Syzbot reported uninit value in mcs7830_bind(). The problem was in
missing validation check for bytes read via usbnet_read_cmd().
usbnet_read_cmd() internally calls usb_control_msg(), that returns
number of bytes read. Code should validate that requested number of bytes
was actually read.
So, this patch adds missing size validation check inside
mcs7830_get_reg() to prevent uninit value bugs
CC: Arnd Bergmann <arnd@xxxxxxxx>
Reported-and-tested-by: syzbot+003c0a286b9af5412510@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 2a36d7083438 ("USB: driver for mcs7830 (aka DeLOCK) USB ethernet adapter")
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
---
@Arnd, I am not sure about mcs7830_get_rev() function.
Is get_reg(22, 2) == 1 valid read? If so, I think, we should call
usbnet_read_cmd() directly here, since other callers care only about
negative error values.
Thanks
---
drivers/net/usb/mcs7830.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/net/usb/mcs7830.c b/drivers/net/usb/mcs7830.c
index 326cc4e749d8..fdda0616704e 100644
--- a/drivers/net/usb/mcs7830.c
+++ b/drivers/net/usb/mcs7830.c
@@ -108,8 +108,16 @@ static const char driver_name[] = "MOSCHIP usb-ethernet driver";
static int mcs7830_get_reg(struct usbnet *dev, u16 index, u16 size, void *data)
{
- return usbnet_read_cmd(dev, MCS7830_RD_BREQ, MCS7830_RD_BMREQ,
- 0x0000, index, data, size);
+ int ret;
+
+ ret = usbnet_read_cmd(dev, MCS7830_RD_BREQ, MCS7830_RD_BMREQ,
+ 0x0000, index, data, size);
+ if (ret < 0)
+ return ret;
+ else if (ret < size)
+ return -ENODATA;
+
+ return ret;
}
static int mcs7830_set_reg(struct usbnet *dev, u16 index, u16 size, const void *data)
--
2.34.1
