As suggested by Marc and Lorenzo, first we need to check whether the platform_timer pointer is within gtdt bounds (< gtdt_end) before de-referencing what it points at to detect the (first) platform timer entry length and check that next platform_timer pointer is within gtdt_end too. Now we do that only in next_platform_timer() for subsequent platform timers. So add check against table length (gtdt_end) for the first platform timer entry. Suggested-by: Marc Zyngier <maz@xxxxxxxxxx> Suggested-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx> Signed-off-by: Zheng Zengkai <zhengzengkai@xxxxxxxxxx> --- drivers/acpi/arm64/gtdt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index c0e77c1c8e09..f249af1ed1cd 100644 --- a/drivers/acpi/arm64/gtdt.c +++ b/drivers/acpi/arm64/gtdt.c @@ -177,7 +177,8 @@ 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)) { + if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt) || + platform_timer >= acpi_gtdt_desc.gtdt_end) { pr_err(FW_BUG "invalid timer data.\n"); return -EINVAL; } -- 2.20.1