Commit 263e22d6 authored by Zheng Zengkai's avatar Zheng Zengkai Committed by Catalin Marinas
Browse files

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 also valid, i.e. the length is not zero and within gtdt_end.
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 and the existing check in function
acpi_gtdt_init() is also not enough.

Modify the for_each_platform_timer() iterator and use it combined with
a dedicated check function platform_timer_valid() to do the check
against table length (gtdt_end) for each element of platform timer
array in function acpi_gtdt_init(), making sure that both their entry
and length actually fit in the table.

Suggested-by: default avatarLorenzo Pieralisi <lpieralisi@kernel.org>
Co-developed-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: default avatarLorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
Tested-by: default avatarHanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20241016095458.34126-1-zhengzengkai@huawei.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 525fd6a1

drivers/acpi/arm64/gtdt.c

+20 −9
Original line number Diff line number Diff line
@@ -36,19 +36,25 @@ struct acpi_gtdt_descriptor { 


static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;



static inline __init void *next_platform_timer(void *platform_timer)

static __init bool platform_timer_valid(void *platform_timer)

{

	struct acpi_gtdt_header *gh = platform_timer;



	platform_timer += gh->length;

	if (platform_timer < acpi_gtdt_desc.gtdt_end)

		return platform_timer;

	return (platform_timer >= (void *)(acpi_gtdt_desc.gtdt + 1) &&

		platform_timer < acpi_gtdt_desc.gtdt_end &&

		gh->length != 0 &&

		platform_timer + gh->length <= acpi_gtdt_desc.gtdt_end);

}



static __init void *next_platform_timer(void *platform_timer)

{

	struct acpi_gtdt_header *gh = platform_timer;



	return NULL;

	return platform_timer + gh->length;

}



#define for_each_platform_timer(_g)				\

	for (_g = acpi_gtdt_desc.platform_timer; _g;	\

	for (_g = acpi_gtdt_desc.platform_timer; platform_timer_valid(_g);\

	     _g = next_platform_timer(_g))



static inline bool is_timer_block(void *platform_timer)
@@ -157,6 +163,7 @@ int __init acpi_gtdt_init(struct acpi_table_header *table, 
{

	void *platform_timer;

	struct acpi_table_gtdt *gtdt;

	int cnt = 0;



	gtdt = container_of(table, struct acpi_table_gtdt, header);

	acpi_gtdt_desc.gtdt = gtdt;
@@ -176,12 +183,16 @@ int __init acpi_gtdt_init(struct acpi_table_header *table, 
		return 0;

	}



	platform_timer = (void *)gtdt + gtdt->platform_timer_offset;

	if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {

	acpi_gtdt_desc.platform_timer = (void *)gtdt + gtdt->platform_timer_offset;

	for_each_platform_timer(platform_timer)

		cnt++;



	if (cnt != gtdt->platform_timer_count) {

		acpi_gtdt_desc.platform_timer = NULL;

		pr_err(FW_BUG "invalid timer data.\n");

		return -EINVAL;

	}

	acpi_gtdt_desc.platform_timer = platform_timer;



	if (platform_timer_count)

		*platform_timer_count = gtdt->platform_timer_count;