Re: [PATCH v2 1/6] uaccess: Add copy_from_user_nul helper

[Alice Ryhl]

On Mon, Jan 12, 2026 at 03:30:34PM +0800, Fushuai Wang wrote:
> From: Fushuai Wang <wangfushuai@xxxxxxxxx>
> 
> Many places call copy_from_user() to copy a buffer from user space,
> and then manually add a NULL terminator to the destination buffer,
> e.g.:
> 
> 	if (copy_from_user(dest, src, len))
> 		return -EFAULT;
> 	dest[len] = '\0';
> 
> This is repetitive and error-prone. Add a copy_from_user_nul() helper to
> simplify such patterns. It copied n bytes from user space to kernel space,
> and NUL-terminates the destination buffer.
> 
> Signed-off-by: Fushuai Wang <wangfushuai@xxxxxxxxx>

Hmm, this function is very very similar to strncpy_from_user(). Should
they be using that instead?

Alice