[PATCH 4.9 124/240] media: m88rs6000t: avoid potential out-of-bounds reads on arrays

Greg Kroah-Hartman
2021-05-20T11:14:16Z

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 9baa3d64e8e2373ddd11c346439e5dfccb2cbb0d ]

There a 3 array for-loops that don't check the upper bounds of the
index into arrays and this may lead to potential out-of-bounds
reads. Fix this by adding array size upper bounds checks to be
full safe.

Addresses-Coverity: ("Out-of-bounds read")

Link: https://lore.kernel.org/linux-media/20201007121628.20676-1-colin.king@canonical.com
Fixes: 333829110f1d ("[media] m88rs6000t: add new dvb-s/s2 tuner for integrated chip M88RS6000")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/tuners/m88rs6000t.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/tuners/m88rs6000t.c b/drivers/media/tuners/m88rs6000t.c
index 9f3e0fd4cad9..d4443f9c9fa3 100644
--- a/drivers/media/tuners/m88rs6000t.c
+++ b/drivers/media/tuners/m88rs6000t.c
@@ -534,7 +534,7 @@ static int m88rs6000t_get_rf_strength(struct dvb_frontend *fe, u16 *strength)
PGA2_cri = PGA2_GC >> 2;
PGA2_crf = PGA2_GC & 0x03;

- for (i = 0; i <= RF_GC; i++)
+ for (i = 0; i <= RF_GC && i < ARRAY_SIZE(RFGS); i++)
RFG += RFGS[i];

if (RF_GC == 0)
@@ -546,12 +546,12 @@ static int m88rs6000t_get_rf_strength(struct dvb_frontend *fe, u16 *strength)
if (RF_GC == 3)
RFG += 100;

- for (i = 0; i <= IF_GC; i++)
+ for (i = 0; i <= IF_GC && i < ARRAY_SIZE(IFGS); i++)
IFG += IFGS[i];

TIAG = TIA_GC * TIA_GS;

- for (i = 0; i <= BB_GC; i++)
+ for (i = 0; i <= BB_GC && i < ARRAY_SIZE(BBGS); i++)
BBG += BBGS[i];

PGA2G = PGA2_cri * PGA2_cri_GS + PGA2_crf * PGA2_crf_GS;
--
2.30.2