[PATCH 4.14 05/17] usbnet: fix memory leak in error case

Greg Kroah-Hartman
2022-07-11T09:09:58Z

From: Oliver Neukum <oneukum@suse.com>

commit b55a21b764c1e182014630fa5486d717484ac58f upstream.

usbnet_write_cmd_async() mixed up which buffers
need to be freed in which error case.

v2: add Fixes tag
v3: fix uninitialized buf pointer

Fixes: 877bd862f32b8 ("usbnet: introduce usbnet 3 command helpers")
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20220705125351.17309-1-oneukum@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/usb/usbnet.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -2135,7 +2135,7 @@ static void usbnet_async_cmd_cb(struct u
int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
u16 value, u16 index, const void *data, u16 size)
{
- struct usb_ctrlrequest *req = NULL;
+ struct usb_ctrlrequest *req;
struct urb *urb;
int err = -ENOMEM;
void *buf = NULL;
@@ -2153,7 +2153,7 @@ int usbnet_write_cmd_async(struct usbnet
if (!buf) {
netdev_err(dev->net, "Error allocating buffer"
" in %s!\n", __func__);
- goto fail_free;
+ goto fail_free_urb;
}
}

@@ -2177,14 +2177,21 @@ int usbnet_write_cmd_async(struct usbnet
if (err < 0) {
netdev_err(dev->net, "Error submitting the control"
" message: status=%d\n", err);
- goto fail_free;
+ goto fail_free_all;
}
return 0;

+fail_free_all:
+ kfree(req);
fail_free_buf:
kfree(buf);
-fail_free:
- kfree(req);
+ /*
+ * avoid a double free
+ * needed because the flag can be set only
+ * after filling the URB
+ */
+ urb->transfer_flags = 0;
+fail_free_urb:
usb_free_urb(urb);
fail:
return err;