Messages in this thread Patch in this message | | | Date | Fri, 26 May 2023 14:00:50 -0700 | From | Kees Cook <> | Subject | Re: [PATCH][next] iavf: Replace one-element array with flexible-array member |
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On Tue, May 23, 2023 at 11:19:00AM -0700, Tony Nguyen wrote: > On 5/15/2023 5:44 PM, Gustavo A. R. Silva wrote: > > One-element arrays are deprecated, and we are replacing them with flexible > > array members instead. So, replace one-element array with flexible-array > > member in struct iavf_qvlist_info, and refactor the rest of the code, > > accordingly. > > > > This helps with the ongoing efforts to tighten the FORTIFY_SOURCE > > routines on memcpy() and help us make progress towards globally > > enabling -fstrict-flex-arrays=3 [1]. > > > > Link: https://github.com/KSPP/linux/issues/79 > > Link: https://github.com/KSPP/linux/issues/289 > > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > > --- > > drivers/net/ethernet/intel/iavf/iavf_client.c | 2 +- > > drivers/net/ethernet/intel/iavf/iavf_client.h | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/iavf/iavf_client.c b/drivers/net/ethernet/intel/iavf/iavf_client.c > > index 93c903c02c64..782384b3aa38 100644 > > --- a/drivers/net/ethernet/intel/iavf/iavf_client.c > > +++ b/drivers/net/ethernet/intel/iavf/iavf_client.c > > @@ -470,7 +470,7 @@ static int iavf_client_setup_qvlist(struct iavf_info *ldev, > > v_qvlist_info = (struct virtchnl_rdma_qvlist_info *)qvlist_info; > > msg_size = struct_size(v_qvlist_info, qv_info, > > - v_qvlist_info->num_vectors - 1); > > + v_qvlist_info->num_vectors); > > The problem is this mirrors the virtchnl struct (virtchnl_rdma_qvlist_info) > so that structure needs to change as well... However, this goes back to the > interface that virtchnl provides between PF and VF [1]. > > I think removing the iavf structure and directly using the virtchnl one > would make sense. We'd need to adjust virtchnl and follow Kees' suggestion > [2].
Note that at the time I suggested "[0]", but it should have been "[]". But, yes, Keeping the "over allocation" is fine since it's a hardware ABI.
Alternatively, it could be defined with a union to keep all the sizes the same:
struct iavf_qvlist_info { u32 num_vectors; - struct iavf_qv_info qv_info[1]; + union { + struct iavf_qv_info single_qv_info; + DECLARE_FLEX_ARRAY(struct iavf_qv_info, qv_info) + }; };
-Kees
> > > adapter->client_pending |= BIT(VIRTCHNL_OP_CONFIG_RDMA_IRQ_MAP); > > err = iavf_aq_send_msg_to_pf(&adapter->hw, > > diff --git a/drivers/net/ethernet/intel/iavf/iavf_client.h b/drivers/net/ethernet/intel/iavf/iavf_client.h > > index c5d51d7dc7cc..500269bc0f5b 100644 > > --- a/drivers/net/ethernet/intel/iavf/iavf_client.h > > +++ b/drivers/net/ethernet/intel/iavf/iavf_client.h > > @@ -53,7 +53,7 @@ struct iavf_qv_info { > > struct iavf_qvlist_info { > > u32 num_vectors; > > - struct iavf_qv_info qv_info[1]; > > + struct iavf_qv_info qv_info[]; > > }; > > #define IAVF_CLIENT_MSIX_ALL 0xFFFFFFFF > > [1] https://lore.kernel.org/intel-wired-lan/f3674339c0390ced22b365101f2d3e3a2bf26845.camel@intel.com/ > [2] https://lore.kernel.org/intel-wired-lan/202106091424.37E833794@keescook/
-- Kees Cook
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