Hi Lorenzo,
在 2024/10/16 0:44, Lorenzo Pieralisi 写道:
On Tue, Oct 15, 2024 at 11:26:02PM +0800, Zheng Zengkai wrote:
As suggested by Marc and Lorenzo, first we need to check whether the
I would just describe the change, the tags and Link: are there to
describe this patch history.
Do you mean that the previous patch below also need to be listed in this
change log history?
https://lore.kernel.org/all/20240930030716.179992-1-zhengzengkai@xxxxxxxxxx/
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@xxxxxxxxxx>
Co-developed-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Zheng Zengkai <zhengzengkai@xxxxxxxxxx>
---
Changes in v3:
- based on Marc's patch and reuse the for_each_platform_timer() loop
Changes in v2:
- Check against gtdt_end for both entry and len of each array element
Link to v2: https://lore.kernel.org/linux-arm-kernel/20241012085343.6594-1-zhengzengkai@xxxxxxxxxx/
Link to v1: https://lore.kernel.org/all/20241010144703.113728-1-zhengzengkai@xxxxxxxxxx/
---
drivers/acpi/arm64/gtdt.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
index c0e77c1c8e09..3583c99afb0d 100644
--- a/drivers/acpi/arm64/gtdt.c
+++ b/drivers/acpi/arm64/gtdt.c
@@ -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; \
+#define for_each_platform_timer(_g, first_entry) \
+ for (_g = first_entry; platform_timer_valid(_g); \
_g = next_platform_timer(_g))
static inline bool is_timer_block(void *platform_timer)
@@ -155,8 +161,9 @@ bool __init acpi_gtdt_c3stop(int type)
int __init acpi_gtdt_init(struct acpi_table_header *table,
int *platform_timer_count)
{
- void *platform_timer;
+ void *platform_timer, *tmp;
It makes more sense - thank you and Marc.
Nit: you don't really need another pointer (ie tmp) but you may keep
it if that makes the code clearer - all you need to do is using
platform_timer as an iterator and initialize
Yes, the tmp pointer can be removed for conciseness.
Thanks!
acpi_gtdt_desc.platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
if all checks passed (you are using tmp just because after the loop
platform_timer can't be used to initialize acpi_gtdt_desc.platform_timer).
Reviewed-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
(now let's see if this survives GTDTs out there :))
struct acpi_table_gtdt *gtdt;
+ int cnt = 0;
gtdt = container_of(table, struct acpi_table_gtdt, header);
acpi_gtdt_desc.gtdt = gtdt;
@@ -177,7 +184,10 @@ 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)) {
+ for_each_platform_timer(tmp, platform_timer)
+ cnt++;
+
+ if (cnt != gtdt->platform_timer_count) {
pr_err(FW_BUG "invalid timer data.\n");
return -EINVAL;
}
@@ -305,7 +315,7 @@ int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,
void *platform_timer;
*timer_count = 0;
- for_each_platform_timer(platform_timer) {
+ for_each_platform_timer(platform_timer, acpi_gtdt_desc.platform_timer) {
if (is_timer_block(platform_timer)) {
ret = gtdt_parse_timer_block(platform_timer, timer_mem);
if (ret)
@@ -398,7 +408,7 @@ static int __init gtdt_sbsa_gwdt_init(void)
if (ret || !timer_count)
goto out_put_gtdt;
- for_each_platform_timer(platform_timer) {
+ for_each_platform_timer(platform_timer, acpi_gtdt_desc.platform_timer) {
if (is_non_secure_watchdog(platform_timer)) {
ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count);
if (ret)
--
2.20.1
.
