[ldv-project] [PATCH] platform/x86: intel_pmc_core: Fix potential buffer overflows

[Evgeny Novikov]

It looks like pmc_core_get_low_power_modes() mixes up modes and
priorities. In addition to invalid behavior, potentially this can
cause buffer overflows since the driver reads priorities from the
register and then it uses them as indexes for array lpm_priority
that can contain 8 elements at most. The patch swaps modes and
priorities.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: 005125bfd70e ("platform/x86: intel_pmc_core: Handle sub-states generically")
Signed-off-by: Evgeny Novikov <novikov at ispras.ru>
---
 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 b0e486a6bdfb..667b3df03764 100644
--- a/drivers/platform/x86/intel_pmc_core.c
+++ b/drivers/platform/x86/intel_pmc_core.c
@@ -1469,8 +1469,8 @@ static void pmc_core_get_low_power_modes(struct pmc_dev *pmcdev)
 		int pri0 = GENMASK(3, 0) & priority;
 		int pri1 = (GENMASK(7, 4) & priority) >> 4;
 
-		lpm_priority[pri0] = mode;
-		lpm_priority[pri1] = mode + 1;
+		lpm_priority[mode] = pri0;
+		lpm_priority[mode + 1] = pri1;
 	}
 
 	/*
-- 
2.26.2