From: Takashi Iwai <tiwai@suse.de>
To: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
Stefan Seyfried <seife+kernel@b1-systems.com>
Subject: [PATCH 2/2] media: dvb-usb: Fix use-after-free access
Date: Wed, 20 Jan 2021 11:20:57 +0100 [thread overview]
Message-ID: <20210120102057.21143-3-tiwai@suse.de> (raw)
In-Reply-To: <20210120102057.21143-1-tiwai@suse.de>
dvb_usb_device_init() copies the properties to the own data, so that
the callers can release the original properties later (as done in the
commit 299c7007e936 "media: dw2102: Fix memleak on sequence of
probes"). However, it also stores dev->desc pointer that is a
reference to the original properties data. Since dev->desc is
referred later, it may result in use-after-free, in the worst case,
leading to a kernel Oops as reported.
This patch addresses the problem by allocating and copying the
properties at first, then get the desc from the copied properties.
Reported-and-tested-by: Stefan Seyfried <seife+kernel@b1-systems.com>
BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1181104
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/usb/dvb-usb/dvb-usb-init.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
index 5befec87f26a..07ff9b4d2f34 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
@@ -255,27 +255,30 @@ int dvb_usb_device_init(struct usb_interface *intf,
if (du != NULL)
*du = NULL;
- if ((desc = dvb_usb_find_device(udev, props, &cold)) == NULL) {
+ d = kzalloc(sizeof(struct dvb_usb_device), GFP_KERNEL);
+ if (!d) {
+ err("no memory for 'struct dvb_usb_device'");
+ return -ENOMEM;
+ }
+
+ memcpy(&d->props, props, sizeof(struct dvb_usb_device_properties));
+
+ desc = dvb_usb_find_device(udev, &d->props, &cold);
+ if (!desc) {
deb_err("something went very wrong, device was not found in current device list - let's see what comes next.\n");
- return -ENODEV;
+ ret = -ENODEV;
+ goto error;
}
if (cold) {
info("found a '%s' in cold state, will try to load a firmware", desc->name);
ret = dvb_usb_download_firmware(udev, props);
if (!props->no_reconnect || ret != 0)
- return ret;
+ goto error;
}
info("found a '%s' in warm state.", desc->name);
- d = kzalloc(sizeof(struct dvb_usb_device), GFP_KERNEL);
- if (d == NULL) {
- err("no memory for 'struct dvb_usb_device'");
- return -ENOMEM;
- }
-
d->udev = udev;
- memcpy(&d->props, props, sizeof(struct dvb_usb_device_properties));
d->desc = desc;
d->owner = owner;
--
2.26.2
next prev parent reply other threads:[~2021-01-20 10:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 10:20 [PATCH 0/2] media: dvb-usb: Fix UAF and memory leaks Takashi Iwai
2021-01-20 10:20 ` [PATCH 1/2] media: dvb-usb: Fix memory leak at error in dvb_usb_device_init() Takashi Iwai
2021-01-22 9:24 ` Robert Foss
2021-01-31 14:53 ` Sean Young
2021-02-01 8:18 ` Takashi Iwai
2021-01-20 10:20 ` Takashi Iwai [this message]
2021-01-22 15:47 ` [PATCH 2/2] media: dvb-usb: Fix use-after-free access Robert Foss
2021-01-31 15:04 ` Sean Young
2021-02-01 8:22 ` Takashi Iwai
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