[PATCH] media: si2165: fix a missing check of return value

[PATCH] media: si2165: fix a missing check of return value

[Kangjie Lu]

si2165_readreg8() may fail. Looking into si2165_readreg8(), we will find
that "val_tmp" will be an uninitialized value when regmap_read() fails.
"val_tmp" is then assigned to "val". So if si2165_readreg8() fails,
"val" will be a random value. Further use will lead to undefined
behaviors. The fix checks if si2165_readreg8() fails, and if so, returns
"-EINVAL".

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/media/dvb-frontends/si2165.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c
index feacd8da421d..c134f312fa5b 100644
--- a/drivers/media/dvb-frontends/si2165.c
+++ b/drivers/media/dvb-frontends/si2165.c
@@ -275,18 +275,20 @@ static u32 si2165_get_fe_clk(struct si2165_state *state)
 
 static int si2165_wait_init_done(struct si2165_state *state)
 {
-	int ret = -EINVAL;
+	int ret;
 	u8 val = 0;
 	int i;
 
 	for (i = 0; i < 3; ++i) {
-		si2165_readreg8(state, REG_INIT_DONE, &val);
+		ret = si2165_readreg8(state, REG_INIT_DONE, &val);
+		if (ret < 0)
+			return -EINVAL;
 		if (val == 0x01)
 			return 0;
 		usleep_range(1000, 50000);
 	}
 	dev_err(&state->client->dev, "init_done was not set\n");
-	return ret;
+	return -EINVAL;
 }
 
 static int si2165_upload_firmware_block(struct si2165_state *state,
-- 
2.17.2 (Apple Git-113)

Re: [PATCH] media: si2165: fix a missing check of return value

[Matthias Schwarzott]

Am 20.12.18 um 09:12 schrieb Kangjie Lu:
> si2165_readreg8() may fail. Looking into si2165_readreg8(), we will find
> that "val_tmp" will be an uninitialized value when regmap_read() fails.
> "val_tmp" is then assigned to "val". So if si2165_readreg8() fails,
> "val" will be a random value. Further use will lead to undefined
> behaviors. The fix checks if si2165_readreg8() fails, and if so, returns
> "-EINVAL".
> 
Good catch. I reviewed it.
See below.

> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/media/dvb-frontends/si2165.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c
> index feacd8da421d..c134f312fa5b 100644
> --- a/drivers/media/dvb-frontends/si2165.c
> +++ b/drivers/media/dvb-frontends/si2165.c
> @@ -275,18 +275,20 @@ static u32 si2165_get_fe_clk(struct si2165_state *state)
>  
>  static int si2165_wait_init_done(struct si2165_state *state)
>  {
> -	int ret = -EINVAL;
> +	int ret;
>  	u8 val = 0;
>  	int i;
>  
>  	for (i = 0; i < 3; ++i) {
> -		si2165_readreg8(state, REG_INIT_DONE, &val);
> +		ret = si2165_readreg8(state, REG_INIT_DONE, &val);
> +		if (ret < 0)
> +			return -EINVAL;
This code should return "ret" instead of "-EINVAL".

>  		if (val == 0x01)
>  			return 0;
>  		usleep_range(1000, 50000);
>  	}
>  	dev_err(&state->client->dev, "init_done was not set\n");
> -	return ret;
> +	return -EINVAL;

Here I am not sure if -ETIMEDOUT would be a better return code.

>  }
>  
>  static int si2165_upload_firmware_block(struct si2165_state *state,
>