Commit b13de701 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Darren Hart
Browse files

dell-wmi: Clean up hotkey table size check 



Checking the table for a minimum size of 7 bytes makes no sense: any valid
hotkey table has a size that's a multiple of 4.

Clean this up: replace the hardcoded header length with a sizeof and
change the check to ignore an empty hotkey table.  The only behavior
change is that a 7-byte table (which is nonsensical) will now be
treated as absent instead of as valid but empty.

Reported-by: default avatarJean Delvare <jdelvare@suse.de>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Acked-by: default avatarPali Rohár <pali.rohar@gmail.com>
Signed-off-by: default avatarDarren Hart <dvhart@linux.intel.com>
parent a570af48

drivers/platform/x86/dell-wmi.c

+13 −2
Original line number Diff line number Diff line
@@ -351,13 +351,24 @@ static void __init handle_dmi_entry(const struct dmi_header *dm, 
	if (results->err || results->keymap)

		return;		/* We already found the hotkey table. */



	if (dm->type != 0xb2 || dm->length <= 6)

	if (dm->type != 0xb2)

		return;



	table = container_of(dm, struct dell_bios_hotkey_table, header);



	hotkey_num = (table->header.length - 4) /

	hotkey_num = (table->header.length -

		      sizeof(struct dell_bios_hotkey_table)) /

				sizeof(struct dell_bios_keymap_entry);

	if (hotkey_num < 1) {

		/*

		 * Historically, dell-wmi would ignore a DMI entry of

		 * fewer than 7 bytes.  Sizes between 4 and 8 bytes are

		 * nonsensical (both the header and all entries are 4

		 * bytes), so we approximate the old behavior by

		 * ignoring tables with fewer than one entry.

		 */

		return;

	}



	keymap = kcalloc(hotkey_num + 1, sizeof(struct key_entry), GFP_KERNEL);

	if (!keymap) {