[PATCH 5.10 360/491] media: dvb-frontends: w7090p: fix null-ptr-deref in w7090p_tuner_write_serpar and w7090p_tuner_read_serpar

Greg Kroah-Hartman
2026-04-13T16:58:08Z

From: Alex Guo <alexguo1023@gmail.com>

[ Upstream commit ed0234c8458b3149f15e496b48a1c9874dd24a1b ]

In w7090p_tuner_write_serpar, msg is controlled by user. When msg[0].buf is null and msg[0].len is zero, former checks on msg[0].buf would be passed. If accessing msg[0].buf[2] without sanity check, null pointer deref would happen. We add
check on msg[0].len to prevent crash.

Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")

Signed-off-by: Alex Guo <alexguo1023@gmail.com>
Link: https://lore.kernel.org/r/20250616013353.738790-1-alexguo1023@gmail.com
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/dvb-frontends/dib7000p.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/media/dvb-frontends/dib7000p.c b/drivers/media/dvb-frontends/dib7000p.c
index a4d060fb1babd..18b48a3984291 100644
--- a/drivers/media/dvb-frontends/dib7000p.c
+++ b/drivers/media/dvb-frontends/dib7000p.c
@@ -2198,7 +2198,11 @@ static int w7090p_tuner_write_serpar(struct i2c_adapter *i2c_adap, struct i2c_ms
struct dib7000p_state *state = i2c_get_adapdata(i2c_adap);
u8 n_overflow = 1;
u16 i = 1000;
- u16 serpar_num = msg[0].buf[0];
+ u16 serpar_num;
+
+ if (msg[0].len < 3)
+ return -EOPNOTSUPP;
+ serpar_num = msg[0].buf[0];

while (n_overflow == 1 && i) {
n_overflow = (dib7000p_read_word(state, 1984) >> 1) & 0x1;
@@ -2217,9 +2221,13 @@ static int w7090p_tuner_read_serpar(struct i2c_adapter *i2c_adap, struct i2c_msg
struct dib7000p_state *state = i2c_get_adapdata(i2c_adap);
u8 n_overflow = 1, n_empty = 1;
u16 i = 1000;
- u16 serpar_num = msg[0].buf[0];
+ u16 serpar_num;
u16 read_word;

+ if (msg[0].len < 1 || msg[1].len < 2)
+ return -EOPNOTSUPP;
+ serpar_num = msg[0].buf[0];
+
while (n_overflow == 1 && i) {
n_overflow = (dib7000p_read_word(state, 1984) >> 1) & 0x1;
i--;
--
2.53.0