hwrng: u2fzero - account for high quality RNG

The U2F zero apparently has a real TRNG in it with maximum quality, not
one with quality of "1", which was likely a misinterpretation of the
field as a

hwrng: u2fzero - account for high quality RNG

The U2F zero apparently has a real TRNG in it with maximum quality, not
one with quality of "1", which was likely a misinterpretation of the
field as a boolean. So remove the assignment entirely, so that we get
the default quality setting.

In the u2f-zero firmware, the 0x21 RNG command used by this driver is
handled as such [1]:

case U2F_CUSTOM_GET_RNG:
if (atecc_send_recv(ATECC_CMD_RNG,ATECC_RNG_P1,ATECC_RNG_P2,
NULL, 0,
appdata.tmp,
sizeof(appdata.tmp), &res) == 0 )
{
memmove(msg->pkt.init.payload, res.buf, 32);
U2FHID_SET_LEN(msg, 32);
usb_write((uint8_t*)msg, 64);
}
else
{
U2FHID_SET_LEN(msg, 0);
usb_write((uint8_t*)msg, 64);
}

This same call to `atecc_send_recv(ATECC_CMD_RNG,ATECC_RNG_P1,
ATECC_RNG_P2,...)` is then also used in the token's cryptographically
critical "u2f_new_keypair" function, as its rather straightforward
source of random bytes [2]:

int8_t u2f_new_keypair(uint8_t * handle, uint8_t * appid, uint8_t * pubkey)
{
struct atecc_response res;
uint8_t private_key[36];
int i;

watchdog();

if (atecc_send_recv(ATECC_CMD_RNG,ATECC_RNG_P1,ATECC_RNG_P2,
NULL, 0,
appdata.tmp,
sizeof(appdata.tmp), &res) != 0 )
{
return -1;
}

So it seems rather plain that the ATECC RNG is considered to provide
good random numbers.

[1] https://github.com/conorpp/u2f-zero/blob/master/firmware/src/custom.c
[2] https://github.com/conorpp/u2f-zero/blob/master/firmware/src/u2f_atecc.c

Cc: Andrej Shadura <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Herbert Xu <[email protected]>
Signed-off-by: Jason A. Donenfeld <[email protected]>
Acked-by: Andrej Shadura <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

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HID: add hid_is_usb() function to make it simpler for USB detection

A number of HID drivers already call hid_is_using_ll_driver() but only
for the detection of if this is a USB device or not. Make

HID: add hid_is_usb() function to make it simpler for USB detection

A number of HID drivers already call hid_is_using_ll_driver() but only
for the detection of if this is a USB device or not. Make this more
obvious by creating hid_is_usb() and calling the function that way.

Also converts the existing hid_is_using_ll_driver() functions to use the
new call.

Cc: Jiri Kosina <[email protected]>
Cc: Benjamin Tissoires <[email protected]>
Cc: [email protected]
Cc: [email protected]
Tested-by: Benjamin Tissoires <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Benjamin Tissoires <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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HID: u2fzero: properly handle timeouts in usb_submit_urb

The wait_for_completion_timeout function returns 0 if timed out or a
positive value if completed. Hence, "less than zero" comparison always
m

HID: u2fzero: properly handle timeouts in usb_submit_urb

The wait_for_completion_timeout function returns 0 if timed out or a
positive value if completed. Hence, "less than zero" comparison always
misses timeouts and doesn't kill the URB as it should, leading to
re-sending it while it is active.

Fixes: 42337b9d4d95 ("HID: add driver for U2F Zero built-in LED and RNG")
Signed-off-by: Andrej Shadura <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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HID: u2fzero: clarify error check and length calculations

The previous commit fixed handling of incomplete packets but broke error
handling: offsetof returns an unsigned value (size_t), but when com

HID: u2fzero: clarify error check and length calculations

The previous commit fixed handling of incomplete packets but broke error
handling: offsetof returns an unsigned value (size_t), but when compared
against the signed return value, the return value is interpreted as if
it were unsigned, so negative return values are never less than the
offset.

To make the code easier to read, calculate the minimal packet length
once and separately, and assign it to a signed int variable to eliminate
unsigned math and the need for type casts. It then becomes immediately
obvious how the actual data length is calculated and why the return
value cannot be less than the minimal length.

Fixes: 22d65765f211 ("HID: u2fzero: ignore incomplete packets without data")
Fixes: 42337b9d4d95 ("HID: add driver for U2F Zero built-in LED and RNG")
Signed-off-by: Andrej Shadura <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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HID: u2fzero: Support NitroKey U2F revision of the device

NitroKey produced a clone of U2F Zero with a different firmware,
which moved extra commands into the vendor range.
Disambiguate hardware rev

HID: u2fzero: Support NitroKey U2F revision of the device

NitroKey produced a clone of U2F Zero with a different firmware,
which moved extra commands into the vendor range.
Disambiguate hardware revisions and select the correct configuration in
u2fzero_probe.

Link: https://github.com/Nitrokey/nitrokey-fido-u2f-firmware/commit/a93c16b41f
Signed-off-by: Andrej Shadura <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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HID: u2fzero: ignore incomplete packets without data

Since the actual_length calculation is performed unsigned, packets
shorter than 7 bytes (e.g. packets without data or otherwise truncated)
or non

HID: u2fzero: ignore incomplete packets without data

Since the actual_length calculation is performed unsigned, packets
shorter than 7 bytes (e.g. packets without data or otherwise truncated)
or non-received packets ("zero" bytes) can cause buffer overflow.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=214437
Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
Signed-off-by: Andrej Shadura <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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HID: u2fzero: ignore incomplete packets without data

Since the actual_length calculation is performed unsigned, packets
shorter than 7 bytes (e.g. packets without data or otherwise truncated)
or non

HID: u2fzero: ignore incomplete packets without data

Since the actual_length calculation is performed unsigned, packets
shorter than 7 bytes (e.g. packets without data or otherwise truncated)
or non-received packets ("zero" bytes) can cause buffer overflow.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=214437
Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
Signed-off-by: Andrej Shadura <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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HID: u2fzero: fail probe if not using USB transport

u2fzero driver is USB-only. Therefore we have to give up in ->probe()
callback in case we're called with non-USB transport driver bound,
otherwise

HID: u2fzero: fail probe if not using USB transport

u2fzero driver is USB-only. Therefore we have to give up in ->probe()
callback in case we're called with non-USB transport driver bound,
otherwise the kernel will crash trying to use USBHID API on a non-USB
transport.

Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
Reported-by: Benjamin Tissoires <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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HID: add driver for U2F Zero built-in LED and RNG

U2F Zero supports custom commands for blinking the LED and getting data
from the internal hardware RNG. Expose the blinking function as a LED
device

HID: add driver for U2F Zero built-in LED and RNG

U2F Zero supports custom commands for blinking the LED and getting data
from the internal hardware RNG. Expose the blinking function as a LED
device, and the internal hardware RNG as an HWRNG so that it can be used
to feed the enthropy pool.

Signed-off-by: Andrej Shadura <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

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