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Subject: Re: [PATCH] selinuxfs: use scnprinft to get real length in
 sel_read_class
To:     liuyang34 <yangliuxm34@gmail.com>,
        Paul Moore <paul@paul-moore.com>,
        Eric Paris <eparis@parisplace.org>, selinux@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     liuyang34 <liuyang34@xiaomi.com>
References: <cover.1578274288.git.liuyang34@xiaomi.com>
 <ba3290e18f9867e110b77d058c3f8c7015bd868b.1578274288.git.liuyang34@xiaomi.com>
From:   Stephen Smalley <sds@tycho.nsa.gov>
Message-ID: <f6dab965-b248-41e0-4cc2-06e140174f68@tycho.nsa.gov>
Date:   Mon, 6 Jan 2020 15:49:16 -0500
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On 1/5/20 8:56 PM, liuyang34 wrote:
> as the return value of snprintf maybe over the size of TMPBUFLEN,
> use scnprintf to instead of it

Is there a reason you didn't make the same change to sel_read_perm()?

> 
> Signed-off-by: liuyang34 <liuyang34@xiaomi.com>
> ---
>   security/selinux/selinuxfs.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
> index ee94fa4..977c32d 100644
> --- a/security/selinux/selinuxfs.c
> +++ b/security/selinux/selinuxfs.c
> @@ -1672,7 +1672,7 @@ static ssize_t sel_read_class(struct file *file, char __user *buf,
>   {
>   	unsigned long ino = file_inode(file)->i_ino;
>   	char res[TMPBUFLEN];
> -	ssize_t len = snprintf(res, sizeof(res), "%d", sel_ino_to_class(ino));
> +	ssize_t len = scnprintf(res, sizeof(res), "%d", sel_ino_to_class(ino));
>   	return simple_read_from_buffer(buf, count, ppos, res, len);
>   }
>   
>