber.3
  3. +167
    -0
      src/lib/libutil/ber_add_string.3
  4. +120
    -0
      src/lib/libutil/ber_get_string.3
  5. +109
    -0
      src/lib/libutil/ber_oid_cmp.3
  6. +225
    -0
      src/lib/libutil/ber_read_elements.3
  7. +144
    -0
      src/lib/libutil/ber_set_header.3

+ 4
- 2
src/lib/libutil/Makefile View File

@ -1,4 +1,4 @@
# $OpenBSD: Makefile,v 1.41 2019/05/11 17:46:02 rob Exp $
# $OpenBSD: Makefile,v 1.42 2019/05/15 03:11:52 rob Exp $
# $NetBSD: Makefile,v 1.8 1996/05/16 07:03:28 thorpej Exp $ # $NetBSD: Makefile,v 1.8 1996/05/16 07:03:28 thorpej Exp $
LIB= util LIB= util
@ -12,7 +12,9 @@ SRCS= bcrypt_pbkdf.c ber.c check_expire.c duid.c getmaxpartitions.c \
login_fbtab.c uucplock.c fparseln.c opendisk.c pidfile.c \ login_fbtab.c uucplock.c fparseln.c opendisk.c pidfile.c \
fmt_scaled.c imsg.c imsg-buffer.c pkcs5_pbkdf2.c fmt_scaled.c imsg.c imsg-buffer.c pkcs5_pbkdf2.c
MAN= bcrypt_pbkdf.3 ber.3 check_expire.3 getmaxpartitions.3 \
MAN= bcrypt_pbkdf.3 ber_add_string.3 ber_get_string.3 ber_oid_cmp.3 \
ber_read_elements.3 ber_set_header.3 \
check_expire.3 getmaxpartitions.3 \
getrawpartition.3 \ getrawpartition.3 \
isduid.3 login.3 \ isduid.3 login.3 \
opendev.3 openpty.3 pw_init.3 pw_lock.3 readlabelfs.3 uucplock.3 \ opendev.3 openpty.3 pw_init.3 pw_lock.3 readlabelfs.3 uucplock.3 \


+ 0
- 454
src/lib/libutil/ber.3 View File

@ -1,454 +0,0 @@
.\" $OpenBSD: ber.3,v 1.2 2019/05/12 19:29:41 rob Exp $
.\"
.\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
.\"
.\" 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: May 12 2019 $
.Dt BER 3
.Os
.Sh NAME
.Nm ber_get_element ,
.Nm ber_set_header ,
.Nm ber_link_elements ,
.Nm ber_unlink_elements ,
.Nm ber_replace_elements ,
.Nm ber_add_sequence ,
.Nm ber_add_set ,
.Nm ber_add_enumerated ,
.Nm ber_add_integer ,
.Nm ber_get_integer ,
.Nm ber_get_enumerated ,
.Nm ber_add_boolean ,
.Nm ber_get_boolean ,
.Nm ber_add_string ,
.Nm ber_add_nstring ,
.Nm ber_add_ostring ,
.Nm ber_add_bitstring ,
.Nm ber_get_string ,
.Nm ber_get_nstring ,
.Nm ber_get_ostring ,
.Nm ber_get_bitstring ,
.Nm ber_add_null ,
.Nm ber_get_null ,
.Nm ber_add_eoc ,
.Nm ber_get_eoc ,
.Nm ber_add_oid ,
.Nm ber_add_noid ,
.Nm ber_add_oidstring ,
.Nm ber_get_oid ,
.Nm ber_oid2ber ,
.Nm ber_string2oid ,
.Nm ber_oid_cmp ,
.Nm ber_printf_elements ,
.Nm ber_scanf_elements ,
.Nm ber_get_writebuf ,
.Nm ber_write_elements ,
.Nm ber_set_readbuf ,
.Nm ber_read_elements ,
.Nm ber_getpos ,
.Nm ber_free_element ,
.Nm ber_free_elements ,
.Nm ber_calc_len ,
.Nm ber_set_application ,
.Nm ber_set_writecallback ,
.Nm ber_free
.Nd encode and decode ASN.1 with Basic Encoding Rules
.Sh SYNOPSIS
.In sys/types.h
.In ber.h
.Ft "struct ber_element *"
.Fn "ber_get_element" "unsigned int encoding"
.Ft "void"
.Fn "ber_set_header" "struct ber_element *elm" "int class" "unsigned int type"
.Ft "void"
.Fn "ber_link_elements" "struct ber_element *prev" "struct ber_element *elm"
.Ft "struct ber_element *"
.Fn "ber_unlink_elements" "struct ber_element *prev"
.Ft "void"
.Fn "ber_replace_elements" "struct ber_element *prev" "struct ber_element *elm"
.Ft "struct ber_element *"
.Fn "ber_add_sequence" "struct ber_element *prev"
.Ft "struct ber_element *"
.Fn "ber_add_set" "struct ber_element *prev"
.Ft "struct ber_element *"
.Fn "ber_add_integer" "struct ber_element *prev" "long long val"
.Ft "int"
.Fn "ber_get_integer" "struct ber_element *root" "long long *val"
.Ft "struct ber_element *"
.Fn "ber_add_enumerated" "struct ber_element *prev" "long long val"
.Ft "int"
.Fn "ber_get_enumerated" "struct ber_element *root" "long long *val"
.Ft "struct ber_element *"
.Fn "ber_add_boolean" "struct ber_element *prev" "int bool"
.Ft "int"
.Fn "ber_get_boolean" "struct ber_element *root" "int *bool"
.Ft "struct ber_element *"
.Fn "ber_add_string" "struct ber_element *prev" "const char *string"
.Ft "struct ber_element *"
.Fn "ber_add_nstring" "struct ber_element *prev" "const char *string" "size_t size"
.Ft "struct ber_element *"
.Fo "ber_add_ostring"
.Fa "struct ber_element *prev"
.Fa "struct ber_octetstring *ostring"
.Fc
.Ft "int"
.Fn "ber_get_string" "struct ber_element *root" "char **charbuf"
.Ft "int"
.Fn "ber_get_nstring" "struct ber_element *root" "void **buf" "size_t *size"
.Ft "int"
.Fn "ber_get_ostring" "struct ber_element *root" "struct ber_octetstring *ostring"
.Ft "struct ber_element *"
.Fo "ber_add_bitstring"
.Fa "struct ber_element *prev"
.Fa "const void *buf"
.Fa "size_t size"
.Fc
.Ft "int"
.Fn "ber_get_bitstring" "struct ber_element *root" "void **buf" "size_t *size"
.Ft "struct ber_element *"
.Fn "ber_add_null" "struct ber_element *prev"
.Ft "int"
.Fn "ber_get_null" "struct ber_element *root"
.Ft "struct ber_element *"
.Fn "ber_add_eoc" "struct ber_element *prev"
.Ft "int"
.Fn "ber_get_eoc" "struct ber_element *root"
.Ft "struct ber_element *"
.Fn "ber_add_oid" "struct ber_element *prev" "struct ber_oid *oid"
.Ft "struct ber_element *"
.Fn "ber_add_noid" "struct ber_element *prev" "struct ber_oid *oid" "int n"
.Ft "struct ber_element *"
.Fn "ber_add_oidstring" "struct ber_element *prev" "const char *string"
.Ft "int"
.Fn "ber_get_oid" "struct ber_element *root" "struct ber_oid *oid"
.Ft "size_t"
.Fn "ber_oid2ber" "struct ber_oid *oid" "u_int8_t *buf" "size_t size"
.Ft "int"
.Fn "ber_string2oid" "const char *string" "struct ber_oid *oid"
.Ft "int"
.Fn "ber_oid_cmp" "struct ber_oid *oid" "struct ber_oid *oid"
.Ft "struct ber_element *"
.Fn "ber_printf_elements" "struct ber_element *prev" "char *format" "..."
.Ft "int"
.Fn "ber_scanf_elements" "struct ber_element *root" "char *format" "..."
.Ft "ssize_t"
.Fn "ber_get_writebuf" "struct ber *ber" "void **buf"
.Ft "ssize_t"
.Fn "ber_write_elements" "struct ber *ber" "struct ber_element *root"
.Ft "void"
.Fn "ber_set_readbuf" "struct ber *ber" "void *buf" "size_t len"
.Ft "struct ber_element *"
.Fn "ber_read_elements" "struct ber *ber" "struct ber_element *root"
.Ft off_t
.Fn "ber_getpos" "struct ber_element *elm"
.Ft "void"
.Fn "ber_free_element" "struct ber_element *root"
.Ft "void"
.Fn "ber_free_elements" "struct ber_element *root"
.Ft "size_t"
.Fn "ber_calc_len" "struct ber_element *root"
.Ft "void"
.Fo "ber_set_application"
.Fa "struct ber *ber"
.Fa "unsigned int (*cb)(struct ber_element *)"
.Fc
.Ft "void"
.Fo "ber_set_writecallback"
.Fa "struct ber_element *elm"
.Fa "void (*cb)(void *arg, size_t offs)"
.Fa "void *arg"
.Fc
.Ft "void"
.Fn "ber_free" "struct ber *ber"
.Sh DESCRIPTION
The
.Nm ber
API provides a mechanism to read and write ASN.1 streams and buffers using the
Basic Encoding Rules.
.Pp
Encoded
.Nm ber
is stored in the following structure:
.Bd -literal
struct ber {
off_t br_offs;
u_char *br_wbuf;
u_char *br_wptr;
u_char *br_wend;
u_char *br_rbuf;
u_char *br_rptr;
u_char *br_rend;
unsigned int (*br_application)(struct ber_element *);
};
.Ed
.Pp
.Fa br_rbuf
and
.Fa br_wbuf
are the read and write buffers for a
.Nm ber
stream.
These buffers are used when reading an existing byte stream (e.g. received from
a TLS connection), or when writing a new byte stream in preparation for
subsequent operations performed by the calling application (e.g. network
transmission or export to a file).
.Pp
Intermediary storage of ber elements during decoding and encoding uses the
following structure:
.Bd -literal
struct ber_element {
struct ber_element *be_next;
unsigned int be_type;
unsigned int be_encoding;
size_t be_len;
off_t be_offs;
int be_free;
u_int8_t be_class;
void (*be_cb)(void *, size_t);
void *be_cbarg;
union {
struct ber_element *bv_sub;
void *bv_val;
long long bv_numeric;
} be_union;
#define be_sub be_union.bv_sub
#define be_val be_union.bv_val
#define be_numeric be_union.bv_numeric
};
.Ed
.Pp
A linked list containing one or more
.Vt ber_element
is created during the decoding and encoding of
.Vt ber .
.Pp
Once the
.Vt ber
and
.Vt ber_element
data structures have been declared,
.Fn ber_set_readbuf
may be called to initialize
.Fa br_rbuf
in preparation for decoding.
It is assumed that a pointer to a ber byte stream is already available to the
application, commonly obtained by
.Xr read 2 ,
.Xr recv 2 ,
or
.Xr tls_read 3 .
.Fn ber_read_elements
may then be called to parse, validate, and store the data stream into its
consituent parts for subsequent processing.
.Fn ber_read_elements
returns a pointer to a fully populated list of one or more
.Vt ber_element ,
or
.Dv NULL
on a type mismatch or read error.
.Pp
The calling application must have explicit knowledge of the expected data
types in order for correct decoding.
.Fn ber_scanf_elements
may be called to extract
.Vt ber_element
content into local variables.
The
.Fn ber_get_*
functions extract the value of a single
.Vt ber_element
instance.
.Fn ber_scanf_elements
and the
.Fn ber_get_*
functions return 0 on success and -1 on failure.
.Pp
The first step when creating new ber is to populate
.Vt ber_element
with the desired content.
This may be achieved using the
.Fn ber_add_*
and
.Fn ber_printf_elements
functions, each of which return a pointer to
.Vt ber_element
on success or
.Dv NULL
on failure.
.Pp
Once
.Vt ber_element
has been fully populated,
.Fn ber_get_writebuf
may be used to initialize
.Fa br_wbuf
for writing.
.Fn ber_write_elements
encodes
.Vt ber_element
into a compliant
.Nm ber
byte stream for subsequent use by the calling application, most commonly using
.Xr send 2 ,
.Xr write 2 ,
or
.Xr tls_write 3 .
.Sh I/O OPERATIONS
.Fn ber_get_writebuf ,
.Fn ber_write_elements ,
.Fn ber_set_readbuf ,
.Fn ber_read_elements ,
.Fn ber_getpos ,
.Fn ber_free_element ,
.Fn ber_free_elements ,
.Fn ber_set_application ,
.Fn ber_set_writecallback ,
.Fn ber_free
.Sh BER ELEMENTS
.Fn ber_get_element ,
.Fn ber_set_header ,
.Fn ber_link_elements ,
.Fn ber_unlink_elements ,
.Fn ber_replace_elements ,
.Fn ber_calc_len
.Sh BER TYPES
.Fn ber_add_sequence ,
.Fn ber_add_set ,
.Fn ber_add_integer ,
.Fn ber_get_integer ,
.Fn ber_add_enumerated ,
.Fn ber_get_enumerated ,
.Fn ber_add_boolean ,
.Fn ber_get_boolean ,
.Fn ber_add_string ,
.Fn ber_add_nstring ,
.Fn ber_add_ostring ,
.Fn ber_add_bitstring ,
.Fn ber_get_string ,
.Fn ber_get_nstring ,
.Fn ber_get_ostring ,
.Fn ber_get_bitstring ,
.Fn ber_add_null ,
.Fn ber_get_null ,
.Fn ber_add_eoc ,
.Fn ber_get_eoc
.Sh FORMAT STRINGS
.Fn ber_printf_elements ,
.Fn ber_scanf_elements
.Sh OBJECT IDS
Object Identifiers are commonly used in ASN.1-based protocols.
These functions provide an interface to parse OIDs.
For internal representation of OIDs, the following structure
.Vt struct ber_oid
is being used:
.Bd -literal
#define BER_MIN_OID_LEN 2
#define BER_MAX_OID_LEN 32
struct ber_oid {
u_int32_t bo_id[BER_MAX_OID_LEN + 1];
size_t bo_n;
};
.Ed
.Pp
.Fn ber_add_oid ,
.Fn ber_add_noid ,
.Fn ber_add_oidstring ,
.Fn ber_get_oid ,
.Fn ber_oid2ber ,
.Fn ber_string2oid
.Fn ber_oid_cmp ,
.Sh RETURN VALUES
Upon successful completion
.Fn ber_get_integer ,
.Fn ber_get_enumerated ,
.Fn ber_get_boolean ,
.Fn ber_get_string ,
.Fn ber_get_nstring ,
.Fn ber_get_ostring ,
.Fn ber_get_bitstring ,
.Fn ber_get_null ,
.Fn ber_get_eoc ,
.Fn ber_get_oid ,
.Fn ber_string2oid
and
.Fn ber_scanf_elements
return 0, while
.Fn ber_write_elements
returns the number of bytes written.
Otherwise, \-1 is returned and the global variable errno is
set to indicate the error.
.Sh SEE ALSO
.Xr read 2 ,
.Xr recv 2 ,
.Xr send 2 ,
.Xr write 2 ,
.Xr tls_read 3
.Sh STANDARDS
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1:
Information technology - ASN.1 encoding rules.
.Sh HISTORY
The
.Nm ber
manpage first appeared in
.Ox 4.3 .
.Sh AUTHORS
.An -nosplit
The
.Nm ber
library was written by
.An Claudio Jeker Aq Mt claudio@openbsd.org ,
.An Marc Balmer Aq Mt marc@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .
.Sh CAVEATS
The
.Nm ber
API is subject to the following restrictions which are common to the
Distinguished Encoding Rules as defined by X.690:
.Pp
.Bl -enum -compact
.It
Only the definite form of length encoding shall be used, encoded in the
minimum number of octets.
.It
For bitstring, octetstring and restricted character string types, the
constructed form of encoding shall not be used.
.It
If a boolean encoding represents the boolean value TRUE, its single contents
octet shall have all eight bits set to one.
.It
Each unused bit in the final octet of the encoding of a bit string value shall
be set to zero.
.It
If a bitstring value has no 1 bits, then an encoder shall encode the value with
a length of 1 and an initial octet set to 0.
.El
.Pp
In addition, set and sequence values are limited to a maximum of 65535 elements.
No alternative encodings are permitted.
.Pp
.Do
Whereas the basic encoding rules give the sender of an encoding various choices
as to how data values may be encoded, the canonical and distinguished encoding
rules select just one encoding from those allowed by the basic encoding rules.
.Dc
.Bq X.690
.Pp
The restrictions placed on this API avoid the ambiguity inherent in
.Nm ber
encoded ASN.1 thereby acting as a security mitigation.
.Sh BUGS
This manpage is a stub.

+ 167
- 0
src/lib/libutil/ber_add_string.3 View File

@ -0,0 +1,167 @@
.\" $OpenBSD: ber_add_string.3,v 1.1 2019/05/15 03:11:52 rob Exp $
.\"
.\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
.\"
.\" 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: May 15 2019 $
.Dt BER_ADD_STRING 3
.Os
.Sh NAME
.Nm ber_get_element ,
.Nm ber_add_sequence ,
.Nm ber_add_set ,
.Nm ber_add_null ,
.Nm ber_add_eoc ,
.Nm ber_add_integer ,
.Nm ber_add_enumerated ,
.Nm ber_add_boolean ,
.Nm ber_add_string ,
.Nm ber_add_nstring ,
.Nm ber_add_ostring ,
.Nm ber_add_bitstring ,
.Nm ber_add_oid ,
.Nm ber_add_noid ,
.Nm ber_add_oidstring ,
.Nm ber_printf_elements
.Nd create ASN.1 objects for BER encoding
.Sh SYNOPSIS
.In sys/types.h
.In ber.h
.Ft "struct ber_element *"
.Fn "ber_get_element" "unsigned int encoding"
.Ft "struct ber_element *"
.Fn "ber_add_sequence" "struct ber_element *prev"
.Ft "struct ber_element *"
.Fn "ber_add_set" "struct ber_element *prev"
.Ft "struct ber_element *"
.Fn "ber_add_null" "struct ber_element *prev"
.Ft "struct ber_element *"
.Fn "ber_add_eoc" "struct ber_element *prev"
.Ft "struct ber_element *"
.Fn "ber_add_integer" "struct ber_element *prev" "long long val"
.Ft "struct ber_element *"
.Fn "ber_add_enumerated" "struct ber_element *prev" "long long val"
.Ft "struct ber_element *"
.Fn "ber_add_boolean" "struct ber_element *prev" "int bool"
.Ft "struct ber_element *"
.Fn "ber_add_string" "struct ber_element *prev" "const char *string"
.Ft "struct ber_element *"
.Fn "ber_add_nstring" "struct ber_element *prev" "const char *string" "size_t size"
.Ft "struct ber_element *"
.Fo "ber_add_ostring"
.Fa "struct ber_element *prev"
.Fa "struct ber_octetstring *ostring"
.Fc
.Ft "struct ber_element *"
.Fo "ber_add_bitstring"
.Fa "struct ber_element *prev"
.Fa "const void *buf"
.Fa "size_t size"
.Fc
.Ft "struct ber_element *"
.Fn "ber_add_oid" "struct ber_element *prev" "struct ber_oid *oid"
.Ft "struct ber_element *"
.Fn "ber_add_noid" "struct ber_element *prev" "struct ber_oid *oid" "int n"
.Ft "struct ber_element *"
.Fn "ber_add_oidstring" "struct ber_element *prev" "const char *string"
.Ft "struct ber_element *"
.Fn "ber_printf_elements" "struct ber_element *prev" "char *format" "..."
.Sh DESCRIPTION
Intermediary storage of BER elements during encoding and decoding uses the
following structure:
.Bd -literal
struct ber_element {
struct ber_element *be_next;
unsigned int be_type;
unsigned int be_encoding;
size_t be_len;
off_t be_offs;
int be_free;
u_int8_t be_class;
void (*be_cb)(void *, size_t);
void *be_cbarg;
union {
struct ber_element *bv_sub;
void *bv_val;
long long bv_numeric;
} be_union;
#define be_sub be_union.bv_sub
#define be_val be_union.bv_val
#define be_numeric be_union.bv_numeric
};
.Ed
.Pp
.Fn ber_get_element
creates a new
.Vt ber_element
with default values, dynamically allocates required storage, and sets
.Fa be_encoding
to
.Fa encoding .
.Pp
The
.Fn ber_add_*
and
.Fn ber_printf_elements
functions may be used to populate
.Vt ber_element .
.Sh RETURN VALUES
Upon successful completion,
.Fn ber_get_element ,
.Fn ber_add_sequence ,
.Fn ber_add_set ,
.Fn ber_add_null ,
.Fn ber_add_eoc ,
.Fn ber_add_integer ,
.Fn ber_add_enumerated ,
.Fn ber_add_boolean ,
.Fn ber_add_string ,
.Fn ber_add_nstring ,
.Fn ber_add_ostring ,
.Fn ber_add_bitstring ,
.Fn ber_add_oid ,
.Fn ber_add_noid ,
.Fn ber_add_oidstring ,
and
.Fn ber_printf_elements
return a pointer to a populated
.Vt ber_element .
Otherwise
.Dv NULL
is returned and the global variable errno is
set to indicate the error.
.Sh SEE ALSO
.Xr ber_get_string 3 ,
.Xr ber_oid_cmp 3 ,
.Xr ber_read_elements 3 ,
.Xr ber_set_header 3
.Sh STANDARDS
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1:
Information technology - ASN.1 encoding rules.
.Sh HISTORY
These functions first appeared as internal functions in
.Xr snmpd 8
in
.Ox 4.2
and were moved to libutil in
.Ox 6.6 .
.Sh AUTHORS
.An -nosplit
The
.Nm ber
library was written by
.An Claudio Jeker Aq Mt claudio@openbsd.org ,
.An Marc Balmer Aq Mt marc@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .

+ 120
- 0
src/lib/libutil/ber_get_string.3 View File

@ -0,0 +1,120 @@
.\" $OpenBSD: ber_get_string.3,v 1.1 2019/05/15 03:11:52 rob Exp $
.\"
.\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
.\"
.\" 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: May 15 2019 $
.Dt BER_GET_STRING 3
.Os
.Sh NAME
.Nm ber_get_null ,
.Nm ber_get_eoc ,
.Nm ber_get_integer ,
.Nm ber_get_enumerated ,
.Nm ber_get_boolean ,
.Nm ber_get_string ,
.Nm ber_get_nstring ,
.Nm ber_get_ostring ,
.Nm ber_get_bitstring ,
.Nm ber_get_oid ,
.Nm ber_getpos ,
.Nm ber_scanf_elements
.Nd access properties of ASN.1 objects decoded from BER
.Sh SYNOPSIS
.In sys/types.h
.In ber.h
.Ft "int"
.Fn "ber_get_null" "struct ber_element *root"
.Ft "int"
.Fn "ber_get_eoc" "struct ber_element *root"
.Ft "int"
.Fn "ber_get_integer" "struct ber_element *root" "long long *val"
.Ft "int"
.Fn "ber_get_enumerated" "struct ber_element *root" "long long *val"
.Ft "int"
.Fn "ber_get_boolean" "struct ber_element *root" "int *bool"
.Ft "int"
.Fn "ber_get_string" "struct ber_element *root" "char **charbuf"
.Ft "int"
.Fn "ber_get_nstring" "struct ber_element *root" "void **buf" "size_t *size"
.Ft "int"
.Fn "ber_get_ostring" "struct ber_element *root" "struct ber_octetstring *ostring"
.Ft "int"
.Fn "ber_get_bitstring" "struct ber_element *root" "void **buf" "size_t *size"
.Ft "int"
.Fn "ber_get_oid" "struct ber_element *root" "struct ber_oid *oid"
.Ft off_t
.Fn "ber_getpos" "struct ber_element *elm"
.Ft "int"
.Fn "ber_scanf_elements" "struct ber_element *root" "char *format" "..."
.Sh DESCRIPTION
The
.Fn ber_get_*
and
.Fn ber_scanf_elements
functions may be used to save
.Vt ber_element
values into local variables.
.Pp
.Fn ber_getpos
may be used to obtain the
.Vt ber_element
offset
.Fa be_offs .
.Sh RETURN VALUES
Upon successful completion,
.Fn ber_get_null ,
.Fn ber_get_eoc ,
.Fn ber_get_integer ,
.Fn ber_get_enumerated ,
.Fn ber_get_boolean ,
.Fn ber_get_string ,
.Fn ber_get_nstring ,
.Fn ber_get_ostring ,
.Fn ber_get_bitstring ,
.Fn ber_get_oid ,
.Fn ber_string2oid
and
.Fn ber_scanf_elements
return 0.
Otherwise \-1 is returned and the global variable errno is
set to indicate the error.
.Pp
.Fn ber_getpos
returns the value of
.Vt be_offs .
.Sh SEE ALSO
.Xr ber_add_string 3 ,
.Xr ber_oid_cmp 3 ,
.Xr ber_read_elements 3 ,
.Xr ber_set_header 3
.Sh STANDARDS
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1:
Information technology - ASN.1 encoding rules.
.Sh HISTORY
These functions first appeared as internal functions in
.Xr snmpd 8
in
.Ox 4.2
and were moved to libutil in
.Ox 6.6 .
.Sh AUTHORS
.An -nosplit
The
.Nm ber
library was written by
.An Claudio Jeker Aq Mt claudio@openbsd.org ,
.An Marc Balmer Aq Mt marc@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .

+ 109
- 0
src/lib/libutil/ber_oid_cmp.3 View File

@ -0,0 +1,109 @@
.\" $OpenBSD: ber_oid_cmp.3,v 1.1 2019/05/15 03:11:52 rob Exp $
.\"
.\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
.\"
.\" 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: May 15 2019 $
.Dt BER_OID_CMP 3
.Os
.Sh NAME
.Nm ber_oid_cmp ,
.Nm ber_oid2ber ,
.Nm ber_string2oid
.Nd OID helper functions for the BER library
.Sh SYNOPSIS
.In sys/types.h
.In ber.h
.Ft "int"
.Fn "ber_oid_cmp" "struct ber_oid *a" "struct ber_oid *b"
.Ft "size_t"
.Fn "ber_oid2ber" "struct ber_oid *oid" "u_int8_t *buf" "size_t size"
.Ft "int"
.Fn "ber_string2oid" "const char *string" "struct ber_oid *oid"
.Sh DESCRIPTION
Object Identifiers are commonly used in ASN.1-based protocols.
These functions provide an interface to parse OIDs.
For internal representation of OIDs, the following structure
.Vt struct ber_oid
is being used:
.Bd -literal
#define BER_MIN_OID_LEN 2
#define BER_MAX_OID_LEN 32
struct ber_oid {
u_int32_t bo_id[BER_MAX_OID_LEN + 1];
size_t bo_n;
};
.Ed
.Pp
The
.Fn ber_oid2ber
and
.Fn ber_string2oid
functions may be used to convert from and to
.Vt struct ber_oid .
.Pp
.Fn ber_oid_cmp
may be used to compare two
.Vt ber_oid
structures.
.Sh RETURN VALUES
.Fn ber_oid2ber
returns the number of bytes written or 0 on faliure.
.Pp
.Fn ber_string2oid
returns 0 on success or -1 on failure.
.Pp
.Fn ber_oid_cmp
returns 0 when oids
.Fa a
and
.Fa b
are identical.
If
.Fa b
is a successor of
.Fa a ,
1 is returned.
If
.Fa b
is a predecessor of
.Fa a ,
-1 is returned.
If
.Fa b
is larger, but a child of
.Fa a ,
2 is returned.
.Sh SEE ALSO
.Xr ber_add_string 3 ,
.Xr ber_get_string 3 ,
.Xr ber_read_elements 3 ,
.Xr ber_set_header 3
.Sh HISTORY
These functions first appeared as internal functions in
.Xr snmpd 8
in
.Ox 4.2
and were moved to libutil in
.Ox 6.6 .
.Sh AUTHORS
.An -nosplit
The
.Nm ber
library was written by
.An Claudio Jeker Aq Mt claudio@openbsd.org ,
.An Marc Balmer Aq Mt marc@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .

+ 225
- 0
src/lib/libutil/ber_read_elements.3 View File

@ -0,0 +1,225 @@
.\" $OpenBSD: ber_read_elements.3,v 1.1 2019/05/15 03:11:52 rob Exp $
.\"
.\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
.\"
.\" 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: May 15 2019 $
.Dt BER_READ_ELEMENTS 3
.Os
.Sh NAME
.Nm ber_set_readbuf ,
.Nm ber_set_application ,
.Nm ber_read_elements ,
.Nm ber_get_writebuf ,
.Nm ber_write_elements ,
.Nm ber_free
.Nd encode and decode ASN.1 with Basic Encoding Rules
.Sh SYNOPSIS
.In sys/types.h
.In ber.h
.Ft "void"
.Fn "ber_set_readbuf" "struct ber *ber" "void *buf" "size_t len"
.Ft "void"
.Fo "ber_set_application"
.Fa "struct ber *ber"
.Fa "unsigned int (*cb)(struct ber_element *)"
.Fc
.Ft "struct ber_element *"
.Fn "ber_read_elements" "struct ber *ber" "struct ber_element *root"
.Ft "ssize_t"
.Fn "ber_get_writebuf" "struct ber *ber" "void **buf"
.Ft "ssize_t"
.Fn "ber_write_elements" "struct ber *ber" "struct ber_element *root"
.Ft "void"
.Fn "ber_free" "struct ber *ber"
.Sh DESCRIPTION
The BER API provides a mechanism to read and write ASN.1 using the
Basic Encoding Rules.
.Pp
Encoded BER is stored in the following structure:
.Bd -literal
struct ber {
off_t br_offs;
u_char *br_wbuf;
u_char *br_wptr;
u_char *br_wend;
u_char *br_rbuf;
u_char *br_rptr;
u_char *br_rend;
unsigned int (*br_application)(struct ber_element *);
};
.Ed
.Pp
.Fa br_rbuf
and
.Fa br_wbuf
are the read and write buffers for a BER byte stream.
These buffers are used when reading an existing byte stream (e.g. received from
a TLS connection), or when writing a new byte stream in preparation for
subsequent operations performed by the calling application (e.g. network
transmission or export to a file).
.Pp
Intermediary storage of BER elements during encoding and decoding uses the
following structure:
.Bd -literal
struct ber_element {
struct ber_element *be_next;
unsigned int be_type;
unsigned int be_encoding;
size_t be_len;
off_t be_offs;
int be_free;
u_int8_t be_class;
void (*be_cb)(void *, size_t);
void *be_cbarg;
union {
struct ber_element *bv_sub;
void *bv_val;
long long bv_numeric;
} be_union;
#define be_sub be_union.bv_sub
#define be_val be_union.bv_val
#define be_numeric be_union.bv_numeric
};
.Ed
.Pp
.Fn ber_set_readbuf
sets
.Fa br_rbuf
to point an input buffer of BER encoded bytes in preparation for decoding.
It is assumed that
.Fa br_rbuf
is already populated and available to the
application, commonly obtained by
.Xr read 2 ,
.Xr recv 2 ,
or
.Xr tls_read 3 .
.Pp
.Fn ber_read_elements
may then be called to parse, validate, and store the
.Fa ber
data stream into its
consituent
.Vt ber_element
parts for subsequent processing.
The calling application must have explicit knowledge of the expected data
types in order for correct decoding.
.Pp
.Fn ber_get_writebuf
sets
.Fa br_wbuf
to point to an output buffer for writing a BER byte stream.
.Pp
.Fn ber_write_elements
encodes
.Fa root
into a compliant BER byte stream which is written to
.Fa ber
for subsequent use by the calling
functions such as
.Xr send 2 ,
.Xr write 2 ,
or
.Xr tls_write 3 .
.Pp
.Fn ber_free
frees any dynamically allocated storage associated with
.Fa ber .
.Sh RETURN VALUES
.Fn ber_read_elements
returns a pointer to a fully populated list of one or more
.Vt ber_element
structures or
.Dv NULL
on a type mismatch or read error.
.Pp
.Fn ber_get_writebuf
returns the number of bytes contained within buffer
.Vt b
within the buffer
.Fa buf
or \-1 on failure.
.Pp
.Fn ber_write_elements
returns the number of bytes written.
Otherwise \-1 is returned and the global variable errno is
set to indicate the error.
.Sh SEE ALSO
.Xr read 2 ,
.Xr recv 2 ,
.Xr send 2 ,
.Xr write 2 ,
.Xr ber_add_string 3 ,
.Xr ber_get_string 3 ,
.Xr ber_oid_cmp 3 ,
.Xr ber_set_header 3 ,
.Xr tls_read 3
.Sh STANDARDS
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1:
Information technology - ASN.1 encoding rules.
.Sh HISTORY
These functions first appeared as internal functions in
.Xr snmpd 8
in
.Ox 4.2
and were moved to libutil in
.Ox 6.6 .
.Sh AUTHORS
.An -nosplit
The
.Nm ber
library was written by
.An Claudio Jeker Aq Mt claudio@openbsd.org ,
.An Marc Balmer Aq Mt marc@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .
.Sh CAVEATS
The
.Nm ber
API is subject to the following restrictions which are common to the
Distinguished Encoding Rules as defined by X.690:
.Pp
.Bl -enum -compact
.It
Only the definite form of length encoding shall be used, encoded in the
minimum number of octets.
.It
For bitstring, octetstring and restricted character string types, the
constructed form of encoding shall not be used.
.It
If a boolean encoding represents the boolean value TRUE, its single contents
octet shall have all eight bits set to one.
.It
Each unused bit in the final octet of the encoding of a bit string value shall
be set to zero.
.It
If a bitstring value has no 1 bits, then an encoder shall encode the value with
a length of 1 and an initial octet set to 0.
.El
.Pp
In addition, set and sequence values are limited to a maximum of 65535 elements.
No alternative encodings are permitted.
.Pp
.Do
Whereas the basic encoding rules give the sender of an encoding various choices
as to how data values may be encoded, the canonical and distinguished encoding
rules select just one encoding from those allowed by the basic encoding rules.
.Dc
.Bq X.690
.Pp
The restrictions placed on this API avoid the ambiguity inherent in
.Nm ber
encoded ASN.1 thereby acting as a security mitigation.

+ 144
- 0
src/lib/libutil/ber_set_header.3 View File

@ -0,0 +1,144 @@
.\" $OpenBSD: ber_set_header.3,v 1.1 2019/05/15 03:11:52 rob Exp $
.\"
.\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
.\"
.\" 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: May 15 2019 $
.Dt BER_SET_HEADER 3
.Os
.Sh NAME
.Nm ber_set_header ,
.Nm ber_calc_len ,
.Nm ber_set_writecallback ,
.Nm ber_link_elements ,
.Nm ber_replace_elements ,
.Nm ber_unlink_elements ,
.Nm ber_free_element ,
.Nm ber_free_elements
.Nd change and destroy ASN.1 objects for BER encoding
.Sh SYNOPSIS
.In sys/types.h
.In ber.h
.Ft "void"
.Fn "ber_set_header" "struct ber_element *elm" "int class" "unsigned int type"
.Ft "size_t"
.Fn "ber_calc_len" "struct ber_element *root"
.Ft "void"
.Fo "ber_set_writecallback"
.Fa "void (*cb)(void *arg, sizeof_t offs)"
.Fc
.Ft "void"
.Fn "ber_link_elements" "struct ber_element *prev" "struct ber_element *elm"
.Ft "void"
.Fn "ber_replace_elements" "struct ber_element *prev" "struct ber_element *elm"
.Ft "struct ber_element *"
.Fn "ber_unlink_elements" "struct ber_element *prev"
.Ft "void"
.Fn "ber_free_element" "struct ber_element *root"
.Ft "void"
.Fn "ber_free_elements" "struct ber_element *root"
.Pp
.Fd #define BER_TYPE_BOOLEAN 1
.Fd #define BER_TYPE_INTEGER 2
.Fd #define BER_TYPE_BITSTRING 3
.Fd #define BER_TYPE_OCTETSTRING 4
.Fd #define BER_TYPE_NULL 5
.Fd #define BER_TYPE_OBJECT 6
.Fd #define BER_TYPE_ENUMERATED 10
.Fd #define BER_TYPE_SEQUENCE 16
.Fd #define BER_TYPE_SET 17
.Pp
.Fd #define BER_TYPE_CONSTRUCTED 0x20
.Pp
.Fd #define BER_CLASS_UNIVERSAL 0x0
.Fd #define BER_CLASS_UNIV BER_CLASS_UNIVERSAL
.Fd #define BER_CLASS_APPLICATION 0x1
.Fd #define BER_CLASS_APP BER_CLASS_APPLICATION
.Fd #define BER_CLASS_CONTEXT 0x2
.Fd #define BER_CLASS_PRIVATE 0x3
.Sh DESCRIPTION
.Fn ber_set_header
sets the
.Fa class
and
.Fa type
of
.Fa elm .
.Pp
.Fn ber_calc_len
determines the total length of
.Fa root .
.Pp
.Fn ber_set_writecallback
registers the
.Vt br_cb
callback function.
.Pp
.Fn ber_link_elements
links
.Fa prev
and
.Fa elm .
.Pp
.Fn ber_replace_elements
replaces
.Fa prev
with
.Fa new
and frees any dynamically allocated storage assocated with
.Fa prev .
.Pp
.Fn ber_unlink_elements
unlinks
.Fa prev .
.Pp
.Fn ber_free_element
and
.Fn ber_free_elements
free any dynamically allocated storage associated with
.Fa root .
.Sh RETURN VALUES
.Fn ber_calc_len
returns the total length of a fully populated
.Fa root
containing one or more
.Vt ber_element .
.Pp
.Fn ber_unlink_elements
returns a pointer to
.Vt ber_element .
.Sh SEE ALSO
.Xr ber_add_string 3 ,
.Xr ber_get_string 3 ,
.Xr ber_oid_cmp 3 ,
.Xr ber_read_elements 3
.Sh STANDARDS
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1:
Information technology - ASN.1 encoding rules.
.Sh HISTORY
These functions first appeared as internal functions in
.Xr snmpd 8
in
.Ox 4.2
and were moved to libutil in
.Ox 6.6 .
.Sh AUTHORS
.An -nosplit
The
.Nm ber
library was written by
.An Claudio Jeker Aq Mt claudio@openbsd.org ,
.An Marc Balmer Aq Mt marc@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .

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