| Message ID | AS8PR02MB7237A21355C86EC0DCC0D83B8B022@AS8PR02MB7237.eurprd02.prod.outlook.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | a68292eb431619a5f8db9d4868346837c5606424 |
| Headers | show |
| Series | RDMA/mana_ib: Add flex array to struct mana_cfg_rx_steer_req_v2 | expand |
Hi, On Sat, Apr 06, 2024 at 04:23:37PM +0200, Erick Archer wrote: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1][2]. > > As the "req" variable is a pointer to "struct mana_cfg_rx_steer_req_v2" > and this structure ends in a flexible array: > > struct mana_cfg_rx_steer_req_v2 { > [...] > mana_handle_t indir_tab[] __counted_by(num_indir_entries); > }; > > the preferred way in the kernel is to use the struct_size() helper to > do the arithmetic instead of the calculation "size + size * count" in > the kzalloc() function. > > 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 way, the code is more readable and safer. > > This code was detected with the help of Coccinelle, and audited and > modified manually. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] > Link: https://github.com/KSPP/linux/issues/160 [2] > Signed-off-by: Erick Archer <erick.archer@outlook.com> Reviewed-by: Justin Stitt <justinstitt@google.com> > --- > drivers/net/ethernet/microsoft/mana/mana_en.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c > index d8af5e7e15b4..f2fae659bf3b 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)); > -- > 2.25.1 > Thanks Justin
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c index d8af5e7e15b4..f2fae659bf3b 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));
This is an effort to get rid of all multiplications from allocation functions in order to prevent integer overflows [1][2]. As the "req" variable is a pointer to "struct mana_cfg_rx_steer_req_v2" and this structure ends in a flexible array: struct mana_cfg_rx_steer_req_v2 { [...] mana_handle_t indir_tab[] __counted_by(num_indir_entries); }; the preferred way in the kernel is to use the struct_size() helper to do the arithmetic instead of the calculation "size + size * count" in the kzalloc() function. 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 way, the code is more readable and safer. This code was detected with the help of Coccinelle, and audited and modified manually. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] Link: https://github.com/KSPP/linux/issues/160 [2] Signed-off-by: Erick Archer <erick.archer@outlook.com> --- drivers/net/ethernet/microsoft/mana/mana_en.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)