* [PATCH] net: mcs7830: handle usb read errors properly
@ 2022-01-06 22:57 Pavel Skripkin
2022-01-07 2:31 ` Arnd Bergmann
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Pavel Skripkin @ 2022-01-06 22:57 UTC (permalink / raw)
To: davem, kuba, tanghui20, andrew, oneukum, arnd
Cc: linux-usb, netdev, linux-kernel, Pavel Skripkin,
syzbot+003c0a286b9af5412510
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
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] net: mcs7830: handle usb read errors properly
2022-01-06 22:57 [PATCH] net: mcs7830: handle usb read errors properly Pavel Skripkin
@ 2022-01-07 2:31 ` Arnd Bergmann
2022-01-07 10:06 ` Greg KH
2022-01-10 1:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: Arnd Bergmann @ 2022-01-07 2:31 UTC (permalink / raw)
To: Pavel Skripkin
Cc: David Miller, Jakub Kicinski, tanghui20, Andrew Lunn,
Oliver Neukum, Arnd Bergmann, USB list, Networking,
Linux Kernel Mailing List, syzbot+003c0a286b9af5412510
On Thu, Jan 6, 2022 at 5:57 PM Pavel Skripkin <paskripkin@gmail.com> wrote:
>
> 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")
Looks good to me.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> 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.
I have no idea, I never had a datasheet for this device, only
the hardware I bought cheaply and vendor source code I
found somewhere on the net, and that was 16 years ago.
I would not expect the hardware to ever return less data than
was asked for, so any length checking would only have to
account for attackers that fake this device.
Arnd
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: mcs7830: handle usb read errors properly
2022-01-06 22:57 [PATCH] net: mcs7830: handle usb read errors properly Pavel Skripkin
2022-01-07 2:31 ` Arnd Bergmann
@ 2022-01-07 10:06 ` Greg KH
2022-01-07 10:18 ` Pavel Skripkin
2022-01-10 1:00 ` patchwork-bot+netdevbpf
2 siblings, 1 reply; 5+ messages in thread
From: Greg KH @ 2022-01-07 10:06 UTC (permalink / raw)
To: Pavel Skripkin
Cc: davem, kuba, tanghui20, andrew, oneukum, arnd, linux-usb, netdev,
linux-kernel, syzbot+003c0a286b9af5412510
On Fri, Jan 07, 2022 at 01:57:16AM +0300, Pavel Skripkin wrote:
> 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;
We have a usb core function that handles these "short reads are an
error" issue. Perhaps usbnet_read_cmd() should be converted to use it
instead?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: mcs7830: handle usb read errors properly
2022-01-07 10:06 ` Greg KH
@ 2022-01-07 10:18 ` Pavel Skripkin
0 siblings, 0 replies; 5+ messages in thread
From: Pavel Skripkin @ 2022-01-07 10:18 UTC (permalink / raw)
To: Greg KH
Cc: davem, kuba, tanghui20, andrew, oneukum, arnd, linux-usb, netdev,
linux-kernel, syzbot+003c0a286b9af5412510
Hi Greg,
On 1/7/22 13:06, Greg KH wrote:
>
> We have a usb core function that handles these "short reads are an
> error" issue. Perhaps usbnet_read_cmd() should be converted to use it
> instead?
>
I thought about it. I am not sure, that there are no callers, that
expect various length data. I remember, that I met such problem in atusb
driver, but it uses plain usb API.
I believe, we can provide new usbnet API, that will use
usb_control_msg_{recv,send} and сarefully convert drivers to use it.
When there won't be any callers of the old one we can just rename it.
I might be missing something about usbnet, so, please, correct me if I
am wrong here :)
With regards,
Pavel Skripkin
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: mcs7830: handle usb read errors properly
2022-01-06 22:57 [PATCH] net: mcs7830: handle usb read errors properly Pavel Skripkin
2022-01-07 2:31 ` Arnd Bergmann
2022-01-07 10:06 ` Greg KH
@ 2022-01-10 1:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-01-10 1:00 UTC (permalink / raw)
To: Pavel Skripkin
Cc: davem, kuba, tanghui20, andrew, oneukum, arnd, linux-usb, netdev,
linux-kernel, syzbot+003c0a286b9af5412510
Hello:
This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:
On Fri, 7 Jan 2022 01:57:16 +0300 you wrote:
> 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.
>
> [...]
Here is the summary with links:
- net: mcs7830: handle usb read errors properly
https://git.kernel.org/netdev/net/c/d668769eb9c5
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-01-10 1:00 UTC | newest]
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2022-01-06 22:57 [PATCH] net: mcs7830: handle usb read errors properly Pavel Skripkin
2022-01-07 2:31 ` Arnd Bergmann
2022-01-07 10:06 ` Greg KH
2022-01-07 10:18 ` Pavel Skripkin
2022-01-10 1:00 ` patchwork-bot+netdevbpf
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