On Thu, May 03, 2018 at 04:37:03PM +0300, Leon Romanovsky wrote:
> From: Matan Barak <matanb@xxxxxxxxxxxx>
>
> Adding uverbs_copy_from_and_alloc which allocates and copies enough
> space to copy the user-space attribute. This function could return a
> PTR_ERR. The user is required to free the memory by using kfree().
> The length of the allocated space could be queried by using
> uverbs_attr_get_len.
>
> Signed-off-by: Matan Barak <matanb@xxxxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> include/rdma/uverbs_ioctl.h | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
> index 9aa05bfc89b7..24689f3fe454 100644
> +++ b/include/rdma/uverbs_ioctl.h
> @@ -650,6 +650,38 @@ static inline int _uverbs_copy_from_or_zero(void *to,
> return 0;
> }
>
> +static inline void *uverbs_copy_from_and_alloc(const struct uverbs_attr_bundle *attrs_bundle,
> + size_t idx, gfp_t flags)
> +{
> + int len = uverbs_attr_get_len(attrs_bundle, idx);
> + void *to;
> + int ret;
> +
> + if (len < 0)
> + return ERR_PTR(len);
> +
> + /* It doesn't make any sense to re-allocate and copy if it was already
> + * done by the parser.
> + */
> + ret = uverbs_validate_actual_spec_debug(attrs_bundle, idx, spec,
> + spec->type == UVERBS_ATTR_TYPE_PTR_IN &&
> + spec->flags & ~UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + to = kmalloc(len, flags);
> + if (!to)
> + return ERR_PTR(-ENOMEM);
> +
> + ret = _uverbs_copy_from(to, attrs_bundle, idx, len);
> + if (ret) {
> + kfree(to);
> + return ERR_PTR(ret);
> + }
> +
> + return to;
> +}
This is really too big to be an inline
Can we safely use kmalloc with user arguments? Eg this could be as
large as 64k which is a higher order allocation under user
control.. Should it be kvmalloc/kvfree or something?
Jason
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