Because the blen is not properly bounds-checked in __az6007_read/write, it is easy to get out-of-bounds errors in az6007_i2c_xfer later.
Therefore, we need to add bounds-checking to __az6007_read/write to resolve this.
Cc: stable@vger.kernel.org Reported-by: syzbot+0192952caa411a3be209@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0192952caa411a3be209 Fixes: 786baecfe78f ("[media] dvb-usb: move it to drivers/media/usb/dvb-usb") Signed-off-by: Jeongjun Park aha310510@gmail.com --- v2: Change to fix the root cause of oob - Link to v1: https://lore.kernel.org/all/20250421105555.34984-1-aha310510@gmail.com/ --- drivers/media/usb/dvb-usb-v2/az6007.c | 62 +++++++++++++++------------ 1 file changed, 34 insertions(+), 28 deletions(-)
diff --git a/drivers/media/usb/dvb-usb-v2/az6007.c b/drivers/media/usb/dvb-usb-v2/az6007.c index 65ef045b74ca..4202042bdb55 100644 --- a/drivers/media/usb/dvb-usb-v2/az6007.c +++ b/drivers/media/usb/dvb-usb-v2/az6007.c @@ -97,11 +97,17 @@ static struct mt2063_config az6007_mt2063_config = { .refclock = 36125000, };
-static int __az6007_read(struct usb_device *udev, u8 req, u16 value, - u16 index, u8 *b, int blen) +static int __az6007_read(struct usb_device *udev, struct az6007_device_state *st, + u8 req, u16 value, u16 index, u8 *b, int blen) { int ret;
+ if (blen > sizeof(st->data)) { + pr_err("az6007: tried to read %d bytes, but I2C max size is %lu bytes\n", + blen, sizeof(st->data)); + return -EOPNOTSUPP; + } + ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), req, @@ -125,24 +131,30 @@ static int __az6007_read(struct usb_device *udev, u8 req, u16 value, static int az6007_read(struct dvb_usb_device *d, u8 req, u16 value, u16 index, u8 *b, int blen) { - struct az6007_device_state *st = d->priv; + struct az6007_device_state *st = d_to_priv(d); int ret;
if (mutex_lock_interruptible(&st->mutex) < 0) return -EAGAIN;
- ret = __az6007_read(d->udev, req, value, index, b, blen); + ret = __az6007_read(d->udev, st, req, value, index, b, blen);
mutex_unlock(&st->mutex);
return ret; }
-static int __az6007_write(struct usb_device *udev, u8 req, u16 value, - u16 index, u8 *b, int blen) +static int __az6007_write(struct usb_device *udev, struct az6007_device_state *st, + u8 req, u16 value, u16 index, u8 *b, int blen) { int ret;
+ if (blen > sizeof(st->data)) { + pr_err("az6007: tried to write %d bytes, but I2C max size is %lu bytes\n", + blen, sizeof(st->data)); + return -EOPNOTSUPP; + } + if (az6007_xfer_debug) { printk(KERN_DEBUG "az6007: OUT req: %02x, value: %04x, index: %04x\n", req, value, index); @@ -150,12 +162,6 @@ static int __az6007_write(struct usb_device *udev, u8 req, u16 value, DUMP_PREFIX_NONE, b, blen); }
- if (blen > 64) { - pr_err("az6007: tried to write %d bytes, but I2C max size is 64 bytes\n", - blen); - return -EOPNOTSUPP; - } - ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), req, @@ -172,13 +178,13 @@ static int __az6007_write(struct usb_device *udev, u8 req, u16 value, static int az6007_write(struct dvb_usb_device *d, u8 req, u16 value, u16 index, u8 *b, int blen) { - struct az6007_device_state *st = d->priv; + struct az6007_device_state *st = d_to_priv(d); int ret;
if (mutex_lock_interruptible(&st->mutex) < 0) return -EAGAIN;
- ret = __az6007_write(d->udev, req, value, index, b, blen); + ret = __az6007_write(d->udev, st, req, value, index, b, blen);
mutex_unlock(&st->mutex);
@@ -775,7 +781,7 @@ static int az6007_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], value = addr | (1 << 8); length = 6 + msgs[i + 1].len; len = msgs[i + 1].len; - ret = __az6007_read(d->udev, req, value, index, + ret = __az6007_read(d->udev, st, req, value, index, st->data, length); if (ret >= len) { for (j = 0; j < len; j++) @@ -788,7 +794,7 @@ static int az6007_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], if (az6007_xfer_debug) printk(KERN_DEBUG "az6007: I2C W addr=0x%x len=%d\n", addr, msgs[i].len); - if (msgs[i].len < 1) { + if (msgs[i].len < 1 && msgs[i].len > 64) { ret = -EIO; goto err; } @@ -796,11 +802,8 @@ static int az6007_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], index = msgs[i].buf[0]; value = addr | (1 << 8); length = msgs[i].len - 1; - len = msgs[i].len - 1; - for (j = 0; j < len; j++) - st->data[j] = msgs[i].buf[j + 1]; - ret = __az6007_write(d->udev, req, value, index, - st->data, length); + ret = __az6007_write(d->udev, st, req, value, index, + &msgs[i].buf[1], length); } else { /* read bytes */ if (az6007_xfer_debug) @@ -815,10 +818,12 @@ static int az6007_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], value = addr; length = msgs[i].len + 6; len = msgs[i].len; - ret = __az6007_read(d->udev, req, value, index, + ret = __az6007_read(d->udev, st, req, value, index, st->data, length); - for (j = 0; j < len; j++) - msgs[i].buf[j] = st->data[j + 5]; + if (ret >= len) { + for (j = 0; j < len; j++) + msgs[i].buf[j] = st->data[j + 5]; + } } if (ret < 0) goto err; @@ -845,6 +850,7 @@ static const struct i2c_algorithm az6007_i2c_algo = {
static int az6007_identify_state(struct dvb_usb_device *d, const char **name) { + struct az6007_device_state *state = d_to_priv(d); int ret; u8 *mac;
@@ -855,7 +861,7 @@ static int az6007_identify_state(struct dvb_usb_device *d, const char **name) return -ENOMEM;
/* Try to read the mac address */ - ret = __az6007_read(d->udev, AZ6007_READ_DATA, 6, 0, mac, 6); + ret = __az6007_read(d->udev, state, AZ6007_READ_DATA, 6, 0, mac, 6); if (ret == 6) ret = WARM; else @@ -864,9 +870,9 @@ static int az6007_identify_state(struct dvb_usb_device *d, const char **name) kfree(mac);
if (ret == COLD) { - __az6007_write(d->udev, 0x09, 1, 0, NULL, 0); - __az6007_write(d->udev, 0x00, 0, 0, NULL, 0); - __az6007_write(d->udev, 0x00, 0, 0, NULL, 0); + __az6007_write(d->udev, state, 0x09, 1, 0, NULL, 0); + __az6007_write(d->udev, state, 0x00, 0, 0, NULL, 0); + __az6007_write(d->udev, state, 0x00, 0, 0, NULL, 0); }
pr_debug("Device is on %s state\n", --