linux-kernel - [PATCH net-next] net: usb: cdc-phonet: use struct_size() in alloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190208031313.GA2848@embeddedor>
Date:   Thu, 7 Feb 2019 21:13:13 -0600
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     linux-usb@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Subject: [PATCH net-next] net: usb: cdc-phonet: use struct_size() in
 alloc_netdev()

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;
    void *entry[];
};

instance = alloc(sizeof(struct foo) + count * sizeof(void *));

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = alloc(struct_size(instance, entry, count));

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
---
 drivers/net/usb/cdc-phonet.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/cdc-phonet.c b/drivers/net/usb/cdc-phonet.c
index 78b16eb9e58c..63aaae487995 100644
--- a/drivers/net/usb/cdc-phonet.c
+++ b/drivers/net/usb/cdc-phonet.c
@@ -361,8 +361,8 @@ static int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *i
 	else
 		return -EINVAL;
 
-	dev = alloc_netdev(sizeof(*pnd) + sizeof(pnd->urbs[0]) * rxq_size,
-			   ifname, NET_NAME_UNKNOWN, usbpn_setup);
+	dev = alloc_netdev(struct_size(pnd, urbs, rxq_size), ifname,
+			   NET_NAME_UNKNOWN, usbpn_setup);
 	if (!dev)
 		return -ENOMEM;
 
-- 
2.20.1