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Bluetooth: mgmt: Use struct_size() helper 

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 mgmt_rp_get_connections {
	...
        struct mgmt_addr_info addr[0];
} __packed;

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*rp) + (i * sizeof(struct mgmt_addr_info));

with:

struct_size(rp, addr, i)

Also, notice that, in this case, variable rp_len is not necessary,
hence it is removed.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Gustavo A. R. Silva 2019-08-29 20:12:11 -05:00 committed by Marcel Holtmann
parent f1300c0340
commit 72bb169e02
1 changed files with 2 additions and 6 deletions
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8
net/bluetooth/mgmt.c
View File

@ -2588,7 +2588,6 @@ static int get_connections(struct sock *sk, struct hci_dev *hdev, void *data,
{
struct mgmt_rp_get_connections *rp;
struct hci_conn *c;
size_t rp_len;
int err;
u16 i;
@ -2608,8 +2607,7 @@ static int get_connections(struct sock *sk, struct hci_dev *hdev, void *data,
i++;
}
rp_len = sizeof(*rp) + (i * sizeof(struct mgmt_addr_info));
rp = kmalloc(rp_len, GFP_KERNEL);
rp = kmalloc(struct_size(rp, addr, i), GFP_KERNEL);
if (!rp) {
err = -ENOMEM;
goto unlock;
@ -2629,10 +2627,8 @@ static int get_connections(struct sock *sk, struct hci_dev *hdev, void *data,
rp->conn_count = cpu_to_le16(i);
/* Recalculate length in case of filtered SCO connections, etc */
rp_len = sizeof(*rp) + (i * sizeof(struct mgmt_addr_info));
err = mgmt_cmd_complete(sk, hdev->id, MGMT_OP_GET_CONNECTIONS, 0, rp,
rp_len);
struct_size(rp, addr, i));
kfree(rp);