2024-05-12 16:11:02

by Erick Archer

[permalink] [raw]
Subject: [PATCH] net: prestera: Add flex arrays to some structs

The "struct prestera_msg_vtcam_rule_add_req" uses a dynamically sized
set of trailing elements. Specifically, it uses an array of structures
of type "prestera_msg_acl_action actions_msg".

The "struct prestera_msg_flood_domain_ports_set_req" also uses a
dynamically sized set of trailing elements. Specifically, it uses an
array of structures of type "prestera_msg_acl_action actions_msg".

So, use the preferred way in the kernel declaring flexible arrays [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). In this case, it is important to note
that the attribute used is specifically __counted_by_le since the
counters are of type __le32.

The logic does not need to change since the counters for the flexible
arrays are asigned before any access to the arrays.

The order in which the structure prestera_msg_vtcam_rule_add_req and the
structure prestera_msg_flood_domain_ports_set_req are defined must be
changed to avoid incomplete type errors.

Also, avoid the open-coded arithmetic in memory allocator functions [2]
using the "struct_size" macro.

Moreover, the new structure members also allow us to avoid the open-
coded arithmetic on pointers. So, take advantage of this refactoring
accordingly.

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 <[email protected]>
---
.../ethernet/marvell/prestera/prestera_hw.c | 83 +++++++++----------
1 file changed, 37 insertions(+), 46 deletions(-)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_hw.c b/drivers/net/ethernet/marvell/prestera/prestera_hw.c
index fc6f7d2746e8..197198ba61b1 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_hw.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_hw.c
@@ -419,15 +419,6 @@ struct prestera_msg_vtcam_destroy_req {
__le32 vtcam_id;
};

-struct prestera_msg_vtcam_rule_add_req {
- struct prestera_msg_cmd cmd;
- __le32 key[__PRESTERA_ACL_RULE_MATCH_TYPE_MAX];
- __le32 keymask[__PRESTERA_ACL_RULE_MATCH_TYPE_MAX];
- __le32 vtcam_id;
- __le32 prio;
- __le32 n_act;
-};
-
struct prestera_msg_vtcam_rule_del_req {
struct prestera_msg_cmd cmd;
__le32 vtcam_id;
@@ -471,6 +462,16 @@ struct prestera_msg_acl_action {
};
};

+struct prestera_msg_vtcam_rule_add_req {
+ struct prestera_msg_cmd cmd;
+ __le32 key[__PRESTERA_ACL_RULE_MATCH_TYPE_MAX];
+ __le32 keymask[__PRESTERA_ACL_RULE_MATCH_TYPE_MAX];
+ __le32 vtcam_id;
+ __le32 prio;
+ __le32 n_act;
+ struct prestera_msg_acl_action actions_msg[] __counted_by_le(n_act);
+};
+
struct prestera_msg_counter_req {
struct prestera_msg_cmd cmd;
__le32 client;
@@ -702,12 +703,6 @@ struct prestera_msg_flood_domain_destroy_req {
__le32 flood_domain_idx;
};

-struct prestera_msg_flood_domain_ports_set_req {
- struct prestera_msg_cmd cmd;
- __le32 flood_domain_idx;
- __le32 ports_num;
-};
-
struct prestera_msg_flood_domain_ports_reset_req {
struct prestera_msg_cmd cmd;
__le32 flood_domain_idx;
@@ -725,6 +720,13 @@ struct prestera_msg_flood_domain_port {
__le16 port_type;
};

+struct prestera_msg_flood_domain_ports_set_req {
+ struct prestera_msg_cmd cmd;
+ __le32 flood_domain_idx;
+ __le32 ports_num;
+ struct prestera_msg_flood_domain_port ports[] __counted_by_le(ports_num);
+};
+
struct prestera_msg_mdb_create_req {
struct prestera_msg_cmd cmd;
__le32 flood_domain_idx;
@@ -1371,23 +1373,18 @@ int prestera_hw_vtcam_rule_add(struct prestera_switch *sw,
struct prestera_acl_hw_action_info *act,
u8 n_act, u32 *rule_id)
{
- struct prestera_msg_acl_action *actions_msg;
struct prestera_msg_vtcam_rule_add_req *req;
struct prestera_msg_vtcam_resp resp;
- void *buff;
- u32 size;
+ size_t size;
int err;
u8 i;

- size = sizeof(*req) + sizeof(*actions_msg) * n_act;
-
- buff = kzalloc(size, GFP_KERNEL);
- if (!buff)
+ size = struct_size(req, actions_msg, n_act);
+ req = kzalloc(size, GFP_KERNEL);
+ if (!req)
return -ENOMEM;

- req = buff;
req->n_act = __cpu_to_le32(n_act);
- actions_msg = buff + sizeof(*req);

/* put acl matches into the message */
memcpy(req->key, key, sizeof(req->key));
@@ -1395,7 +1392,7 @@ int prestera_hw_vtcam_rule_add(struct prestera_switch *sw,

/* put acl actions into the message */
for (i = 0; i < n_act; i++) {
- err = prestera_acl_rule_add_put_action(&actions_msg[i],
+ err = prestera_acl_rule_add_put_action(&req->actions_msg[i],
&act[i]);
if (err)
goto free_buff;
@@ -1411,7 +1408,7 @@ int prestera_hw_vtcam_rule_add(struct prestera_switch *sw,

*rule_id = __le32_to_cpu(resp.rule_id);
free_buff:
- kfree(buff);
+ kfree(req);
return err;
}

@@ -2461,14 +2458,13 @@ int prestera_hw_flood_domain_ports_set(struct prestera_flood_domain *domain)
{
struct prestera_flood_domain_port *flood_domain_port;
struct prestera_msg_flood_domain_ports_set_req *req;
- struct prestera_msg_flood_domain_port *ports;
struct prestera_switch *sw = domain->sw;
struct prestera_port *port;
u32 ports_num = 0;
- int buf_size;
- void *buff;
+ size_t buf_size;
u16 lag_id;
int err;
+ int i = 0;

list_for_each_entry(flood_domain_port, &domain->flood_domain_port_list,
flood_domain_port_node)
@@ -2477,15 +2473,11 @@ int prestera_hw_flood_domain_ports_set(struct prestera_flood_domain *domain)
if (!ports_num)
return -EINVAL;

- buf_size = sizeof(*req) + sizeof(*ports) * ports_num;
-
- buff = kmalloc(buf_size, GFP_KERNEL);
- if (!buff)
+ buf_size = struct_size(req, ports, ports_num);
+ req = kmalloc(buf_size, GFP_KERNEL);
+ if (!req)
return -ENOMEM;

- req = buff;
- ports = buff + sizeof(*req);
-
req->flood_domain_idx = __cpu_to_le32(domain->idx);
req->ports_num = __cpu_to_le32(ports_num);

@@ -2494,31 +2486,30 @@ int prestera_hw_flood_domain_ports_set(struct prestera_flood_domain *domain)
if (netif_is_lag_master(flood_domain_port->dev)) {
if (prestera_lag_id(sw, flood_domain_port->dev,
&lag_id)) {
- kfree(buff);
+ kfree(req);
return -EINVAL;
}

- ports->port_type =
+ req->ports[i].port_type =
__cpu_to_le16(PRESTERA_HW_FLOOD_DOMAIN_PORT_TYPE_LAG);
- ports->lag_id = __cpu_to_le16(lag_id);
+ req->ports[i].lag_id = __cpu_to_le16(lag_id);
} else {
port = prestera_port_dev_lower_find(flood_domain_port->dev);

- ports->port_type =
+ req->ports[i].port_type =
__cpu_to_le16(PRESTERA_HW_FDB_ENTRY_TYPE_REG_PORT);
- ports->dev_num = __cpu_to_le32(port->dev_id);
- ports->port_num = __cpu_to_le32(port->hw_id);
+ req->ports[i].dev_num = __cpu_to_le32(port->dev_id);
+ req->ports[i].port_num = __cpu_to_le32(port->hw_id);
}

- ports->vid = __cpu_to_le16(flood_domain_port->vid);
-
- ports++;
+ req->ports[i].vid = __cpu_to_le16(flood_domain_port->vid);
+ i++;
}

err = prestera_cmd(sw, PRESTERA_CMD_TYPE_FLOOD_DOMAIN_PORTS_SET,
&req->cmd, buf_size);

- kfree(buff);
+ kfree(req);

return err;
}
--
2.25.1



2024-05-13 08:56:18

by Simon Horman

[permalink] [raw]
Subject: Re: [PATCH] net: prestera: Add flex arrays to some structs

On Sun, May 12, 2024 at 06:10:27PM +0200, Erick Archer wrote:
> The "struct prestera_msg_vtcam_rule_add_req" uses a dynamically sized
> set of trailing elements. Specifically, it uses an array of structures
> of type "prestera_msg_acl_action actions_msg".
>
> The "struct prestera_msg_flood_domain_ports_set_req" also uses a
> dynamically sized set of trailing elements. Specifically, it uses an
> array of structures of type "prestera_msg_acl_action actions_msg".
>
> So, use the preferred way in the kernel declaring flexible arrays [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). In this case, it is important to note
> that the attribute used is specifically __counted_by_le since the
> counters are of type __le32.
>
> The logic does not need to change since the counters for the flexible
> arrays are asigned before any access to the arrays.
>
> The order in which the structure prestera_msg_vtcam_rule_add_req and the
> structure prestera_msg_flood_domain_ports_set_req are defined must be
> changed to avoid incomplete type errors.
>
> Also, avoid the open-coded arithmetic in memory allocator functions [2]
> using the "struct_size" macro.
>
> Moreover, the new structure members also allow us to avoid the open-
> coded arithmetic on pointers. So, take advantage of this refactoring
> accordingly.
>
> 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 <[email protected]>

Reviewed-by: Simon Horman <[email protected]>


2024-05-13 18:58:44

by Kees Cook

[permalink] [raw]
Subject: Re: [PATCH] net: prestera: Add flex arrays to some structs

On Sun, May 12, 2024 at 06:10:27PM +0200, Erick Archer wrote:
> The "struct prestera_msg_vtcam_rule_add_req" uses a dynamically sized
> set of trailing elements. Specifically, it uses an array of structures
> of type "prestera_msg_acl_action actions_msg".
>
> The "struct prestera_msg_flood_domain_ports_set_req" also uses a
> dynamically sized set of trailing elements. Specifically, it uses an
> array of structures of type "prestera_msg_acl_action actions_msg".
>
> So, use the preferred way in the kernel declaring flexible arrays [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). In this case, it is important to note
> that the attribute used is specifically __counted_by_le since the
> counters are of type __le32.
>
> The logic does not need to change since the counters for the flexible
> arrays are asigned before any access to the arrays.
>
> The order in which the structure prestera_msg_vtcam_rule_add_req and the
> structure prestera_msg_flood_domain_ports_set_req are defined must be
> changed to avoid incomplete type errors.
>
> Also, avoid the open-coded arithmetic in memory allocator functions [2]
> using the "struct_size" macro.
>
> Moreover, the new structure members also allow us to avoid the open-
> coded arithmetic on pointers. So, take advantage of this refactoring
> accordingly.
>
> 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 <[email protected]>

This is a really nice cleanup. :) Fewer lines of code, more readable,
and protected by __counted_by!

Reviewed-by: Kees Cook <[email protected]>

--
Kees Cook

2024-05-14 01:00:57

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH] net: prestera: Add flex arrays to some structs

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <[email protected]>:

On Sun, 12 May 2024 18:10:27 +0200 you wrote:
> The "struct prestera_msg_vtcam_rule_add_req" uses a dynamically sized
> set of trailing elements. Specifically, it uses an array of structures
> of type "prestera_msg_acl_action actions_msg".
>
> The "struct prestera_msg_flood_domain_ports_set_req" also uses a
> dynamically sized set of trailing elements. Specifically, it uses an
> array of structures of type "prestera_msg_acl_action actions_msg".
>
> [...]

Here is the summary with links:
- net: prestera: Add flex arrays to some structs
https://git.kernel.org/netdev/net-next/c/86348d217661

You are awesome, thank you!
--
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