From b97719a66970601cd3151a3e2020f4454a1c4ff6 Mon Sep 17 00:00:00 2001 From: Zhang Shurong Date: Mon, 10 Jul 2023 13:32:13 +0800 Subject: [PATCH] media: dvb-usb-v2: gl861: Fix null-ptr-deref in gl861_i2c_master_xfer In gl861_i2c_master_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 gl861_i2c_master_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 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()") Signed-off-by: Zhang Shurong Signed-off-by: Hans Verkuil --- drivers/media/usb/dvb-usb-v2/gl861.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/usb/dvb-usb-v2/gl861.c b/drivers/media/usb/dvb-usb-v2/gl861.c index 0c43425..c71e7b9 100644 --- a/drivers/media/usb/dvb-usb-v2/gl861.c +++ b/drivers/media/usb/dvb-usb-v2/gl861.c @@ -120,7 +120,7 @@ static int gl861_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], } else if (num == 2 && !(msg[0].flags & I2C_M_RD) && (msg[1].flags & I2C_M_RD)) { /* I2C write + read */ - if (msg[0].len > 1 || msg[1].len > sizeof(ctx->buf)) { + if (msg[0].len != 1 || msg[1].len > sizeof(ctx->buf)) { ret = -EOPNOTSUPP; goto err; } -- 2.7.4