Messages in this thread Patch in this message | | | From | Pavel Skripkin <> | Subject | [PATCH] net: mcs7830: handle usb read errors properly | Date | Fri, 7 Jan 2022 01:57:16 +0300 |
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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@arndb.de> Reported-and-tested-by: syzbot+003c0a286b9af5412510@syzkaller.appspotmail.com Fixes: 2a36d7083438 ("USB: driver for mcs7830 (aka DeLOCK) USB ethernet adapter") Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> ---
@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
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