linux-kernel - Re: [PATCH] iio: scd4x: check return of scd4x_write_and

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <b13706f7-4a9e-ba3d-2828-8570c409096c@redhat.com>
Date:   Mon, 28 Feb 2022 13:06:32 -0800
From:   Tom Rix <trix@...hat.com>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     roan@...tonic.nl, lars@...afoo.de, nathan@...nel.org,
        ndesaulniers@...gle.com, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev
Subject: Re: [PATCH] iio: scd4x: check return of scd4x_write_and_fetch


On 2/27/22 9:48 AM, Jonathan Cameron wrote:
> On Sun, 27 Feb 2022 07:43:31 -0800
> trix@...hat.com wrote:
>
>> From: Tom Rix <trix@...hat.com>
>>
>> Clang static analysis reports this problem
>> scd4x.c:474:10: warning: The left operand of '==' is a
>>    garbage value
>>    if (val == 0xff) {
>>        ~~~ ^
>> val is only set from a successful call to scd4x_write_and_fetch()
>> So check it's return.
>>
>> Fixes: 49d22b695cbb ("drivers: iio: chemical: Add support for Sensirion SCD4x CO2 sensor")
>> Signed-off-by: Tom Rix <trix@...hat.com>
> Good find, but I'd prefer a separate check on ret inline with what the
> other error checking paths in that function are doing.
>
>> ---
>>   drivers/iio/chemical/scd4x.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/chemical/scd4x.c b/drivers/iio/chemical/scd4x.c
>> index 20d4e7584e923..b978330fb761c 100644
>> --- a/drivers/iio/chemical/scd4x.c
>> +++ b/drivers/iio/chemical/scd4x.c
>> @@ -471,7 +471,7 @@ static ssize_t calibration_forced_value_store(struct device *dev,
>>   	ret = scd4x_write_and_fetch(state, CMD_FRC, arg, &val, sizeof(val));
>>   	mutex_unlock(&state->lock);
>>   
>> -	if (val == 0xff) {
>> +	if (!ret && val == 0xff) {
>>   		dev_err(dev, "forced calibration has failed");
>>   		return -EINVAL;
>>   	}
> Prefer
>
> 	if (ret)
> 		return ret;
>
> 	if (val == 0xff) {
> 		dev_err(dev, "...
> 		return -EINVAL;
> 	}

ok and the next line can be simplified to

return len;

Tom

> Thanks,
>
> Jonathan
>