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Add default_range glblub support

Browse source 
Policy developers can set a default_range default to glblub and
computed contexts will be the intersection of the ranges of the
source and target contexts. This can be used by MLS userspace
object managers to find the range of clearances that two contexts
have in common. An example usage is computing a transition between
the network context and the context of a user logging into an MLS
application.

For example, one can add a default with
this cil:

(defaultrange db_table glblub)

or in te (base module only):

default_range db_table glblub;

and then test using the compute_create utility:

$ ./compute_create system_u:system_r:kernel_t:s0:c1,c2,c5-s0:c1.c20 system_u:system_r:kernel_t:s0:c0.c20-s0:c0.c36 db_table
system_u:object_r:kernel_t:s0:c1,c2,c5-s0:c1.c20

Some example range transitions are:

User Permitted Range | Network Device Label | Computed Label
---------------------|----------------------|----------------
s0-s1:c0.c12         | s0                   | s0
s0-s1:c0.c12         | s0-s1:c0.c1023       | s0-s1:c0.c12
s0-s4:c0.c512        | s1-s1:c0.c1023       | s1-s1:c0.c512
s0-s15:c0,c2         | s4-s6:c0.c128        | s4-s6:c0,c2
s0-s4                | s2-s6                | s2-s4
s0-s4                | s5-s8                | INVALID
s5-s8                | s0-s4                | INVALID

Signed-off-by: Joshua Brindle <joshua.brindle@crunchydata.com>
This commit is contained in:
Joshua Brindle 2019-09-09 11:05:57 -07:00 committed by James Carter
parent 6177a6f2c4
commit 9ba35fe8c2
16 changed files with 105 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
checkpolicy/policy_parse.y
View file

@ -155,7 +155,7 @@ typedef int (* require_func_t)(int pass);
%token PERMISSIVE
%token FILESYSTEM
%token DEFAULT_USER DEFAULT_ROLE DEFAULT_TYPE DEFAULT_RANGE
%token LOW_HIGH LOW HIGH
%token LOW_HIGH LOW HIGH GLBLUB
%left OR
%left XOR
@ -247,6 +247,8 @@ default_range_def : DEFAULT_RANGE names SOURCE LOW ';'
{if (define_default_range(DEFAULT_TARGET_HIGH)) return -1; }
| DEFAULT_RANGE names TARGET LOW_HIGH ';'
{if (define_default_range(DEFAULT_TARGET_LOW_HIGH)) return -1; }
| DEFAULT_RANGE names GLBLUB';'
{if (define_default_range(DEFAULT_GLBLUB)) return -1; }
;
opt_mls : mls
|

2
checkpolicy/policy_scan.l
View file

@ -256,6 +256,8 @@ high |
HIGH { return(HIGH); }
low |
LOW { return(LOW); }
glblub |
GLBLUB { return(GLBLUB); }
"/"[^ \n\r\t\f]* { return(PATH); }
\""/"[^\"\n]*\" { return(QPATH); }
\"[^"/"\"\n]+\" { return(FILENAME); }

1
libsepol/cil/src/cil.c
View file

@ -227,6 +227,7 @@ static void cil_init_keys(void)
CIL_KEY_LOW = cil_strpool_add("low");
CIL_KEY_HIGH = cil_strpool_add("high");
CIL_KEY_LOW_HIGH = cil_strpool_add("low-high");
CIL_KEY_GLBLUB = cil_strpool_add("glblub");
CIL_KEY_ROOT = cil_strpool_add("<root>");
CIL_KEY_NODE = cil_strpool_add("<node>");
CIL_KEY_PERM = cil_strpool_add("perm");

11
libsepol/cil/src/cil_build_ast.c
View file

@ -5894,7 +5894,7 @@ int cil_gen_defaultrange(struct cil_tree_node *parse_current, struct cil_tree_no
CIL_SYN_STRING,
CIL_SYN_STRING | CIL_SYN_LIST,
CIL_SYN_STRING,
CIL_SYN_STRING,
CIL_SYN_STRING | CIL_SYN_END,
CIL_SYN_END
};
int syntax_len = sizeof(syntax)/sizeof(*syntax);
@ -5917,8 +5917,8 @@ int cil_gen_defaultrange(struct cil_tree_node *parse_current, struct cil_tree_no
}
object = parse_current->next->next->data;
range = parse_current->next->next->next->data;
if (object == CIL_KEY_SOURCE) {
range = parse_current->next->next->next->data;
if (range == CIL_KEY_LOW) {
def->object_range = CIL_DEFAULT_SOURCE_LOW;
} else if (range == CIL_KEY_HIGH) {
@ -5930,7 +5930,8 @@ int cil_gen_defaultrange(struct cil_tree_node *parse_current, struct cil_tree_no
rc = SEPOL_ERR;
goto exit;
}
} else if (parse_current->next->next->data == CIL_KEY_TARGET) {
} else if (object == CIL_KEY_TARGET) {
range = parse_current->next->next->next->data;
if (range == CIL_KEY_LOW) {
def->object_range = CIL_DEFAULT_TARGET_LOW;
} else if (range == CIL_KEY_HIGH) {
@ -5942,8 +5943,10 @@ int cil_gen_defaultrange(struct cil_tree_node *parse_current, struct cil_tree_no
rc = SEPOL_ERR;
goto exit;
}
} else if (object == CIL_KEY_GLBLUB) {
def->object_range = CIL_DEFAULT_GLBLUB;
} else {
cil_log(CIL_ERR,"Expected either \'source\' or \'target\'\n");
cil_log(CIL_ERR,"Expected \'source\', \'target\', or \'glblub\'\n");
rc = SEPOL_ERR;
goto exit;
}

2
libsepol/cil/src/cil_internal.h
View file

@ -149,6 +149,7 @@ char *CIL_KEY_TARGET;
char *CIL_KEY_LOW;
char *CIL_KEY_HIGH;
char *CIL_KEY_LOW_HIGH;
char *CIL_KEY_GLBLUB;
char *CIL_KEY_HANDLEUNKNOWN;
char *CIL_KEY_HANDLEUNKNOWN_ALLOW;
char *CIL_KEY_HANDLEUNKNOWN_DENY;
@ -941,6 +942,7 @@ enum cil_default_object_range {
CIL_DEFAULT_TARGET_LOW = DEFAULT_TARGET_LOW,
CIL_DEFAULT_TARGET_HIGH = DEFAULT_TARGET_HIGH,
CIL_DEFAULT_TARGET_LOW_HIGH = DEFAULT_TARGET_LOW_HIGH,
CIL_DEFAULT_GLBLUB = DEFAULT_GLBLUB,
};
/* Default labeling behavior for range */

3
libsepol/cil/src/cil_policy.c
View file

@ -834,6 +834,9 @@ static void cil_default_ranges_to_policy(FILE *out, struct cil_list *defaults)
case CIL_DEFAULT_TARGET_LOW_HIGH:
fprintf(out," %s %s", CIL_KEY_TARGET, CIL_KEY_LOW_HIGH);
break;
case CIL_DEFAULT_GLBLUB:
fprintf(out," %s", CIL_KEY_GLBLUB);
break;
default:
break;
}

5
libsepol/include/sepol/policydb/context.h
View file

@ -92,6 +92,11 @@ out:
return rc;
}
static inline int mls_context_glblub(context_struct_t *dst, context_struct_t *c1, context_struct_t *c2)
{
return mls_range_glblub(&dst->range, &c1->range, &c2->range);
}
static inline int mls_context_cmp(context_struct_t * c1, context_struct_t * c2)
{
return (mls_level_eq(&c1->range.level[0], &c2->range.level[0]) &&

26
libsepol/include/sepol/policydb/mls_types.h
View file

@ -30,8 +30,10 @@
#ifndef _SEPOL_POLICYDB_MLS_TYPES_H_
#define _SEPOL_POLICYDB_MLS_TYPES_H_
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/param.h>
#include <sepol/policydb/ebitmap.h>
#include <sepol/policydb/flask_types.h>
@ -48,6 +50,30 @@ typedef struct mls_range {
mls_level_t level[2]; /* low == level[0], high == level[1] */
} mls_range_t;
static inline int mls_range_glblub(struct mls_range *dst, struct mls_range *r1, struct mls_range *r2)
{
if (r1->level[1].sens < r2->level[0].sens || r2->level[1].sens < r1->level[0].sens) {
/* These ranges have no common sensitivities */
return -EINVAL;
}
/* Take the greatest of the low */
dst->level[0].sens = MAX(r1->level[0].sens, r2->level[0].sens);
/* Take the least of the high */
dst->level[1].sens = MIN(r1->level[1].sens, r2->level[1].sens);
if (ebitmap_and(&dst->level[0].cat, &r1->level[0].cat, &r2->level[0].cat) < 0) {
return -1;
}
if (ebitmap_and(&dst->level[1].cat, &r1->level[1].cat, &r2->level[1].cat) < 0) {
return -1;
}
return 0;
}
static inline int mls_level_cpy(struct mls_level *dst, struct mls_level *src)
{

7
libsepol/include/sepol/policydb/policydb.h
View file

@ -130,6 +130,7 @@ typedef struct class_datum {
#define DEFAULT_TARGET_LOW 4
#define DEFAULT_TARGET_HIGH 5
#define DEFAULT_TARGET_LOW_HIGH 6
#define DEFAULT_GLBLUB 7
char default_range;
} class_datum_t;
@ -741,10 +742,11 @@ extern int policydb_set_target_platform(policydb_t *p, int platform);
#define POLICYDB_VERSION_XEN_DEVICETREE 30 /* Xen-specific */
#define POLICYDB_VERSION_XPERMS_IOCTL 30 /* Linux-specific */
#define POLICYDB_VERSION_INFINIBAND 31 /* Linux-specific */
#define POLICYDB_VERSION_GLBLUB 32
/* Range of policy versions we understand*/
#define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_INFINIBAND
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_GLBLUB
/* Module versions and specific changes*/
#define MOD_POLICYDB_VERSION_BASE 4
@ -765,9 +767,10 @@ extern int policydb_set_target_platform(policydb_t *p, int platform);
#define MOD_POLICYDB_VERSION_CONSTRAINT_NAMES 17
#define MOD_POLICYDB_VERSION_XPERMS_IOCTL 18
#define MOD_POLICYDB_VERSION_INFINIBAND 19
#define MOD_POLICYDB_VERSION_GLBLUB 20
#define MOD_POLICYDB_VERSION_MIN MOD_POLICYDB_VERSION_BASE
#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_INFINIBAND
#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_GLBLUB
#define POLICYDB_CONFIG_MLS 1

3
libsepol/src/kernel_to_cil.c
View file

@ -698,6 +698,9 @@ static int write_default_range_to_cil(FILE *out, char *class_name, class_datum_t
case DEFAULT_TARGET_LOW_HIGH:
dft = "target low-high";
break;
case DEFAULT_GLBLUB:
dft = "glblub";
break;
default:
sepol_log_err("Unknown default type value: %i", class->default_range);
return -1;

3
libsepol/src/kernel_to_conf.c
View file

@ -673,6 +673,9 @@ static int write_default_range_to_conf(FILE *out, char *class_name, class_datum_
case DEFAULT_TARGET_LOW_HIGH:
dft = "target low-high";
break;
case DEFAULT_GLBLUB:
dft = "glblub";
break;
default:
sepol_log_err("Unknown default type value: %i", class->default_range);
return -1;

2
libsepol/src/mls.c
View file

@ -643,6 +643,8 @@ int mls_compute_sid(policydb_t * policydb,
return mls_context_cpy_high(newcontext, tcontext);
case DEFAULT_TARGET_LOW_HIGH:
return mls_context_cpy(newcontext, tcontext);
case DEFAULT_GLBLUB:
return mls_context_glblub(newcontext, scontext, tcontext);
}
/* Fallthrough */

1
libsepol/src/module_to_cil.c
View file

@ -2033,6 +2033,7 @@ static int class_to_cil(int indent, struct policydb *pdb, struct avrule_block *U
case DEFAULT_TARGET_LOW: dflt = "target low"; break;
case DEFAULT_TARGET_HIGH: dflt = "target high"; break;
case DEFAULT_TARGET_LOW_HIGH: dflt = "target low-high"; break;
case DEFAULT_GLBLUB: dflt = "glblub"; break;
default:
log_err("Unknown default range value: %i", class->default_range);
rc = -1;

22
libsepol/src/policydb.c
View file

@ -194,6 +194,13 @@ static struct policydb_compat_info policydb_compat[] = {
.ocon_num = OCON_IBENDPORT + 1,
.target_platform = SEPOL_TARGET_SELINUX,
},
{
.type = POLICY_KERN,
.version = POLICYDB_VERSION_GLBLUB,
.sym_num = SYM_NUM,
.ocon_num = OCON_IBENDPORT + 1,
.target_platform = SEPOL_TARGET_SELINUX,
},
{
.type = POLICY_BASE,
.version = MOD_POLICYDB_VERSION_BASE,
@ -306,6 +313,13 @@ static struct policydb_compat_info policydb_compat[] = {
.ocon_num = OCON_IBENDPORT + 1,
.target_platform = SEPOL_TARGET_SELINUX,
},
{
.type = POLICY_BASE,
.version = MOD_POLICYDB_VERSION_GLBLUB,
.sym_num = SYM_NUM,
.ocon_num = OCON_IBENDPORT + 1,
.target_platform = SEPOL_TARGET_SELINUX,
},
{
.type = POLICY_MOD,
.version = MOD_POLICYDB_VERSION_BASE,
@ -418,6 +432,14 @@ static struct policydb_compat_info policydb_compat[] = {
.ocon_num = 0,
.target_platform = SEPOL_TARGET_SELINUX,
},
{
.type = POLICY_MOD,
.version = MOD_POLICYDB_VERSION_GLBLUB,
.sym_num = SYM_NUM,
.ocon_num = 0,
.target_platform = SEPOL_TARGET_SELINUX,
},
};
#if 0

12
libsepol/src/write.c
View file

@ -46,6 +46,11 @@
#include "private.h"
#include "mls.h"
#define glblub_version ((p->policy_type == POLICY_KERN && \
p->policyvers >= POLICYDB_VERSION_GLBLUB) || \
(p->policy_type == POLICY_BASE && \
p->policyvers >= MOD_POLICYDB_VERSION_GLBLUB))
struct policy_data {
struct policy_file *fp;
struct policydb *p;
@ -1034,6 +1039,13 @@ static int class_write(hashtab_key_t key, hashtab_datum_t datum, void *ptr)
p->policyvers >= MOD_POLICYDB_VERSION_NEW_OBJECT_DEFAULTS)) {
buf[0] = cpu_to_le32(cladatum->default_user);
buf[1] = cpu_to_le32(cladatum->default_role);
if (!glblub_version && cladatum->default_range == DEFAULT_GLBLUB) {
WARN(fp->handle,
"class %s default_range set to GLBLUB but policy version is %d (%d required), discarding",
p->p_class_val_to_name[cladatum->s.value - 1], p->policyvers,
p->policy_type == POLICY_KERN? POLICYDB_VERSION_GLBLUB:MOD_POLICYDB_VERSION_GLBLUB);
cladatum->default_range = 0;
}
buf[2] = cpu_to_le32(cladatum->default_range);
items = put_entry(buf, sizeof(uint32_t), 3, fp);
if (items != 3)

12
secilc/docs/cil_default_object_statements.md
View file

@ -143,11 +143,11 @@ When creating a new `socket` object, the [`type`](cil_type_statements.md#type) c
defaultrange
------------
Allows the default level or range to be taken from the source or target context when computing a new context for the object [`class`](cil_class_and_permission_statements.md#class) identifier. Requires policy version 27.
Allows the default level or range to be taken from the source, target, or both contexts when computing a new context for the object [`class`](cil_class_and_permission_statements.md#class) identifier. Requires policy version 27. glblub as the default requires policy version 32.
**Statement definition:**
(defaultrange class_id default range)
(defaultrange class_id default <range>)
**Where:**
@ -167,11 +167,11 @@ Allows the default level or range to be taken from the source or target context
</tr>
<tr class="odd">
<td align="left"><p><code>default</code></p></td>
<td align="left"><p>A keyword of either <code>source</code> or <code>target</code>.</p></td>
<td align="left"><p>A keyword of either <code>source</code>, <code>target</code>, or <code>glblub</code>.</p></td>
</tr>
<tr class="even">
<td align="left"><p><code>range</code></p></td>
<td align="left"><p>A keyword of either <code>low</code>, <code>high</code> or <code>low-high</code>.</p></td>
<td align="left"><p>A keyword of either <code>low</code>, <code>high</code>, or <code>low-high</code>.</p></td>
</tr>
</tbody>
</table>
@ -181,3 +181,7 @@ Allows the default level or range to be taken from the source or target context
When creating a new `file` object, the appropriate `range` component of the new security context will be taken from the `target` context:
(defaultrange file target low_high)
MLS userspace object managers may need to compute the common parts of a range such that the object is created with the range common to the subject and containing object:
(defaultrange db_table glblub)