Re: [PATH 0/2] strndup_user, description

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Maw, 2006-02-14 at 21:47 -0300, Davi Arnaut wrote:
> This patch series creates a strndup_user() function in order to avoid duplicated
> and error-prone (userspace modifying the string after the strlen_user()) code.

Well userspace can still modify in this case. So you could still get a
\0 mid buffer but that seems harmless.

However

> +#define strdup_user(s)	strndup_user(s, PAGE_SIZE)

Better this doesn't exist as it is a wrapper for a bad habit that isnt
yet used so why encourage it.



> +	length = strlen_user(s);

What if n is very large ? Should use strnlen_user clipped by n

Also say the length limit is 8 and the text is "hello\0"

We get length = 5  5 < 8, alloc 5 bytes set 5th to \0 and return "hell
\0"



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