Re: [PATCH] proc: use vmalloc for our kernel buffer

Matthew Wilcox
2020-08-13T14:59:49Z

On Thu, Aug 13, 2020 at 10:53:05AM -0400, Josef Bacik wrote:
> +/**
> + * vmemdup_user - duplicate memory region from user space and NUL-terminate

vmemdup_user_nul()

> +void *vmemdup_user_nul(const void __user *src, size_t len)
> +{
> + void *p;
> +
> + p = kvmalloc(len, GFP_USER);

len+1, shirley?

> + if (!p)
> + return ERR_PTR(-ENOMEM);
> +
> + if (copy_from_user(p, src, len)) {
> + kvfree(p);
> + return ERR_PTR(-EFAULT);
> + }

I think you forgot

p[len] = '\0';

> + return p;
> +}
> +EXPORT_SYMBOL(vmemdup_user_nul);
> +
> /**
> * strndup_user - duplicate an existing string from user space
> * @s: The string to duplicate
> --
> 2.24.1
>