Re: [PATCH 2/2] SUNRPC: Rename xdr_buf_read_netobj to xdr_buf_read_mic

Chuck Lever
2019-09-13T17:29:13Z

> On Sep 13, 2019, at 1:26 PM, Benjamin Coddington <bcodding@redhat.com> wrote:
>
> On 13 Sep 2019, at 11:16, Chuck Lever wrote:
>
>>> On Sep 12, 2019, at 1:07 PM, Benjamin Coddington <bcodding@redhat.com> wrote:
>>>
>>> Let the name reflect the single user and purpose.
>>
>> And perhaps the assumption that the MIC is always the last item in the xdr_buf?
>> I'm still reviewing 1/2, but this function might make that assumption.
>
> It does.. is that a bad assumption, or maybe you'd like a different name?

Just documenting it is enough for now; there is only one user.

In the long run I'd like to see this kind of xdr_buf manipulation replaced
with the use of a scratch buffer.

>>> Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
>>> ---
>>> include/linux/sunrpc/xdr.h | 2 +-
>>> net/sunrpc/auth_gss/auth_gss.c | 2 +-
>>> net/sunrpc/xdr.c | 42 +++++++++++++++++-----------------
>>> 3 files changed, 23 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
>>> index 9ee3970ba59c..a6b63e47a79b 100644
>>> --- a/include/linux/sunrpc/xdr.h
>>> +++ b/include/linux/sunrpc/xdr.h
>>> @@ -179,7 +179,7 @@ xdr_adjust_iovec(struct kvec *iov, __be32 *p)
>>> extern void xdr_shift_buf(struct xdr_buf *, size_t);
>>> extern void xdr_buf_from_iov(struct kvec *, struct xdr_buf *);
>>> extern int xdr_buf_subsegment(struct xdr_buf *, struct xdr_buf *, unsigned int, unsigned int);
>>> -extern int xdr_buf_read_netobj(struct xdr_buf *, struct xdr_netobj *, unsigned int);
>>> +extern int xdr_buf_read_mic(struct xdr_buf *, struct xdr_netobj *, unsigned int);
>>> extern int read_bytes_from_xdr_buf(struct xdr_buf *, unsigned int, void *, unsigned int);
>>> extern int write_bytes_to_xdr_buf(struct xdr_buf *, unsigned int, void *, unsigned int);
>>>
>>> diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
>>> index 4ce42c62458e..d75fddca44c9 100644
>>> --- a/net/sunrpc/auth_gss/auth_gss.c
>>> +++ b/net/sunrpc/auth_gss/auth_gss.c
>>> @@ -1960,7 +1960,7 @@ gss_unwrap_resp_integ(struct rpc_task *task, struct rpc_cred *cred,
>>>
>>> if (xdr_buf_subsegment(rcv_buf, &integ_buf, data_offset, integ_len))
>>> goto unwrap_failed;
>>> - if (xdr_buf_read_netobj(rcv_buf, &mic, mic_offset))
>>> + if (xdr_buf_read_mic(rcv_buf, &mic, mic_offset))
>>> goto unwrap_failed;
>>> maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &integ_buf, &mic);
>>> if (maj_stat == GSS_S_CONTEXT_EXPIRED)
>>> diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
>>> index 6e05a9693568..90dfde50f0ef 100644
>>> --- a/net/sunrpc/xdr.c
>>> +++ b/net/sunrpc/xdr.c
>>> @@ -1236,52 +1236,52 @@ xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
>>> }
>>> EXPORT_SYMBOL_GPL(xdr_encode_word);
>>>
>>> -/* If the netobj starting offset bytes from the start of xdr_buf is contained
>>> - * entirely in the head, pages, or tail, set object to point to it; otherwise
>>> - * shift the buffer until it is contained entirely within the pages or tail.
>>> +/* If the mic starting offset bytes from the start of xdr_buf is contained
>>> + * entirely in the head, pages, or tail, set mic to point to it; otherwise
>>> + * shift the buf until it is contained entirely within the pages or tail.
>>> */
>>
>> Nit: Could the patch convert this into a kernel Doxygen style comment?
>
> Yes, can do that.
>
> Ben
>
>>> -int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
>>> +int xdr_buf_read_mic(struct xdr_buf *buf, struct xdr_netobj *mic, unsigned int offset)
>>> {
>>> struct xdr_buf subbuf;
>>> unsigned int len_to_boundary;
>>>
>>> - if (xdr_decode_word(buf, offset, &obj->len))
>>> + if (xdr_decode_word(buf, offset, &mic->len))
>>> return -EFAULT;
>>>
>>> offset += 4;
>>>
>>> - /* Is the obj partially in the head? */
>>> + /* Is the mic partially in the head? */
>>> len_to_boundary = buf->head->iov_len - offset;
>>> - if (len_to_boundary > 0 && len_to_boundary < obj->len)
>>> + if (len_to_boundary > 0 && len_to_boundary < mic->len)
>>> xdr_shift_buf(buf, len_to_boundary);
>>>
>>> - /* Is the obj partially in the pages? */
>>> + /* Is the mic partially in the pages? */
>>> len_to_boundary = buf->head->iov_len + buf->page_len - offset;
>>> - if (len_to_boundary > 0 && len_to_boundary < obj->len)
>>> + if (len_to_boundary > 0 && len_to_boundary < mic->len)
>>> xdr_shrink_pagelen(buf, len_to_boundary);
>>>
>>> - if (xdr_buf_subsegment(buf, &subbuf, offset, obj->len))
>>> + if (xdr_buf_subsegment(buf, &subbuf, offset, mic->len))
>>> return -EFAULT;
>>>
>>> - /* Most likely: is the obj contained entirely in the tail? */
>>> - obj->data = subbuf.tail[0].iov_base;
>>> - if (subbuf.tail[0].iov_len == obj->len)
>>> + /* Most likely: is the mic contained entirely in the tail? */
>>> + mic->data = subbuf.tail[0].iov_base;
>>> + if (subbuf.tail[0].iov_len == mic->len)
>>> return 0;
>>>
>>> - /* ..or is the obj contained entirely in the head? */
>>> - obj->data = subbuf.head[0].iov_base;
>>> - if (subbuf.head[0].iov_len == obj->len)
>>> + /* ..or is the mic contained entirely in the head? */
>>> + mic->data = subbuf.head[0].iov_base;
>>> + if (subbuf.head[0].iov_len == mic->len)
>>> return 0;
>>>
>>> - /* obj is in the pages: move to tail */
>>> - if (obj->len > buf->buflen - buf->len)
>>> + /* mic is in the pages: move to tail */
>>> + if (mic->len > buf->buflen - buf->len)
>>> return -ENOMEM;
>>> - obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
>>> - __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
>>> + mic->data = buf->head[0].iov_base + buf->head[0].iov_len;
>>> + __read_bytes_from_xdr_buf(&subbuf, mic->data, mic->len);
>>>
>>> return 0;
>>> }
>>> -EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
>>> +EXPORT_SYMBOL_GPL(xdr_buf_read_mic);
>>>
>>> /* Returns 0 on success, or else a negative error code. */
>>> static int
>>> --
>>> 2.20.1
>>>
>>
>> --
>> Chuck Lever

--
Chuck Lever