kernel/linux.git/drivers/hid/hid-ft260.c, branch linux-7.1.y

HID: ft260: validate i2c input report length

2026-04-28T16:24:52+00:00

Add two checks to ft260_raw_event() to prevent out-of-bounds reads from malicious or malfunctioning devices: First, reject reports shorter than the 2-byte header (report ID + length fields). Without this, even accessing xfer->length on a 1-byte report is an OOB read. Second, validate xfer->length against the actual data capacity of the received HID report. Each I2C data report ID (0xD0 through 0xDE) defines a different report size in the HID descriptor, so the available payload varies per report. A corrupted length field could cause memcpy to read beyond the report buffer. Reported-by: Sebastián Josué Alba Vives Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: fix 'cast to restricted' kernel CI bot warnings

2022-11-11T10:09:36+00:00

Fix 'cast to restricted' sparse warnings reported by kernel test robot in https://lore.kernel.org/all/202211021607.ssjymlKi-lkp@intel.com/ Reported-by: kernel test robot Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: missed NACK from busy device

2022-11-11T10:09:36+00:00

When writing into a slow device like an EEPROM chip, the controller may exit the busy state before the device releases the bus. In this case, the ft260_xfer_status returns success before the data transfer completion. The patch fixes it by returning from the ft260_xfer_status() with the "-EAGAIN" on both controller and bus busy status when appropriate. It does not apply to the i2c combined transactions when after the write IO, the controller keeps the bus busy until the read IO and then between reading IOs to ensure an atomic operation. Co-developed-by: Germain Hebert Signed-off-by: Germain Hebert Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: fix a NULL pointer dereference in ft260_i2c_write

2022-11-11T10:09:36+00:00

The zero-length passed into the ft260_i2c_write() triggered the NULL pointer dereference in the debug message on data[0] access. Since the controller does not support a write of zero length, let's not allow it. Before: $ sudo i2ctransfer -y 13 w0@0x51 Killed After: $ sudo i2ctransfer -y 13 w0@0x51 Error: Sending messages failed: Invalid argument Reported-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: wake up device from power saving mode

2022-11-11T10:09:36+00:00

The FT260 can enter a power saving mode after being idle for longer than 5 seconds. When being woken up from power saving mode by an I2C write request, a possible NACK is not correctly reported by the controller. As a workaround, the driver will issue an I2C status report two times in ft260_xfer_status() after the chip has been idle for more than 5s. Co-developed-by: Enrik Berkhan Signed-off-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: missed NACK from big i2c read

2022-11-11T10:09:36+00:00

The FT260 controller does not return NACK when performing a big read (of multiple hid reports size) from a non-existing device or from the device responding with NACK when it is not ready to serve the request. However, it responds correctly with NACK to a read of up to a single hid report size. To overcome this issue, we split the muli-report read request into a read of a single HID report of 60 bytes size and a multi-report read. Big read of 256 bytes with first read of 60 bytes: $ sudo ./i2cperf -d 2 -o 2 -s 256 -r 0-0xff 1 0x50 -S [ +5.633280] ft260_i2c_write_read: off 0x0 rlen 255 wlen 2 [ +0.000006] ft260_i2c_write: rep 0xd0 addr 0x50 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.013205] ft260_xfer_status: bus_status 0x20, clock 100 [ +0.000007] ft260_i2c_read: rep 0xc2 addr 0x50 len 255 rlen 60 flag 0x3 [ +0.010932] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.004733] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000006] ft260_i2c_read: rep 0xc2 addr 0x50 len 195 rlen 128 flag 0x0 [ +0.012572] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.005789] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.003189] ft260_raw_event: i2c resp: rep 0xd1 len 8 [ +0.004092] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000010] ft260_i2c_read: rep 0xc2 addr 0x50 len 67 rlen 67 flag 0x4 [ +0.011688] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.004700] ft260_raw_event: i2c resp: rep 0xd1 len 7 [ +0.004858] ft260_xfer_status: bus_status 0x20, clock 100 Read from non-existing device at address 8. The first 60 read responded with NACK. $ sudo ./i2cperf -d 2 -o 2 -s 256 -r 0-0xff 1 0x8 -S [Oct19 15:37] ft260_i2c_write_read: off 0x0 rlen 255 wlen 2 [ +0.000007] ft260_i2c_write: rep 0xd0 addr 0x8 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.022820] ft260_xfer_status: bus_status 0x20, clock 100 [ +0.000007] ft260_i2c_read: rep 0xc2 addr 0x8 len 255 rlen 60 flag 0x3 [ +0.010658] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.005965] ft260_xfer_status: bus_status 0x46, clock 100 <-- NACK [ +0.000009] ft260 0003:0403:6030.0004: i2c bus error: 0x46 [ +0.007784] ft260_i2c_reset: done Co-developed-by: Enrik Berkhan Signed-off-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: remove SMBus Quick command support

2022-11-11T10:09:36+00:00

The i2cdetect uses the SMBus Quick command by default to scan devices on the I2C bus. The FT260 implements an I2C bus controller. The SMBus is derived from I2C, but there are several differences between the specifications of the two buses in the areas of timing, protocols, operation modes, and electrical characteristics. One of the differences is that the I2C devices allow the slave not to ACK its slave address, but SMBus requires it to always ACK it as a mechanism to detect a detachable device’s presence on the bus. Since FT260 is the I2C bus controller, it does not acknowledge the SMBus Quick write command, which sends a single bit to the device at the place of the RD/WR bit. The ft260 driver attempted to mimic the SMBus Quick Write functionality by writing a single byte as the SMBus Byte Write command does. Usually, one byte in the SMBus Quick Write will be fine. However, it may cause problems with devices with a control register at offset 0, like i2c muxes, for example, when scanned with the i2cdetect utility. The i2cdetect with the "-r" option uses the SMBus Read Byte command, which is a reasonable workaround. To prevent the I2C bus from locking at write-only devices (most notably clock chips at address 0x69), use the "-r" option in conjunction with scanning range parameters. This patch removes the SMBus Quick command support. $ sudo i2cdetect -y 13 Warning: Can't use SMBus Quick Write command, will skip some addresses 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: 10: 20: 30: -- -- -- -- -- -- -- -- 40: 50: 50 51 -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: 70: $ sudo i2cdetect -y -r 13 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: 50 51 -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- Reported-by: Vince Asbridge Reported-by: Stephen Shirron Reported-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: skip unexpected HID input reports

2022-11-11T10:09:36+00:00

The FT260 is not supposed to generate unexpected HID reports. However, in theory, the unsolicited HID Input reports can be issued by a specially crafted malicious USB device masquerading as FT260 when the attacker has physical access to the USB port. In this case, the read_buf pointer points to the final data portion of the previous I2C Read transfer, and the memcpy invoked in the ft260_raw_event() will try copying the content of the unexpected report into the wrong location. This commit sets the Read buffer pointer to NULL on the I2C Read transaction completion and checks it in the ft260_raw_event() to detect and skip the unsolicited Input report. Reported-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: do not populate /dev/hidraw device

2022-11-11T10:09:35+00:00

Do not populate the /dev/hidraw on ft260 interfaces when the hid-ft260 driver is loaded. $ sudo insmod hid-ft260.ko $ ls /dev/hidraw* /dev/hidraw0 $ sudo rmmod hid-ft260.ko $ ls /dev/hidraw* /dev/hidraw0 /dev/hidraw1 /dev/hidraw2 Reported-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina

HID: ft260: improve i2c large reads performance

2022-11-11T10:09:35+00:00

The patch increases the read buffer size to 180 bytes. It reduces the number of ft260_i2c_read() calls by three, improving the big reads performance. $ sudo i2ctransfer -y -f 13 w2@0x51 0x0 0x0 r180 Before: [ +4.071878] ft260_i2c_write_read: off 0x0 rlen 180 wlen 2 [ +0.000005] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.001097] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000175] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000004] ft260_i2c_read: rep 0xc2 addr 0x51 len 180 rlen 60 flag 0x3 [ +0.008579] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000208] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 120 rlen 60 flag 0x0 [ +0.008794] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000181] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 60 rlen 60 flag 0x4 [ +0.008817] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000223] ft260_xfer_status: bus_status 0x20, clock 100 After: [ +11.611642] ft260_i2c_write_read: off 0x0 rlen 180 wlen 2 [ +0.000005] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.008001] ft260_xfer_status: bus_status 0x20, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 180 rlen 180 flag 0x7 [ +0.008994] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.007987] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.007992] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000206] ft260_xfer_status: bus_status 0x20, clock 100 Suggested-by: Enrik Berkhan Signed-off-by: Michael Zaidman Signed-off-by: Jiri Kosina