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 <jdelv...@suse.de>
Fixes: 6deae96b42eb ("firmware, DMI: Add function to look up a handle and
return DIMM size")
Cc: Tony Luck <tony.l...@intel.com>
Cc: Borislav Petkov <b...@suse.de>
---
drivers/firmware/dmi_scan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-5.3.orig/drivers/firmware/dmi_scan.c 2019-10-04 16:14:24.575714482
+0200
+++ linux-5.3/drivers/firmware/dmi_scan.c 2019-10-04 16:18:18.878669652
+0200
@@ -408,7 +408,7 @@ static void __init save_mem_devices(cons
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;
--
Jean Delvare
SUSE L3 Support
