Tribblix: manual page: stobl.3tsol

STOBL(3TSOL) Trusted Extensions Library Functions STOBL(3TSOL)

NAME

stobl, stobsl, stobclear - translate character-coded labels to binary
labels

SYNOPSIS

cc [flag...] file... -ltsol [library...]

#include <tsol/label.h>

int stobsl(const char *string, m_label_t *label, const int flags,
int *error);

int stobclear(const char *string, m_label_t *clearance,
const int flags, int *error);

DESCRIPTION

The stobsl() and stobclear() functions translate character-coded
labels into binary labels. They also modify an existing binary label
by incrementing or decrementing it to produce a new binary label
relative to its existing value.

The calling process must have PRIV_SYS_TRANS_LABEL in its set of
effective privileges to perform label translation on character-coded
labels that dominate the process's sensitivity label.

The generic form of an input character-coded label string is:

[ + ] classification name ] [ [ + | - ] word ...

Leading and trailing white space is ignored. Fields are separated by
white space, a `/' (slash), or a `,' (comma). Case is irrelevant. If
string starts with + or -, string is interpreted a modification to an
existing label. If string starts with a classification name followed
by a + or -, the new classification is used and the rest of the old
label is retained and modified as specified by string. + modifies an
existing label by adding words. - modifies an existing label by
removing words. To the maximum extent possible, errors in string are
corrected in the resulting binary label label.

The stobsl() and stobclear() functions also translate hexadecimal
label representations into binary labels (see hextob(3TSOL)) when the
string starts with 0x and either NEW_LABEL or NO_CORRECTION is
specified in flags.

The flags argument can take the following values:

NEW_LABEL
label contents is not used, is formatted as a label
of the relevant type, and is assumed to be ADMIN_LOW
for modification changes. If NEW_LABEL is not
present, label is validated as a defined label of
the correct type dominated by the process's
sensitivity label.

NO_CORRECTION
No corrections are made if there are errors in the
character-coded label string. string must be
complete and contain all the label components that
are required by the label_encodings file. The
NO_CORRECTION flag implies the NEW_LABEL flag.

0 (zero)
The default action is taken.

The error argument is a return parameter that is set only if the
function is unsuccessful.

The stobsl() function translates the character-coded sensitivity
label string into a binary sensitivity label and places the result in
the return parameter label.

The flags argument can be either NEW_LABEL, NO_CORRECTION, or 0
(zero). Unless NO_CORRECTION is specified, this translation forces
the label to dominate the minimum classification, and initial
compartments set that is specified in the label_encodings file and
corrects the label to include other label components required by the
label_encodings file, but not present in string.

The stobclear() function translates the character-coded clearance
string into a binary clearance and places the result in the return
parameter clearance.

The flags argument can be either NEW_LABEL, NO_CORRECTION, or 0
(zero). Unless NO_CORRECTION is specified, this translation forces
the label to dominate the minimum classification, and initial
compartments set that is specified in the label_encodings file and
corrects the label to include other label components that are
required by the label_encodings file, but not present in string. The
translation of a clearance might not be the same as the translation
of a sensitivity label. These functions use different tables of the
label_encodings file that might contain different words and
constraints.

RETURN VALUES

These functions return 1 if the translation was successful and a
valid binary label was returned. Otherwise they return 0 and the
value of the error argument indicates the error.

ERRORS

When these functions return zero, error contains one of the following
values:

-1
Unable to access the label_encodings file.

0
The label label is not valid for this translation and the
NEW_LABEL or NO_CORRECTION flag was not specified, or the
label label is not dominated by the process's sensitivity
label and the process does not have PRIV_SYS_TRANS_LABEL in
its set of effective privileges.

>0
The character-coded label string is in error. error is a
one-based index into string indicating where the translation
error occurred.

FILES

/etc/security/tsol/label_encodings

The label encodings file contains the classification names,
words, constraints, and values for the defined labels of this
system.

ATTRIBUTES

NOTES

The functionality described on this manual page is available only if
the system is configured with Trusted Extensions.

In addition to the ADMIN_LOW name and ADMIN_HIGH name strings defined
in the label_encodings file, the strings "ADMIN_LOW" and "ADMIN_HIGH"
are always accepted as character-coded labels to be translated to the
appropriate ADMIN_LOW and ADMIN_HIGH label, respectively.

Modifying an existing ADMIN_LOW label acts as the specification of a
NEW_LABEL and forces the label to start at the minimum label that is
specified in the label_encodings file.

Modifying an existing ADMIN_HIGH label is treated as an attempt to
change a label that represents the highest defined classification and
all the defined compartments that are specified in the
label_encodings file.

The NO_CORRECTION flag is used when the character-coded label must be
complete and accurate so that translation to and from the binary form
results in an equivalent character-coded label.

July 20, 2007 STOBL(3TSOL)