* [PATCH][next] Bluetooth: Use struct_size() helper
@ 2019-03-28 17:30 Gustavo A. R. Silva
2019-03-28 17:46 ` Joe Perches
2019-04-23 17:31 ` Marcel Holtmann
0 siblings, 2 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2019-03-28 17:30 UTC (permalink / raw)
To: Marcel Holtmann, Johan Hedberg, David S. Miller
Cc: linux-bluetooth, netdev, linux-kernel, Gustavo A. R. Silva
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
size = struct_size(instance, entry, count);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
net/bluetooth/mgmt.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 2457f408d17d..150114e33b20 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -2301,8 +2301,7 @@ static int load_link_keys(struct sock *sk, struct hci_dev *hdev, void *data,
MGMT_STATUS_INVALID_PARAMS);
}
- expected_len = sizeof(*cp) + key_count *
- sizeof(struct mgmt_link_key_info);
+ expected_len = struct_size(cp, keys, key_count);
if (expected_len != len) {
bt_dev_err(hdev, "load_link_keys: expected %u bytes, got %u bytes",
expected_len, len);
@@ -5030,7 +5029,7 @@ static int load_irks(struct sock *sk, struct hci_dev *hdev, void *cp_data,
MGMT_STATUS_INVALID_PARAMS);
}
- expected_len = sizeof(*cp) + irk_count * sizeof(struct mgmt_irk_info);
+ expected_len = struct_size(cp, irks, irk_count);
if (expected_len != len) {
bt_dev_err(hdev, "load_irks: expected %u bytes, got %u bytes",
expected_len, len);
@@ -5112,8 +5111,7 @@ static int load_long_term_keys(struct sock *sk, struct hci_dev *hdev,
MGMT_STATUS_INVALID_PARAMS);
}
- expected_len = sizeof(*cp) + key_count *
- sizeof(struct mgmt_ltk_info);
+ expected_len = struct_size(cp, keys, key_count);
if (expected_len != len) {
bt_dev_err(hdev, "load_keys: expected %u bytes, got %u bytes",
expected_len, len);
@@ -5847,8 +5845,7 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
MGMT_STATUS_INVALID_PARAMS);
}
- expected_len = sizeof(*cp) + param_count *
- sizeof(struct mgmt_conn_param);
+ expected_len = struct_size(cp, params, param_count);
if (expected_len != len) {
bt_dev_err(hdev, "load_conn_param: expected %u bytes, got %u bytes",
expected_len, len);
--
2.21.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH][next] Bluetooth: Use struct_size() helper
2019-03-28 17:30 [PATCH][next] Bluetooth: Use struct_size() helper Gustavo A. R. Silva
@ 2019-03-28 17:46 ` Joe Perches
2019-04-23 17:31 ` Marcel Holtmann
1 sibling, 0 replies; 4+ messages in thread
From: Joe Perches @ 2019-03-28 17:46 UTC (permalink / raw)
To: Gustavo A. R. Silva, Marcel Holtmann, Johan Hedberg, David S. Miller
Cc: linux-bluetooth, netdev, linux-kernel
On Thu, 2019-03-28 at 12:30 -0500, Gustavo A. R. Silva wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct foo {
> int stuff;
> struct boo entry[];
> };
>
> size = sizeof(struct foo) + count * sizeof(struct boo);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> size = struct_size(instance, entry, count);
[]
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
[]
> @@ -2301,8 +2301,7 @@ static int load_link_keys(struct sock *sk, struct hci_dev *hdev, void *data,
> MGMT_STATUS_INVALID_PARAMS);
> }
>
> - expected_len = sizeof(*cp) + key_count *
> - sizeof(struct mgmt_link_key_info);
> + expected_len = struct_size(cp, keys, key_count);
> if (expected_len != len) {
> bt_dev_err(hdev, "load_link_keys: expected %u bytes, got %u bytes",
> expected_len, len);
> @@ -5030,7 +5029,7 @@ static int load_irks(struct sock *sk, struct hci_dev *hdev, void *cp_data,
> MGMT_STATUS_INVALID_PARAMS);
> }
>
> - expected_len = sizeof(*cp) + irk_count * sizeof(struct mgmt_irk_info);
> + expected_len = struct_size(cp, irks, irk_count);
> if (expected_len != len) {
> bt_dev_err(hdev, "load_irks: expected %u bytes, got %u bytes",
> expected_len, len);
> @@ -5112,8 +5111,7 @@ static int load_long_term_keys(struct sock *sk, struct hci_dev *hdev,
> MGMT_STATUS_INVALID_PARAMS);
> }
>
> - expected_len = sizeof(*cp) + key_count *
> - sizeof(struct mgmt_ltk_info);
> + expected_len = struct_size(cp, keys, key_count);
> if (expected_len != len) {
> bt_dev_err(hdev, "load_keys: expected %u bytes, got %u bytes",
> expected_len, len);
> @@ -5847,8 +5845,7 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
> MGMT_STATUS_INVALID_PARAMS);
> }
>
> - expected_len = sizeof(*cp) + param_count *
> - sizeof(struct mgmt_conn_param);
> + expected_len = struct_size(cp, params, param_count);
> if (expected_len != len) {
> bt_dev_err(hdev, "load_conn_param: expected %u bytes, got %u bytes",
> expected_len, len);
Maybe add a helper function for all of these.
Perhaps something like:
static bool verify_len(size_t actual, size_t expected)
{
if (actual == expected)
return true;
bt_dev_err("%ps: expected %zu bytes, got %zu bytes",
__builtin_return_address(1), expected, actual);
return false;
}
So the last block above might be
if (!verify_len(len, struct_size(cp, params, param_count),))
return mgmt_cmd_status(sk, hdev->id, MGMT_OP_LOAD_CONN_PARAM,
MGMT_STATUS_INVALID_PARAMS);
etc...
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next] Bluetooth: Use struct_size() helper
2019-03-28 17:30 [PATCH][next] Bluetooth: Use struct_size() helper Gustavo A. R. Silva
2019-03-28 17:46 ` Joe Perches
@ 2019-04-23 17:31 ` Marcel Holtmann
2019-04-23 17:37 ` Gustavo A. R. Silva
1 sibling, 1 reply; 4+ messages in thread
From: Marcel Holtmann @ 2019-04-23 17:31 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Johan Hedberg, David S. Miller, linux-bluetooth, netdev, linux-kernel
Hi Gustavo,
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct foo {
> int stuff;
> struct boo entry[];
> };
>
> size = sizeof(struct foo) + count * sizeof(struct boo);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> size = struct_size(instance, entry, count);
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> net/bluetooth/mgmt.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
patch has been applied to bluetooth-next tree.
Regards
Marcel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next] Bluetooth: Use struct_size() helper
2019-04-23 17:31 ` Marcel Holtmann
@ 2019-04-23 17:37 ` Gustavo A. R. Silva
0 siblings, 0 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2019-04-23 17:37 UTC (permalink / raw)
To: Marcel Holtmann
Cc: Johan Hedberg, David S. Miller, linux-bluetooth, netdev, linux-kernel
On 4/23/19 12:31 PM, Marcel Holtmann wrote:
> Hi Gustavo,
>
[..]
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>> net/bluetooth/mgmt.c | 11 ++++-------
>> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> patch has been applied to bluetooth-next tree.
>
Awesome.
Thanks, Marcel.
--
Gustavo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-03-28 17:30 [PATCH][next] Bluetooth: Use struct_size() helper Gustavo A. R. Silva
2019-03-28 17:46 ` Joe Perches
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2019-04-23 17:37 ` Gustavo A. R. Silva
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