From: Joe Perches <joe@perches.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org,
Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
syzbot+a4387f5b6b799f6becbf@syzkaller.appspotmail.com
Subject: Re: [PATCH 5.2 10/20] media: radio-raremono: change devm_k*alloc to k*alloc
Date: Fri, 02 Aug 2019 03:04:25 -0700 [thread overview]
Message-ID: <9403fd1e250bb4dd8e1bcf0536e6d224be7c889c.camel@perches.com> (raw)
In-Reply-To: <20190802092100.285432717@linuxfoundation.org>
On Fri, 2019-08-02 at 11:40 +0200, Greg Kroah-Hartman wrote:
> From: Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>
>
> commit c666355e60ddb4748ead3bdd983e3f7f2224aaf0 upstream.
>
> Change devm_k*alloc to k*alloc to manually allocate memory
>
> The manual allocation and freeing of memory is necessary because when
> the USB radio is disconnected, the memory associated with devm_k*alloc
> is freed. Meaning if we still have unresolved references to the radio
> device, then we get use-after-free errors.
>
> This patch fixes this by manually allocating memory, and freeing it in
> the v4l2.release callback that gets called when the last radio device
> exits.
This really should be commented in the code
and not just in the commit changelog as some
unsuspecting person will likely undo this in
the future without one.
> Reported-and-tested-by: syzbot+a4387f5b6b799f6becbf@syzkaller.appspotmail.com
>
> Signed-off-by: Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> [hverkuil-cisco@xs4all.nl: cleaned up two small checkpatch.pl warnings]
> [hverkuil-cisco@xs4all.nl: prefix subject with driver name]
> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> ---
> drivers/media/radio/radio-raremono.c | 30 +++++++++++++++++++++++-------
> 1 file changed, 23 insertions(+), 7 deletions(-)
>
> --- a/drivers/media/radio/radio-raremono.c
> +++ b/drivers/media/radio/radio-raremono.c
> @@ -271,6 +271,14 @@ static int vidioc_g_frequency(struct fil
> return 0;
> }
>
> +static void raremono_device_release(struct v4l2_device *v4l2_dev)
> +{
> + struct raremono_device *radio = to_raremono_dev(v4l2_dev);
> +
> + kfree(radio->buffer);
> + kfree(radio);
> +}
> +
> /* File system interface */
> static const struct v4l2_file_operations usb_raremono_fops = {
> .owner = THIS_MODULE,
> @@ -295,12 +303,14 @@ static int usb_raremono_probe(struct usb
> struct raremono_device *radio;
> int retval = 0;
>
> - radio = devm_kzalloc(&intf->dev, sizeof(struct raremono_device), GFP_KERNEL);
> - if (radio)
> - radio->buffer = devm_kmalloc(&intf->dev, BUFFER_LENGTH, GFP_KERNEL);
> -
> - if (!radio || !radio->buffer)
> + radio = kzalloc(sizeof(*radio), GFP_KERNEL);
> + if (!radio)
> + return -ENOMEM;
> + radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
> + if (!radio->buffer) {
> + kfree(radio);
> return -ENOMEM;
> + }
>
> radio->usbdev = interface_to_usbdev(intf);
> radio->intf = intf;
> @@ -324,7 +334,8 @@ static int usb_raremono_probe(struct usb
> if (retval != 3 ||
> (get_unaligned_be16(&radio->buffer[1]) & 0xfff) == 0x0242) {
> dev_info(&intf->dev, "this is not Thanko's Raremono.\n");
> - return -ENODEV;
> + retval = -ENODEV;
> + goto free_mem;
> }
>
> dev_info(&intf->dev, "Thanko's Raremono connected: (%04X:%04X)\n",
> @@ -333,7 +344,7 @@ static int usb_raremono_probe(struct usb
> retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
> if (retval < 0) {
> dev_err(&intf->dev, "couldn't register v4l2_device\n");
> - return retval;
> + goto free_mem;
> }
>
> mutex_init(&radio->lock);
> @@ -345,6 +356,7 @@ static int usb_raremono_probe(struct usb
> radio->vdev.ioctl_ops = &usb_raremono_ioctl_ops;
> radio->vdev.lock = &radio->lock;
> radio->vdev.release = video_device_release_empty;
> + radio->v4l2_dev.release = raremono_device_release;
>
> usb_set_intfdata(intf, &radio->v4l2_dev);
>
> @@ -360,6 +372,10 @@ static int usb_raremono_probe(struct usb
> }
> dev_err(&intf->dev, "could not register video device\n");
> v4l2_device_unregister(&radio->v4l2_dev);
> +
> +free_mem:
> + kfree(radio->buffer);
> + kfree(radio);
> return retval;
> }
>
>
>
next prev parent reply other threads:[~2019-08-02 10:10 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-02 9:39 [PATCH 5.2 00/20] 5.2.6-stable review Greg Kroah-Hartman
2019-08-02 9:39 ` [PATCH 5.2 01/20] vsock: correct removal of socket from the list Greg Kroah-Hartman
2019-08-02 9:39 ` [PATCH 5.2 02/20] ISDN: hfcsusb: checking idx of ep configuration Greg Kroah-Hartman
2019-08-02 9:39 ` [PATCH 5.2 03/20] ALSA: usb-audio: Sanity checks for each pipe and EP types Greg Kroah-Hartman
2019-08-02 13:48 ` Sasha Levin
2019-08-02 15:51 ` Greg Kroah-Hartman
2019-08-07 2:38 ` Sasha Levin
2019-08-02 9:39 ` [PATCH 5.2 04/20] bpf: fix NULL deref in btf_type_is_resolve_source_only Greg Kroah-Hartman
2019-08-02 9:39 ` [PATCH 5.2 05/20] media: au0828: fix null dereference in error path Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 06/20] ath10k: Change the warning message string Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 07/20] media: cpia2_usb: first wake up, then free in disconnect Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 08/20] media: pvrusb2: use a different format for warnings Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 09/20] NFS: Cleanup if nfs_match_client is interrupted Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 10/20] media: radio-raremono: change devm_k*alloc to k*alloc Greg Kroah-Hartman
2019-08-02 10:04 ` Joe Perches [this message]
2019-08-06 5:34 ` Luke Nowakowski-Krijger
2019-08-02 9:40 ` [PATCH 5.2 11/20] xfrm: policy: fix bydst hlist corruption on hash rebuild Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 12/20] nvme: fix multipath crash when ANA is deactivated Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 13/20] Bluetooth: hci_uart: check for missing tty operations Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 14/20] sched/fair: Dont free p->numa_faults with concurrent readers Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 15/20] sched/fair: Use RCU accessors consistently for ->numa_group Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 16/20] /proc/<pid>/cmdline: remove all the special cases Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 17/20] /proc/<pid>/cmdline: add back the setproctitle() special case Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 18/20] drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 19/20] Fix allyesconfig output Greg Kroah-Hartman
2019-08-02 9:40 ` [PATCH 5.2 20/20] ceph: hold i_ceph_lock when removing caps for freeing inode Greg Kroah-Hartman
2019-08-02 17:21 ` [PATCH 5.2 00/20] 5.2.6-stable review Thierry Reding
2019-08-03 7:09 ` Greg Kroah-Hartman
2019-08-05 11:48 ` Thierry Reding
2019-08-09 8:52 ` Greg Kroah-Hartman
2019-08-09 13:04 ` Thierry Reding
2019-08-09 15:49 ` Greg Kroah-Hartman
2019-08-12 9:05 ` Thierry Reding
2021-01-04 12:39 ` Greg Kroah-Hartman
2019-08-02 23:25 ` shuah
2019-08-03 7:08 ` Greg Kroah-Hartman
2019-08-03 5:50 ` Naresh Kamboju
2019-08-03 7:11 ` Greg Kroah-Hartman
2019-08-03 16:00 ` Guenter Roeck
2019-08-04 7:15 ` Greg Kroah-Hartman
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