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From: Daniel Scheller <d.scheller.oss@gmail.com>
To: linux-media@vger.kernel.org, mchehab@kernel.org,
	mchehab@s-opensource.com
Cc: r.scobie@clear.net.nz, jasmin@anw.at, d_spingler@freenet.de,
	Manfred.Knick@t-online.de, rjkm@metzlerbros.de
Subject: [PATCH v4 09/11] [media] ddbridge: fix dereference before check
Date: Sat, 12 Aug 2017 13:56:00 +0200	[thread overview]
Message-ID: <20170812115602.18124-10-d.scheller.oss@gmail.com> (raw)
In-Reply-To: <20170812115602.18124-1-d.scheller.oss@gmail.com>

From: Daniel Scheller <d.scheller@gmx.net>

Both ts_release() and ts_open() can use "output" before check (smatch):

  drivers/media/pci/ddbridge/ddbridge-core.c:816 ts_release() warn: variable dereferenced before check 'output' (see line 809)
  drivers/media/pci/ddbridge/ddbridge-core.c:836 ts_open() warn: variable dereferenced before check 'output' (see line 828)

Fix by performing checks on those pointers.

Cc: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Tested-by: Richard Scobie <r.scobie@clear.net.nz>
Tested-by: Jasmin Jessich <jasmin@anw.at>
Tested-by: Dietmar Spingler <d_spingler@freenet.de>
Tested-by: Manfred Knick <Manfred.Knick@t-online.de>
---
 drivers/media/pci/ddbridge/ddbridge-core.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c b/drivers/media/pci/ddbridge/ddbridge-core.c
index 66b520d131a0..e051a691eb42 100644
--- a/drivers/media/pci/ddbridge/ddbridge-core.c
+++ b/drivers/media/pci/ddbridge/ddbridge-core.c
@@ -738,8 +738,13 @@ static unsigned int ts_poll(struct file *file, poll_table *wait)
 static int ts_release(struct inode *inode, struct file *file)
 {
 	struct dvb_device *dvbdev = file->private_data;
-	struct ddb_output *output = dvbdev->priv;
-	struct ddb_input *input = output->port->input[0];
+	struct ddb_output *output = NULL;
+	struct ddb_input *input = NULL;
+
+	if (dvbdev) {
+		output = dvbdev->priv;
+		input = output->port->input[0];
+	}
 
 	if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
 		if (!input)
@@ -757,8 +762,13 @@ static int ts_open(struct inode *inode, struct file *file)
 {
 	int err;
 	struct dvb_device *dvbdev = file->private_data;
-	struct ddb_output *output = dvbdev->priv;
-	struct ddb_input *input = output->port->input[0];
+	struct ddb_output *output = NULL;
+	struct ddb_input *input = NULL;
+
+	if (dvbdev) {
+		output = dvbdev->priv;
+		input = output->port->input[0];
+	}
 
 	if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
 		if (!input)
-- 
2.13.0

  parent reply	other threads:[~2017-08-12 11:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-12 11:55 [PATCH v4 00/11] ddbridge: bump to ddbridge-0.9.29 Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 01/11] [media] ddbridge: bump ddbridge code to version 0.9.29 Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 02/11] [media] ddbridge: split I/O related functions off from ddbridge.h Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 03/11] [media] ddbridge: split off hardware definitions and mappings Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 04/11] [media] ddbridge: check pointers before dereferencing Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 05/11] [media] ddbridge: only register frontends in fe2 if fe is not NULL Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 06/11] [media] ddbridge: fix possible buffer overflow in ddb_ports_init() Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 07/11] [media] ddbridge: remove unreachable code Daniel Scheller
2017-08-12 11:55 ` [PATCH v4 08/11] [media] ddbridge: fix impossible condition warning Daniel Scheller
2017-08-12 11:56 ` Daniel Scheller [this message]
2017-08-12 11:56 ` [PATCH v4 10/11] [media] ddbridge: Kconfig option to control the MSI modparam default Daniel Scheller
2017-08-12 11:56 ` [PATCH v4 11/11] [media] MAINTAINERS: add entry for ddbridge Daniel Scheller

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