| Message ID | 20211130161538.182313-1-zhou1615@umn.edu |
|---|---|
| State | Superseded |
| Headers | show |
| Series | media: saa7146: hexium_gemini: Fix a NULL pointer dereference in hexium_attach() | expand |
On 30/11/2021 17:15, Zhou Qingyang wrote: > In hexium_attach(dev, info), saa7146_vv_init() is called to allocate > a new memory for dev->vv_data. saa7146_vv_release() will be called on > failure of saa7146_register_device(). There is a dereference of > dev->vv_data in saa7146_vv_release(), which could lead to a NULL > pointer dereference on failure of saa7146_vv_init(). > > Fix this bug by adding a check of saa7146_vv_init(). > > This bug was found by a static analyzer. 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. > > Builds with CONFIG_VIDEO_HEXIUM_GEMINI=m show no new warnings, > and our static analyzer no longer warns about this code. > > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> > --- > drivers/media/pci/saa7146/hexium_gemini.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/pci/saa7146/hexium_gemini.c b/drivers/media/pci/saa7146/hexium_gemini.c > index 2214c74bbbf1..549b1ddc59b5 100644 > --- a/drivers/media/pci/saa7146/hexium_gemini.c > +++ b/drivers/media/pci/saa7146/hexium_gemini.c > @@ -284,7 +284,11 @@ static int hexium_attach(struct saa7146_dev *dev, struct saa7146_pci_extension_d > hexium_set_input(hexium, 0); > hexium->cur_input = 0; > > - saa7146_vv_init(dev, &vv_data); > + ret = saa7146_vv_init(dev, &vv_data); > + if (ret) { > + kfree(hexium); You need to call i2c_del_adapter(&hexium->i2c_adapter); as well. Also, saa7146_vv_init() needs be fixed since it can return -1: that should be -ENOMEM. Otherwise a -1 error code could be returned here, that's not what you want. Regards, Hans > + return ret; > + } > > vv_data.vid_ops.vidioc_enum_input = vidioc_enum_input; > vv_data.vid_ops.vidioc_g_input = vidioc_g_input; >
diff --git a/drivers/media/pci/saa7146/hexium_gemini.c b/drivers/media/pci/saa7146/hexium_gemini.c index 2214c74bbbf1..549b1ddc59b5 100644 --- a/drivers/media/pci/saa7146/hexium_gemini.c +++ b/drivers/media/pci/saa7146/hexium_gemini.c @@ -284,7 +284,11 @@ static int hexium_attach(struct saa7146_dev *dev, struct saa7146_pci_extension_d hexium_set_input(hexium, 0); hexium->cur_input = 0; - saa7146_vv_init(dev, &vv_data); + ret = saa7146_vv_init(dev, &vv_data); + if (ret) { + kfree(hexium); + return ret; + } vv_data.vid_ops.vidioc_enum_input = vidioc_enum_input; vv_data.vid_ops.vidioc_g_input = vidioc_g_input;
In hexium_attach(dev, info), saa7146_vv_init() is called to allocate a new memory for dev->vv_data. saa7146_vv_release() will be called on failure of saa7146_register_device(). There is a dereference of dev->vv_data in saa7146_vv_release(), which could lead to a NULL pointer dereference on failure of saa7146_vv_init(). Fix this bug by adding a check of saa7146_vv_init(). This bug was found by a static analyzer. 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. Builds with CONFIG_VIDEO_HEXIUM_GEMINI=m show no new warnings, and our static analyzer no longer warns about this code. Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> --- drivers/media/pci/saa7146/hexium_gemini.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)