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Commit f405c171 authored by Pavel Skripkin's avatar Pavel Skripkin Committed by Greg Kroah-Hartman
Browse files

net: mcs7830: handle usb read errors properly 



[ Upstream commit d668769eb9c52b150753f1653f7f5a0aeb8239d2 ]

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

Reported-and-tested-by: default avatar <syzbot+003c0a286b9af5412510@syzkaller.appspotmail.com>
Fixes: 2a36d708 ("USB: driver for mcs7830 (aka DeLOCK) USB ethernet adapter")
Signed-off-by: default avatarPavel Skripkin <paskripkin@gmail.com>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220106225716.7425-1-paskripkin@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a328c29b

drivers/net/usb/mcs7830.c

+10 −2
Original line number Diff line number Diff line
@@ -121,8 +121,16 @@ 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,

	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)