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)

1 files changed, 3 insertions, 3 deletions

diff --git a/usr.sbin/sysinstall/index.c b/usr.sbin/sysinstall/index.c
index b6d5c00..c30403a 100644
--- a/usr.sbin/sysinstall/index.c
+++ b/usr.sbin/sysinstall/index.c
@@ -727,21 +727,21 @@ index_initialize(char *path)
 	}
 
 	/* Does it move when you kick it? */
-	if (!mediaDevice->init(mediaDevice)) {
+	if (!DEVICE_INIT(mediaDevice)) {
 	    restorescr(w);
 	    return DITEM_FAILURE;
 	}
 
 	dialog_clear_norefresh();
 	msgNotify("Attempting to fetch %s file from selected media.", path);
-	fp = mediaDevice->get(mediaDevice, path, TRUE);
+	fp = DEVICE_GET(mediaDevice, path, TRUE);
 	if (!fp) {
 	    msgConfirm("Unable to get packages/INDEX file from selected media.\n\n"
 		       "This may be because the packages collection is not available\n"
 		       "on the distribution media you've chosen, most likely an FTP site\n"
 		       "without the packages collection mirrored.  Please verify that\n"
 		       "your media, or your path to the media, is correct and try again.");
-	    mediaDevice->shutdown(mediaDevice);
+	    DEVICE_SHUTDOWN(mediaDevice);
 	    restorescr(w);
 	    return DITEM_FAILURE;
 	}