| Message ID | 20241016095458.34126-1-zhengzengkai@huawei.com |
|---|---|
| State | Accepted |
| Commit | 263e22d6bd1f8a12dc2e770cf190f8dfb31f867e |
| Headers | show |
| Series | [v4] ACPI: GTDT: Tighten the check for the array of platform timer structures | expand |
On 2024/10/16 17:54, Zheng Zengkai wrote: > 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> Nit: since there is a "Co-developed-by:" for Marc, the "Signed-off-by:" can be removed. The rest of the patch looks good to me. I did a test again Kunpeng ARM sever and no regressions, hopefully will not trigger firmware bugs for other platforms. Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Tested-by: Hanjun Guo <guohanjun@huawei.com> Thanks Hanjun
On 2024/10/19 14:41, Hanjun Guo wrote: > On 2024/10/16 17:54, Zheng Zengkai wrote: >> 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> > > Nit: since there is a "Co-developed-by:" for Marc, the > "Signed-off-by:" can be removed. Forget about this comment, the guide from submit patches needs the Signed-off-by:, sorry for the noise. Thanks Hanjun
On Wed, 16 Oct 2024 17:54:58 +0800, Zheng Zengkai wrote: > 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. > > [...] Applied to arm64 (for-next/misc), thanks! [1/1] ACPI: GTDT: Tighten the check for the array of platform timer structures https://git.kernel.org/arm64/c/263e22d6bd1f
diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index c0e77c1c8e09..d7c4e1b9915b 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; \ + 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;