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

From: Dmitry Kandybka
Date: Thu Jan 23 2025 - 17:07:53 EST


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@xxxxxxxxx>
---
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