[PATCH] selinuxfs: use scnprinft to get real length in sel_read_class

[PATCH] selinuxfs: use scnprinft to get real length in sel_read_class

[liuyang34]

as the return value of snprintf maybe over the size of TMPBUFLEN, 
use scnprintf to instead of it

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);
 }
 
-- 
2.7.4

Re: [PATCH] selinuxfs: use scnprinft to get real length in sel_read_class

[Stephen Smalley]

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);
>   }
>   
> 

Re: [PATCH] selinuxfs: use scnprintf to get real length in sel_read_class

[Markus Elfring]

> as the return value of snprintf maybe over the size of TMPBUFLEN,
> use scnprintf to instead of it

Please improve your commit message.


> Signed-off-by: liuyang34 …

Will this information need also an adjustment for the desired specification
of a real name?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=b07f636fca1c8fbba124b0082487c0b3890a0e0c#n458

Regards,
Markus