| Message ID | 20220124171931.62174-1-zhou1615@umn.edu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | media: saa7134: Fix a NULL pointer dereference in saa7134_initdev() | expand |
On Tue, Jan 25, 2022 at 01:19:30AM +0800, Zhou Qingyang wrote: > In saa7134_initdev(), the return value of vdev_init() is assigned to > dev->video_dev and there is a dereference of it after that. The return > value of vdev_init() will be NULL on the failure allocation, which could > lead to NULL pointer dereference. > > The same as dev->vbi_dev. > > Fix this bug by adding a NULL check of dev->video_dev and dev->vbi_dev. > > This bug was found by a static analyzer. > > Builds with 'make allyesconfig' show no new warnings, > and our static analyzer no longer warns about this code. > > Fixes: a9622391acb ("V4L/DVB (6792): Fix VBI support") > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> > --- > The analysis employs differential checking to identify inconsistent > security operations (e.g., checks or kfrees) between two code paths > and confirms that the inconsistent operations are not recovered in the > current function or the callers, so they constitute bugs. > > Note that, as a bug found by static analysis, it can be a false > positive or hard to trigger. Multiple researchers have cross-reviewed > the bug. > > drivers/media/pci/saa7134/saa7134-core.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/media/pci/saa7134/saa7134-core.c b/drivers/media/pci/saa7134/saa7134-core.c > index 96328b0af164..0de0b00540b6 100644 > --- a/drivers/media/pci/saa7134/saa7134-core.c > +++ b/drivers/media/pci/saa7134/saa7134-core.c > @@ -1202,6 +1202,11 @@ static int saa7134_initdev(struct pci_dev *pci_dev, > pr_info("%s: Overlay support disabled.\n", dev->name); > > dev->video_dev = vdev_init(dev,&saa7134_video_template,"video"); > + if (!dev->video_dev) { > + err = -ENOMEM; > + goto err_unregister_video; > + } > + > dev->video_dev->ctrl_handler = &dev->ctrl_handler; > dev->video_dev->lock = &dev->lock; > dev->video_dev->queue = &dev->video_vbq; > @@ -1224,6 +1229,11 @@ static int saa7134_initdev(struct pci_dev *pci_dev, > dev->name, video_device_node_name(dev->video_dev)); > > dev->vbi_dev = vdev_init(dev, &saa7134_video_template, "vbi"); > + if (!dev->vbi_dev) { > + err = -ENOMEM; > + goto err_unregister_video; > + } > + > dev->vbi_dev->ctrl_handler = &dev->ctrl_handler; > dev->vbi_dev->lock = &dev->lock; > dev->vbi_dev->queue = &dev->vbi_vbq; > -- > 2.25.1 > As stated before, umn.edu is still not allowed to contribute to the Linux kernel. Please work with your administration to resolve this issue.
diff --git a/drivers/media/pci/saa7134/saa7134-core.c b/drivers/media/pci/saa7134/saa7134-core.c index 96328b0af164..0de0b00540b6 100644 --- a/drivers/media/pci/saa7134/saa7134-core.c +++ b/drivers/media/pci/saa7134/saa7134-core.c @@ -1202,6 +1202,11 @@ static int saa7134_initdev(struct pci_dev *pci_dev, pr_info("%s: Overlay support disabled.\n", dev->name); dev->video_dev = vdev_init(dev,&saa7134_video_template,"video"); + if (!dev->video_dev) { + err = -ENOMEM; + goto err_unregister_video; + } + dev->video_dev->ctrl_handler = &dev->ctrl_handler; dev->video_dev->lock = &dev->lock; dev->video_dev->queue = &dev->video_vbq; @@ -1224,6 +1229,11 @@ static int saa7134_initdev(struct pci_dev *pci_dev, dev->name, video_device_node_name(dev->video_dev)); dev->vbi_dev = vdev_init(dev, &saa7134_video_template, "vbi"); + if (!dev->vbi_dev) { + err = -ENOMEM; + goto err_unregister_video; + } + dev->vbi_dev->ctrl_handler = &dev->ctrl_handler; dev->vbi_dev->lock = &dev->lock; dev->vbi_dev->queue = &dev->vbi_vbq;
In saa7134_initdev(), the return value of vdev_init() is assigned to dev->video_dev and there is a dereference of it after that. The return value of vdev_init() will be NULL on the failure allocation, which could lead to NULL pointer dereference. The same as dev->vbi_dev. Fix this bug by adding a NULL check of dev->video_dev and dev->vbi_dev. This bug was found by a static analyzer. Builds with 'make allyesconfig' show no new warnings, and our static analyzer no longer warns about this code. Fixes: a9622391acb ("V4L/DVB (6792): Fix VBI support") Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> --- The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. drivers/media/pci/saa7134/saa7134-core.c | 10 ++++++++++ 1 file changed, 10 insertions(+)