From 87e9201108b7d63cc4a50faca3baad48c4ec99f8 Mon Sep 17 00:00:00 2001 From: Eugeniu Rosca Date: Sun, 13 Aug 2017 06:06:29 -0400 Subject: [PATCH] media: mxl111sf: Fix potential null pointer dereference 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 Reviewed-by: Michael Ira Krufky Signed-off-by: Mauro Carvalho Chehab --- 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);