[PATCH v4 2/6] drm/amdgpu/aca: Add upper bounds check in aca_bank_hwip_is_matched

[Sreeraj S Kurup <sreekuttan2156239@gmail.com>]

In aca_bank_hwip_is_matched(), the 'type' parameter is used directly
as an array index into aca_hwid_mcatypes[]. The function previously
checked whether 'type' was equal to ACA_HWIP_TYPE_UNKNOW, but did not
validate whether 'type' was less than ACA_HWIP_TYPE_COUNT or negative.

If an invalid or out-of-bounds enum value is passed, an out-of-bounds
memory read occurs on the aca_hwid_mcatypes array.

Fix this by validating that 'type' is strictly greater than
ACA_HWIP_TYPE_UNKNOW and less than ACA_HWIP_TYPE_COUNT before
performing the array lookup.

Signed-off-by: Sreeraj S Kurup <sreekuttan2156239@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c
index d0d473082431..c76664af9902 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_aca.c
@@ -138,7 +138,7 @@ static bool aca_bank_hwip_is_matched(struct aca_bank *bank, enum aca_hwip_type t
 	int hwid, mcatype;
 	u64 ipid;
 
-	if (!bank || type == ACA_HWIP_TYPE_UNKNOW)
+	if (!bank || type <= ACA_HWIP_TYPE_UNKNOW || type >= ACA_HWIP_TYPE_COUNT)
 		return false;
 
 	hwip = &aca_hwid_mcatypes[type];
-- 
2.54.0