[media.git/next] media: dvb-frontends: w7090p: fix null-ptr-deref in w7090p_tuner_write_serpar and w7090p_tuner_read_serpar

[media-ci]

On Sun Jun 15 21:33:53 2025 -0400, Alex Guo wrote:
> 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 <alexguo1...@gmail.com>
> Link: https://lore.kernel.org/r/20250616013353.738790-1-alexguo1...@gmail.com
> Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>

Patch committed.

Thanks,
Mauro Carvalho Chehab

 drivers/media/dvb-frontends/dib7000p.c | 4 ++++
 1 file changed, 4 insertions(+)

---

diff --git a/drivers/media/dvb-frontends/dib7000p.c 
b/drivers/media/dvb-frontends/dib7000p.c
index b40daf242046..2c2354dd547d 100644
--- 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;