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[Selinux-commits] SF.net SVN: selinux: [2471] trunk/libselinux
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From: <ew...@us...> - 2007-06-11 16:59:15
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Revision: 2471
http://svn.sourceforge.net/selinux/?rev=2471&view=rev
Author: ewalsh
Date: 2007-06-11 09:59:08 -0700 (Mon, 11 Jun 2007)
Log Message:
-----------
Author: Eamon Walsh
Email: ew...@ty...
Subject: libselinux: class and permission mapping support (try 3)
Date: Fri, 08 Jun 2007 13:26:21 -0400
Changes from the second version: rebase to object class discovery
patchset; flush the AVC when setting a mapping.
Changes from the first version: disallow a NULL mapping with
error EINVAL; add assert statements to the map/unmap helpers
to catch out-of-bounds value bugs in callers.
This provides support for userspace object managers to register a
mapping of class and permission values. After the mapping is
registered all libselinux functions that take a security class
or permission value must be provided with mapped values instead
of the "real," kernel values.
Changes from the original interface proposal: No selinux_init()
function, just a straight set_mapping() function. Also, to
simplify things the incoming mapping does not include explicit
values; the classes and permissions are numbered implicitly by
their ordering. NULL strings are used to terminate the lists.
Tested with X server, no problems encountered.
This patch includes the interface and implementation of the
mapping set function.
Signed-off-by: Eamon Walsh <ew...@ty...>
Acked-by: Stephen Smalley <sd...@ty...>
Modified Paths:
--------------
trunk/libselinux/include/selinux/selinux.h
Added Paths:
-----------
trunk/libselinux/src/mapping.c
Modified: trunk/libselinux/include/selinux/selinux.h
===================================================================
--- trunk/libselinux/include/selinux/selinux.h 2007-06-07 18:42:44 UTC (rev 2470)
+++ trunk/libselinux/include/selinux/selinux.h 2007-06-11 16:59:08 UTC (rev 2471)
@@ -280,6 +280,14 @@
/* Commit the pending values for the booleans */
extern int security_commit_booleans(void);
+/* Userspace class mapping support */
+struct security_class_mapping {
+ const char *name;
+ const char *perms[sizeof(access_vector_t) * 8 + 1];
+};
+
+int selinux_set_mapping(struct security_class_mapping *map);
+
/* Common helpers */
/* Convert between security class values and string names */
Added: trunk/libselinux/src/mapping.c
===================================================================
--- trunk/libselinux/src/mapping.c (rev 0)
+++ trunk/libselinux/src/mapping.c 2007-06-11 16:59:08 UTC (rev 2471)
@@ -0,0 +1,189 @@
+/*
+ * Class and permission mappings.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <assert.h>
+#include <selinux/selinux.h>
+#include <selinux/avc.h>
+#include "mapping.h"
+
+/*
+ * Class and permission mappings
+ */
+
+struct selinux_mapping {
+ security_class_t value; /* real, kernel value */
+ unsigned num_perms;
+ access_vector_t perms[sizeof(access_vector_t) * 8];
+};
+
+static struct selinux_mapping *current_mapping = NULL;
+static security_class_t current_mapping_size = 0;
+
+/*
+ * Mapping setting function
+ */
+
+int
+selinux_set_mapping(struct security_class_mapping *map)
+{
+ size_t size = sizeof(struct selinux_mapping);
+ security_class_t i, j;
+ unsigned k;
+
+ free(current_mapping);
+ current_mapping = NULL;
+ current_mapping_size = 0;
+
+ if (avc_reset() < 0)
+ goto err;
+
+ /* Find number of classes in the input mapping */
+ if (!map) {
+ errno = EINVAL;
+ goto err;
+ }
+ i = 0;
+ while (map[i].name)
+ i++;
+
+ /* Allocate space for the class records, plus one for class zero */
+ current_mapping = (struct selinux_mapping *)calloc(++i, size);
+ if (!current_mapping)
+ goto err;
+
+ /* Store the raw class and permission values */
+ j = 0;
+ while (map[j].name) {
+ struct security_class_mapping *p_in = map + (j++);
+ struct selinux_mapping *p_out = current_mapping + j;
+
+ p_out->value = string_to_security_class(p_in->name);
+ if (!p_out->value)
+ goto err2;
+
+ k = 0;
+ while (p_in->perms && p_in->perms[k]) {
+ p_out->perms[k] = string_to_av_perm(p_out->value,
+ p_in->perms[k]);
+ if (!p_out->perms[k])
+ goto err2;
+ k++;
+ }
+ p_out->num_perms = k;
+ }
+
+ /* Set the mapping size here so the above lookups are "raw" */
+ current_mapping_size = i;
+ return 0;
+err2:
+ free(current_mapping);
+ current_mapping = NULL;
+ current_mapping_size = 0;
+err:
+ return -1;
+}
+
+/*
+ * Get real, kernel values from mapped values
+ */
+
+security_class_t
+unmap_class(security_class_t tclass)
+{
+ if (tclass < current_mapping_size)
+ return current_mapping[tclass].value;
+
+ assert(current_mapping_size == 0);
+ return tclass;
+}
+
+access_vector_t
+unmap_perm(security_class_t tclass, access_vector_t tperm)
+{
+ if (tclass < current_mapping_size) {
+ unsigned i;
+ access_vector_t kperm = 0;
+
+ for (i=0; i<current_mapping[tclass].num_perms; i++)
+ if (tperm & (1<<i)) {
+ kperm |= current_mapping[tclass].perms[i];
+ tperm &= ~(1<<i);
+ }
+ assert(tperm == 0);
+ return kperm;
+ }
+
+ assert(current_mapping_size == 0);
+ return tperm;
+}
+
+/*
+ * Get mapped values from real, kernel values
+ */
+
+security_class_t
+map_class(security_class_t kclass)
+{
+ security_class_t i;
+
+ for (i=0; i<current_mapping_size; i++)
+ if (current_mapping[i].value == kclass)
+ return i;
+
+ assert(current_mapping_size == 0);
+ return kclass;
+}
+
+access_vector_t
+map_perm(security_class_t tclass, access_vector_t kperm)
+{
+ if (tclass < current_mapping_size) {
+ unsigned i;
+ access_vector_t tperm = 0;
+
+ for (i=0; i<current_mapping[tclass].num_perms; i++)
+ if (kperm & current_mapping[tclass].perms[i]) {
+ tperm |= 1<<i;
+ kperm &= ~current_mapping[tclass].perms[i];
+ }
+ assert(kperm == 0);
+ return tperm;
+ }
+
+ assert(current_mapping_size == 0);
+ return kperm;
+}
+
+void
+map_decision(security_class_t tclass, struct av_decision *avd)
+{
+ if (tclass < current_mapping_size) {
+ unsigned i;
+ access_vector_t result;
+
+ for (i=0, result=0; i<current_mapping[tclass].num_perms; i++)
+ if (avd->allowed & current_mapping[tclass].perms[i])
+ result |= 1<<i;
+ avd->allowed = result;
+
+ for (i=0, result=0; i<current_mapping[tclass].num_perms; i++)
+ if (avd->decided & current_mapping[tclass].perms[i])
+ result |= 1<<i;
+ avd->decided = result;
+
+ for (i=0, result=0; i<current_mapping[tclass].num_perms; i++)
+ if (avd->auditallow & current_mapping[tclass].perms[i])
+ result |= 1<<i;
+ avd->auditallow = result;
+
+ for (i=0, result=0; i<current_mapping[tclass].num_perms; i++)
+ if (avd->auditdeny & current_mapping[tclass].perms[i])
+ result |= 1<<i;
+ avd->auditdeny = result;
+ }
+}
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