The test which ensures that the DMI type 1 structure is long enough to hold the UUID is off by one. It would fail if the structure is exactly 24 bytes long, while that's sufficient to hold the UUID.
I don't expect this bug to cause problem in practice because all implementations I have seen had length 8, 25 or 27 bytes, in line with the SMBIOS specifications. But let's fix it still. Signed-off-by: Jean Delvare <[email protected]> Fixes: a814c3597a6b ("firmware: dmi_scan: Check DMI structure length") Cc: Mika Westerberg <[email protected]> --- drivers/firmware/dmi_scan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- linux-4.16.orig/drivers/firmware/dmi_scan.c 2018-04-08 09:32:20.508719012 +0200 +++ linux-4.16/drivers/firmware/dmi_scan.c 2018-04-09 11:24:57.937044642 +0200 @@ -186,7 +186,7 @@ static void __init dmi_save_uuid(const s char *s; int is_ff = 1, is_00 = 1, i; - if (dmi_ident[slot] || dm->length <= index + 16) + if (dmi_ident[slot] || dm->length < index + 16) return; d = (u8 *) dm + index; -- Jean Delvare SUSE L3 Support
