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Diffstat (limited to 'xorg-server/Xext/xselinux_label.c')
-rw-r--r--xorg-server/Xext/xselinux_label.c381
1 files changed, 381 insertions, 0 deletions
diff --git a/xorg-server/Xext/xselinux_label.c b/xorg-server/Xext/xselinux_label.c
new file mode 100644
index 000000000..239536cf3
--- /dev/null
+++ b/xorg-server/Xext/xselinux_label.c
@@ -0,0 +1,381 @@
+/************************************************************
+
+Author: Eamon Walsh <ewalsh@tycho.nsa.gov>
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+this permission notice appear in supporting documentation. This permission
+notice shall be included in all copies or substantial portions of the
+Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+********************************************************/
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <selinux/label.h>
+
+#include "registry.h"
+#include "xselinuxint.h"
+
+/* selection and property atom cache */
+typedef struct {
+ SELinuxObjectRec prp;
+ SELinuxObjectRec sel;
+} SELinuxAtomRec;
+
+/* dynamic array */
+typedef struct {
+ unsigned size;
+ void **array;
+} SELinuxArrayRec;
+
+/* labeling handle */
+static struct selabel_handle *label_hnd;
+
+/* Array of object classes indexed by resource type */
+SELinuxArrayRec arr_types;
+/* Array of event SIDs indexed by event type */
+SELinuxArrayRec arr_events;
+/* Array of property and selection SID structures */
+SELinuxArrayRec arr_atoms;
+
+/*
+ * Dynamic array helpers
+ */
+static void *
+SELinuxArrayGet(SELinuxArrayRec *rec, unsigned key)
+{
+ return (rec->size > key) ? rec->array[key] : 0;
+}
+
+static int
+SELinuxArraySet(SELinuxArrayRec *rec, unsigned key, void *val)
+{
+ if (key >= rec->size) {
+ /* Need to increase size of array */
+ rec->array = xrealloc(rec->array, (key + 1) * sizeof(val));
+ if (!rec->array)
+ return FALSE;
+ memset(rec->array + rec->size, 0, (key - rec->size + 1) * sizeof(val));
+ rec->size = key + 1;
+ }
+
+ rec->array[key] = val;
+ return TRUE;
+}
+
+static void
+SELinuxArrayFree(SELinuxArrayRec *rec, int free_elements)
+{
+ if (free_elements) {
+ unsigned i = rec->size;
+ while (i)
+ xfree(rec->array[--i]);
+ }
+
+ xfree(rec->array);
+ rec->size = 0;
+ rec->array = NULL;
+}
+
+/*
+ * Looks up a name in the selection or property mappings
+ */
+static int
+SELinuxAtomToSIDLookup(Atom atom, SELinuxObjectRec *obj, int map, int polymap)
+{
+ const char *name = NameForAtom(atom);
+ security_context_t ctx;
+ int rc = Success;
+
+ obj->poly = 1;
+
+ /* Look in the mappings of names to contexts */
+ if (selabel_lookup_raw(label_hnd, &ctx, name, map) == 0) {
+ obj->poly = 0;
+ } else if (errno != ENOENT) {
+ ErrorF("SELinux: a property label lookup failed!\n");
+ return BadValue;
+ } else if (selabel_lookup_raw(label_hnd, &ctx, name, polymap) < 0) {
+ ErrorF("SELinux: a property label lookup failed!\n");
+ return BadValue;
+ }
+
+ /* Get a SID for context */
+ if (avc_context_to_sid_raw(ctx, &obj->sid) < 0) {
+ ErrorF("SELinux: a context_to_SID_raw call failed!\n");
+ rc = BadAlloc;
+ }
+
+ freecon(ctx);
+ return rc;
+}
+
+/*
+ * Looks up the SID corresponding to the given property or selection atom
+ */
+int
+SELinuxAtomToSID(Atom atom, int prop, SELinuxObjectRec **obj_rtn)
+{
+ SELinuxAtomRec *rec;
+ SELinuxObjectRec *obj;
+ int rc, map, polymap;
+
+ rec = SELinuxArrayGet(&arr_atoms, atom);
+ if (!rec) {
+ rec = xcalloc(1, sizeof(SELinuxAtomRec));
+ if (!rec || !SELinuxArraySet(&arr_atoms, atom, rec))
+ return BadAlloc;
+ }
+
+ if (prop) {
+ obj = &rec->prp;
+ map = SELABEL_X_PROP;
+ polymap = SELABEL_X_POLYPROP;
+ } else {
+ obj = &rec->sel;
+ map = SELABEL_X_SELN;
+ polymap = SELABEL_X_POLYSELN;
+ }
+
+ if (!obj->sid) {
+ rc = SELinuxAtomToSIDLookup(atom, obj, map, polymap);
+ if (rc != Success)
+ goto out;
+ }
+
+ *obj_rtn = obj;
+ rc = Success;
+out:
+ return rc;
+}
+
+/*
+ * Looks up a SID for a selection/subject pair
+ */
+int
+SELinuxSelectionToSID(Atom selection, SELinuxSubjectRec *subj,
+ security_id_t *sid_rtn, int *poly_rtn)
+{
+ int rc;
+ SELinuxObjectRec *obj;
+ security_id_t tsid;
+
+ /* Get the default context and polyinstantiation bit */
+ rc = SELinuxAtomToSID(selection, 0, &obj);
+ if (rc != Success)
+ return rc;
+
+ /* Check for an override context next */
+ if (subj->sel_use_sid) {
+ sidget(tsid = subj->sel_use_sid);
+ goto out;
+ }
+
+ sidget(tsid = obj->sid);
+
+ /* Polyinstantiate if necessary to obtain the final SID */
+ if (obj->poly) {
+ sidput(tsid);
+ if (avc_compute_member(subj->sid, obj->sid,
+ SECCLASS_X_SELECTION, &tsid) < 0) {
+ ErrorF("SELinux: a compute_member call failed!\n");
+ return BadValue;
+ }
+ }
+out:
+ *sid_rtn = tsid;
+ if (poly_rtn)
+ *poly_rtn = obj->poly;
+ return Success;
+}
+
+/*
+ * Looks up a SID for a property/subject pair
+ */
+int
+SELinuxPropertyToSID(Atom property, SELinuxSubjectRec *subj,
+ security_id_t *sid_rtn, int *poly_rtn)
+{
+ int rc;
+ SELinuxObjectRec *obj;
+ security_id_t tsid, tsid2;
+
+ /* Get the default context and polyinstantiation bit */
+ rc = SELinuxAtomToSID(property, 1, &obj);
+ if (rc != Success)
+ return rc;
+
+ /* Check for an override context next */
+ if (subj->prp_use_sid) {
+ sidget(tsid = subj->prp_use_sid);
+ goto out;
+ }
+
+ /* Perform a transition */
+ if (avc_compute_create(subj->sid, obj->sid,
+ SECCLASS_X_PROPERTY, &tsid) < 0) {
+ ErrorF("SELinux: a compute_create call failed!\n");
+ return BadValue;
+ }
+
+ /* Polyinstantiate if necessary to obtain the final SID */
+ if (obj->poly) {
+ tsid2 = tsid;
+ if (avc_compute_member(subj->sid, tsid2,
+ SECCLASS_X_PROPERTY, &tsid) < 0) {
+ ErrorF("SELinux: a compute_member call failed!\n");
+ sidput(tsid2);
+ return BadValue;
+ }
+ sidput(tsid2);
+ }
+out:
+ *sid_rtn = tsid;
+ if (poly_rtn)
+ *poly_rtn = obj->poly;
+ return Success;
+}
+
+/*
+ * Looks up the SID corresponding to the given event type
+ */
+int
+SELinuxEventToSID(unsigned type, security_id_t sid_of_window,
+ SELinuxObjectRec *sid_return)
+{
+ const char *name = LookupEventName(type);
+ security_id_t sid;
+ security_context_t ctx;
+ type &= 127;
+
+ sid = SELinuxArrayGet(&arr_events, type);
+ if (!sid) {
+ /* Look in the mappings of event names to contexts */
+ if (selabel_lookup_raw(label_hnd, &ctx, name, SELABEL_X_EVENT) < 0) {
+ ErrorF("SELinux: an event label lookup failed!\n");
+ return BadValue;
+ }
+ /* Get a SID for context */
+ if (avc_context_to_sid_raw(ctx, &sid) < 0) {
+ ErrorF("SELinux: a context_to_SID_raw call failed!\n");
+ freecon(ctx);
+ return BadAlloc;
+ }
+ freecon(ctx);
+ /* Cache the SID value */
+ if (!SELinuxArraySet(&arr_events, type, sid)) {
+ sidput(sid);
+ return BadAlloc;
+ }
+ }
+
+ /* Perform a transition to obtain the final SID */
+ if (avc_compute_create(sid_of_window, sid, SECCLASS_X_EVENT,
+ &sid_return->sid) < 0) {
+ ErrorF("SELinux: a compute_create call failed!\n");
+ return BadValue;
+ }
+
+ return Success;
+}
+
+int
+SELinuxExtensionToSID(const char *name, security_id_t *sid_rtn)
+{
+ security_context_t ctx;
+
+ /* Look in the mappings of extension names to contexts */
+ if (selabel_lookup_raw(label_hnd, &ctx, name, SELABEL_X_EXT) < 0) {
+ ErrorF("SELinux: a property label lookup failed!\n");
+ return BadValue;
+ }
+ /* Get a SID for context */
+ if (avc_context_to_sid_raw(ctx, sid_rtn) < 0) {
+ ErrorF("SELinux: a context_to_SID_raw call failed!\n");
+ freecon(ctx);
+ return BadAlloc;
+ }
+ freecon(ctx);
+ return Success;
+}
+
+/*
+ * Returns the object class corresponding to the given resource type.
+ */
+security_class_t
+SELinuxTypeToClass(RESTYPE type)
+{
+ void *tmp;
+
+ tmp = SELinuxArrayGet(&arr_types, type & TypeMask);
+ if (!tmp) {
+ unsigned long class = SECCLASS_X_RESOURCE;
+
+ if (type & RC_DRAWABLE)
+ class = SECCLASS_X_DRAWABLE;
+ else if (type == RT_GC)
+ class = SECCLASS_X_GC;
+ else if (type == RT_FONT)
+ class = SECCLASS_X_FONT;
+ else if (type == RT_CURSOR)
+ class = SECCLASS_X_CURSOR;
+ else if (type == RT_COLORMAP)
+ class = SECCLASS_X_COLORMAP;
+ else {
+ /* Need to do a string lookup */
+ const char *str = LookupResourceName(type);
+ if (!strcmp(str, "PICTURE"))
+ class = SECCLASS_X_DRAWABLE;
+ else if (!strcmp(str, "GLYPHSET"))
+ class = SECCLASS_X_FONT;
+ }
+
+ tmp = (void *)class;
+ SELinuxArraySet(&arr_types, type & TypeMask, tmp);
+ }
+
+ return (security_class_t)(unsigned long)tmp;
+}
+
+security_context_t
+SELinuxDefaultClientLabel(void)
+{
+ security_context_t ctx;
+
+ if (selabel_lookup_raw(label_hnd, &ctx, "remote", SELABEL_X_CLIENT) < 0)
+ FatalError("SELinux: failed to look up remote-client context\n");
+
+ return ctx;
+}
+
+void
+SELinuxLabelInit(void)
+{
+ struct selinux_opt selabel_option = { SELABEL_OPT_VALIDATE, (char *)1 };
+
+ label_hnd = selabel_open(SELABEL_CTX_X, &selabel_option, 1);
+ if (!label_hnd)
+ FatalError("SELinux: Failed to open x_contexts mapping in policy\n");
+}
+
+void
+SELinuxLabelReset(void)
+{
+ selabel_close(label_hnd);
+ label_hnd = NULL;
+
+ /* Free local state */
+ SELinuxArrayFree(&arr_types, 0);
+ SELinuxArrayFree(&arr_events, 0);
+ SELinuxArrayFree(&arr_atoms, 1);
+}