Re: [PATCH] overflow: Add struct_size_t() helper

Darrick J. Wong
2023-05-23T05:19:42Z

On Mon, May 22, 2023 at 02:18:13PM -0700, Kees Cook wrote:
> While struct_size() is normally used in situations where the structure
> type already has a pointer instance, there are places where no variable
> is available. In the past, this has been worked around by using a typed
> NULL first argument, but this is a bit ugly. Add a helper to do this,
> and replace the handful of instances of the code pattern with it.
>
> Instances were found with this Coccinelle script:
>
> @struct_size_t@
> identifier STRUCT, MEMBER;
> expression COUNT;
> @@
>
> - struct_size((struct STRUCT *)\(0\|NULL\),
> + struct_size_t(struct STRUCT,
> MEMBER, COUNT)
>
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: James Smart <james.smart@broadcom.com>
> Cc: Keith Busch <kbusch@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Sagi Grimberg <sagi@grimberg.me>
> Cc: HighPoint Linux Team <linux@highpoint-tech.com>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: Kashyap Desai <kashyap.desai@broadcom.com>
> Cc: Sumit Saxena <sumit.saxena@broadcom.com>
> Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
> Cc: Don Brace <don.brace@microchip.com>
> Cc: "Darrick J. Wong" <djwong@kernel.org>
> Cc: Dave Chinner <dchinner@redhat.com>
> Cc: Guo Xuenan <guoxuenan@huawei.com>
> Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Daniel Latypov <dlatypov@google.com>
> Cc: kernel test robot <lkp@intel.com>
> Cc: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org
> Cc: linux-nvme@lists.infradead.org
> Cc: linux-scsi@vger.kernel.org
> Cc: megaraidlinux.pdl@broadcom.com
> Cc: storagedev@microchip.com
> Cc: linux-xfs@vger.kernel.org
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Unless there are objections, I'll just take this via my tree...
> ---
> drivers/net/ethernet/intel/ice/ice_ddp.h | 9 ++++-----
> drivers/nvme/host/fc.c | 8 ++++----
> drivers/scsi/hptiop.c | 4 ++--
> drivers/scsi/megaraid/megaraid_sas_base.c | 12 ++++++------
> drivers/scsi/megaraid/megaraid_sas_fp.c | 6 +++---
> drivers/scsi/smartpqi/smartpqi_init.c | 2 +-
> fs/xfs/libxfs/xfs_btree.h | 2 +-
> fs/xfs/scrub/btree.h | 2 +-
> include/linux/overflow.h | 18 +++++++++++++++++-
> lib/overflow_kunit.c | 2 +-
> 10 files changed, 40 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_ddp.h b/drivers/net/ethernet/intel/ice/ice_ddp.h
> index 37eadb3d27a8..41acfe26df1c 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ddp.h
> +++ b/drivers/net/ethernet/intel/ice/ice_ddp.h
> @@ -185,7 +185,7 @@ struct ice_buf_hdr {
>
> #define ICE_MAX_ENTRIES_IN_BUF(hd_sz, ent_sz) \
> ((ICE_PKG_BUF_SIZE - \
> - struct_size((struct ice_buf_hdr *)0, section_entry, 1) - (hd_sz)) / \
> + struct_size_t(struct ice_buf_hdr, section_entry, 1) - (hd_sz)) / \
> (ent_sz))
>
> /* ice package section IDs */
> @@ -297,7 +297,7 @@ struct ice_label_section {
> };
>
> #define ICE_MAX_LABELS_IN_BUF \
> - ICE_MAX_ENTRIES_IN_BUF(struct_size((struct ice_label_section *)0, \
> + ICE_MAX_ENTRIES_IN_BUF(struct_size_t(struct ice_label_section, \
> label, 1) - \
> sizeof(struct ice_label), \
> sizeof(struct ice_label))
> @@ -352,7 +352,7 @@ struct ice_boost_tcam_section {
> };
>
> #define ICE_MAX_BST_TCAMS_IN_BUF \
> - ICE_MAX_ENTRIES_IN_BUF(struct_size((struct ice_boost_tcam_section *)0, \
> + ICE_MAX_ENTRIES_IN_BUF(struct_size_t(struct ice_boost_tcam_section, \
> tcam, 1) - \
> sizeof(struct ice_boost_tcam_entry), \
> sizeof(struct ice_boost_tcam_entry))
> @@ -372,8 +372,7 @@ struct ice_marker_ptype_tcam_section {
> };
>
> #define ICE_MAX_MARKER_PTYPE_TCAMS_IN_BUF \
> - ICE_MAX_ENTRIES_IN_BUF( \
> - struct_size((struct ice_marker_ptype_tcam_section *)0, tcam, \
> + ICE_MAX_ENTRIES_IN_BUF(struct_size_t(struct ice_marker_ptype_tcam_section, tcam, \
> 1) - \
> sizeof(struct ice_marker_ptype_tcam_entry), \
> sizeof(struct ice_marker_ptype_tcam_entry))
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 2ed75923507d..691f2df574ce 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -2917,8 +2917,8 @@ nvme_fc_create_io_queues(struct nvme_fc_ctrl *ctrl)
>
> ret = nvme_alloc_io_tag_set(&ctrl->ctrl, &ctrl->tag_set,
> &nvme_fc_mq_ops, 1,
> - struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
> - ctrl->lport->ops->fcprqst_priv_sz));
> + struct_size_t(struct nvme_fcp_op_w_sgl, priv,
> + ctrl->lport->ops->fcprqst_priv_sz));
> if (ret)
> return ret;
>
> @@ -3536,8 +3536,8 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
>
> ret = nvme_alloc_admin_tag_set(&ctrl->ctrl, &ctrl->admin_tag_set,
> &nvme_fc_admin_mq_ops,
> - struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
> - ctrl->lport->ops->fcprqst_priv_sz));
> + struct_size_t(struct nvme_fcp_op_w_sgl, priv,
> + ctrl->lport->ops->fcprqst_priv_sz));
> if (ret)
> goto fail_ctrl;
>
> diff --git a/drivers/scsi/hptiop.c b/drivers/scsi/hptiop.c
> index 06ccb51bf6a9..f5334ccbf2ca 100644
> --- a/drivers/scsi/hptiop.c
> +++ b/drivers/scsi/hptiop.c
> @@ -1394,8 +1394,8 @@ static int hptiop_probe(struct pci_dev *pcidev, const struct pci_device_id *id)
> host->cmd_per_lun = le32_to_cpu(iop_config.max_requests);
> host->max_cmd_len = 16;
>
> - req_size = struct_size((struct hpt_iop_request_scsi_command *)0,
> - sg_list, hba->max_sg_descriptors);
> + req_size = struct_size_t(struct hpt_iop_request_scsi_command,
> + sg_list, hba->max_sg_descriptors);
> if ((req_size & 0x1f) != 0)
> req_size = (req_size + 0x1f) & ~0x1f;
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
> index 317c944c68e3..050eed8e2684 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -5153,8 +5153,8 @@ static void megasas_update_ext_vd_details(struct megasas_instance *instance)
> fusion->max_map_sz = ventura_map_sz;
> } else {
> fusion->old_map_sz =
> - struct_size((struct MR_FW_RAID_MAP *)0, ldSpanMap,
> - instance->fw_supported_vd_count);
> + struct_size_t(struct MR_FW_RAID_MAP, ldSpanMap,
> + instance->fw_supported_vd_count);
> fusion->new_map_sz = sizeof(struct MR_FW_RAID_MAP_EXT);
>
> fusion->max_map_sz =
> @@ -5789,8 +5789,8 @@ megasas_setup_jbod_map(struct megasas_instance *instance)
> struct fusion_context *fusion = instance->ctrl_context;
> size_t pd_seq_map_sz;
>
> - pd_seq_map_sz = struct_size((struct MR_PD_CFG_SEQ_NUM_SYNC *)0, seq,
> - MAX_PHYSICAL_DEVICES);
> + pd_seq_map_sz = struct_size_t(struct MR_PD_CFG_SEQ_NUM_SYNC, seq,
> + MAX_PHYSICAL_DEVICES);
>
> instance->use_seqnum_jbod_fp =
> instance->support_seqnum_jbod_fp;
> @@ -8033,8 +8033,8 @@ static void megasas_detach_one(struct pci_dev *pdev)
> if (instance->adapter_type != MFI_SERIES) {
> megasas_release_fusion(instance);
> pd_seq_map_sz =
> - struct_size((struct MR_PD_CFG_SEQ_NUM_SYNC *)0,
> - seq, MAX_PHYSICAL_DEVICES);
> + struct_size_t(struct MR_PD_CFG_SEQ_NUM_SYNC,
> + seq, MAX_PHYSICAL_DEVICES);
> for (i = 0; i < 2 ; i++) {
> if (fusion->ld_map[i])
> dma_free_coherent(&instance->pdev->dev,
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c b/drivers/scsi/megaraid/megaraid_sas_fp.c
> index 4463a538102a..b8b388a4e28f 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fp.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fp.c
> @@ -326,9 +326,9 @@ u8 MR_ValidateMapInfo(struct megasas_instance *instance, u64 map_id)
> else if (instance->supportmax256vd)
> expected_size = sizeof(struct MR_FW_RAID_MAP_EXT);
> else
> - expected_size = struct_size((struct MR_FW_RAID_MAP *)0,
> - ldSpanMap,
> - le16_to_cpu(pDrvRaidMap->ldCount));
> + expected_size = struct_size_t(struct MR_FW_RAID_MAP,
> + ldSpanMap,
> + le16_to_cpu(pDrvRaidMap->ldCount));
>
> if (le32_to_cpu(pDrvRaidMap->totalSize) != expected_size) {
> dev_dbg(&instance->pdev->dev, "megasas: map info structure size 0x%x",
> diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
> index 03de97cd72c2..f4e0aa262164 100644
> --- a/drivers/scsi/smartpqi/smartpqi_init.c
> +++ b/drivers/scsi/smartpqi/smartpqi_init.c
> @@ -5015,7 +5015,7 @@ static int pqi_create_queues(struct pqi_ctrl_info *ctrl_info)
> }
>
> #define PQI_REPORT_EVENT_CONFIG_BUFFER_LENGTH \
> - struct_size((struct pqi_event_config *)0, descriptors, PQI_MAX_EVENT_DESCRIPTORS)
> + struct_size_t(struct pqi_event_config, descriptors, PQI_MAX_EVENT_DESCRIPTORS)
>
> static int pqi_configure_events(struct pqi_ctrl_info *ctrl_info,
> bool enable_events)
> diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> index a2aa36b23e25..4d68a58be160 100644
> --- a/fs/xfs/libxfs/xfs_btree.h
> +++ b/fs/xfs/libxfs/xfs_btree.h
> @@ -301,7 +301,7 @@ struct xfs_btree_cur
> static inline size_t
> xfs_btree_cur_sizeof(unsigned int nlevels)
> {
> - return struct_size((struct xfs_btree_cur *)NULL, bc_levels, nlevels);
> + return struct_size_t(struct xfs_btree_cur, bc_levels, nlevels);

Oh, hey, this thing ^^^^^^^^ again. I'm excited!

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> }
>
> /* cursor flags */
> diff --git a/fs/xfs/scrub/btree.h b/fs/xfs/scrub/btree.h
> index 9d7b9ee8bef4..c32b5fad6174 100644
> --- a/fs/xfs/scrub/btree.h
> +++ b/fs/xfs/scrub/btree.h
> @@ -60,7 +60,7 @@ struct xchk_btree {
> static inline size_t
> xchk_btree_sizeof(unsigned int nlevels)
> {
> - return struct_size((struct xchk_btree *)NULL, lastkey, nlevels - 1);
> + return struct_size_t(struct xchk_btree, lastkey, nlevels - 1);
> }
>
> int xchk_btree(struct xfs_scrub *sc, struct xfs_btree_cur *cur,
> diff --git a/include/linux/overflow.h b/include/linux/overflow.h
> index 0e33b5cbdb9f..f9b60313eaea 100644
> --- a/include/linux/overflow.h
> +++ b/include/linux/overflow.h
> @@ -283,7 +283,7 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
> * @member: Name of the array member.
> * @count: Number of elements in the array.
> *
> - * Calculates size of memory needed for structure @p followed by an
> + * Calculates size of memory needed for structure of @p followed by an
> * array of @count number of @member elements.
> *
> * Return: number of bytes needed or SIZE_MAX on overflow.
> @@ -293,4 +293,20 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
> sizeof(*(p)) + flex_array_size(p, member, count), \
> size_add(sizeof(*(p)), flex_array_size(p, member, count)))
>
> +/**
> + * struct_size_t() - Calculate size of structure with trailing flexible array
> + * @type: structure type name.
> + * @member: Name of the array member.
> + * @count: Number of elements in the array.
> + *
> + * Calculates size of memory needed for structure @type followed by an
> + * array of @count number of @member elements. Prefer using struct_size()
> + * when possible instead, to keep calculations associated with a specific
> + * instance variable of type @type.
> + *
> + * Return: number of bytes needed or SIZE_MAX on overflow.
> + */
> +#define struct_size_t(type, member, count) \
> + struct_size((type *)NULL, member, count)
> +
> #endif /* __LINUX_OVERFLOW_H */
> diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c
> index dcd3ba102db6..34db0b3aa502 100644
> --- a/lib/overflow_kunit.c
> +++ b/lib/overflow_kunit.c
> @@ -649,7 +649,7 @@ struct __test_flex_array {
> static void overflow_size_helpers_test(struct kunit *test)
> {
> /* Make sure struct_size() can be used in a constant expression. */
> - u8 ce_array[struct_size((struct __test_flex_array *)0, data, 55)];
> + u8 ce_array[struct_size_t(struct __test_flex_array, data, 55)];
> struct __test_flex_array *obj;
> int count = 0;
> int var;
> --
> 2.34.1
>