On Tue, 2016-09-20 at 13:45 +0300, Yishai Hadas wrote:
> On 9/16/2016 9:31 PM, Knut Omang wrote:
> >
> > The ib_uverbs_reg_mr_resp structure was not 64 bit end aligned
> > as required by the protocol. This causes alignment issues
> > if a device specific driver needs to transfer extra response
> > arguments.
> >
> > Avoid breaking backward compatibility by improving the handling
> > of the length checking in ib_uverbs_reg_mr to consider the case
> > where the kernel has been updated, but user space still has
> > the old length without padding.
> >
> > Signed-off-by: Knut Omang <knut.om...@oracle.com>
> > ---
> > drivers/infiniband/core/uverbs_cmd.c | 10 ++++++----
> > include/uapi/rdma/ib_user_verbs.h | 1 +
> > 2 files changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/infiniband/core/uverbs_cmd.c
> > b/drivers/infiniband/core/uverbs_cmd.c
> > index dbc5885..fa8a717 100644
> > --- a/drivers/infiniband/core/uverbs_cmd.c
> > +++ b/drivers/infiniband/core/uverbs_cmd.c
> > @@ -967,16 +967,18 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
> > struct ib_pd *pd;
> > struct ib_mr *mr;
> > int ret;
> > + size_t resp_size = sizeof resp;
> >
> > - if (out_len < sizeof resp)
> > - return -ENOSPC;
> > + if (out_len < resp_size) {
> > + resp_size = out_len;
> > + }
> You don't preserve the minimum response size error checking in your code
> (i.e -ENOSPC). We can expect an error if outlen is less than the
> offset of rkey in ib_uverbs_reg_mr_resp.
I agree, the minimal size needs to be the minimal supported size,
in particular since the memory for cmd may contain arbitrary stack content.
Good catch!
> Please note that below call to copy_to_user will succeed as it copies
> now based on resp_size and won't return the basic mandatory output.
Get it - will fix,
Thanks,
Knut
>
> >
> > if (copy_from_user(&cmd, buf, sizeof cmd))
> > return -EFAULT;
> >
> > INIT_UDATA(&udata, buf + sizeof cmd,
> > (unsigned long) cmd.response + sizeof resp,
> > - in_len - sizeof cmd, out_len - sizeof resp);
> > + in_len - sizeof cmd, out_len - resp_size);
> >
> > if ((cmd.start & ~PAGE_MASK) != (cmd.hca_va & ~PAGE_MASK))
> > return -EINVAL;
> > @@ -1030,7 +1032,7 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
> > resp.mr_handle = uobj->id;
> >
> > if (copy_to_user((void __user *) (unsigned long) cmd.response,
> > - &resp, sizeof resp)) {
> > + &resp, resp_size)) {
> > ret = -EFAULT;
> > goto err_copy;
> > }
> > diff --git a/include/uapi/rdma/ib_user_verbs.h
> > b/include/uapi/rdma/ib_user_verbs.h
> > index 7f035f4..6b8c9c0 100644
> > --- a/include/uapi/rdma/ib_user_verbs.h
> > +++ b/include/uapi/rdma/ib_user_verbs.h
> > @@ -307,6 +307,7 @@ struct ib_uverbs_reg_mr_resp {
> > __u32 mr_handle;
> > __u32 lkey;
> > __u32 rkey;
> > + __u32 reserved;
> > };
> >
> > struct ib_uverbs_rereg_mr {
> >
