From: Zhou Qingyang zhou1615@umn.edu
[ Upstream commit 348df8035301dd212e3cc2860efe4c86cb0d3303 ]
In hexium_attach(dev, info), saa7146_vv_init() is called to allocate a new memory for dev->vv_data. In hexium_detach(), saa7146_vv_release() will be called and 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() according to the following logic.
Both hexium_attach() and hexium_detach() are callback functions of the variable 'extension', so there exists a possible call chain directly from hexium_attach() to hexium_detach():
hexium_attach(dev, info) -- fail to alloc memory to dev->vv_data | in saa7146_vv_init(). | | hexium_detach() -- a dereference of dev->vv_data in saa7146_vv_release()
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_ORION=m show no new warnings, and our static analyzer no longer warns about this code.
Signed-off-by: Zhou Qingyang zhou1615@umn.edu Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/pci/saa7146/hexium_orion.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/media/pci/saa7146/hexium_orion.c b/drivers/media/pci/saa7146/hexium_orion.c index 214396b1ca73c..2f3b4e01ff289 100644 --- a/drivers/media/pci/saa7146/hexium_orion.c +++ b/drivers/media/pci/saa7146/hexium_orion.c @@ -366,10 +366,16 @@ static struct saa7146_ext_vv vv_data; static int hexium_attach(struct saa7146_dev *dev, struct saa7146_pci_extension_data *info) { struct hexium *hexium = (struct hexium *) dev->ext_priv; + int ret;
DEB_EE("\n");
- saa7146_vv_init(dev, &vv_data); + ret = saa7146_vv_init(dev, &vv_data); + if (ret) { + pr_err("Error in saa7146_vv_init()\n"); + return ret; + } + vv_data.vid_ops.vidioc_enum_input = vidioc_enum_input; vv_data.vid_ops.vidioc_g_input = vidioc_g_input; vv_data.vid_ops.vidioc_s_input = vidioc_s_input;