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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: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
This commit is contained in:
Andy Lutomirski 2016-02-15 08:32:35 -08:00 committed by Darren Hart
parent a570af4850
commit b13de7019c
1 changed files with 13 additions and 2 deletions
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15
drivers/platform/x86/dell-wmi.c
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@ -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) {