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Date:   Wed, 19 Jan 2022 16:24:29 -0800
From:   Bjorn Andersson <bjorn.andersson@linaro.org>
To:     Alistair Delva <adelva@google.com>
Cc:     linux-kernel@vger.kernel.org,
        Rishabh Bhatnagar <rishabhb@codeaurora.org>,
        stable@vger.kernel.org, Ohad Ben-Cohen <ohad@wizery.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Sibi Sankar <sibis@codeaurora.org>,
        linux-remoteproc@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH] remoteproc: Fix count check in rproc_coredump_write()
Message-ID: <YeirvbTh5Cztcgxh@ripper>
References: <20220119232139.1125908-1-adelva@google.com>
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On Wed 19 Jan 15:21 PST 2022, Alistair Delva wrote:

> Check count for 0, to avoid a potential underflow. Make the check the
> same as the one in rproc_recovery_write().
> 
> Fixes: 3afdc59e4390 ("remoteproc: Add coredump debugfs entry")
> Signed-off-by: Alistair Delva <adelva@google.com>
> Cc: Rishabh Bhatnagar <rishabhb@codeaurora.org>
> Cc: stable@vger.kernel.org
> Cc: Ohad Ben-Cohen <ohad@wizery.com>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Sibi Sankar <sibis@codeaurora.org>
> Cc: linux-remoteproc@vger.kernel.org
> Cc: kernel-team@android.com

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/remoteproc/remoteproc_debugfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
> index b5a1e3b697d9..581930483ef8 100644
> --- a/drivers/remoteproc/remoteproc_debugfs.c
> +++ b/drivers/remoteproc/remoteproc_debugfs.c
> @@ -76,7 +76,7 @@ static ssize_t rproc_coredump_write(struct file *filp,
>  	int ret, err = 0;
>  	char buf[20];
>  
> -	if (count > sizeof(buf))
> +	if (count < 1 || count > sizeof(buf))
>  		return -EINVAL;
>  
>  	ret = copy_from_user(buf, user_buf, count);
> -- 
> 2.30.2
>