5.10-stable review patch. If anyone has any objections, please let me know.
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From: Zhang Shurong zhang_shurong@foxmail.com
[ Upstream commit 7bf744f2de0a848fb1d717f5831b03db96feae89 ]
In af9035_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 af9035_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 zhang_shurong@foxmail.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Sasha Levin sashal@kernel.org [ moved variable declaration to fix build issues in older kernels - gregkh ] Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/media/usb/dvb-usb-v2/af9035.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
--- a/drivers/media/usb/dvb-usb-v2/af9035.c +++ b/drivers/media/usb/dvb-usb-v2/af9035.c @@ -269,6 +269,7 @@ static int af9035_i2c_master_xfer(struct struct dvb_usb_device *d = i2c_get_adapdata(adap); struct state *state = d_to_priv(d); int ret; + u32 reg;
if (mutex_lock_interruptible(&d->i2c_mutex) < 0) return -EAGAIN; @@ -321,8 +322,10 @@ static int af9035_i2c_master_xfer(struct ret = -EOPNOTSUPP; } else if ((msg[0].addr == state->af9033_i2c_addr[0]) || (msg[0].addr == state->af9033_i2c_addr[1])) { + if (msg[0].len < 3 || msg[1].len < 1) + return -EOPNOTSUPP; /* demod access via firmware interface */ - u32 reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 | + reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 | msg[0].buf[2];
if (msg[0].addr == state->af9033_i2c_addr[1]) @@ -380,17 +383,16 @@ static int af9035_i2c_master_xfer(struct ret = -EOPNOTSUPP; } else if ((msg[0].addr == state->af9033_i2c_addr[0]) || (msg[0].addr == state->af9033_i2c_addr[1])) { + if (msg[0].len < 3) + return -EOPNOTSUPP; /* demod access via firmware interface */ - u32 reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 | + reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 | msg[0].buf[2];
if (msg[0].addr == state->af9033_i2c_addr[1]) reg |= 0x100000;
- ret = (msg[0].len >= 3) ? af9035_wr_regs(d, reg, - &msg[0].buf[3], - msg[0].len - 3) - : -EOPNOTSUPP; + ret = af9035_wr_regs(d, reg, &msg[0].buf[3], msg[0].len - 3); } else { /* I2C write */ u8 buf[MAX_XFER_SIZE];