Re: [PATCH v2] RDMA/mana_ib: Add flex array to struct mana_cfg_rx_steer_req_v2

Leon Romanovsky
2024-04-02T18:58:16Z

On Mon, Apr 01, 2024 at 05:37:03PM +0200, Erick Archer wrote:
> The "struct mana_cfg_rx_steer_req_v2" uses a dynamically sized set of
> trailing elements. Specifically, it uses a "mana_handle_t" array. So,
> use the preferred way in the kernel declaring a flexible array [1].
>
> At the same time, prepare for the coming implementation by GCC and Clang
> of the __counted_by attribute. Flexible array members annotated with
> __counted_by can have their accesses bounds-checked at run-time via
> CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for
> strcpy/memcpy-family functions).
>
> Also, avoid the open-coded arithmetic in the memory allocator functions
> [2] using the "struct_size" macro.
>
> Moreover, use the "offsetof" helper to get the indirect table offset
> instead of the "sizeof" operator and avoid the open-coded arithmetic in
> pointers using the new flex member. This new structure member also allow
> us to remove the "req_indir_tab" variable since it is no longer needed.
>
> Now, it is also possible to use the "flex_array_size" helper to compute
> the size of these trailing elements in the "memcpy" function.
>
> This code was detected with the help of Coccinelle, and audited and
> modified manually.
>
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#zero-length-and-one-element-arrays [1]
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
> Signed-off-by: Erick Archer <erick.archer@outlook.com>
> ---
> Changes in v2:
> - Remove the "req_indir_tab" variable (Gustavo A. R. Silva).
> - Update the commit message.
> - Add the "__counted_by" attribute.
>
> Previous versions:
> v1 -> https://lore.kernel.org/linux-hardening/AS8PR02MB7237974EF1B9BAFA618166C38B382@AS8PR02MB7237.eurprd02.prod.outlook.com/
>
> Hi,
>
> The Coccinelle script used to detect this code pattern is the following:
>
> virtual report
>
> @rule1@
> type t1;
> type t2;
> identifier i0;
> identifier i1;
> identifier i2;
> identifier ALLOC =~ "kmalloc|kzalloc|kmalloc_node|kzalloc_node|vmalloc|vzalloc|kvmalloc|kvzalloc";
> position p1;
> @@
>
> i0 = sizeof(t1) + sizeof(t2) * i1;
> ...
> i2 = ALLOC@p1(..., i0, ...);
>
> @script:python depends on report@
> p1 << rule1.p1;
> @@
>
> msg = "WARNING: verify allocation on line %s" % (p1[0].line)
> coccilib.report.print_report(p1[0],msg)
>
> Regards,
> Erick
> ---
> drivers/infiniband/hw/mana/qp.c | 12 +++++-------
> drivers/net/ethernet/microsoft/mana/mana_en.c | 14 ++++++--------
> include/net/mana/mana.h | 1 +
> 3 files changed, 12 insertions(+), 15 deletions(-)

Is it possible to separate this patch to two patches? One for netdev
with drivers/net/ethernet/microsoft/mana/mana_en.c changes and another
with drivers/infiniband/hw/mana/qp.c changes.

It will simplify the acceptance process.

Thanks

>
> diff --git a/drivers/infiniband/hw/mana/qp.c b/drivers/infiniband/hw/mana/qp.c
> index 6e7627745c95..258f89464c10 100644
> --- a/drivers/infiniband/hw/mana/qp.c
> +++ b/drivers/infiniband/hw/mana/qp.c
> @@ -15,15 +15,13 @@ static int mana_ib_cfg_vport_steering(struct mana_ib_dev *dev,
> struct mana_port_context *mpc = netdev_priv(ndev);
> struct mana_cfg_rx_steer_req_v2 *req;
> struct mana_cfg_rx_steer_resp resp = {};
> - mana_handle_t *req_indir_tab;
> struct gdma_context *gc;
> u32 req_buf_size;
> int i, err;
>
> gc = mdev_to_gc(dev);
>
> - req_buf_size =
> - sizeof(*req) + sizeof(mana_handle_t) * MANA_INDIRECT_TABLE_SIZE;
> + req_buf_size = struct_size(req, indir_tab, MANA_INDIRECT_TABLE_SIZE);
> req = kzalloc(req_buf_size, GFP_KERNEL);
> if (!req)
> return -ENOMEM;
> @@ -44,20 +42,20 @@ static int mana_ib_cfg_vport_steering(struct mana_ib_dev *dev,
> req->rss_enable = true;
>
> req->num_indir_entries = MANA_INDIRECT_TABLE_SIZE;
> - req->indir_tab_offset = sizeof(*req);
> + req->indir_tab_offset = offsetof(struct mana_cfg_rx_steer_req_v2,
> + indir_tab);
> req->update_indir_tab = true;
> req->cqe_coalescing_enable = 1;
>
> - req_indir_tab = (mana_handle_t *)(req + 1);
> /* The ind table passed to the hardware must have
> * MANA_INDIRECT_TABLE_SIZE entries. Adjust the verb
> * ind_table to MANA_INDIRECT_TABLE_SIZE if required
> */
> ibdev_dbg(&dev->ib_dev, "ind table size %u\n", 1 << log_ind_tbl_size);
> for (i = 0; i < MANA_INDIRECT_TABLE_SIZE; i++) {
> - req_indir_tab[i] = ind_table[i % (1 << log_ind_tbl_size)];
> + req->indir_tab[i] = ind_table[i % (1 << log_ind_tbl_size)];
> ibdev_dbg(&dev->ib_dev, "index %u handle 0x%llx\n", i,
> - req_indir_tab[i]);
> + req->indir_tab[i]);
> }
>
> req->update_hashkey = true;
> diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
> index 59287c6e6cee..62bf3e5661a6 100644
> --- a/drivers/net/ethernet/microsoft/mana/mana_en.c
> +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
> @@ -1058,11 +1058,10 @@ static int mana_cfg_vport_steering(struct mana_port_context *apc,
> struct mana_cfg_rx_steer_req_v2 *req;
> struct mana_cfg_rx_steer_resp resp = {};
> struct net_device *ndev = apc->ndev;
> - mana_handle_t *req_indir_tab;
> u32 req_buf_size;
> int err;
>
> - req_buf_size = sizeof(*req) + sizeof(mana_handle_t) * num_entries;
> + req_buf_size = struct_size(req, indir_tab, num_entries);
> req = kzalloc(req_buf_size, GFP_KERNEL);
> if (!req)
> return -ENOMEM;
> @@ -1074,7 +1073,8 @@ static int mana_cfg_vport_steering(struct mana_port_context *apc,
>
> req->vport = apc->port_handle;
> req->num_indir_entries = num_entries;
> - req->indir_tab_offset = sizeof(*req);
> + req->indir_tab_offset = offsetof(struct mana_cfg_rx_steer_req_v2,
> + indir_tab);
> req->rx_enable = rx;
> req->rss_enable = apc->rss_state;
> req->update_default_rxobj = update_default_rxobj;
> @@ -1086,11 +1086,9 @@ static int mana_cfg_vport_steering(struct mana_port_context *apc,
> if (update_key)
> memcpy(&req->hashkey, apc->hashkey, MANA_HASH_KEY_SIZE);
>
> - if (update_tab) {
> - req_indir_tab = (mana_handle_t *)(req + 1);
> - memcpy(req_indir_tab, apc->rxobj_table,
> - req->num_indir_entries * sizeof(mana_handle_t));
> - }
> + if (update_tab)
> + memcpy(req->indir_tab, apc->rxobj_table,
> + flex_array_size(req, indir_tab, req->num_indir_entries));
>
> err = mana_send_request(apc->ac, req, req_buf_size, &resp,
> sizeof(resp));
> diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
> index 76147feb0d10..46f741ebce21 100644
> --- a/include/net/mana/mana.h
> +++ b/include/net/mana/mana.h
> @@ -671,6 +671,7 @@ struct mana_cfg_rx_steer_req_v2 {
> u8 hashkey[MANA_HASH_KEY_SIZE];
> u8 cqe_coalescing_enable;
> u8 reserved2[7];
> + mana_handle_t indir_tab[] __counted_by(num_indir_entries);
> }; /* HW DATA */
>
> struct mana_cfg_rx_steer_resp {
> --
> 2.25.1
>
>