On Thu, 10 Oct 2024 15:47:03 +0100, Zheng Zengkai <zhengzengkai@xxxxxxxxxx> wrote: > > 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; > } You are only checking the base pointer for the platform_timer array. This doesn't say anything about the *size* of that array (or at least its first element), and whether that actually fits in the table. M. -- Without deviation from the norm, progress is not possible.