[PATCH 2/2] platform/x86: ISST: Validate level in perf mask ioctls

[HyeongJun An <sammiee5311@gmail.com>]

isst_if_get_perf_level_mask() and isst_if_get_base_freq_mask() use the
user-provided level as an index into perf_levels[] via
_read_pp_level_info() and _read_bf_level_info(), but neither helper
validates it first.

The adjacent level-info helpers reject levels above max_level before
reading the same per-level register block. Add the same bounds checks to
the mask helpers, and reject disabled SST-PP levels in
isst_if_get_perf_level_mask() to match isst_if_get_perf_level_info().

This prevents out-of-bounds reads from the per-level offset table on
invalid ioctl input.

Fixes: ea009e4769fa3 ("platform/x86: ISST: Add SST-PP support via TPMI")
Fixes: 06a61df83209 ("platform/x86: ISST: Add SST-BF support via TPMI")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-5
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
---
 .../platform/x86/intel/speed_select_if/isst_tpmi_core.c  | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
index b2965baeaa36..f1b6109521c5 100644
--- a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
+++ b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
@@ -1263,6 +1263,12 @@ static int isst_if_get_perf_level_mask(void __user *argp)
 	if (!power_domain_info)
 		return -EINVAL;
 
+	if (cpumask.level > power_domain_info->max_level)
+		return -EINVAL;
+
+	if (!(power_domain_info->pp_header.level_en_mask & BIT(cpumask.level)))
+		return -EINVAL;
+
 	_read_pp_level_info("mask", mask, cpumask.level, SST_PP_INFO_2_OFFSET,
 			    SST_PP_RSLVD_CORE_MASK_START, SST_PP_RSLVD_CORE_MASK_WIDTH,
 			    SST_MUL_FACTOR_NONE)
@@ -1344,6 +1350,9 @@ static int isst_if_get_base_freq_mask(void __user *argp)
 	if (!power_domain_info)
 		return -EINVAL;
 
+	if (cpumask.level > power_domain_info->max_level)
+		return -EINVAL;
+
 	_read_bf_level_info("BF-cpumask", mask, cpumask.level, SST_BF_INFO_1_OFFSET,
 			    P1_HI_CORE_MASK_START, P1_HI_CORE_MASK_WIDTH,
 			    SST_MUL_FACTOR_NONE)
-- 
2.43.0