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Message-ID: <20241012085343.6594-1-zhengzengkai@huawei.com>
Date: Sat, 12 Oct 2024 16:53:43 +0800
From: Zheng Zengkai <zhengzengkai@...wei.com>
To: <lpieralisi@...nel.org>, <guohanjun@...wei.com>, <sudeep.holla@....com>,
<mark.rutland@....com>, <maz@...nel.org>, <rafael@...nel.org>,
<lenb@...nel.org>
CC: <daniel.lezcano@...aro.org>, <tglx@...utronix.de>,
<linux-acpi@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <zhengzengkai@...wei.com>
Subject: [PATCH v2] ACPI: GTDT: Tighten the check for the array of platform timer structures
As suggested by Marc and Lorenzo, first we need to check whether the
platform_timer entry pointer is within gtdt bounds (< gtdt_end) before
de-referencing what it points at to detect the length of the platform
timer struct and then check that the length of current platform_timer
struct is within gtdt_end too. Now next_platform_timer() only checks
against gtdt_end for the entry of subsequent platform timer without
checking the length of it and will not report error if the check failed.
Add check against table length (gtdt_end) for each element of platform
timer array in acpi_gtdt_init() early, making sure that both their entry
and length actually fit in the table.
For the first platform timer, keep the check against the end of the
acpi_table_gtdt struct, it is unnecessary for subsequent platform timer.
Suggested-by: Marc Zyngier <maz@...nel.org>
Suggested-by: Lorenzo Pieralisi <lpieralisi@...nel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@...wei.com>
---
Changes in v2:
- Check against gtdt_end for both entry and len of each array element
v1: https://lore.kernel.org/all/20241010144703.113728-1-zhengzengkai@huawei.com/
---
drivers/acpi/arm64/gtdt.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
index c0e77c1c8e09..f5f62643899d 100644
--- a/drivers/acpi/arm64/gtdt.c
+++ b/drivers/acpi/arm64/gtdt.c
@@ -157,6 +157,8 @@ int __init acpi_gtdt_init(struct acpi_table_header *table,
{
void *platform_timer;
struct acpi_table_gtdt *gtdt;
+ struct acpi_gtdt_header *gh;
+ void *struct_end;
gtdt = container_of(table, struct acpi_table_gtdt, header);
acpi_gtdt_desc.gtdt = gtdt;
@@ -177,11 +179,20 @@ int __init acpi_gtdt_init(struct acpi_table_header *table,
}
platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
- if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {
- pr_err(FW_BUG "invalid timer data.\n");
- return -EINVAL;
+ struct_end = (void *)table + sizeof(struct acpi_table_gtdt);
+ for (int i = 0; i < gtdt->platform_timer_count; i++) {
+ gh = platform_timer;
+ if (((i == 0 && platform_timer >= struct_end) || i != 0) &&
+ platform_timer < acpi_gtdt_desc.gtdt_end &&
+ platform_timer + gh->length <= acpi_gtdt_desc.gtdt_end) {
+ platform_timer += gh->length;
+ } else {
+ pr_err(FW_BUG "invalid timer data.\n");
+ return -EINVAL;
+ }
}
- acpi_gtdt_desc.platform_timer = platform_timer;
+
+ acpi_gtdt_desc.platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
if (platform_timer_count)
*platform_timer_count = gtdt->platform_timer_count;
--
2.20.1
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