xselinux: refactor extension code into smaller files.

New files:
xselinux_ext.c: Extension init and request handlers.
xselinux_hooks.c: XACE hook functions and other callbacks.
xselinux_label.c: Object security-labeling code.
xselinuxint.h: Shared internal functions.

Signed-off-by: Eamon Walsh <ewalsh@tycho.nsa.gov>

1 files changed, 1040 insertions, 0 deletions

diff --git a/Xext/xselinux_hooks.c b/Xext/xselinux_hooks.c
new file mode 100644
index 000000000..a27067319
--- /dev/null
+++ b/Xext/xselinux_hooks.c
@@ -0,0 +1,1040 @@
+/************************************************************
+
+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.
+
+********************************************************/
+
+/*
+ * Portions of this code copyright (c) 2005 by Trusted Computer Solutions, Inc.
+ * All rights reserved.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <sys/socket.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libaudit.h>
+
+#include <X11/Xatom.h>
+#include "selection.h"
+#include "inputstr.h"
+#include "scrnintstr.h"
+#include "windowstr.h"
+#include "propertyst.h"
+#include "extnsionst.h"
+#include "xacestr.h"
+#include "../os/osdep.h"
+#define _XSELINUX_NEED_FLASK_MAP
+#include "xselinuxint.h"
+
+
+/* structure passed to auditing callback */
+typedef struct {
+    ClientPtr client;	/* client */
+    DeviceIntPtr dev;	/* device */
+    char *command;	/* client's executable path */
+    unsigned id;	/* resource id, if any */
+    int restype;	/* resource type, if any */
+    int event;		/* event type, if any */
+    Atom property;	/* property name, if any */
+    Atom selection;	/* selection name, if any */
+    char *extension;	/* extension name, if any */
+} SELinuxAuditRec;
+
+/* private state keys */
+static int subjectKeyIndex;
+DevPrivateKey subjectKey = &subjectKeyIndex;
+static int objectKeyIndex;
+DevPrivateKey objectKey = &objectKeyIndex;
+static int dataKeyIndex;
+DevPrivateKey dataKey = &dataKeyIndex;
+
+/* audit file descriptor */
+static int audit_fd;
+
+/* whether AVC is active */
+static int avc_active;
+
+/* atoms for window label properties */
+static Atom atom_ctx;
+static Atom atom_client_ctx;
+
+/* The unlabeled SID */
+static security_id_t unlabeled_sid;
+
+/* forward declarations */
+static void SELinuxScreen(CallbackListPtr *, pointer, pointer);
+
+/* "true" pointer value for use as callback data */
+static pointer truep = (pointer)1;
+
+
+/*
+ * Performs an SELinux permission check.
+ */
+static int
+SELinuxDoCheck(SELinuxSubjectRec *subj, SELinuxObjectRec *obj,
+	       security_class_t class, Mask mode, SELinuxAuditRec *auditdata)
+{
+    /* serverClient requests OK */
+    if (subj->privileged)
+	return Success;
+
+    auditdata->command = subj->command;
+    errno = 0;
+
+    if (avc_has_perm(subj->sid, obj->sid, class, mode, &subj->aeref,
+		     auditdata) < 0) {
+	if (mode == DixUnknownAccess)
+	    return Success; /* DixUnknownAccess requests OK ... for now */
+	if (errno == EACCES)
+	    return BadAccess;
+	ErrorF("SELinux: avc_has_perm: unexpected error %d\n", errno);
+	return BadValue;
+    }
+
+    return Success;
+}
+
+/*
+ * Labels a newly connected client.
+ */
+static void
+SELinuxLabelClient(ClientPtr client)
+{
+    int fd = XaceGetConnectionNumber(client);
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    security_context_t ctx;
+
+    subj = dixLookupPrivate(&client->devPrivates, subjectKey);
+    sidput(subj->sid);
+    obj = dixLookupPrivate(&client->devPrivates, objectKey);
+    sidput(obj->sid);
+
+    /* Try to get a context from the socket */
+    if (fd < 0 || getpeercon_raw(fd, &ctx) < 0) {
+	/* Otherwise, fall back to a default context */
+	ctx = SELinuxDefaultClientLabel();
+    }
+
+    /* For local clients, try and determine the executable name */
+    if (XaceIsLocal(client)) {
+	struct ucred creds;
+	socklen_t len = sizeof(creds);
+	char path[PATH_MAX + 1];
+	size_t bytes;
+
+	memset(&creds, 0, sizeof(creds));
+	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &creds, &len) < 0)
+	    goto finish;
+
+	snprintf(path, PATH_MAX + 1, "/proc/%d/cmdline", creds.pid);
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+	    goto finish;
+
+	bytes = read(fd, path, PATH_MAX + 1);
+	close(fd);
+	if (bytes <= 0)
+	    goto finish;
+
+	subj->command = xalloc(bytes);
+	if (!subj->command)
+	    goto finish;
+
+	memcpy(subj->command, path, bytes);
+	subj->command[bytes - 1] = 0;
+    }
+
+finish:
+    /* Get a SID from the context */
+    if (avc_context_to_sid_raw(ctx, &subj->sid) < 0)
+	FatalError("SELinux: client %d: context_to_sid_raw(%s) failed\n",
+		   client->index, ctx);
+
+    sidget(obj->sid = subj->sid);
+    freecon(ctx);
+}
+
+/*
+ * Labels initial server objects.
+ */
+static void
+SELinuxLabelInitial(void)
+{
+    int i;
+    XaceScreenAccessRec srec;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    security_context_t ctx;
+    pointer unused;
+
+    /* Do the serverClient */
+    subj = dixLookupPrivate(&serverClient->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&serverClient->devPrivates, objectKey);
+    subj->privileged = 1;
+    sidput(subj->sid);
+
+    /* Use the context of the X server process for the serverClient */
+    if (getcon_raw(&ctx) < 0)
+	FatalError("SELinux: couldn't get context of X server process\n");
+
+    /* Get a SID from the context */
+    if (avc_context_to_sid_raw(ctx, &subj->sid) < 0)
+	FatalError("SELinux: serverClient: context_to_sid(%s) failed\n", ctx);
+
+    sidget(obj->sid = subj->sid);
+    freecon(ctx);
+
+    srec.client = serverClient;
+    srec.access_mode = DixCreateAccess;
+    srec.status = Success;
+
+    for (i = 0; i < screenInfo.numScreens; i++) {
+	/* Do the screen object */
+	srec.screen = screenInfo.screens[i];
+	SELinuxScreen(NULL, NULL, &srec);
+
+	/* Do the default colormap */
+	dixLookupResourceByType(&unused, screenInfo.screens[i]->defColormap,
+			  RT_COLORMAP, serverClient, DixCreateAccess);
+    }
+}
+
+/*
+ * Labels new resource objects.
+ */
+static int
+SELinuxLabelResource(XaceResourceAccessRec *rec, SELinuxSubjectRec *subj,
+		     SELinuxObjectRec *obj, security_class_t class)
+{
+    int offset;
+    security_id_t tsid;
+
+    /* Check for a create context */
+    if (rec->rtype == RT_WINDOW && subj->win_create_sid) {
+	sidget(obj->sid = subj->win_create_sid);
+	return Success;
+    }
+
+    if (rec->parent)
+	offset = dixLookupPrivateOffset(rec->ptype);
+
+    if (rec->parent && offset >= 0) {
+	/* Use the SID of the parent object in the labeling operation */
+	PrivateRec **privatePtr = DEVPRIV_AT(rec->parent, offset);
+	SELinuxObjectRec *pobj = dixLookupPrivate(privatePtr, objectKey);
+	tsid = pobj->sid;
+    } else {
+	/* Use the SID of the subject */
+	tsid = subj->sid;
+    }
+
+    /* Perform a transition to obtain the final SID */
+    if (avc_compute_create(subj->sid, tsid, class, &obj->sid) < 0) {
+	ErrorF("SELinux: a compute_create call failed!\n");
+	return BadValue;
+    }
+
+    return Success;
+}
+
+
+/*
+ * Libselinux Callbacks
+ */
+
+static int
+SELinuxAudit(void *auditdata,
+	     security_class_t class,
+	     char *msgbuf,
+	     size_t msgbufsize)
+{
+    SELinuxAuditRec *audit = auditdata;
+    ClientPtr client = audit->client;
+    char idNum[16];
+    const char *propertyName, *selectionName;
+    int major = -1, minor = -1;
+
+    if (client) {
+	REQUEST(xReq);
+	if (stuff) {
+	    major = stuff->reqType;
+	    minor = MinorOpcodeOfRequest(client);
+	}
+    }
+    if (audit->id)
+	snprintf(idNum, 16, "%x", audit->id);
+
+    propertyName = audit->property ? NameForAtom(audit->property) : NULL;
+    selectionName = audit->selection ? NameForAtom(audit->selection) : NULL;
+
+    return snprintf(msgbuf, msgbufsize,
+		    "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
+		    (major >= 0) ? "request=" : "",
+		    (major >= 0) ? LookupRequestName(major, minor) : "",
+		    audit->command ? " comm=" : "",
+		    audit->command ? audit->command : "",
+		    audit->dev ? " xdevice=\"" : "",
+		    audit->dev ? audit->dev->name : "",
+		    audit->dev ? "\"" : "",
+		    audit->id ? " resid=" : "",
+		    audit->id ? idNum : "",
+		    audit->restype ? " restype=" : "",
+		    audit->restype ? LookupResourceName(audit->restype) : "",
+		    audit->event ? " event=" : "",
+		    audit->event ? LookupEventName(audit->event & 127) : "",
+		    audit->property ? " property=" : "",
+		    audit->property ? propertyName : "",
+		    audit->selection ? " selection=" : "",
+		    audit->selection ? selectionName : "",
+		    audit->extension ? " extension=" : "",
+		    audit->extension ? audit->extension : "");
+}
+
+static int
+SELinuxLog(int type, const char *fmt, ...)
+{
+    va_list ap;
+    char buf[MAX_AUDIT_MESSAGE_LENGTH];
+    int rc, aut;
+
+    switch (type) {
+    case SELINUX_INFO:
+	aut = AUDIT_USER_MAC_POLICY_LOAD;
+	break;
+    case SELINUX_AVC:
+	aut = AUDIT_USER_AVC;
+	break;
+    default:
+	aut = AUDIT_USER_SELINUX_ERR;
+	break;
+    }
+
+    va_start(ap, fmt);
+    vsnprintf(buf, MAX_AUDIT_MESSAGE_LENGTH, fmt, ap);
+    rc = audit_log_user_avc_message(audit_fd, aut, buf, NULL, NULL, NULL, 0);
+    va_end(ap);
+    LogMessageVerb(X_WARNING, 0, "%s", buf);
+    return 0;
+}
+
+/*
+ * XACE Callbacks
+ */
+
+static void
+SELinuxDevice(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceDeviceAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    SELinuxAuditRec auditdata = { .client = rec->client, .dev = rec->dev };
+    int rc;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&rec->dev->devPrivates, objectKey);
+
+    /* If this is a new object that needs labeling, do it now */
+    if (rec->access_mode & DixCreateAccess) {
+	SELinuxSubjectRec *dsubj;
+	dsubj = dixLookupPrivate(&rec->dev->devPrivates, subjectKey);
+
+	sidput(dsubj->sid);
+	sidput(obj->sid);
+
+	if (subj->dev_create_sid) {
+	    /* Label the device with the create context */
+	    sidget(obj->sid = subj->dev_create_sid);
+	    sidget(dsubj->sid = subj->dev_create_sid);
+	} else {
+	    /* Label the device directly with the process SID */
+	    sidget(obj->sid = subj->sid);
+	    sidget(dsubj->sid = subj->sid);
+	}
+    }
+
+    /* XXX only check read permission on XQueryKeymap */
+    /* This is to allow the numerous apps that call XQueryPointer to work */
+    if (rec->access_mode & DixReadAccess) {
+	ClientPtr client = rec->client;
+	REQUEST(xReq);
+	if (stuff && stuff->reqType != X_QueryKeymap) {
+	    rec->access_mode &= ~DixReadAccess;
+	    rec->access_mode |= DixGetAttrAccess;
+	}
+    }
+
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_DEVICE, rec->access_mode,
+			&auditdata);
+    if (rc != Success)
+	rec->status = rc;
+}
+
+static void
+SELinuxSend(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceSendAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj, ev_sid;
+    SELinuxAuditRec auditdata = { .client = rec->client, .dev = rec->dev };
+    security_class_t class;
+    int rc, i, type;
+
+    if (rec->dev)
+	subj = dixLookupPrivate(&rec->dev->devPrivates, subjectKey);
+    else
+	subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+
+    obj = dixLookupPrivate(&rec->pWin->devPrivates, objectKey);
+
+    /* Check send permission on window */
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_DRAWABLE, DixSendAccess,
+			&auditdata);
+    if (rc != Success)
+	goto err;
+
+    /* Check send permission on specific event types */
+    for (i = 0; i < rec->count; i++) {
+	type = rec->events[i].u.u.type;
+	class = (type & 128) ? SECCLASS_X_FAKEEVENT : SECCLASS_X_EVENT;
+
+	rc = SELinuxEventToSID(type, obj->sid, &ev_sid);
+	if (rc != Success)
+	    goto err;
+
+	auditdata.event = type;
+	rc = SELinuxDoCheck(subj, &ev_sid, class, DixSendAccess, &auditdata);
+	if (rc != Success)
+	    goto err;
+    }
+    return;
+err:
+    rec->status = rc;
+}
+
+static void
+SELinuxReceive(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceReceiveAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj, ev_sid;
+    SELinuxAuditRec auditdata = { .client = NULL };
+    security_class_t class;
+    int rc, i, type;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&rec->pWin->devPrivates, objectKey);
+
+    /* Check receive permission on window */
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_DRAWABLE, DixReceiveAccess,
+			&auditdata);
+    if (rc != Success)
+	goto err;
+
+    /* Check receive permission on specific event types */
+    for (i = 0; i < rec->count; i++) {
+	type = rec->events[i].u.u.type;
+	class = (type & 128) ? SECCLASS_X_FAKEEVENT : SECCLASS_X_EVENT;
+
+	rc = SELinuxEventToSID(type, obj->sid, &ev_sid);
+	if (rc != Success)
+	    goto err;
+
+	auditdata.event = type;
+	rc = SELinuxDoCheck(subj, &ev_sid, class, DixReceiveAccess, &auditdata);
+	if (rc != Success)
+	    goto err;
+    }
+    return;
+err:
+    rec->status = rc;
+}
+
+static void
+SELinuxExtension(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceExtAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj, *serv;
+    SELinuxObjectRec *obj;
+    SELinuxAuditRec auditdata = { .client = rec->client };
+    int rc;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&rec->ext->devPrivates, objectKey);
+
+    /* If this is a new object that needs labeling, do it now */
+    /* XXX there should be a separate callback for this */
+    if (obj->sid == unlabeled_sid) {
+	security_id_t sid;
+
+	serv = dixLookupPrivate(&serverClient->devPrivates, subjectKey);
+	rc = SELinuxExtensionToSID(rec->ext->name, &sid);
+	if (rc != Success) {
+	    rec->status = rc;
+	    return;
+	}
+
+	sidput(obj->sid);
+
+	/* Perform a transition to obtain the final SID */
+	if (avc_compute_create(serv->sid, sid, SECCLASS_X_EXTENSION,
+			       &obj->sid) < 0) {
+	    ErrorF("SELinux: a SID transition call failed!\n");
+	    rec->status = BadValue;
+	    return;
+	}
+    }
+
+    /* Perform the security check */
+    auditdata.extension = rec->ext->name;
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_EXTENSION, rec->access_mode,
+			&auditdata);
+    if (rc != Success)
+	rec->status = rc;
+}
+
+static void
+SELinuxSelection(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceSelectionAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj, *data;
+    Selection *pSel = *rec->ppSel;
+    Atom name = pSel->selection;
+    Mask access_mode = rec->access_mode;
+    SELinuxAuditRec auditdata = { .client = rec->client, .selection = name };
+    security_id_t tsid;
+    int rc;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&pSel->devPrivates, objectKey);
+
+    /* If this is a new object that needs labeling, do it now */
+    if (access_mode & DixCreateAccess) {
+	sidput(obj->sid);
+	rc = SELinuxSelectionToSID(name, subj, &obj->sid, &obj->poly);
+	if (rc != Success)
+	    obj->sid = unlabeled_sid;
+	access_mode = DixSetAttrAccess;
+    }
+    /* If this is a polyinstantiated object, find the right instance */
+    else if (obj->poly) {
+	rc = SELinuxSelectionToSID(name, subj, &tsid, NULL);
+	if (rc != Success) {
+	    rec->status = rc;
+	    return;
+	}
+	while (pSel->selection != name || obj->sid != tsid) {
+	    if ((pSel = pSel->next) == NULL)
+		break;
+	    obj = dixLookupPrivate(&pSel->devPrivates, objectKey);
+	}
+	sidput(tsid);
+
+	if (pSel)
+	    *rec->ppSel = pSel;
+	else {
+	    rec->status = BadMatch;
+	    return;
+	}
+    }
+
+    /* Perform the security check */
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_SELECTION, access_mode,
+			&auditdata);
+    if (rc != Success)
+	rec->status = rc;
+
+    /* Label the content (advisory only) */
+    if (access_mode & DixSetAttrAccess) {
+	data = dixLookupPrivate(&pSel->devPrivates, dataKey);
+	sidput(data->sid);
+	if (subj->sel_create_sid)
+	    sidget(data->sid = subj->sel_create_sid);
+	else
+	    sidget(data->sid = obj->sid);
+    }
+}
+
+static void
+SELinuxProperty(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XacePropertyAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj, *data;
+    PropertyPtr pProp = *rec->ppProp;
+    Atom name = pProp->propertyName;
+    SELinuxAuditRec auditdata = { .client = rec->client, .property = name };
+    security_id_t tsid;
+    int rc;
+
+    /* Don't care about the new content check */
+    if (rec->access_mode & DixPostAccess)
+	return;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&pProp->devPrivates, objectKey);
+
+    /* If this is a new object that needs labeling, do it now */
+    if (rec->access_mode & DixCreateAccess) {
+	sidput(obj->sid);
+	rc = SELinuxPropertyToSID(name, subj, &obj->sid, &obj->poly);
+	if (rc != Success) {
+	    rec->status = rc;
+	    return;
+	}
+    }
+    /* If this is a polyinstantiated object, find the right instance */
+    else if (obj->poly) {
+	rc = SELinuxPropertyToSID(name, subj, &tsid, NULL);
+	if (rc != Success) {
+	    rec->status = rc;
+	    return;
+	}
+	while (pProp->propertyName != name || obj->sid != tsid) {
+	    if ((pProp = pProp->next) == NULL)
+		break;
+	    obj = dixLookupPrivate(&pProp->devPrivates, objectKey);
+	}
+	sidput(tsid);
+
+	if (pProp)
+	    *rec->ppProp = pProp;
+	else {
+	    rec->status = BadMatch;
+	    return;
+	}
+    }
+
+    /* Perform the security check */
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_PROPERTY, rec->access_mode,
+			&auditdata);
+    if (rc != Success)
+	rec->status = rc;
+
+    /* Label the content (advisory only) */
+    if (rec->access_mode & DixWriteAccess) {
+	data = dixLookupPrivate(&pProp->devPrivates, dataKey);
+	sidput(data->sid);
+	if (subj->prp_create_sid)
+	    sidget(data->sid = subj->prp_create_sid);
+	else
+	    sidget(data->sid = obj->sid);
+    }
+}
+
+static void
+SELinuxResource(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceResourceAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    SELinuxAuditRec auditdata = { .client = rec->client };
+    Mask access_mode = rec->access_mode;
+    PrivateRec **privatePtr;
+    security_class_t class;
+    int rc, offset;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+
+    /* Determine if the resource object has a devPrivates field */
+    offset = dixLookupPrivateOffset(rec->rtype);
+    if (offset < 0) {
+	/* No: use the SID of the owning client */
+	class = SECCLASS_X_RESOURCE;
+	privatePtr = &clients[CLIENT_ID(rec->id)]->devPrivates;
+	obj = dixLookupPrivate(privatePtr, objectKey);
+    } else {
+	/* Yes: use the SID from the resource object itself */
+	class = SELinuxTypeToClass(rec->rtype);
+	privatePtr = DEVPRIV_AT(rec->res, offset);
+	obj = dixLookupPrivate(privatePtr, objectKey);
+    }
+
+    /* If this is a new object that needs labeling, do it now */
+    if (access_mode & DixCreateAccess && offset >= 0) {
+	rc = SELinuxLabelResource(rec, subj, obj, class);
+	if (rc != Success) {
+	    rec->status = rc;
+	    return;
+	}
+    }
+
+    /* Collapse generic resource permissions down to read/write */
+    if (class == SECCLASS_X_RESOURCE) {
+	access_mode = !!(rec->access_mode & SELinuxReadMask); /* rd */
+	access_mode |= !!(rec->access_mode & ~SELinuxReadMask) << 1; /* wr */
+    }
+
+    /* Perform the security check */
+    auditdata.restype = rec->rtype;
+    auditdata.id = rec->id;
+    rc = SELinuxDoCheck(subj, obj, class, access_mode, &auditdata);
+    if (rc != Success)
+	rec->status = rc;
+
+    /* Perform the background none check on windows */
+    if (access_mode & DixCreateAccess && rec->rtype == RT_WINDOW) {
+	rc = SELinuxDoCheck(subj, obj, class, DixBlendAccess, &auditdata);
+	if (rc != Success)
+	    ((WindowPtr)rec->res)->forcedBG = TRUE;
+    }
+}
+
+static void
+SELinuxScreen(CallbackListPtr *pcbl, pointer is_saver, pointer calldata)
+{
+    XaceScreenAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    SELinuxAuditRec auditdata = { .client = rec->client };
+    Mask access_mode = rec->access_mode;
+    int rc;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&rec->screen->devPrivates, objectKey);
+
+    /* If this is a new object that needs labeling, do it now */
+    if (access_mode & DixCreateAccess) {
+	sidput(obj->sid);
+
+	/* Perform a transition to obtain the final SID */
+	if (avc_compute_create(subj->sid, subj->sid, SECCLASS_X_SCREEN,
+			       &obj->sid) < 0) {
+	    ErrorF("SELinux: a compute_create call failed!\n");
+	    rec->status = BadValue;
+	    return;
+	}
+    }
+
+    if (is_saver)
+	access_mode <<= 2;
+
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_SCREEN, access_mode, &auditdata);
+    if (rc != Success)
+	rec->status = rc;
+}
+
+static void
+SELinuxClient(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceClientAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    SELinuxAuditRec auditdata = { .client = rec->client };
+    int rc;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&rec->target->devPrivates, objectKey);
+
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_CLIENT, rec->access_mode,
+			&auditdata);
+    if (rc != Success)
+	rec->status = rc;
+}
+
+static void
+SELinuxServer(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    XaceServerAccessRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    SELinuxAuditRec auditdata = { .client = rec->client };
+    int rc;
+
+    subj = dixLookupPrivate(&rec->client->devPrivates, subjectKey);
+    obj = dixLookupPrivate(&serverClient->devPrivates, objectKey);
+
+    rc = SELinuxDoCheck(subj, obj, SECCLASS_X_SERVER, rec->access_mode,
+			&auditdata);
+    if (rc != Success)
+	rec->status = rc;
+}
+
+
+/*
+ * DIX Callbacks
+ */
+
+static void
+SELinuxClientState(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    NewClientInfoRec *pci = calldata;
+
+    switch (pci->client->clientState) {
+    case ClientStateInitial:
+	SELinuxLabelClient(pci->client);
+	break;
+
+    default:
+	break;
+    }
+}
+
+static void
+SELinuxResourceState(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    ResourceStateInfoRec *rec = calldata;
+    SELinuxSubjectRec *subj;
+    SELinuxObjectRec *obj;
+    WindowPtr pWin;
+
+    if (rec->type != RT_WINDOW)
+	return;
+    if (rec->state != ResourceStateAdding)
+	return;
+
+    pWin = (WindowPtr)rec->value;
+    subj = dixLookupPrivate(&wClient(pWin)->devPrivates, subjectKey);
+
+    if (subj->sid) {
+	security_context_t ctx;
+	int rc = avc_sid_to_context_raw(subj->sid, &ctx);
+	if (rc < 0)
+	    FatalError("SELinux: Failed to get security context!\n");
+	rc = dixChangeWindowProperty(serverClient,
+				     pWin, atom_client_ctx, XA_STRING, 8,
+				     PropModeReplace, strlen(ctx), ctx, FALSE);
+	if (rc != Success)
+	    FatalError("SELinux: Failed to set label property on window!\n");
+	freecon(ctx);
+    } else
+	FatalError("SELinux: Unexpected unlabeled client found\n");
+
+    obj = dixLookupPrivate(&pWin->devPrivates, objectKey);
+
+    if (obj->sid) {
+	security_context_t ctx;
+	int rc = avc_sid_to_context_raw(obj->sid, &ctx);
+	if (rc < 0)
+	    FatalError("SELinux: Failed to get security context!\n");
+	rc = dixChangeWindowProperty(serverClient,
+				     pWin, atom_ctx, XA_STRING, 8,
+				     PropModeReplace, strlen(ctx), ctx, FALSE);
+	if (rc != Success)
+	    FatalError("SELinux: Failed to set label property on window!\n");
+	freecon(ctx);
+    } else
+	FatalError("SELinux: Unexpected unlabeled window found\n");
+}
+
+
+/*
+ * DevPrivates Callbacks
+ */
+
+static void
+SELinuxSubjectInit(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    PrivateCallbackRec *rec = calldata;
+    SELinuxSubjectRec *subj = *rec->value;
+
+    sidget(unlabeled_sid);
+    subj->sid = unlabeled_sid;
+
+    avc_entry_ref_init(&subj->aeref);
+}
+
+static void
+SELinuxSubjectFree(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    PrivateCallbackRec *rec = calldata;
+    SELinuxSubjectRec *subj = *rec->value;
+
+    xfree(subj->command);
+
+    if (avc_active) {
+	sidput(subj->sid);
+	sidput(subj->dev_create_sid);
+	sidput(subj->win_create_sid);
+	sidput(subj->sel_create_sid);
+	sidput(subj->prp_create_sid);
+    }
+}
+
+static void
+SELinuxObjectInit(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    PrivateCallbackRec *rec = calldata;
+    SELinuxObjectRec *obj = *rec->value;
+
+    sidget(unlabeled_sid);
+    obj->sid = unlabeled_sid;
+}
+
+static void
+SELinuxObjectFree(CallbackListPtr *pcbl, pointer unused, pointer calldata)
+{
+    PrivateCallbackRec *rec = calldata;
+    SELinuxObjectRec *obj = *rec->value;
+
+    if (avc_active)
+	sidput(obj->sid);
+}
+
+#ifdef HAVE_AVC_NETLINK_ACQUIRE_FD
+static int netlink_fd;
+
+static void
+SELinuxBlockHandler(void *data, struct timeval **tv, void *read_mask)
+{
+}
+
+static void
+SELinuxWakeupHandler(void *data, int err, void *read_mask)
+{
+    if (FD_ISSET(netlink_fd, (fd_set *)read_mask))
+        avc_netlink_check_nb();
+}
+#endif
+
+void
+SELinuxFlaskReset(void)
+{
+    /* Unregister callbacks */
+    DeleteCallback(&ClientStateCallback, SELinuxClientState, NULL);
+    DeleteCallback(&ResourceStateCallback, SELinuxResourceState, NULL);
+
+    XaceDeleteCallback(XACE_EXT_DISPATCH, SELinuxExtension, NULL);
+    XaceDeleteCallback(XACE_RESOURCE_ACCESS, SELinuxResource, NULL);
+    XaceDeleteCallback(XACE_DEVICE_ACCESS, SELinuxDevice, NULL);
+    XaceDeleteCallback(XACE_PROPERTY_ACCESS, SELinuxProperty, NULL);
+    XaceDeleteCallback(XACE_SEND_ACCESS, SELinuxSend, NULL);
+    XaceDeleteCallback(XACE_RECEIVE_ACCESS, SELinuxReceive, NULL);
+    XaceDeleteCallback(XACE_CLIENT_ACCESS, SELinuxClient, NULL);
+    XaceDeleteCallback(XACE_EXT_ACCESS, SELinuxExtension, NULL);
+    XaceDeleteCallback(XACE_SERVER_ACCESS, SELinuxServer, NULL);
+    XaceDeleteCallback(XACE_SELECTION_ACCESS, SELinuxSelection, NULL);
+    XaceDeleteCallback(XACE_SCREEN_ACCESS, SELinuxScreen, NULL);
+    XaceDeleteCallback(XACE_SCREENSAVER_ACCESS, SELinuxScreen, truep);
+
+    /* Tear down SELinux stuff */
+    audit_close(audit_fd);
+#ifdef HAVE_AVC_NETLINK_ACQUIRE_FD
+    avc_netlink_release_fd();
+    RemoveBlockAndWakeupHandlers(SELinuxBlockHandler, SELinuxWakeupHandler,
+                                 NULL);
+    RemoveGeneralSocket(netlink_fd);
+#endif
+
+    avc_destroy();
+    avc_active = 0;
+}
+
+void
+SELinuxFlaskInit(void)
+{
+    struct selinux_opt avc_option = { AVC_OPT_SETENFORCE, (char *)0 };
+    security_context_t ctx;
+    int ret = TRUE;
+
+    switch(selinuxEnforcingState) {
+    case SELINUX_MODE_ENFORCING:
+	LogMessage(X_INFO, "SELinux: Configured in enforcing mode\n");
+	avc_option.value = (char *)1;
+	break;
+    case SELINUX_MODE_PERMISSIVE:
+	LogMessage(X_INFO, "SELinux: Configured in permissive mode\n");
+	avc_option.value = (char *)0;
+	break;
+    default:
+	avc_option.type = AVC_OPT_UNUSED;
+	break;
+    }
+
+    /* Set up SELinux stuff */
+    selinux_set_callback(SELINUX_CB_LOG, (union selinux_callback)SELinuxLog);
+    selinux_set_callback(SELINUX_CB_AUDIT, (union selinux_callback)SELinuxAudit);
+
+    if (selinux_set_mapping(map) < 0) {
+	if (errno == EINVAL) {
+	    ErrorF("SELinux: Invalid object class mapping, disabling SELinux support.\n");
+	    return;
+	}
+	FatalError("SELinux: Failed to set up security class mapping\n");
+    }
+
+    if (avc_open(&avc_option, 1) < 0)
+	FatalError("SELinux: Couldn't initialize SELinux userspace AVC\n");
+    avc_active = 1;
+
+    if (security_get_initial_context_raw("unlabeled", &ctx) < 0)
+	FatalError("SELinux: Failed to look up unlabeled context\n");
+    if (avc_context_to_sid_raw(ctx, &unlabeled_sid) < 0)
+	FatalError("SELinux: a context_to_SID call failed!\n");
+    freecon(ctx);
+
+    /* Prepare for auditing */
+    audit_fd = audit_open();
+    if (audit_fd < 0)
+	FatalError("SELinux: Failed to open the system audit log\n");
+
+    /* Allocate private storage */
+    if (!dixRequestPrivate(subjectKey, sizeof(SELinuxSubjectRec)) ||
+	!dixRequestPrivate(objectKey, sizeof(SELinuxObjectRec)) ||
+	!dixRequestPrivate(dataKey, sizeof(SELinuxObjectRec)))
+	FatalError("SELinux: Failed to allocate private storage.\n");
+
+    /* Create atoms for doing window labeling */
+    atom_ctx = MakeAtom("_SELINUX_CONTEXT", 16, TRUE);
+    if (atom_ctx == BAD_RESOURCE)
+	FatalError("SELinux: Failed to create atom\n");
+    atom_client_ctx = MakeAtom("_SELINUX_CLIENT_CONTEXT", 23, TRUE);
+    if (atom_client_ctx == BAD_RESOURCE)
+	FatalError("SELinux: Failed to create atom\n");
+
+#ifdef HAVE_AVC_NETLINK_ACQUIRE_FD
+    netlink_fd = avc_netlink_acquire_fd();
+    AddGeneralSocket(netlink_fd);
+    RegisterBlockAndWakeupHandlers(SELinuxBlockHandler, SELinuxWakeupHandler,
+                                   NULL);
+#endif
+
+    /* Register callbacks */
+    ret &= dixRegisterPrivateInitFunc(subjectKey, SELinuxSubjectInit, NULL);
+    ret &= dixRegisterPrivateDeleteFunc(subjectKey, SELinuxSubjectFree, NULL);
+    ret &= dixRegisterPrivateInitFunc(objectKey, SELinuxObjectInit, NULL);
+    ret &= dixRegisterPrivateDeleteFunc(objectKey, SELinuxObjectFree, NULL);
+    ret &= dixRegisterPrivateInitFunc(dataKey, SELinuxObjectInit, NULL);
+    ret &= dixRegisterPrivateDeleteFunc(dataKey, SELinuxObjectFree, NULL);
+
+    ret &= AddCallback(&ClientStateCallback, SELinuxClientState, NULL);
+    ret &= AddCallback(&ResourceStateCallback, SELinuxResourceState, NULL);
+
+    ret &= XaceRegisterCallback(XACE_EXT_DISPATCH, SELinuxExtension, NULL);
+    ret &= XaceRegisterCallback(XACE_RESOURCE_ACCESS, SELinuxResource, NULL);
+    ret &= XaceRegisterCallback(XACE_DEVICE_ACCESS, SELinuxDevice, NULL);
+    ret &= XaceRegisterCallback(XACE_PROPERTY_ACCESS, SELinuxProperty, NULL);
+    ret &= XaceRegisterCallback(XACE_SEND_ACCESS, SELinuxSend, NULL);
+    ret &= XaceRegisterCallback(XACE_RECEIVE_ACCESS, SELinuxReceive, NULL);
+    ret &= XaceRegisterCallback(XACE_CLIENT_ACCESS, SELinuxClient, NULL);
+    ret &= XaceRegisterCallback(XACE_EXT_ACCESS, SELinuxExtension, NULL);
+    ret &= XaceRegisterCallback(XACE_SERVER_ACCESS, SELinuxServer, NULL);
+    ret &= XaceRegisterCallback(XACE_SELECTION_ACCESS, SELinuxSelection, NULL);
+    ret &= XaceRegisterCallback(XACE_SCREEN_ACCESS, SELinuxScreen, NULL);
+    ret &= XaceRegisterCallback(XACE_SCREENSAVER_ACCESS, SELinuxScreen, truep);
+    if (!ret)
+	FatalError("SELinux: Failed to register one or more callbacks\n");
+
+    /* Label objects that were created before we could register ourself */
+    SELinuxLabelInitial();
+}