linux-kernel - [PATCH] ACPI: FPDT: break out of the loop if record length is zero

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Date:   Mon, 25 Sep 2023 14:40:21 -0700
From:   Vasily Khoruzhick <anarsoul@...il.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Vasily Khoruzhick <anarsoul@...il.com>, stable@...r.kernel.org
Subject: [PATCH] ACPI: FPDT: break out of the loop if record length is zero

Buggy BIOSes may have zero-length records in FPDT, table, as a result
fpdt_process_subtable() spins in eternal loop.

Break out of the loop if record length is zero.

Fixes: d1eb86e59be0 ("ACPI: tables: introduce support for FPDT table")
Cc: stable@...r.kernel.org

Signed-off-by: Vasily Khoruzhick <anarsoul@...il.com>
---
 drivers/acpi/acpi_fpdt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/acpi/acpi_fpdt.c b/drivers/acpi/acpi_fpdt.c
index a2056c4c8cb7..53d8f9601a55 100644
--- a/drivers/acpi/acpi_fpdt.c
+++ b/drivers/acpi/acpi_fpdt.c
@@ -194,6 +194,11 @@ static int fpdt_process_subtable(u64 address, u32 subtable_type)
 		record_header = (void *)subtable_header + offset;
 		offset += record_header->length;
 
+		if (!record_header->length) {
+			pr_info(FW_BUG "Zero-length record found.\n");
+			break;
+		}
+
 		switch (record_header->type) {
 		case RECORD_S3_RESUME:
 			if (subtable_type != SUBTABLE_S3PT) {
-- 
2.42.0