This is a note to let you know that I've just added the patch titled
firmware: dmi: Stop decoding on broken entry
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
firmware-dmi-stop-decoding-on-broken-entry.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c89e427fe29f6bd58a2a25645b3f34ac8703286e
Author: Jean Delvare <jdelvare@xxxxxxx>
Date: Tue Apr 30 18:29:32 2024 +0200
firmware: dmi: Stop decoding on broken entry
[ Upstream commit 0ef11f604503b1862a21597436283f158114d77e ]
If a DMI table entry is shorter than 4 bytes, it is invalid. Due to
how DMI table parsing works, it is impossible to safely recover from
such an error, so we have to stop decoding the table.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
Link: https://lore.kernel.org/linux-kernel/Zh2K3-HLXOesT_vZ@liuwe-devbox-debian-v2/T/
Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 0dc0c78f1fdb2..311c396bdda7d 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -95,6 +95,17 @@ static void dmi_decode_table(u8 *buf,
(data - buf + sizeof(struct dmi_header)) <= dmi_len) {
const struct dmi_header *dm = (const struct dmi_header *)data;
+ /*
+ * If a short entry is found (less than 4 bytes), not only it
+ * is invalid, but we cannot reliably locate the next entry.
+ */
+ if (dm->length < sizeof(struct dmi_header)) {
+ pr_warn(FW_BUG
+ "Corrupted DMI table, offset %zd (only %d entries processed)\n",
+ data - buf, i);
+ break;
+ }
+
/*
* We want to know the total length (formatted area and
* strings) before decoding to make sure we won't run off the
