From 312f73b648626a0526a3aceebb0a3192aaba05ce Mon Sep 17 00:00:00 2001
From: Jozef Balga <jozef.balga@gmail.com>
Date: Tue, 21 Aug 2018 05:01:04 -0400
Subject: [PATCH] media: af9035: prevent buffer overflow on write
Git-commit: 312f73b648626a0526a3aceebb0a3192aaba05ce
Patch-mainline: v4.19-rc6
References: bsc#1051510
When less than 3 bytes are written to the device, memcpy is called with
negative array size which leads to buffer overflow and kernel panic. This
patch adds a condition and returns -EOPNOTSUPP instead.
Fixes bugzilla issue 64871
[mchehab+samsung@kernel.org: fix a merge conflict and changed the condition to match the patch's comment, e. g. len == 3 could also be valid]
Signed-off-by: Jozef Balga <jozef.balga@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/usb/dvb-usb-v2/af9035.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
index 666d319d3d1a..1f6c1eefe389 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -402,8 +402,10 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
if (msg[0].addr == state->af9033_i2c_addr[1])
reg |= 0x100000;
- ret = af9035_wr_regs(d, reg, &msg[0].buf[3],
- msg[0].len - 3);
+ ret = (msg[0].len >= 3) ? af9035_wr_regs(d, reg,
+ &msg[0].buf[3],
+ msg[0].len - 3)
+ : -EOPNOTSUPP;
} else {
/* I2C write */
u8 buf[MAX_XFER_SIZE];
--
2.19.1