Rewrite Biba and MLS label externalization code to use sbufs instead
of C strings internally; C strings require a lot of return value
checking that (a) takes a lot of space, and (b) is difficult to get
right. Prior to the advent of compartment support, modeling APIs
for helper functions on snprintf worked fine; with the additional
complexity, the sbuf_printf() API makes a lot more sense.
While doing this, break out the printing of sequential compartment
lists into a helper function, mac_{biba,mls}_compartment_to_string().
This permits the main body of mac_{biba,mls}_element_to_string()
to be concerned only with identifying sequential ranges rather
than rendering.
At a less disruptive moment, we'll push the move from snprintf()-like
interface to sbuf()-like interface up into the MAC Framework layer.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
This commit is contained in:
Robert Watson
parent
01bfa91fa2
commit
05e830f1e7
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=115497
@ -1,6 +1,6 @@
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/*-
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* Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
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* Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
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* Copyright (c) 2001, 2002, 2003 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert Watson for the TrustedBSD Project.
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@ -49,6 +49,7 @@
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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@ -528,36 +529,45 @@ mac_biba_destroy_label(struct label *label)
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}
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/*
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* mac_biba_element_to_string() is basically an snprintf wrapper with
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* the same properties as snprintf(). It returns the length it would
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* have added to the string in the event the string is too short.
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* mac_biba_element_to_string() accepts an sbuf and Biba element. It
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* converts the Biba element to a string and stores the result in the
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* sbuf; if there isn't space in the sbuf, -1 is returned.
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*/
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static size_t
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mac_biba_element_to_string(char *string, size_t size,
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struct mac_biba_element *element)
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static int
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mac_biba_element_to_string(struct sbuf *sb, struct mac_biba_element *element)
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{
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int pos, bit = 1;
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int i, first;
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switch (element->mbe_type) {
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case MAC_BIBA_TYPE_HIGH:
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return (snprintf(string, size, "high"));
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return (sbuf_printf(sb, "high"));
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case MAC_BIBA_TYPE_LOW:
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return (snprintf(string, size, "low"));
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return (sbuf_printf(sb, "low"));
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case MAC_BIBA_TYPE_EQUAL:
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return (snprintf(string, size, "equal"));
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return (sbuf_printf(sb, "equal"));
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case MAC_BIBA_TYPE_GRADE:
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pos = snprintf(string, size, "%d:", element->mbe_grade);
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for (bit = 1; bit <= MAC_BIBA_MAX_COMPARTMENTS; bit++) {
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if (MAC_BIBA_BIT_TEST(bit, element->mbe_compartments))
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pos += snprintf(string + pos, size - pos,
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"%d+", bit);
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if (sbuf_printf(sb, "%d", element->mbe_grade) == -1)
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return (-1);
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first = 1;
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for (i = 1; i <= MAC_BIBA_MAX_COMPARTMENTS; i++) {
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if (MAC_BIBA_BIT_TEST(i, element->mbe_compartments)) {
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if (first) {
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if (sbuf_putc(sb, ':') == -1)
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return (-1);
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if (sbuf_printf(sb, "%d", i) == -1)
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return (-1);
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first = 0;
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} else {
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if (sbuf_printf(sb, "+%d", i) == -1)
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return (-1);
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}
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}
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}
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if (string[pos - 1] == '+' || string[pos - 1] == ':')
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string[--pos] = '\0';
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return (pos);
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return (0);
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default:
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panic("mac_biba_element_to_string: invalid type (%d)",
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@ -565,60 +575,48 @@ mac_biba_element_to_string(char *string, size_t size,
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}
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}
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/*
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* mac_biba_to_string() converts an Biba label to a string, placing the
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* results in the passed string buffer. It returns 0 on success,
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* or EINVAL if there isn't room in the buffer. The size of the
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* string appended, leaving out the nul termination, is returned to
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* the caller via *caller_len. Eventually, we should expose the
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* sbuf to the caller rather than using C strings at this layer.
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*/
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static int
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mac_biba_to_string(char *string, size_t size, size_t *caller_len,
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struct mac_biba *mac_biba)
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{
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size_t left, len;
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char *curptr;
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struct sbuf sb;
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bzero(string, size);
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curptr = string;
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left = size;
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sbuf_new(&sb, string, size, SBUF_FIXEDLEN);
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if (mac_biba->mb_flags & MAC_BIBA_FLAG_SINGLE) {
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len = mac_biba_element_to_string(curptr, left,
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&mac_biba->mb_single);
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if (len >= left)
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if (mac_biba_element_to_string(&sb, &mac_biba->mb_single)
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== -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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}
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if (mac_biba->mb_flags & MAC_BIBA_FLAG_RANGE) {
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len = snprintf(curptr, left, "(");
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if (len >= left)
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if (sbuf_putc(&sb, '(') == -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = mac_biba_element_to_string(curptr, left,
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&mac_biba->mb_rangelow);
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if (len >= left)
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if (mac_biba_element_to_string(&sb, &mac_biba->mb_rangelow)
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== -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = snprintf(curptr, left, "-");
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if (len >= left)
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if (sbuf_putc(&sb, '-') == -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = mac_biba_element_to_string(curptr, left,
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&mac_biba->mb_rangehigh);
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if (len >= left)
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if (mac_biba_element_to_string(&sb, &mac_biba->mb_rangehigh)
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== -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = snprintf(curptr, left, ")");
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if (len >= left)
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if (sbuf_putc(&sb, ')') == -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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}
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sbuf_finish(&sb);
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*caller_len = strlen(string);
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return (0);
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}
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@ -640,7 +638,6 @@ mac_biba_externalize_label(struct label *label, char *element_name,
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if (error)
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return (error);
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*len = strlen(element_data);
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return (0);
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}
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@ -1,6 +1,6 @@
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/*-
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* Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
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* Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
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* Copyright (c) 2001, 2002, 2003 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert Watson for the TrustedBSD Project.
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@ -49,6 +49,7 @@
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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@ -493,36 +494,45 @@ mac_mls_destroy_label(struct label *label)
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}
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/*
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* mac_mls_element_to_string() is basically an snprintf wrapper with
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* the same properties as snprintf(). It returns the length it would
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* have added to the string in the event the string is too short.
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* mac_mls_element_to_string() accepts an sbuf and MLS element. It
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* converts the MLS element to a string and stores the result in the
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* sbuf; if there isn't space in the sbuf, -1 is returned.
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*/
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static size_t
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mac_mls_element_to_string(char *string, size_t size,
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struct mac_mls_element *element)
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static int
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mac_mls_element_to_string(struct sbuf *sb, struct mac_mls_element *element)
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{
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int pos, bit = 1;
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int i, first;
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switch (element->mme_type) {
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case MAC_MLS_TYPE_HIGH:
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return (snprintf(string, size, "high"));
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return (sbuf_printf(sb, "high"));
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case MAC_MLS_TYPE_LOW:
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return (snprintf(string, size, "low"));
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return (sbuf_printf(sb, "low"));
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case MAC_MLS_TYPE_EQUAL:
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return (snprintf(string, size, "equal"));
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return (sbuf_printf(sb, "equal"));
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case MAC_MLS_TYPE_LEVEL:
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pos = snprintf(string, size, "%d:", element->mme_level);
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for (bit = 1; bit <= MAC_MLS_MAX_COMPARTMENTS; bit++) {
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if (MAC_MLS_BIT_TEST(bit, element->mme_compartments))
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pos += snprintf(string + pos, size - pos,
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"%d+", bit);
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if (sbuf_printf(sb, "%d", element->mme_level) == -1)
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return (-1);
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first = 1;
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for (i = 1; i <= MAC_MLS_MAX_COMPARTMENTS; i++) {
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if (MAC_MLS_BIT_TEST(i, element->mme_compartments)) {
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if (first) {
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if (sbuf_putc(sb, ':') == -1)
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return (-1);
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if (sbuf_printf(sb, "%d", i) == -1)
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return (-1);
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first = 0;
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} else {
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if (sbuf_printf(sb, "+%d", i) == -1)
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return (-1);
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}
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}
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}
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if (string[pos - 1] == '+' || string[pos - 1] == ':')
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string[--pos] = NULL;
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return (pos);
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return (0);
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default:
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panic("mac_mls_element_to_string: invalid type (%d)",
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@ -530,60 +540,48 @@ mac_mls_element_to_string(char *string, size_t size,
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}
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}
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static size_t
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/*
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* mac_mls_to_string() converts an MLS label to a string, placing the
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* results in the passed string buffer. It returns 0 on success,
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* or EINVAL if there isn't room in the buffer. The size of the
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* string appended, leaving out the nul termination, is returned to
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* the caller via *caller_len. Eventually, we should expose the
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* sbuf to the caller rather than using C strings at this layer.
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*/
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static int
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mac_mls_to_string(char *string, size_t size, size_t *caller_len,
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struct mac_mls *mac_mls)
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{
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size_t left, len;
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char *curptr;
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struct sbuf sb;
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bzero(string, size);
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curptr = string;
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left = size;
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sbuf_new(&sb, string, size, SBUF_FIXEDLEN);
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if (mac_mls->mm_flags & MAC_MLS_FLAG_SINGLE) {
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len = mac_mls_element_to_string(curptr, left,
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&mac_mls->mm_single);
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if (len >= left)
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if (mac_mls_element_to_string(&sb, &mac_mls->mm_single)
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== -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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}
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if (mac_mls->mm_flags & MAC_MLS_FLAG_RANGE) {
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len = snprintf(curptr, left, "(");
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if (len >= left)
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if (sbuf_putc(&sb, '(') == -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = mac_mls_element_to_string(curptr, left,
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&mac_mls->mm_rangelow);
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if (len >= left)
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if (mac_mls_element_to_string(&sb, &mac_mls->mm_rangelow)
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== -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = snprintf(curptr, left, "-");
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if (len >= left)
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if (sbuf_putc(&sb, '-') == -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = mac_mls_element_to_string(curptr, left,
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&mac_mls->mm_rangehigh);
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if (len >= left)
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if (mac_mls_element_to_string(&sb, &mac_mls->mm_rangehigh)
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== -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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len = snprintf(curptr, left, ")");
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if (len >= left)
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if (sbuf_putc(&sb, ')') == -1)
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return (EINVAL);
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left -= len;
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curptr += len;
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}
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sbuf_finish(&sb);
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*caller_len = strlen(string);
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return (0);
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}
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@ -606,7 +604,6 @@ mac_mls_externalize_label(struct label *label, char *element_name,
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if (error)
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return (error);
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*len = strlen(element_data);
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return (0);
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}
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