media: dvb-frontends: w7090p: fix null-ptr-deref in w7090p_tuner_write_serpar and...

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>

diff --git a/drivers/media/dvb-frontends/dib7000p.c b/drivers/media/dvb-frontends/dib7000p.c
index b40daf2420469b85f9b6995cd4232f7209a507e2..2c2354dd547daa3941f8c9df3cbedc6802f22817 100644 (file)
--- a/drivers/media/dvb-frontends/dib7000p.c
+++ b/drivers/media/dvb-frontends/dib7000p.c
@@ -2193,6 +2193,8 @@ 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;
+       if (msg[0].len < 3)
+               return -EOPNOTSUPP;
        u16 serpar_num = msg[0].buf[0];
 
        while (n_overflow == 1 && i) {
@@ -2212,6 +2214,8 @@ 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;
+       if (msg[0].len < 1 || msg[1].len < 2)
+               return -EOPNOTSUPP;
        u16 serpar_num = msg[0].buf[0];
        u16 read_word;