[PATCH v2] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()

[PATCH v2] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()

[Dmitry Kandybka]

In pmc_core_ltr_show(), promote 'val' to 'u64' to avoid possible integer
overflow. Values (10 bit) are multiplied by the scale, the result of
expression is in a range from 1 to 34,326,183,936 which is bigger then
UINT32_MAX. Compile tested only.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Dmitry Kandybka <d.kandybka@gmail.com>
---
v1 -> v2: 'val' variable declared as 'u64' instead of type casting
at usage points

 drivers/platform/x86/intel/pmc/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 10f04b944117..1ee0fb5f8250 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -626,8 +626,8 @@ static u32 convert_ltr_scale(u32 val)
 static int pmc_core_ltr_show(struct seq_file *s, void *unused)
 {
 	struct pmc_dev *pmcdev = s->private;
-	u64 decoded_snoop_ltr, decoded_non_snoop_ltr;
-	u32 ltr_raw_data, scale, val;
+	u64 decoded_snoop_ltr, decoded_non_snoop_ltr, val;
+	u32 ltr_raw_data, scale;
 	u16 snoop_ltr, nonsnoop_ltr;
 	unsigned int i, index, ltr_index = 0;
 
-- 
2.47.1

Re: [PATCH v2] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()

[Rajneesh Bhardwaj]

Looks good to me.
Reviewed-by: Rajneesh Bhardwaj <irenic.rajneesh@gmail.com>

On Thu, Jan 23, 2025 at 5:07 PM Dmitry Kandybka <d.kandybka@gmail.com> wrote:
>
> In pmc_core_ltr_show(), promote 'val' to 'u64' to avoid possible integer
> overflow. Values (10 bit) are multiplied by the scale, the result of
> expression is in a range from 1 to 34,326,183,936 which is bigger then
> UINT32_MAX. Compile tested only.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Dmitry Kandybka <d.kandybka@gmail.com>
> ---
> v1 -> v2: 'val' variable declared as 'u64' instead of type casting
> at usage points
>
>  drivers/platform/x86/intel/pmc/core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 10f04b944117..1ee0fb5f8250 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -626,8 +626,8 @@ static u32 convert_ltr_scale(u32 val)
>  static int pmc_core_ltr_show(struct seq_file *s, void *unused)
>  {
>         struct pmc_dev *pmcdev = s->private;
> -       u64 decoded_snoop_ltr, decoded_non_snoop_ltr;
> -       u32 ltr_raw_data, scale, val;
> +       u64 decoded_snoop_ltr, decoded_non_snoop_ltr, val;
> +       u32 ltr_raw_data, scale;
>         u16 snoop_ltr, nonsnoop_ltr;
>         unsigned int i, index, ltr_index = 0;
>
> --
> 2.47.1
>


-- 
Thanks,
Rajneesh

Re: [PATCH v2] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 1402 bytes --]

On Fri, 24 Jan 2025, Dmitry Kandybka wrote:

> In pmc_core_ltr_show(), promote 'val' to 'u64' to avoid possible integer
> overflow. Values (10 bit) are multiplied by the scale, the result of
> expression is in a range from 1 to 34,326,183,936 which is bigger then
> UINT32_MAX. Compile tested only.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Dmitry Kandybka <d.kandybka@gmail.com>
> ---
> v1 -> v2: 'val' variable declared as 'u64' instead of type casting
> at usage points
> 
>  drivers/platform/x86/intel/pmc/core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 10f04b944117..1ee0fb5f8250 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -626,8 +626,8 @@ static u32 convert_ltr_scale(u32 val)
>  static int pmc_core_ltr_show(struct seq_file *s, void *unused)
>  {
>  	struct pmc_dev *pmcdev = s->private;
> -	u64 decoded_snoop_ltr, decoded_non_snoop_ltr;
> -	u32 ltr_raw_data, scale, val;
> +	u64 decoded_snoop_ltr, decoded_non_snoop_ltr, val;
> +	u32 ltr_raw_data, scale;
>  	u16 snoop_ltr, nonsnoop_ltr;
>  	unsigned int i, index, ltr_index = 0;

Thanks for the update,

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

-- 
 i.

Re: [PATCH v2] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()

[Ilpo Järvinen]

On Fri, 24 Jan 2025 01:07:39 +0300, Dmitry Kandybka wrote:

> In pmc_core_ltr_show(), promote 'val' to 'u64' to avoid possible integer
> overflow. Values (10 bit) are multiplied by the scale, the result of
> expression is in a range from 1 to 34,326,183,936 which is bigger then
> UINT32_MAX. Compile tested only.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> [...]


Thank you for your contribution, it has been applied to my local
review-ilpo-fixes branch. Note it will show up in the public
platform-drivers-x86/review-ilpo-fixes branch only once I've pushed my
local branch there, which might take a while.

The list of commits applied:
[1/1] platform/x86/intel: pmc: fix ltr decode in pmc_core_ltr_show()
      commit: 4afd0e58a6793b8e4d78cb55dbcf6279936730e5

--
 i.