From 87e9201108b7d63cc4a50faca3baad48c4ec99f8 Mon Sep 17 00:00:00 2001
From: Eugeniu Rosca <erosca@de.adit-jv.com>
Date: Sun, 13 Aug 2017 06:06:29 -0400
Subject: [PATCH] media: mxl111sf: Fix potential null pointer dereference
Git-commit: 87e9201108b7d63cc4a50faca3baad48c4ec99f8
Patch-mainline: v4.14-rc1
References: bsc#1051510
Reviewing the delta between cppcheck output of v4.9.39 and v4.9.40
stable updates, I stumbled on the new warning:
mxl111sf.c:80: (warning) Possible null pointer dereference: rbuf
Since copying state->rcvbuf into rbuf is not needed in the 'write-only'
scenario (i.e. calling mxl111sf_ctrl_msg() from mxl111sf_i2c_send_data()
or from mxl111sf_write_reg()), bypass memcpy() in this case.
Fixes: d90b336f3f65 ("[media] mxl111sf: Fix driver to use heap allocate buffers for USB messages")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Michael Ira Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/usb/dvb-usb-v2/mxl111sf.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
index b0d5904a4ea6..67953360fda5 100644
--- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c
+++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
@@ -77,7 +77,9 @@ int mxl111sf_ctrl_msg(struct mxl111sf_state *state,
dvb_usbv2_generic_rw(d, state->sndbuf, 1+wlen, state->rcvbuf,
rlen);
- memcpy(rbuf, state->rcvbuf, rlen);
+ if (rbuf)
+ memcpy(rbuf, state->rcvbuf, rlen);
+
mutex_unlock(&state->msg_lock);
mxl_fail(ret);
--
2.18.0