From 81dde26de9c08bb04c4962a15608778aaffb3cf9 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Mon, 14 Oct 2019 21:41:24 +0200 Subject: [PATCH] firmware: dmi: Fix unlikely out-of-bounds read in save_mem_devices Before reading the Extended Size field, we should ensure it fits in the DMI record. There is already a record length check but it does not cover that field. It would take a seriously corrupted DMI table to hit that bug, so no need to worry, but we should still fix it. Signed-off-by: Jean Delvare Fixes: 6deae96b42eb ("firmware, DMI: Add function to look up a handle and return DIMM size") Cc: Tony Luck Cc: Borislav Petkov --- drivers/firmware/dmi_scan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c index 35ed56b9c34f..1e21fc3e9851 100644 --- a/drivers/firmware/dmi_scan.c +++ b/drivers/firmware/dmi_scan.c @@ -408,7 +408,7 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v) bytes = ~0ull; else if (size & 0x8000) bytes = (u64)(size & 0x7fff) << 10; - else if (size != 0x7fff) + else if (size != 0x7fff || dm->length < 0x20) bytes = (u64)size << 20; else bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20;