Introduce DEVICE_INIT, DEVICE_GET, and DEVICE_SHUTDOWN macros. As the

names suggest, they perform methods on Device's.  In addition, they
check that the pointer passed to them is valid; if it isn't, they
pretend that the action failed.  This fixes some crashes due to NULL
dereferences (e.g., PR 26509).

Approved by:	jkh (some time ago)

4 files changed, 16 insertions, 8 deletions

diff --git a/usr.sbin/sade/devices.c b/usr.sbin/sade/devices.c
index 484a3d6..aa98bd0 100644
--- a/usr.sbin/sade/devices.c
+++ b/usr.sbin/sade/devices.c
@@ -236,7 +236,7 @@ deviceReset(void)
     int i;
 
     for (i = 0; i < numDevs; i++) {
-	Devices[i]->shutdown(Devices[i]);
+	DEVICE_SHUTDOWN(Devices[i]);
 
 	/* XXX this potentially leaks Devices[i]->private if it's being
 	 * used to point to something dynamic, but you're not supposed
diff --git a/usr.sbin/sade/dispatch.c b/usr.sbin/sade/dispatch.c
index cd64bf0..6373476 100644
--- a/usr.sbin/sade/dispatch.c
+++ b/usr.sbin/sade/dispatch.c
@@ -406,14 +406,14 @@ dispatch_load_floppy(dialogMenuItem *self)
 	return what;
     }
 
-    if (!mediaDevice->init(mediaDevice)) {
+    if (!DEVICE_INIT(mediaDevice)) {
 	msgConfirm("Unable to mount floppy filesystem.");
 	what |= DITEM_FAILURE;
 	mediaClose();
 	return what;
     }
 
-    fp = mediaDevice->get(mediaDevice, cp, TRUE);
+    fp = DEVICE_GET(mediaDevice, cp, TRUE);
     if (fp) {
 	list = dispatch_load_fp(fp);
 	fclose(fp);
diff --git a/usr.sbin/sade/install.c b/usr.sbin/sade/install.c
index d5820a6..3d8539f 100644
--- a/usr.sbin/sade/install.c
+++ b/usr.sbin/sade/install.c
@@ -269,8 +269,9 @@ installFixitCDROM(dialogMenuItem *self)
     (void)rmdir("/mnt2");
 
     while (1) {
-	msgConfirm("Please insert a FreeBSD live filesystem CD/DVD and press return");
-	if (DITEM_STATUS(mediaSetCDROM(NULL)) != DITEM_SUCCESS || !mediaDevice || !mediaDevice->init(mediaDevice)) {
+	msgConfirm("Please insert a FreeBSD live filesystem CDROM and press return");
+	if (DITEM_STATUS(mediaSetCDROM(NULL)) != DITEM_SUCCESS
+	    || !DEVICE_INIT(mediaDevice)) {
 	    /* If we can't initialize it, it's probably not a FreeBSD CDROM so punt on it */
 	    mediaClose();
 	    if (msgYesNo("Unable to mount the disc - do you want to try again?") != 0)
@@ -357,7 +358,7 @@ installFixitFloppy(dialogMenuItem *self)
     variable_set2(SYSTEM_STATE, "fixit", 0);
 
     while (1) {
-	if (!mediaDevice->init(mediaDevice)) {
+	if (!DEVICE_INIT(mediaDevice)) {
 	    if (msgYesNo("The attempt to mount the fixit floppy failed, bad floppy\n"
 			 "or unclean filesystem.  Do you want to try again?"))
 		return DITEM_FAILURE;
@@ -562,7 +563,7 @@ nodisks:
 	    Device *tmp = tcpDeviceSelect();
 
 	    if (tmp && !((DevInfo *)tmp->private)->use_dhcp && !msgYesNo("Would you like to bring the %s interface up right now?", tmp->name))
-		if (!tmp->init(tmp))
+		if (!DEVICE_INIT(tmp))
 		    msgConfirm("Initialization of %s device failed.", tmp->name);
 	}
 	dialog_clear_norefresh();
@@ -702,7 +703,7 @@ installCommit(dialogMenuItem *self)
 	return i;
 
 try_media:
-    if (!mediaDevice->init(mediaDevice)) {
+    if (!DEVICE_INIT(mediaDevice)) {
 	if (!msgYesNo("Unable to initialize selected media. Would you like to\n"
 		      "adjust your media configuration and try again?")) {
 	    mediaDevice = NULL;
diff --git a/usr.sbin/sade/sade.h b/usr.sbin/sade/sade.h
index b8cf0e1..0f8fd75 100644
--- a/usr.sbin/sade/sade.h
+++ b/usr.sbin/sade/sade.h
@@ -770,5 +770,12 @@ extern int	dump_variables(dialogMenuItem *self);
 /* wizard.c */
 extern void	slice_wizard(Disk *d);
 
+/*
+ * Macros.  Please find a better place for us!
+ */
+#define DEVICE_INIT(d)		((d) != NULL ? (d)->init((d)) : NULL)
+#define DEVICE_GET(d, b, f)	((d) != NULL ? (d)->get((d), (b), (f)) : NULL)
+#define DEVICE_SHUTDOWN(d)	((d) != NULL ? (d)->shutdown((d)) : (void)0)
+
 #endif
 /* _SYSINSTALL_H_INCLUDE */