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ACPI: GTDT: Tighten the check for the array of platform timer structures

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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: Lorenzo Pieralisi <lpieralisi@kernel.org>
Co-developed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20241016095458.34126-1-zhengzengkai@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Zheng Zengkai 2024-10-16 17:54:58 +08:00 • committed by Catalin Marinas
parent 525fd6a1b3
commit 263e22d6bd
1 changed files with 20 additions and 9 deletions
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29
drivers/acpi/arm64/gtdt.c
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@ -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);
}
return NULL;
static __init void *next_platform_timer(void *platform_timer)
{
struct acpi_gtdt_header *gh = platform_timer;
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;