From 75261ff8dd03405cd77a03a03774524c40db7cef Mon Sep 17 00:00:00 2001 From: Zhou Qingyang Date: Wed, 27 Apr 2022 11:11:12 +0800 Subject: [PATCH] media: saa7146: mxb: Fix a NULL pointer dereference in mxb_attach() stable inclusion from stable-v5.10.94 commit 7009a5fbc589484c1b6e6e5ed1c47b64b62c5769 bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7009a5fbc589484c1b6e6e5ed1c47b64b62c5769 -------------------------------- [ Upstream commit 0407c49ebe330333478440157c640fffd986f41b ] In mxb_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 mxb_probe(dev). 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_MXB=m show no new warnings, and our static analyzer no longer warns about this code. Fixes: 03b1930efd3c ("V4L/DVB: saa7146: fix regression of the av7110/budget-av driver") Signed-off-by: Zhou Qingyang Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin Signed-off-by: Zheng Zengkai Acked-by: Xie XiuQi --- drivers/media/pci/saa7146/mxb.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/media/pci/saa7146/mxb.c b/drivers/media/pci/saa7146/mxb.c index 73fc901ecf3d..bf0b9b0914cd 100644 --- a/drivers/media/pci/saa7146/mxb.c +++ b/drivers/media/pci/saa7146/mxb.c @@ -683,10 +683,16 @@ static struct saa7146_ext_vv vv_data; static int mxb_attach(struct saa7146_dev *dev, struct saa7146_pci_extension_data *info) { struct mxb *mxb; + int ret; DEB_EE("dev:%p\n", dev); - saa7146_vv_init(dev, &vv_data); + ret = saa7146_vv_init(dev, &vv_data); + if (ret) { + ERR("Error in saa7146_vv_init()"); + return ret; + } + if (mxb_probe(dev)) { saa7146_vv_release(dev); return -1; -- GitLab