media: af9005: Fix null-ptr-deref in af9005_i2c_xfer

stable inclusion
from stable-v5.10.197
commit c7e5ac737db25d7387fe517cb5207706782b6cf8
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I96Q8P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c7e5ac737db25d7387fe517cb5207706782b6cf8



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[ Upstream commit f4ee84f2 ]

In af9005_i2c_xfer, msg is controlled by user. When msg[i].buf
is null and msg[i].len is zero, former checks on msg[i].buf would be
passed. Malicious data finally reach af9005_i2c_xfer. If accessing
msg[i].buf[0] without sanity check, null ptr deref would happen.
We add check on msg[i].len to prevent crash.

Similar commit:
commit 0ed554fd
("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")

Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>